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(C) - Y4 Neurology and Special Senses > 10 - Ophthalmology Presentations 2 > Flashcards

10 - Ophthalmology Presentations 2 Flashcards

1
Q

What does correct light refraction in the eye depend on?

A
  • Distance between cornea and retina
  • Curvature of the cornea and lens
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2
Q

What is myopia and hypermetropia?

A

Myopia: short sighted, can’t see distance

Hypermetropia: long sighted, can’t see things up close

I AM MYOPIC

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3
Q

What is the pathology of myopia?

A

- Eyeball too long

  • Can only see close object

- Images focus in front of the retina so need a concave lens to push the image back

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4
Q

What are some causes of myopia?

A

- Genetic: chromosome 18p & 12q

- Close up work in early decades: changes in the synthesis of mRNA and the concentration of matrix metalloproteinase, normally changes in eyeball length are compensated by change in lens/cornea curvature but this does not occur

Dose-response curve to amount of hours spent indoors to degree of myopia

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5
Q

What is pathological myopia and what is the issue with this?

A

Myopia >6 dioptres

Can lead to secondary degeneration of the vitreous and retina which can lead to retinal detachment, choroidoretinal atrophy and macular bleeding

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6
Q

How is myopia treated?

A

- Concave lenses or contacts: don’t overcorrect as can make it worse, in children do check every 6 months

- LASIK (laser-assisted in situ keratomileusis): side effects are rare but trauma or infection can cause permanent corneal scarring

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7
Q

What is astigmatism?

A

Cornea does not have the same degree of curvature on it’s surface

One half is flatter and one steeper so when light hits the cornea the light rays do not hit together so blurred image longitudinally or vertically

Can occur alone or with hypermetropia/myopia

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8
Q

How is astigmatism treated?

A

- Lenses with prisms

- LASIK

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9
Q

What is the pathology of hypermetropia?

A
  • Eye is too short can’t see close
  • Image focuses behind retina
  • Need convex lens to bring image forward
  • Can lead to tiredness of gaze or childhood squint as the cilliary muscles are having to contract when looking close to make the lens convex
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10
Q

What is presbyopia?

A

- Lens gets stiffer around age 40, complete by 60.

  • Cilliary muscles cannot cause lens to become convex as easily so cannot focus on close objects
  • Need corrective lenses. Can have laser surgery but may get worse and need glasses again as ageing continues
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11
Q

What are some causes of an abnormal red reflex?

A

- Retinoblastoma

- Cataracts

- Vitreous haemorraghe

- Debris over eye surface: blink and try again

- Retinal detachment

- Strabismus: one eye brighter than the other

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12
Q

What are some causes of painful and painless red eye?

A

Painless

  • Subconjunctival haemorraghe
  • Episcleritis (uncomfortable not painful)
  • Conjunctivitis
  • Dry eye

Painful

  • Scleritis
  • Uveitis
  • Corneal abrasion
  • Corneal ulcer
  • Viral keratitis
  • Acute angle closure glaucoma
  • Endophthalmitis
  • FB/Chemical injury
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13
Q

What are some of the differences between scleritis and episcleritis?

A
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14
Q

What are some causes of red eye that need immediate referral as they are a n opthalmic emergency?

A
  • Uveitis
  • Acute angle closure glaucoma
  • Endophthalmitis
  • Corneal ulcer/Abrasion
  • Keratitis
  • Orbital cellulitis
  • Scleritis
  • Trauma/Chemical injuries
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15
Q

How can you tell the difference between

  • Conjunctivitis
  • Episcleritis
  • Scleritis
  • Anterior uveitis
  • Acute angle closure glaucoma
A
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16
Q

What questions do you need to ask in the history when someone presents with a red eye?

A
  • Onset and duration
  • Unilateral or bilateral
  • Associated symptoms e.g pain, discharge, N+V, photophobia
  • Any trauma?
  • Drug Hx
  • FHx of eye and autoimmune conditions
  • PMHx of eye disease or other conditions
  • Wear contacts?
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17
Q

What is squint (a.k.a strabismus) and what are the different types of squint?

A

Misalignment in the axis of the eyes which can lead to diplopia

- Paralytic/Incomitant: diplopia only on certain movements, most on looking in direction of action of paralysed muscle

- Non-Paralytic/Comitant: Squint present with all eye movements

- Convergent: esotropia looking inwards

- Divergent: exotropia looking outwards

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18
Q

What is a pseudo squint?

A

Looks like there is a malalignment of the eyes but there is not there are just prominent epicanthic folds

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19
Q

How is strabismus diagnosed?

A

All squints need opthalmological assessment

Screening:

- Corneal reflection: shine pen torch, reflection of light on cornea should be symmetrical in both eyes if no squint

- Cover test: Movement of uncovered eye to take up fixation as the other eye is covered demonstrates manifest squint. Latent squint is revealed by movement of the covered eye as the cover is removed

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20
Q

What is the difference between manifest and latent squints?

A

Manifest (TROPIA): Squint always present, diagnose with cover test

Latent (PHOREA): Patient appears normal but when they close their eye the eye deviates, can develop into manifest squint. Diagnose with uncover test

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21
Q

Why do people with manifest squints not have diplopia?

A

AMBLYOPIA!!

