Cornea Flashcards

Question

What is the Seidel test?

Answer 1

demonstrates aqueous leakage. A drop of 1% or 2% fluorescein is applied to the surface of the eye. Using a slit lamp the cobalt blue filter is used to detect a change in colour from dark orange to bright yellow–green secondary to localized dilution at a site of leakage.

Answer 2

the study of corneal layers under very high magnification (100 times greater than slit lamp biomicroscopy). It is mainly used to assess the endothelium, which can be analyzed for cellular size, shape, density and distribution.

Answer 3

1) Evaluation of the corneal endothelium functional reserve prior to intraocular surgery. 2) Donor cornea evaluation 3) Demonstrate corneal pathology eg guttata, descemet membrane irregularities, posterior polymorphous dystrophy

Answer 4

Used to image the cornea by placing a series of concentric rings of light on the anterior surface, constituting a Placido image. Reflected light is used to produce a detailed surface map

Answer 5

Antimicrobial agents- Broad spectrum initially, then as per cultures Topical steroids- use with caution as can promote replication of some microorganisms eg HSV, fungi. Systemic immunosuppressive agents-useful in autoimmune disease

Answer 6

1) Reduction of exposure to toxic medication/preservatives 2) Lubrication/taping lids shut 3) Antibiotic ointment prophylaxis 4) Bandage CL 5) Surgical eyelid closure for persistent epithelial defects/non healing ulcers. 6) Botox injected into levator muscle to promote ptosis. 7) Gundersen (conjunctival) flap 8) Amniotic membrane patch grafting for persistent unresponsive epithelial defects 9) Tissue adhesive (cyaoacrylate glue)- seal small perforations 10) Limbal stem cell transplantation for stem cell deficiency eg chemical burns/cicatrizing conjunctivitis 11) Discontinue smoking

Answer 7

Neisseria gonorrhoeae, Neisseria meningitidis, Corynebacterium diphtheriae Haemophilus influenzae

Answer 8

P. aeruginosa- Gram negative rod bacillus. Over 60% bacterial keratitis S. aureus- common Gram +ve coagulase +ve commensal of nares/skin/conjunctiva. Keratitis presents with well defined white/yellow white infiltrate S. Pyogenes- Gram +ve commensal of throat and vagina.

Answer 9

* CL wearing extended. Soft lenses increased risk over gas permeable. * Trauma- refractive surgery LASIK linked to atypical mycobacteria. Consider fungal infection as well * Ocular surface disease- Herpetic keratitis, bullous keratopathy, dry eye, chronic blepharitis, trichiasis, entropion, exposure, severe allergy. * Other factors eg immunosuppression/diabetes/vit A deficiency

Answer 10

Epithelial defect with larger infiltrate and circumcorneal injection Stromal oedema, descemet folds, anterior uveitis, with hypopyon. plaque like KP's on endothelium Chomesis and eyelid swelling in mod-severe cases Severe ulceration may lead to descemetocoele formation mainly in pseudomonas infection. Scleritis can develop Endophthalmitis rare in absence of perforation Improvement noted by reduction in AC activity, shrinking of ED, corneal scarring. Reduced corneal sensation suggests neurotrophic keratopathy Monitor IOP

Answer 11

keratitis due to other microorganisms (fungi, acanthamoeba, stromal herpes simplex keratitis and mycobacteria), marginal keratitis, sterile inflammatory corneal infiltrates associated with contact lens wear, peripheral ulcerative keratitis and toxic keratitis.

Answer 12

Corneal scraping. May not be needed for one without ED/away from visual axis/small infiltrate. Margins/base of lesion are scrpaed. Loose mucous/necrotic tissue should be removed prior to scraping. Do not break the gel surface. Conjunctival swabs may be worthwhile. Calcium alginate swab best option. CL cases- send lab for culture Gram stain MC&S reports obtained ASAP. Resistance on report doesnt always relate to topical instillation as concentration is high

Answer 13

Gram- bacteria/ fungi/ microspordia Giemsa-bacteria/ fungi/ acanthamoeba/ microspordia Calcofluor white- Acanthamoeba/ fungi/ microspordia ZN stain for AFB- Mycobacterium, Nocardia Grocott- Gomori methenamine silver- Fungi, acanthamoeba, microspordia PAS- Fungi, acanthamoeba

Answer 14

Blood agar- most bacteria except Neisseria, Haemophilus Moraxella Chocolate agar- Fastidious bacteria. H. influenza, neisseria, Moraxella Sabouraud dextrose agar- Fungi Non nutrient agar with E-coli- Acanthamoeba Brain- heart infusion- Streptococci and Meningococci Cooked meat broth- Anaerobic (P.acnes) and fastidious bacteria Lowenstein Jensen- mycobacteria, nocardia

Answer 15

Hospital admission for patients with aggressive disease/poor compliance Discontinue CL wear Plastic eyeshield worn between drop instillation if corneal thinning Local therapy. 1) Antibiotic monotherapy- fluoroquinolone usual choice empirically. Ciprofloxacin or Ofloxacin used in areas where resistance to earlier gen fluoroquinolones seen. Moxifloxacin is better. 2) Antibiotic duotherapy may be preferred in aggressive disease or microscopy suggests streptococci. Needs antibiotic to cover gram +/- organisms. 3) Mydriatics- prevent PS formation and reduce pain 4) Steroids- reduce inflammation, improve comfort, minimize scarring. Systemic antibiotics 1) Some infections eg. N. meningitidis- IM benzylpenicillin. H influenzae, N- gonorrhoea 2) Severe corneal thinning with threatened/actual perforation needs Cipro and tetracycline 3) Scleral involvement may respond to PO/IV treatment.

Answer 16

found no eventual benefit in most cases, but severe cases (counting fingers vision or large ulcers involving the central 4 mm of the cornea) tended to do better. A positive culture result was an inclusion criterion and steroids were introduced after 48 hours of moxifloxacin.

Answer 17

If no improvement in 24-48 hours of treatment, review abx regime. No need to change initial therapy if favourable response seen. If no improvement after further 48 hours, suspend treatment and rescrape with inoculation on broader media. If cultures remain negative, perform corneal biopsy for histology and culture Excisional keratoplasty penetrating or deep lamellar may be considered in cases resistant to medical therapy/incipient/actual perforation

Answer 18

small- BCL Tissue glue often inadequate for larger ones. PK/corneal patch may be necessary for larger perforations.

Answer 19

Rare and no specific protocol exists but treat similarly to post operative endophthalmitis

Answer 20

1) Keratoplasty (lamellar) for dense corneal scarring 2) Rigid CL for irregular astigmatism 3) Cataract surgery as cataract forms due to severe uveitis

Answer 21

a group of microorganisms that have rigid walls and a distinct nucleus with multiple chromosomes containing both DNA and RNA.

Answer 22

Yeasts (eg Candida) Filamentous fungi (Fusarium, Aspergillus)

Answer 23

ovoid unicellular organisms that reproduce by budding, are responsible for most cases of fungal keratitis in temperate climates.

Answer 24

multicellular organisms that produce tubular projections known as hyphae. They are the most common pathogens in tropical climates, but are not uncommon in cooler regions. The keratitis frequently follows an aggressive course.

Answer 25

Chronic ocular surface disease Long term topical steroid use Contact lens wear Systemic immunosuppression Diabetes

Answer 26

Gradual onset of pain, grittiness, photophobia, blurred vision and watery or mucopurulent discharge.

Answer 27

Candida- yellow-white densely suppurative infiltrate is typical Filamentous keratitis- grey or yellow white stromal infiltrate with indistinct fluffy margins Progressive infiltration with satelite lesions Feathery branches/ring shaped infiltrate Rapid progression with necrosis and thinning Penetration of intact Descemet may lead to endophthalmitis ED is not invariable sometimes present May have anterior uveitis, hypopyon, endothelial plaque,

Answer 28

*KOH preparations with direct microscopic evaluation *Gram/Giemsa stain 50% sensitive PAS/Calcofluor white and Methenamine silver are fungal stains *Culture- corneal scrapes on *Sabouraud dextrose agar. *PCR analysis of samples sensitive 90% *Corneal biopsy if no improvement after 3-4 days and no growth from scrapings after 1 week. *Anterior chamber tap- for resistant cases with endothelial exudate *Confocal microscopy

Answer 29

*General- consider admission *Remove epithelium over lesion enhances penetration of antifungal agents. *Topical antifungals for 48 hours then reduced as signs permit: *Candida with amphotericin-B /econazole/natamycin/fluconazole/ clotrimazole/ voriconazole *Filametous fingi treated with natamycin 5%/econazole. *Broad spectrum abx considered to prevent/address co-infection *Cyloplegia *Subconj fluconazole in severe cases *Systemic antifungals for severe cases *Tetracycline *Superficial keratectomy- to debulk lesion *Therapeutic keratoplasty (PK/DALK)

Answer 30

obligate intracellular single-celled parasites previously thought to be protozoa but now reclassified as fungi. Cause disease in immunocompromised eg AIDS Most common ocular manifestation is keratoconjunctivitis

Answer 31

Bilateral chronic diffuse PEK Slow progressive deep stromal keratitis Biopsy shows spores and intracellular parasites PCR of scrapings low sensitivity

Answer 32

Medical therapy for epithelial disease- fumagillin HAART for AIDS Stromal disease- topical fumagilin and oral albendazole. Monitor for hepatic toxicity Keratoplasty may be indicated but recurrence is high in graft periphery. Cryotherapy to residual tissue may reduce this risk

Answer 33

Herpetic eye disease As many as 60% of corneal ulcers in developing countries may be due to HSV

Answer 34

enveloped with a cuboidal capsule and has a linear double- stranded DNA genome.

Answer 35

HSV1- infections above waist HSV2- genital infection Both reside in almost all neuronal ganglia.

Answer 36

occurs in childhood and is spread by droplet transmission, or less frequently by direct inoculation. Due to protection by maternal antibodies, it is uncommon during the first 6 months of life.

Answer 37

* After primary infection the virus is carried to the sensory ganglion for that dermatome (e.g. trigeminal ganglion) where latent infection is established. Latent virus is incorporated in host DNA and cannot be eradicated with presently available treatment. *Subclinical reactivation can periodically occur, during which HSV is shed and patients are contagious. *Clinical reactivation. A variety of stress factors such as fever, hormonal change, ultraviolet radiation, trauma, or trigeminal injury may cause clinical reactivation, when the virus replicates and is transported in the sensory axons to the periphery.

Answer 38

fter one episode is about 10% at 1 year and 50% at 10 years. The higher the number of previous attacks the greater the risk of recurrence.

Answer 39

atopic eye disease, childhood, immunodeficiency or suppression, malnutrition, measles and malaria. Inappropriate use of topical steroids may enhance the development of geographic ulceration

Answer 40

Symptoms- mild-mod discomfort/ blurry vision/ photophobia Signs- reduced VA, central desquamation causing linear branching ulcer mostly centrally with terminal bulbs, Reduced corneal sensation, steroids worsen this, mild subepithelial haze, mild AC activity, follicular conjunctivitis, vesicular eyelid lesions, elevated IOP

Answer 41

Ix unnecessary as clinical diagnosis. Pre treatment scrapes can be sent. PCR/immunohistochemistry Giemsa stain

Answer 42

*HZK *Healing abrasion *Acanthamoeba keratitis *Epithelial rejection in corneal graft *Tyrosinaemia type 2 *Dendritiform keratopathy caused by polyquadernium-1 a preservative in *CL solution and tear replacement products

Answer 43

*Topical- Aciclovir 3% or Ganciclovir 0.15% gel 5x/day. Trifluridine but needs 9x/day. *Debridement- for resistant cases. Wipe corneal surface with cotton bud remove epithelium 2mm beyond edge of ulcer. *Signs of tx toxicity- SPEE, follicular conjunctivitis, epithelial whorling means poor/non compliance *PO antivirals eg aciclovir 5x/day for 5-10 days for immunodeficient patients. *Cycloplegia *Skin lesions treated with Aciclovir cream *Interferon monotherapy *IOP control- avoid prostaglandins *Topical steroids not used unless disciform keratitis can cause perforation

Answer 44

The aetiology of disciform keratitis (endotheliitis) is unclear. It may be the result of active HSV infection of keratocytes or endothelium, or a hypersensitivity reaction to viral antigen in the cornea.

Answer 45

Symptoms- gradual blurry vision. A clear past history of epithelial ulceration not always clear. Signs- central stromal oedema with overlying epithelial oedema. Large KP's under oedema, folds in descement membrane in severe cases. Wessly immune ring of deep stromal haze signifies deposition of viral antigen and host antibody complexes. IOP may be elevated. Reduced corneal sensation. Mid - stromal scarring causes interstital keratitis.

Answer 46

* Initial treatment is with topical steroids (prednisolone 1% or dexamethasone 0.1%) with antiviral cover, both four times daily. Monitor IOP. * Subsequent prednisolone 0.5% OD is safe to stop antiviral cover. * Oral steroids are sometimes used. * Topical ciclosporin may be useful in epithelial ulceration and to facilitate tapering of topical steroids eg steroid related IOP elevation. * Fine needle diathermy and laser techniques reported to successfully address established corneal neovascularization

Answer 47

Rare condition thought to result from active viral replication within the stroma with immune mediated inflammation. May be difficult to differentiate from severe disciform keratitis.

Answer 48

*Stromal necrosis and melting with profound interstitial opacification *Anterior uveitis with KP's *ED may be present *Progression to scarring/ vascularization and lipid deposition common

Answer 49

Similar to disciform keratitis but oral antiviral supplementation initially at upper end of dose range commenced. Restoration of ED is critical

Answer 50

Caused by failure of re-repithelialization due to corneal anaesthesia

Answer 51

*Non healing ED *Stroma beneath defect is grey/opaque and may thin *Secondary bacterial and fungal infection may occur

Answer 52

*Treatment same as persistent ED. *Topical steroids to control any inflammation should be kept to a minimum

Answer 53

*Occurs without signs of active corneal inflammation. *May be associated with direct viral activity. *IOP elevation common presumed due to trabeculitis. *Steroid induced IOP elevation may be relatively common in herpetic irits. *Treatment with topical steroids but adjunctive PO aciclovir may be given

Answer 54

*reduces the rate of recurrence of epithelial and stromal keratitis by about 50% *Prophylaxis in patients with frequent debilitating recurrences, particularly if bilateral or involving an only eye. The standard daily dose of aciclovir is 400 mg twice daily, but if necessary a higher dose can be tried, based on practice in the management of systemic herpes simplex infection. Continual use for many years has been documented for systemic indications. The prophylactic effect decreases or disappears when the drug is stopped. Excretion is via the kidney, so renal function should be checked periodically during long-term treatment.

Answer 55

1) Secondary bacterial infection 2) Glaucoma secondary to inflammation/chronic steroid use 3) Cataract due to prolonged steroid use/inflammation 4) Iris atrophy secondary to kerato-uveitis

Answer 56

Recurrence of herpetic eye disease and rejection are common and threaten the survival of corneal grafts.

Answer 57

*Topical antivirals given during a rejection episode may reduce epithelial viral reactivation but toxicity may delay re-epithelialization *Prophylactic PO aciclovir (400mg) BD improves graft survival and given to patients undergoing PK for herpetic eye disease

Answer 58

Estimated that one in three people will develop the condition in their lifetime. Most patients are not immunocompromised.

Answer 59

*Shingles involving the dermatome supplied by the ophthalmic division of the trigeminal nerve *Ocular involvement is rarely clinically significant when disease affects maxillary division alone. *VZV causes both chickenpox and shingles *Primary infection with chickenpox-->virus travels retrograde manner to dorsal root and cranial nerve sensory ganglia--> remains dormant for decades--> reactivation after VZV specific cell mediated immunity fades.

Answer 60

*Direct viral invasion via conjunctivitis and epithelial keratitis *Secondary inflammation with occlusive vasculitis may cause episcleritis/scleritis, keratitis, uveitis optic neuritis, CN palsies. *Reactivation causes necrosis and inflammation in affected sensory ganglia causing corneal anaesthesia causing neurotrophic keratopathy

Answer 61

*Hutchinson sign- vesicles in the skin supplied by external nasal nerve, a branch of nasociliary nerve. Correlates to ocular involvement but not to severity *Age- sixth and seventh decades. More severe signs in elderly *AIDS patients have severe disease and be early indication of HIV infection.

Answer 62

Prodromal phase- 3-5 days with tiredness/fever/malaise. Superficial itch, tingling, burning. Skin lesions- painful erythematous areas with maculopapular rash. Rash respects midline. Vesicles appear within 24 hours becoming confluent over 2-4 days. Vesicles pass through a pustular phase before crusting after 2-3 weeks. Large deep haemorrhagic lesions common in immunodeficient patients. Lesions heal to leave residual scars Disseminated Zoster involving multiple dermatomes may indicate immunodeficiency or malignancy

Answer 63

If uncertain, vesicular fluid for PCR or immunomicroscopy. PCR for plasma VZV DNA positive in 40%. IgM antibodies may be found in minority of early stages.

Answer 64

PO antivirals- given within 72 hours of rash onset reducing risk of post herpetic neuralgia. Aciclovir 800mg 5x/day for 7-10 days. Should NOT be used in combination with 5-FU IV aciclovir TDS for severe disease and mod-severe immunosuppression Systemic steroids with PO pred- controversial. Dont give immunocompromised. Thought to reduce acute pain and accelarated skin healing ID opinion for immunocompromised patients Symptomatic treatment for skin- drying cold compress.

Answer 65

Vaccination- Zoster vaccine live (effect lost within 10 years) Recombinant zoster vaccine- requires at least 2 vaccines has 10% incidence of local/acute systemic reaction

Answer 66

*Acute epithelial keratitis- in over 50% patients, resolves spontaneously over few days.Dendritic lesions with tapered ends rather than bulbs *Conjunctivitis- with lid margin vesicles. Treatment not required in absence of corneal disease *Episcleritis- spontaneously resolves. Mild NSAID may help *Scleritis- Oral fluribropfen TDS. PO steroids with antivirals in severe cases *Nummular keratitis-at the site of epithelial lesions 10 days after rash *Stromal (interstitial) keratitis- 5% 3 weeks after onset of rash with scarring. Responds to topical steroids *Disciform keratitis- less common than with HSV leading to corneal decompensation. Treat with steroids *Anterior uveitis- sectoral iris ischaemia and atrophy *Posterior uveitis- PORN and ARN. *Monitor IOP- avoid prostaglandin analogues

Answer 67

*Neutotrophic keratopathy-in 50% but mild and settles over few months. *Scleritis- chronic leading to patchy scleral atrophy. *Mucous plaque keratitis in 5% *Lipid degeneration with severe nummular/disciform keratitis *Subconjunctival scarring *Eyelid scarring with ptosis/cicatricial entropion, trichasis, lid notching, madarosis

Answer 68

Pain persistent for more than 1 month after rash has healed Improves overtime- 2% affected after 5 years. Impairs QoL lead to depression with danger of suicide. Pain clinic referral indicated.

Answer 69

Local *Cold compress *Topical capsaicin or lidocaine patches Systemic *Analgesia- paracetamol *Codeine *TCA- amitryptilline *Carbamazepine *Gabapentin, sustained release Oxycodone or both

Answer 70

inflammation of the corneal stroma without primary involvement of the epithelium or endothelium. The inflammation is thought to be an immune-mediated process triggered by an appropriate antigen

Answer 71

HSV, VZV, TB, Lyme, Parasitic disease, Sarcoidosis, Cogan syndrome, Non infectious inflammatory conditions

Answer 72

Congenital infection, though acquired infection can happen.

Answer 73

Early- failure to thrive, maculopapular rash, mucosal ulcers, rhagades, organ involvement Late- sensorineural deafness, saddle shaped nasal deformity, sabre tibiae, bulldog jaw, Hutchinson teeth, Clutton joints

Answer 74

Anterior uveitis Dislocated/subluxated lens cataract optic atrophy salt and pepper retinopathy Argyll Robertson pupils

Answer 75

Topical steroids cycloplegics Systemic therapy under GUM/ID

Answer 76

Symptoms- presentation of congenital infection between 5-25 years. Initially severe anterior uveitis with blurring. Bilateral in 80%. Acquired is unilateral commonly. Signs- profoundly decreased VA, Limbitis with deep stromal vascularization, granulomatous anterior uveitis, cornea clears with ghost vessels overtime, if cornea inflamed, can bleed into stroma. Healed stage ghost vessels, feathery deep stromal scarring, mild astigmatism, band keratopathy

Answer 77

Rare autoimmune systemic vasculitis with ocular inflammation/vestibuloauditory dysfunction developing within months of each other. Acute phase may last months- years Susac syndrome should be considered in the differential diagnosis

Answer 78

Vestibuloauditory - deafness, tinnitus, vertigo Ocular- Redness, pain, photophobia, blurry vision. Corneal involvement first with bilateral peripheral anterior stromal opacities. Deeper opacities and corneal neovascularization then ensue with central progression. Uveitis, scleritis and retinal vasculitis may develop

Answer 79

ESR CRP Antibodies to ear antigen MRI may show other inner ear abnormalities

Answer 80

Topical steroids for keratitis, with addition measures as appropriate Systemic steroids- Vestibuloauditory symptoms need immediate IV prednisolone to prevent hearing loss. Immunosuppressive therapy may be required. Sytemic steroids for scleritis/retinal vasculitis

Answer 81

Ubiquitous free living protozoa commonly found in soil, fresh, brackish water and upper respiratory tract

Answer 82

Cystic form is highly resilient and under appropriate environmental conditions cysts turn into trophozoites with tissue penetration and destruction

Answer 83

Often misdiagnosed as herpetic keratitis Symptoms- blurry vision/discomfort. Pain severe and disproportionate to findings Signs- epithelial surface irregular and greyish in early disease. Epithelial pseudodendrites resembling herpetic lesions form, limbitis with diffuse or focal anterior stromal infiltrates, perineural infiltrates seen in first few weeks and pathognomonic. Gradual enlargement of infiltrates to form ring abscess. Scleritis may develop which is reactive. Slow progressive stromal opacification and vascularization. Corneal melting may occur at any stage when stromal disease present.

Answer 84

If limited response to microbial therapy, consider AK! Staining of scrapings using PAS/ calcofluour white. Gram and Giemsa stain can also show cysts Culture- non nutrient agar seeded with dead E-coli which trophoziotes consume Immunohistochemistry, PCR, in vivo confocal microscopy. Corneal biopsy may be needed

Answer 85

Debridement of involved epithelium is believed to help drop penetration Topical amoebicides. Acanthamoeba cysts resistant to most antimicrobials. 1) PHMB 0.02% and chlorhexidine 0.02%. kill trophozoites and cysticidal 2) Hexamidine or propamidine (Brolene). 3) Voriconazole and other azole antifungals may be effective A clear response may take 2 weeks Avoid steroid use but low dose therapy delayed for at least 2 weeks until starting treatment with amoebicides for persistent inflammation. Pain control- NSAIDS Therapeutic keratoplasty for resistant cases eg perforation. Late scarring PK

Answer 86

caused by hypersensitivity reaction to staphylococcal exotoxins and cell wall proteins with deposition of antigen- antibody complexes in peripheral cornea with secondary lymphocytic infiltration. Lesions culture negative but S. aureus isolated from lid margins

Answer 87

Symptoms- mild discomfort, redness, lacrimation. Inflammation may be in both eyes Signs- chronic blepharitis, inferior PEE's early sign, subepithelial marginal infiltrates separated from limbus by clear zone with adjacent conj hyperaemia. Any ED smaller than infiltrate. Coalescense and circumferential spread Little or no AC reaction even with large infiltrates With no treatment may resolve in 1-4 weeks depending on severity. Occasional scarring and thinning with mild pannus

Answer 88

Weak steroid eg FML or Pred 0.5% QDS for 1-2 weeks sometimes combined with topical abx. Oral tetracycline course for recurrent disease.

Answer 89

A self limiting disease but can be severe. Mostly occurs as a result of presumed delayed hypersensitivity reaction to staphylococcal antigen, can be associated with Rosacea. In developing countries associated with TB/Helminth infestiations

Answer 90

Symptoms- photophobia, lacrimation, blepharospasm Signs- small white limbal or conj nodule with intense local hyperaemia, limbal phlycten may extend onto cornea. Spontaneous resolution in 2-3 weeks. Healed lesion leaves triangular limbal based scar with superficial vascularization and thinning. Very large necrotizing or miliary lesions may occur

Answer 91

Consider TB ix in endemic areas/risk factors present

Answer 92

A short course of topical steroid accelerates healing and is often given with a topical antibiotic. Recurrent troublesome disease may require an oral tetracycline and it is important to treat associated blepharitis.

Answer 93

chronic idiopathic dermatosis involving the sun-exposed skin of the face and upper neck. Ocular complications develop in 6–18% of patients. may involve vascular factors, together with an abnormal response to commensal skin bacteria and Demodex follicular mites. Exacerbation by H. pylori infection has been suspected.

Answer 94

Non specific irritation and lacrimation Lid signs- margin telangiectasia, posterior blepharitis associated with recurrent meibomian cyst formation Conj hyperaemia especially bulbar. Rarely cicatricial conjunctivitis, conj granulomas and phlyctenulosis may occur. Cornea- inferior PEE, peripheral vascularization, marginal keratitis, focal/diffuse corneal thinning, perforation, corneal scarring + vascularization

Answer 95

Topical- lubricants, hot compress lid hygiene, topical abx (fusidic acid, erythromycin, azithromycin) to lid margins at bedtime 4/52. Steroids for exacerbations- lowest prep to minimize thinning. Systemic- tetracyclines alter meibomian gland function to lower fatty acid production and direct antiinflammatory effect. Severe disease may require immunosuppression, retinoids can help but worsen features.

Answer 96

Marginal keratitis Mooren ulcer Terrien marginal degeneration Dellen Systemic autoimmune disease Ocular rosacea, furrow degeneration, pellucid marginal degeneration

Answer 97

Rare autoimmune disease with progressive circumferential peripheral stromal ulceration with later central spread. 2 forms. First affects older patients, often in one eye and responds to medical therapy. Second form more aggressive needing immunosuppression with poor prognosis. May be bilateral with severe pain, younger patients

Answer 98

Symptoms: pain is prominent, may be severe. Photophobia, blurred vision Signs: peripheral ulceration involving superficial 1/3rd of stroma with epithelial loss. An undertermined and infiltrated leading edge is characteristic. Limbitis without scleritis may be present which distinguishes from systemic disease associated PUK. Progressive circumferential and central stromal thinning. Vascularization with the bed of the ulcer upto leading edge but not beyond. Healing stage: thinning/ vascularization, scarring

Answer 99

severe astigmatism perforation following minor trauma secondary bacterial infection cataracts glaucoma

Answer 100

*Top steroids: hourly with low frequency prophylactic antibiotic. If effective, taper tx over months *Top ciclosporin may be effective but takes weeks to have effect *Tacrolimus 0.1% ointment for refractory cases *Artificial tears/NAC *Excision of necrotic conjunctival tissue *Systemic immunosuppression *Systemic collagenase inhibitors eg doxycycline *Lamellar keratectomy with dissection of residual central island in advanced disease *Perforation management *Visual rehab with keratoplasty once inflammation settled.

Answer 101

PUK may precede or follow onset of systemic features. Severe peripheral corneal infiltration, ulceration or thinning unexplained by evident ocular surface disease prompt Ix for systemic collagen vascular disease. Immune complex deposition in peripheral cornea, episcleral and conjunctival capillary occlusion with secondary cytokine release and inflammatory cell recruitment, upregulation of collagenases and reduced activity of inhibitors.

Answer 102

RA- Bilateral in 30% cases Granulomatosis with polyangiitis (Wegner Granulomatosis)- 2nd most common systemic association. Ocular complications are the initial presentation in 50% Others eg Polyarteritis nodosa, relapsing polychondriti, SLE, Crohns disease

Answer 103

Crescenteric ulceration with ED, thinning, stromal infiltrate at limbus. Spreading circumferentially and occasionally central. Extension into sclera may occur in contrast to Mooren Limbitis, episcleritis, scleritis. As with Mooren ulcer no separation between ulcerative process and limbus Advanced disease may lead to CL cornea/perforation Rheumatoid paracentral ulcerative keratitis (PCUK)- distinct entity with punched out more central lesion with little infiltrate in quiet eye. Rapid perforation may occur with good response to topical ciclosporin, BCL and glue application.

Answer 104

*Topical steroids- pulsed IV steroids for acute disease and immunosuppressive/ biologics for long term management *Lubricants *Antibiotics prophylaxis if ED present *PO tetracycline for anticollagenase effect *Topical steroids worsen thinning so avoided. Relapsing polychondritis may be an exception

Answer 105

Uncommon idiopathic thinning of peripheral cornea in young adult- elderly patients. Some associated with episcleritis/scleritis. 75% hare male and usually bilateral but asymmetrical

Answer 106

Symptoms- commonly asymptomatic but gradual visual decline due to astigmatism. Few have episodic pain and inflammation. Signs- fine yellow-white refractile stromal opacities, frequently with mild superficial vascularization starting superiorly separated from limbus by clear zone. There is no ED and may resemble arcus senilis. Slow progressive circumferential thinning leads to peripheral gutter, outer slope of which shelves gradually with rise in central part. Band of lipid commonly seen around central edge.

Answer 107

Safety spectacles if thinning ++ CL for astigmatism. Scleral/ soft lenses with rigid gas permeable Surgery- crescenteric or annular excision of gutter with lamellar/ full thickness transplant.

Answer 108

loss of trigeminal innervation to cornea leading to partial/ complete anaesthesia. With loss of protective sensory stimulus, this leads to intracellular oedema/ exfoliation/ loss of goblet cells and epithelial breakdown with persistent ulcers.

Answer 109

*Trigeminal ganglion surgical ablation for neuralgia *Stroke *Tumour *Peripheral neuropathy eg diabetes *Ocular disease eg HSV, HZK

Answer 110

Full CN exam mandatory. Signs- reduced corneal sensation. Stage 1: interpalpebral epithelial irregularity and stain with mild opacification, oedema and tiny focal defects Stage 2: Large persistent ED with rolled and thickened edges and puched out configuration with underlying stromal oedema. Stage 3: Stromal melting with secondary infection Perforation uncommon but can happen quick with sec infection

Answer 111

*Discontinue toxic medication *Lubricants *Anticollagenase agents (NAC/tetracyclines) *Cenergemin- topical recombinant human nerve growth factor beneficial in moderate or severe neurotrophic ulcer in adults. *Protection of ocular surface- lid taping, botox induced ptosis, *Tarsorrhaphy *Therapeutic silicone CL *Amniotic membrane patching with temporary central tarsorrhaphy *Perforation management as previously discussed *Corneal neurotization from supratrochlear nerve using sural graft

Answer 112

A result of incomplete lid closure (lagophthalmos) with corneal drying despite normal tear production. Caused by neuroparalytic (Facial nerve palsy), reduced muscle tone in parkinsonism, mechanical lid scarring, eczematous skin tightening, post blepharoplasty and proptosis

Answer 113

Symptoms- those of dry eye Signs- Mild PEE's inferior 1/3rd of cornea due to lagophthalmos Epithelial breakdown stromal melting inferior fibrovascular changes leading to Salzmann degeneration Secondary infection

Answer 114

Reversible exposure: *Artificial tears during day and ointment at night *Lid taping at night *Bandage silicone hydrogel/ scleral contact lens *Manage proptosis by orbital decompression *Temporary tarsorrhaphy Permanent exposure: *Permanent tarsorrhaphy *Gold weight upper lid insertion for 7th nerve palsy *Permanent central tarsorrhaphy, amniotic membrane graft/ conj flap when poor vision

Answer 115

Rare indolent infection in patients on long term topical steroid therapy with ED following penetrating keratoplasty. Strep viridans commonly isolated but can be other bacteria/fungi.

Answer 116

Slow progressive grey white branching stromal opacities with minimal inflammation usually intact overlying epithelium. Biofilm allows survival of microorganism, reducing antibiotic bioavailability.

Answer 117

Culture/biopsy performed to determine the organism and topical antibiotics for several weeks. Adjunctive therapies are distuption of microorganism biofilm by laser, intrastromal antibiotics and keratectomy. With corneal scarring, corneal transplant required

Answer 118

an uncommon idiopathic, usually bilateral, condition characterized by exacerbations and remissions. It is commonly of onset in young adulthood but can affect patients of any age and may recur over decades.

Answer 119

Symptoms- recurrent attacks of irritation, photophobia, blurry vision and watering Signs- granular, coarse, slightly elevated greyish epithelial lesions staining with fluorescein involving central cornea. Mild subepithelial haze may be present if topical antivirals have been used. Little to no conj hyperaemia.

Answer 120

*Topical Lubricants Steroids- Low potency prep BD with tapering to OW. Ciclosporin- if response to steroids inadequate Antivirals- not helpful *Contact lenses *Phototherapeutic keratectomy short term relief, recurrence is likely.

Answer 121

a common condition that can cause considerable discomfort. It is thought that a loose area of epithelium acts as a focus for deposition of mucus and cellular debris.

Answer 122

*Aqueous deficiency (keratoconjunctivitis sicca) *Excessive contact lens wear *Corneal epithelial instability (recurrent erosion syndrome, corneal graft, cataract surgery, refractive surgery and drug toxicity) *Superior limbic keratoconjunctivitis *Bullous keratopathy *Neurotrophic keratopathy *Prolonged or frequent eye closure

Answer 123

Symptoms- discomfort with FB sensation, redness and photophobia Signs- strands of degenerated epithelial cells and mucus moving with blinking attached to cornea at one end. Filaments stain with Rose Bengal Small ED at base of filaments may be seen. Chronic filaments form plaques.

Answer 124

*Treat underlying causes *Topical medication changed if suspecting toxic effects. Remove preservatives *Mechanical removal of filaments *Mucolytics- NAC drops *NSAIDS- eg diclofenac *Hypertonic saline 5% QDS encourage adhesion of loose epithelium *BCL protect cornea from shearing lid action

Answer 125

Recurrent corneal epithelial erosion is caused by an abnormally weak attachment between the basal cells of the corneal epithelium and their basement membrane. Minor trauma, such as eyelid–cornea interaction during sleep, can be sufficient to precipitate detachment. Erosions may be associated with previous trauma or rarely corneal surgery and with some corneal dystrophies.

Answer 126

Symptoms- severe pain, photophobia, redness, blepharospasm, watering wake the patient at night or in the morning. Usually a history of prior corneal abrasion Signs- ED may not be present on exam as healing rapid but extent of loose epithelium present and reduced BUT. Infiltrate no present though greyish sloughed epithelium may be seen. No sign of abnormality once defect healed but epithelial BM disturbance eg microcysts/punctate/linear fingerprint opacities seen. Typically bilateral in stromal dystrophy.

Answer 127

Acute *Abx ointment QDS, Cyclo TDS *BCL severe cases. Use abx drops rather than ointment *Debridement of epithelium with sterile cellulose sponge/cotton tipped applicator improve comfort allow healing *Topical diclofenac *Topical anaesthetic reduce pain *Hypertonic saline 5% improve epithelial adhesion *After resolution prophylaxis lubricants Recurrent symptoms *Topcial lubricants gel/ ointment *PO Doxy and to steroid to inhibit MMP's *Long term BCL *Simple debridement of epithelium in involved areas with smoothing of bowman layer with diamond burr/excimer laser. *Anterior stromal puncture for off axis areas.

Answer 128

Vit A essential for maintaining body epithelial surfaces, immune function and synthesis of photoreceptor proteins. Xerophthalmia refers to the spectrum ofocular disease caused by inadequate vitamin A intake and is a late manifestation of severe deficiency.

Answer 129

XN = night blindness X1 = conjunctival xerosis (X1A) with Bitot spots (X1B) X2 = corneal xerosis X3 = corneal ulceration, less than one-third (X3A); more than one-third (X3B) XS = corneal scar XF = xerophthalmic fundus

Answer 130

Symptoms- night blindness, discomfort and loss of vision Conj- Dry conj interpalpebral zone loss of goblet cells, squamous metaplasia and keratinization Bitot spots triangular patches of foamy keratinized epithelium. Cornea- lustreless appearance due to secondary xerosis Bilateral PEE's interpalpebral zone progress to ED but reversible Keratinization Sterile corneal melting leading and liquiefactive necrosis (keratomalacia) leading to perforation Retinopathy- yellowish peripheral dots and decreased electroretinogram amplitude

Answer 131

Keratomalacia is an indicator of very severe vitamin A deficiency and should be treated as a medical emergency due to the risk of death, particularly in infants. *Systemic treatment- PO (oil-based 200 000 IU) or IM (aqueous-based 100 000 IU) vitamin A for keratomalacia. Multivitamin supplements and dietary sources of vitamin A are also administered. *Local treatment consists of intense lubrication, topical retinoic acid and management of perforation.

Answer 132

Keratoconus Keratoglobus Pellucid marginal degeneration

Answer 133

a progressive disorder in which central or paracentral corneal stromal thinning occurs, accompanied by apical protrusion and irregular astigmatism. Approximately 50% of normal fellow eyes will progress to KC within 16 years.

Answer 134

It can be graded by the highest axis of corneal power on keratometry as mild (<48 D), moderate (48–54 D) severe (>54 D).

Answer 135

commonly during the teens or twenties, with features initially in only one eye.

Answer 136

Down syndrome Ehlers–Danlos Marfan syndromes osteogenesis imperfecta. Ocular associations include vernal keratoconjunctivitis, blue sclera, aniridia, Leber congenital amaurosis, retinitis pigmentosa, as well as persistent eye rubbing from any cause.

Answer 137

Symptoms- unilateral vision impairment due to progressive myopia and astigmatism. Occasionally present with hydrops Signs- DO from a distance shows oil droplet reflex. Retinoscopy shows irregular scissoring reflex, slit lamp biomicroscopy fine vertical deep stromal stress lines (Vogt striae), disappearing with pressure on globe, epithelial iron deposits with cobalt blue filter surrounding base of the cone (Fleischer ring). Progressive corneal protrusion in cone configuration with thinning maximal at apex, bulging of lower lid in downgaze (Munson sign). Acute hydrops caused by a rupture in stretched descemet membrane allowing aqueous into cornea with pain/photophobia, decreased vision. The break heals within 6-10 weeks oedema clears, stromal scarring develops

Answer 138

treated with cycloplegia, hypertonic (5%) saline ointment and patching or a soft bandage contact lens. Accelerated resolution has been reported with intracameral gas injection in the acute stage.

Answer 139

*Avoid eye rubbing *Spectacles/ soft CL *Rigid contact lenses sometimes scleral for higher degrees of astigmatism. *Collagen cross linking with riboflavin drops to photosensitize the eye after UVA exposure. Can be combined with ring segment insertion. CXL used after documented progression *Intracorneal ring segment implantation- laser/mechanical channel creation safe *Keratoplasty- PK or DALK in severe disease. History of hydrops contraindication to DALK due to descemet membrane discontinuity *LASIK Contraindicated

Answer 140

Pellucid marginal degeneration is a rare progressive peripheral corneal thinning disorder, typically involving the inferior cornea in both eyes. Presentation is usually in adulthood.

Answer 141

Symptoms- slow progressive blurring due to astigmatism Signs- bilateral slow progressive crescenteric 1-2mm band of inferior corneal thinning extending from 4 to 8 o clock 1mm from the limbus Epithelium is intact cornea above thinned area shows ectasia and flattened Corneal topography- butterfly pattern with severe astigmatism and diffuse steepening of inferior cornea

Answer 142

In pellucid marginal degeneration, Fleischer rings and Vogt striae do not occur and acute hydrops is rare. In keratoglobus compared to keratoconus, the cornea develops globular rather than conical ectasia and is associated with generalized corneal thinning

Answer 143

Early cases- specs and CL Surgical- large eccentric PK, thermocauterization, crescenteric lamellar keratoplasty, wedge resection of diseased tissue, epikeratoplasty, intracorneal ring segment implanation. Collagen cross linking results are encouraging

Answer 144

extremely rare condition that can be present at birth when differential diagnosis is from congenital glaucoma and megalocornea and associations may be present, or acquired, with onset in adulthood

Answer 145

Generalised steepening

Answer 146

Surgery is difficult and contact lens wear is often unsatisfactory. Intrastromal ring segments and cross-linking may have utility. Special care should be taken to protect the eyes from trauma.

Answer 147

Cogan (epithelial basement membrane) dystrophy Meesmann epithelial dystrophy Other epithelial and subepithelial dystrophies are Lisch epithelial corneal dystrophy, subepithelial mucinous corneal dystrophy, gelatinous drop like corneal dystrophy

Answer 148

Most patients no family history. Corneal changes considered secondary to degeneration/ trauma The occurrence of bilateral recurrent erosions with no history of trauma suggests basement membrane dystrophy.

Answer 149

Sporadic condition secondary to degeneration AD inheritance

Answer 150

thickening of the basement membrane with deposition of fibrillary protein between the basement membrane and the Bowman layer. Basal epithelial cell hemidesmosomes are deficient

Answer 151

Second decade. 10% develop RCES in 3rd decade, remainder asymptomatic throughout life. Signs- lesions best seen via retroillumination/ scleral scatter. Dot like and microcystic epithelial lesions Subepithelial map like patterns surrounded by faint haze Whorled fingerprint like lines Bleb like subepithelial pebbled glass pattern

Answer 152

Same as RCES

Answer 153

a rare non-progressive abnormality of corneal epithelial metabolism, underlying which mutations in the genes encoding corneal epithelial keratins have been reported. AD inheritance

Answer 154

irregular thickening of the epithelial basement membrane and intraepithelial cysts

Answer 155

Symptoms- may be asymptomatic, mild RCES and blurring. Signs- Myriad tiny intraepithelial cysts of uniform size with variable density maximal centrally extending towards but not reaching limbus. Cornea may be thinned, sensation reduced

Answer 156

Treatment other than lubrication not required

Answer 157

Reis-Bucklers corneal dystrophy Thiel- Behnke corneal dystrophy

Answer 158

may be categorized as an anterior variant of granular stromal dystrophy (GCD type 3) and is also known as corneal basement dystrophy type I (CBD1).

Answer 159

AD Affected gene is TGFB1

Answer 160

Replacement of Bowman layer by connective tissue bands

Answer 161

Symptoms- severe RCES childhood and visual impairment may occur Signs- grey white geographic subepithelial opacities, most dense centrally, increasing in density with age to form reticular pattern Reduced corneal sensation

Answer 162

Tx directed at RCES. Excimer keratectomy achieves good outcome in some patients

Answer 163

Also termed honeycomb-shaped corneal dystrophy and corneal basement dystrophy type II (CBD2); features are generally less severe than Reis–Bücklers. *Inheritance. AD; gene TGFB1 and at least one other.

Answer 164

Bowman layer ‘curly fibres’ on electron microscopy.

Answer 165

* Symptoms. Recurrent erosions in childhood. * Signs. Subepithelial opacities are less individually defined than the granular dystrophy-type lesions seen in Reis– Bücklers dystrophy. They develop in a network of tiny rings or honeycomb-like morphology, predominantly involving the central cornea Treatment not always necessary

Answer 166

*Lattice corneal dystrophy TGFB1 type *Lattice corneal dystrophy gelsolin type *Granular corneal dystrophy, type 1 (classic) *Granular corneal dystrophy, type 2 *Macular corneal dystrophy *Schnyder (crystalline) corneal dystrophy *François central cloudy dystrophy

Answer 167

usually regarded as the classic form of lattice dystrophy. Clinical variants (e.g. IIIA associated with more than 25 heterozygous mutations in TGFB1 have been described. *Inheritance. AD; gene TGFB1. *Histology. Amyloid, staining with Congo red and exhibiting green birefringence with a polarizing filter

Answer 168

Symptoms- Recurrent erosions end of first decade in classic form when typical stromal signs not yet present. Blurring occurs later Signs- refractile anterior stromal dots, coalescing into fine filamentous lattice spreading gradually sparing periphery. Generalised stromal haze may progressively impair vision.

Answer 169

PK or DALK. Recurrence not uncommon

Answer 170

Also known as LCD2 and Meretoja syndrome, this is a systemic condition rather than a true corneal dystrophy. *Inheritance. AD; gene GSN. *Histology shows amyloid deposits in the corneal stroma.

Answer 171

*Ocular symptoms. Ocular irritation and late impairment of vision; erosions are rare. *Ocular signs ○Sparse stromal lattice lines spread centrally from the periphery. ○Corneal sensation is impaired. *Systemic features. Progressive cranial and peripheral neuropathy, mask-like facies and autonomic features. Homozygous disease is rare but severe.

Answer 172

Keratoplasty may rarely be required in later life.

Answer 173

*Inheritance. AD; gene TGFB1. Homozygous disease gives more severe features. *Histology. Amorphous hyaline deposits staining bright red with Masson trichrome

Answer 174

Symptoms- glare and photophobia with blurring as progression occurs, recurrent erosions uncommon Signs- Discrete white central anterior stromal deposits resembling sugar granules, breadcrumbs separated by clear stroma. Gradual increase in number and size of deposits with deeper and outward spread with limbal sparing. Gradual confluence and diffuse haze leads to visual impairment. Corneal sensation impaired

Answer 175

by penetrating or deep lamellar keratoplasty is usually required by the fifth decade. Superficial recurrences may require repeated excimer laser keratectomy.

Answer 176

Also known as Avellino and combined granular-lattice dystrophy. *Inheritance. AD; gene TGFB1. *Histology shows both hyaline and amyloid.

Answer 177

*Symptoms. Recurrent erosions tend to be mild. Visual impairment is a later feature. *Signs are usually present by the end of the first decade in heterozygotes. Fine superficial opacities progress to form stellate or annular lesions, sometimes associated with deeper linear opacities.

Answer 178

*Treatment is usually not required. Corneal trauma accelerates progression; refractive surgery is contraindicated.

Answer 179

*Inheritance. Autosomal recessive (AR); gene CHST6; the condition is relatively common in Iceland. *Histology. Aggregations of glycosaminoglycans intra- and extracellularly; stain with Alcian blue and colloidal iron

Answer 180

*Symptoms. Early (end of first decade) visual deterioration; recurrent erosions are very common. *Signs ○Dense but poorly delineated greyish-white spots centrally in the anterior stroma and peripherally in the posterior stroma. There is no clear delineation between opacities, which may be elevated. ○Progression occurs together with anterior stroma haze involving the central cornea initially. ○Eventual involvement of full thickness stroma extending to limbus with no clear zone ○Thinning is an early feature with thickening from oedema due to endothelial dysfunction

Answer 181

*Treatment. Penetrating keratoplasty. Recurrence is common.

Answer 182

This is a disorder of corneal lipid metabolism, associated in some patients with systemic dyslipidaemia. The use of crystalline in the name is no longer recommended as corneal crystals are not a ubiquitous feature. *Inheritance. AD; gene UBIAD1. *Histology. Phospholipid and cholesterol deposits.

Answer 183

*Symptoms. Visual impairment and glare. *Signs ○Central haze is an early feature, progressing to more widespread full-thickness involvement over time ○Subepithelial crystalline opacities are present in only around 50%. ○Prominent corneal arcus is typical and gradually progresses centrally leading to diffuse haze

Answer 184

excimer keratectomy or corneal transplantation.

Answer 185

It is not certain that this entity is a dystrophy; it may be clinically indistinguishable from the degeneration posterior crocodile shagreen. *Inheritance. AD has been reported, but not clearly established. *Symptoms. Almost always none. *Signs ○Cloudy greyish polygonal or rounded posterior stromal opacities, most prominent centrally *Treatment is not required.

Answer 186

Fuchs endothelial corneal dystrophy Posterior polymorphous corneal dystrophy Congenital hereditary endothelial dystrophy

Answer 187

characterized by bilateral accelerated endothelial cell loss. It is more common in women and is associated with a slightly increased prevalence of open-angle glaucoma. *Inheritance. Most sporadic, with occasional AD inheritance. Mutation in COL8A2 has been identified in an early-onset variant and in the TCF4 gene in most other cases.

Answer 188

*Symptoms. Gradually worsening blurring, particularly in the morning, due to corneal oedema. Onset is usually in middle age or later. *Signs ○Cornea guttata: the presence of ‘excrescences’ on Descemet membrane secreted by abnormal endothelial cells ○Specular reflection- tiny dark spots caused by disruption of regular endothelial mosaic. Progression to beaten metal appearance ○Endothelial decompensation gradually leads to central stromal oedema and blurry vision, worse in the morning ○Epithelial oedema in severe cases with microcysts and bullae and discomfort. Rupture of bullae leads to acute pain due to exposed nerve fibres. ○Subepithelial scarring and peripheral vascularization in longstanding cases

Answer 189

*Conservative- NaCl 5%, reduce IOP and hair dryer for corneal dehydration *Ruptured bullae comfort with BCL, cycloplegia, antibiotics and lubricants *Posterior lamellar (DSAEK, DMEK) and PK have high success rate *Eyes with poor visual potential conjunctival flaps, amniotic membrane transplants

Answer 190

may worsen the corneal status because of endothelial cell loss and protective steps should be taken to reduce this. Modern machines using torsional phacoemulsification use less ultrasound time than the older machines, which used longitudinal phacoemulsification and are therefore less likely to cause endothelial loss. A ‘triple procedure’ (combined cataract surgery, lens implantation and keratoplasty) may be considered in eyes with corneal oedema. Corneal oedema is less likely to occur after cataract surgery if the central corneal thickness is less than 630–640 µm.

Answer 191

There are three forms of posterior polymorphous dystrophy, PPCD1–3. Associations include iris abnormalities, glaucoma and Alport syndrome. The pathological basis involves metaplasia of endothelial cells. *Inheritance is usually AD. The gene VSX1 has been implicated in PPCD1, PPCD2 is caused by mutations in COL8A2 and PPCD3 by ZEB1 mutations. *Symptoms. Usually absent, with incidental diagnosis. *Signs. Subtle vesicular, band-like or diffuse endothelial lesions *Treatment is not required.

Answer 192

Congenital hereditary endothelial dystrophy (CHED) is a rare dystrophy in which there is focal or diffuse thickening of Descemet membrane and endothelial degeneration. CHED2 is a more common and more severe form than CHED1 and is occasionally associated with deafness (Harboyan syndrome).

Answer 193

○CHED1 is AD with the gene locus on chromosome 20. CHED1 may not be distinct from PPCD. ○CHED2 is AR; gene SLC4A11.

Answer 194

*Symptoms Photophobia and watering are common in CHED1, but not in CHED2. *Signs ○Corneal clouding and thickening are neonatal in CHED2 and develop during the first year or two in CHED1. ○Visual impairment is variable and visual acuity may surpass that expected from the corneal appearance. ○Nystagmus is more common in CHED2. *Treatment. Lamellar or penetrating keratoplasty.

Answer 195

Arcus senilis (gerontoxon, arcus lipoides) is the most common peripheral corneal opacity. Frequently occurs in elderly. Associated with dyslipidaemia in younger individuals Signs: Stromal lipid deposition initially in superior and inferior perilimbal cornea progressing circumferentially to form a band 1mm wide. Band wider in vertical than horizontal meridian. Central border is diffuse and peripheral edge is sharp separated from limbus by clear zone that may undergo mild thinning.

Answer 196

An innocuous condition that is present in upto 60% of individuals over 40 Consists of whitish crescentic limbal bands composed of chalk-like flecks centred at 9 and/or 3 o’clock, more often nasally. There may be irregular central extension. Type 1: variant of band keratopathy with swiss cheese hole pattern and clear area separating lesion from scleral margin Type 2: more prevalent and distinguished by absence of holes and juxtalimbal clear zone. Histological changes similar to pinguecula and pterygium

Answer 197

a visually insignificant condition characterized by bilateral, minute, flour-like deposits in the deep stroma, most prominent centrally

Answer 198

characterized by asymptomatic, greyish-white, polygonal stromal opacities separated by relatively clear spaces. The opacities most frequently involve the anterior two-thirds of the stroma (anterior crocodile shagreen), although on occasion they may be found more posteriorly (posterior crocodile shagreen). It may be indistinguishable from François central cloudy dystrophy

Answer 199

an unusual condition of unknown cause that is seen in elderly asymptomatic individuals, generally of West Indian origin. Males are more affected than females. Affects one eye but can be bilateral. Lesions are round 0.5mm or less located at level of bowman membrane extending into superficial stroma. Usually have a central dot intensely white in colour surrounded by paler halo merging with adjacent cornea. No treatment required

Answer 200

rare and occurs apparently spontaneously. It is characterized by white or yellowish, often with a crystalline element, stromal deposits consisting of cholesterol, fats and phospholipids and is not associated with vascularization

Answer 201

more common and associated with previous ocular injury or dis1ease that has resulted in corneal vascularization. The most common causes are herpes simplex and herpes zoster keratitis

Answer 202

aimed at medical control of the underlying inflammatory disease. Other options include: ○Photocoagulation or needle cautery (suture needle grasped with cautery forceps) of feeder vessels. ○Penetrating keratoplasty may be required in advanced but quiescent disease, though vascularization, thinning and reduced sensation may affect the outcome.

Answer 203

age-related deposition of calcium salts in the Bowman layer, epithelial basement membrane and anterior stroma. Causes: chronic anterior uveitis (mainly in children with JIA), glaucoma, phthisis bulbi, silicone oil in AC, chronic corneal oedema, severe chronic keratitis, Age related affecting otherwise healthy individuals, Metabolic (metastatic calcification) secondary to hypercalcemia is uncommon. Hereditary causes are familial and ichthyosis

Answer 204

○Peripheral interpalpebral calcification with clear cornea separating the sharp peripheral margins of the band from the limbus ○Gradual central spread to form a band-like chalky plaque containing transparent small holes and occasionally clefts. ○Advanced lesions may become nodular and elevated with considerable discomfort due to epithelial breakdown.

Answer 205

Treat if vision threatened or eye uncomfortable. Chelation simple for mild cases. Corneal epithelium overlying opacity and solid layer of calcification is scraped off. Cornea then rubbed with cotton tipped applicator dipped in EDTA until all calcium removed. 15-20 mins for this step. >1 session may be needed. Re-epithelialization takes many days. ○Other modalities: diamond burr, excimer laser keratectomy and lamellar keratoplasty

Answer 206

Spheroidal degeneration (Labrador keratopathy, climatic droplet keratopathy) typically occurs in men whose working lives are spent outdoors. Ultraviolet exposure is likely to be an aetiological factor. The condition is relatively innocuous but visual impairment may occur. A secondary form can follow inflammation or injury. *Histology. Irregular proteinaceous deposits in the anterior stroma that replace the Bowman layer.

Answer 207

○Amber-coloured granules in the superficial stroma of the peripheral interpalpebral cornea. ○Increasing opacification, coalescence and central spread. ○Advanced lesions commonly protrude above the corneal surface and the surrounding stroma is often hazy. The conjunctiva can be involved.

Answer 208

Protection against ultraviolet damage with sunglasses and superficial keratectomy or lamellar keratoplasty in a minority.

Answer 209

Salzmann nodular degeneration consists of nodules of hyaline tissue, usually located anterior to the Bowman layer. It can occur in any form of chronic corneal irritation or inflammation such as trachoma, dry eye, chronic blepharitis and chronic allergic keratoconjunctivitis.

Answer 210

○Superficial stromal opacities progressing to elevated whitish or blue–grey nodular lesions that may be round or elongated ○The base of a nodule may be associated with pannus and epithelial iron deposition.

Answer 211

Lubrication together with control of the cause. Removal is via manual superficial keratectomy – the lesions can often be ‘peeled’ away and the surface flattened with a diamond burr. Adjunctive mitomycin C applied for 10 seconds with a sponge may reduce the recurrence rate, though some authorities restrict its use to reoperations. Excimer laser phototherapeutic keratectomy or lamellar keratoplasty are occasionally required.

Answer 212

an irregular advancing epithelial plaque encroaching gradually on the cornea, typically originating at the superior limbus and sometimes extending circumferentially from a pterygium. vision may be affected with central involvement. risk factors include contact lens wear, certain contact lens solutions, topical glaucoma medication, prior ocular surgery and some skin conditions such as rosacea. Treatment of the cause may be curative, but otherwise is with 1% silver nitrate solution to the adjacent limbus or cryotherapy (1–2 seconds twice) to the limbus and abnormal tissue. Distinction from neoplasia may occasionally warrant impression cytology or excision biopsy

Answer 213

Cystinosis Mucipolysaccharidoses Wilson disease Lecithin Cholestrol Acyltransferase deficiency Immunoprotein deposition Tyrosinaemia type 2 Fabry disease

Answer 214

a rare AR (gene: CTNS) lysosomal storage disorder characterized by widespread tissue deposition of cystine crystals, leading to paediatric renal failure and a range of other severe systemic problems. Keratopathy may develop in the first year, with progressive deposition of crystals in the cornea and conjunctiva associated with photophobia, epithelial erosions and visual impairment. Systemic treatment is with cysteamine, which can be given in eye drop form to reverse corneal crystal formation.

Answer 215

a group of lysosomal storage disorders involving enzyme dysfunction along the pathways for breakdown of glycosaminoglycans, long chain carbohydrates formerly known as mucopolysaccharides. Altered metabolites accumulate intracellularly in various tissues. Inheritance is mainly AR. Keratopathy comprises punctate corneal opacification and diffuse stromal haze and occurs in all MPS except Hunter and Sanfilippo. Ocular features may include pigmentary retinopathy and optic atrophy.

Answer 216

(hepatolenticular degeneration) is a rare condition involving the widespread abnormal deposition of copper in tissues. It is caused by a deficiency of caeruloplasmin, the major copper-carrying blood protein. Presentation is with liver disease, basal ganglia dysfunction or psychiatric disturbances. A Kayser–Fleischer ring is present in 95% of patients with neurological signs and consists of a brownish-yellow zone of fine copper dusting in peripheral Descemet membrane deposits are preferentially distributed in the vertical meridian and may disappear with penicillamine therapy. Anterior capsular sunflower cataract is seen in some patients

Answer 217

Lecithin-cholesterol-acyltransferase (LCAT) deficiency is a disorder of lipoprotein metabolism that has complete (Norum disease, with systemic manifestations including renal failure) and partial (fish eye disease, causing only corneal opacification) forms that are both AR (gene: LCAT) Keratopathy is characterized by numerous minute greyish dots throughout the stroma, often concentrated in the periphery in an arcus-like configuration

Answer 218

Diffuse or focal immunoprotein deposition is uncommon manifestation of several systemic diseases, including multiple myeloma, Waldenström macroglobulinaemia, monoclonal gammopathy of unknown cause, some lymphoproliferative disorders and leukaemia. Corneal involvement may be the earliest manifestation. Bands of punctate flake-like opacities are seen, mostly at the level of the posterior stroma. Treatment is that of the underlying disease. Severe corneal involvement may require corneal transplantation.

Answer 219

Tyrosinaemia type 2 (oculocutaneous tyrosinaemia, Richner–Hanhart syndrome) is a very rare AR disease (gene: TAT) in which an enzyme deficiency leads to elevated plasma tyrosine levels. Ocular involvement may occasionally be the presenting feature. Painful palmar and plantar hyperkeratotic lesions and variable CNS involvement are seen. A bilateral pseudodendritic keratitis with crystalline edges often begins in childhood and causes photophobia, watering and redness.

Answer 220

X-linked lysosomal storage disorder caused by a deficiency of the enzyme alpha-galactosidase A that leads to abnormal tissue accumulation of a glycolipid. All males with the gene develop the disease and some heterozygous females. Ocular manifestations include white to golden-brown corneal opacities in a vortex pattern (75%) that may be the first feature of the disease facilitating early intervention, wedge- or spoke-shaped posterior cataract (Fabry cataract), conjunctival vascular tortuosity (corkscrew vessels) and aneurysm formation and retinal vascular tortuosity

Answer 221

Irregular astigmatism associated with keratoconus corrected with rigid CL Superficial corneal irregularities neutralised by rigid CL with smoother optical surface. Only if irregularities are not too severe Anisometropia in which BV cannot be achieved by specs due to anisekonia after cataract surgery with high refractive correction

Answer 222

Persistent ED- often heal if epithelium protected from constant rubbing of lids allowing hemidesosomal attachments to BM Recurrent corneal erosions associated with BM dystrophy may require long term CL wear to reduce recurrence.

Answer 223

Bullous keratopathy managed with soft BCL relieving pain by protecting exposed corneal nerve endings from shearing forces of lids when blinking. Lens can flatten bullae into small cysts Filamentary keratopathy resistant to topical therapy will achieve some comfort from soft CL use. Other indications- thygeson superficial punctate keratitis, protect corneal epithelium from aberrant lashes in trichiasis

Answer 224

Descemetocoele- temporarily capped with tight fitting large diameter soft or scleral lens to prevent perforation and encourage healing. Splinting and apposition of the edges of small corneal wound achieved by CL. Larger perforations sealed with glue then BCL

Answer 225

*Mechanical and hypoxic keratitis *Immune response keratitis *Toxic keratitis *Suppurative keratitis (lowest risk for rigid lenses) *CL associated giant papillary conjunctivitis

Answer 226

The normal neonatal corneal diameter is 10 mm and the adult diameter of 12 mm is usually reached by the age of 2 years.

Answer 227

Microcornea is a rare autosomal dominant (sometimes sporadic) unilateral or bilateral condition in which the horizontal corneal diameter is 10 mm or less over 2 years of age or less than 9 mm in the newborn. The cornea is steep on keratometry. There may be hypermetropia and a shallow anterior chamber but other dimensions are normal. Ocular associations include glaucoma (angle-closure and open angle), congenital cataract, leukoma, persistent fetal vasculature, coloboma, optic nerve hypoplasia, aniridia and nanophthalmos. Systemic associations have been reported. Refractive error and amblyopia should be managed appropriately.

Answer 228

a condition in which the entire eye is small, with an axial length at least two standard deviations below the mean for age. Simple or pure microphthalmos (nanophthalmos) refers to an eye that is structurally normal apart from a short length and complex microphthalmos to eyes with other features of dysgenesis for example: a coloboma or orbital cyst and a range of other ocular anomalies Vision is variably affected, in conjunction with severity. It is typically sporadic but mutations in numerous genes have been implicated. Around 50% of cases may be associated with systemic abnormalities, including of the CNS. Potential environmental causes include fetal alcohol syndrome and intrauterine infections.

Answer 229

the entire eye is small with an axial length of less than 20 mm. Both eyes are usually affected. Ocular associations include glaucoma (especially angle-closure as the lens is large relative to the size of the eye), hypermetropia, ametropia, amblyopia and strabismus. In childhood, management of refractive error and amblyopia are critical. Surgery for glaucoma is particularly hazardous and can result in aqueous misdirection and choroidal effusion (‘small eye–big trouble’). Lens extraction is technically challenging, but has the advantage of deepening the anterior chamber and reducing the refractive error if a suitable high-power lens implant is inserted.

Answer 230

Anophthalmos (anophthalmia) refers to the complete absence of any visible globe structure though a microphthalmic remnant or cyst may be present. It is associated with other abnormalities such as absence of extraocular muscles, a short conjunctival sac and microblepharon. Causative factors are probably broadly similar to those of microphthalmos.

Answer 231

Rare bilateral non-progressive condition that is usually X-linked recessive. Approximately 90% of affected individuals are male. The adult horizontal corneal diameter is 13 mm or more, with a very deep anterior chamber. There is usually high myopia and astigmatism but normal corrected visual acuity. Lens subluxation may occur due to zonular stretching and pigment dispersion syndrome may occur. Numerous systemic associations have been reported.

Answer 232

very rare, usually bilateral, condition that may be associated with cornea plana. Sporadic cases are common, but a milder form can be inherited as AD and a more severe form as AR. Peripheral corneal opacification, with no visible border between the sclera and cornea, confers the appearance of apparently reduced corneal diameter in mild–moderate disease. Occasionally the entire cornea is involved

Answer 233

an extremely rare bilateral condition in which the cornea is flatter than normal – the radius of curvature is larger. There is a corresponding reduction in refractive power resulting in high hypermetropia. Two forms are described, cornea plana 1 (CNA1) being milder than cornea plana 2. Associated ocular abnormalities are common.

Answer 234

a very rare, usually unilateral, condition thought to be the result of intrauterine keratitis and perforation. It is characterized by protuberance between the eyelids of a severely opacified and sometimes vascularized cornea. It is often associated with raised IOP.

Answer 235

a sporadic condition in which there is unilateral non-progressive increase in curvature of the posterior corneal surface. The anterior surface is normal and visual acuity relatively unimpaired because of the similar refractive indices of the cornea and aqueous humour. Generalized (involvement of the entire posterior corneal surface) and localized (paracentral or central posterior indentation – types are described.