The eye that is deviated from normal turns into a ‘lazy eye’. Brain blocks vision coming from it

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22
Q

What are some causes of amblyopia and how is it managed?

A

Causes

  • Squint
  • Congenital cataract
  • Myopia/Hypermetropia

Management

  • If left untreated can lead to central vision in eye never returning to normal
  • Treat underlying pathology e.g corrective lenses, cataracts surgery, squint surgery
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23
Q

How is a squint/strabismus treated?

A

3 O’s ASAP

Optical: Assess refractive state after cyclopentolate 1% drops, the mydriasis allows good view into the eye to exclude abnormality, eg cataract, macular scarring, retinoblastoma, optic atrophy. Then prescribe glasses with prisms etc

Orthoptic: Patch the good eye to force the squint eye to be used, prevents amblyopia

Operation: Squint surgery to realign the extra-occular muscles, or botulin type A toxin. Good cosmetic results

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24
Q

How do the following nerve palsies present:

  • CN 3
  • CN 4
  • CN 6
A

CN 3: Ptosis, proptosis, fixed pupil dilatation, with the eye looking down and out

CN4: Diplopia and the patient may hold head tilted. Eye looks upward, in adduction and can not look down and in

CN6: Eye is medially deviated and cannot move laterally from midline, as the lateral rectus is paralysed. May be due to MS, diabetes, increased ICP compressing nerve against petrous bone

25
Q

How are the best results for strabismus achieved?

A
26
Q

What is the action of IO and SO?

A
27
Q

Why do some people have non-psychotic visual hallucinations?

A

Charles Bonnet Syndrome!!!

When there is vision loss, usually bilateral and sudden and usually in AMD, the brain fills images in.

May see simple repeated patterns (e.g grids) or complex images of people, objects or landscapes

28
Q

What are the criteria to be registered partial sighted and blind and what are the benefits of registering?

A

Partial sighted: Acuity <6/60 or >6/60 with visual field loss

Blind: Acuity <3/60 or >3/60 with extensive visual field loss e.g glaucoma

Benefits: reduced taxes, 50% reduction in TV licence, travel concessions, access to audio books

29
Q

What are the worldwide causes of avoidable blindness?

A

IMPORTANT CARD!!

30
Q

What are the main causes of avoidable blindness in developing countries?

A
31
Q

What are the main causes of blindness in developed countries? (important card)

A

MOST COMMON CAUSE: AMD

SECOND MOST COMMON CAUSE: Diabetic retinopathy

  • Glaucoma
  • Cataract
32
Q

What eye pathology should get an immediate/urgent ophthalmology referral?

A
  • Red eye with red flags (see image)
  • Ophthalmia neonatorum
  • Suspected periorbital or orbital cellulitis
  • Corneal ulcer
  • Infective keratitis
33
Q

What is some eye pathology associated with the following systemic diseases:

  • Infective endocarditis
  • Wilson’s disease
  • Hyperthyroidism
  • Hypothyroidism
A

- Infective endocarditis: Roth spots

- Wilson’s disease: Kayser-Fleicher rings

- Hyperthyroidism: exophthalmos

- Hypothyroidism myxedema, periorbital swelling

34
Q

What systemic disorders can lead to uveitis?

A

Usually granulomatous disorders

  • Sarcoidosis
  • TB
  • Syphillis
  • AS
  • Crohn’s
  • Reactive arthritis
35
Q

What is some eye pathology associated with the following systemic diseases:

  • SLE
  • RA
  • Dermatomyositis
  • Behcet’s
  • GCA
  • Sjogrens
  • HIV
A

- SLE: conjunctivitis, episcleritis, dry eye

- RA: keratoconjunctivitis sicca, episcleritis, scleritis corneal changes, and retinal vasculitis

- Dermatomyositis: orbital oedema and heliotrope rash

- Behcet’s: anterior and posterior uveitis, vitritis, panuveitis,

- GCA: optic nerve ischaemia

- Sjogrens: Keratoconjunctivitis sicca

- HIV: CMV retinitis (use IV ganiclovir)

36
Q

What is Keratoconjunctivitis sicca and how is it managed?

A
  • Dryness of the conjunctiva and cornea that can occur in Sjogren’s and RA. Can cause gritty feeling
  • Do Schirmer Filter paper test and will show reduced tear productive

- Management: Pilocarpine help sicca features and topical ciclosporin helps moderate or severe dry eye. Can use Silicone nasolacrimal punctal plugs help maintain tears on the eye surface for longe

37
Q

What are some causes of dry eye?

A
38
Q

What are some examples of occular disease in pregnancy?

A

Eyelids: mask of pregnancy (cholasma), dry eyes

Corneal sensitivity: decreases

Lens refraction: may change slightly

IOP: decreases so good if glaucoma

Diabetic Retinopathy: can accelerate

Pre-eclampsia: blurring of vision that comes back after delivery

CRVO/CRAO: increased risk of these diseases as women is hypercoagulable, amniotic fluid embolism

39
Q

What are some of the signs of retinoblastoma?

A
  • Strabismus
  • Leukocoria or red reflex is absent (photographs)
40
Q

What is the pathophysiology of retinoblastoma?

A

Hereditary or Non-Hereditary

- Herediatary:

  • RB gene at 13q14. Tumour supressor gene
  • Inherited autosomal dominant
41
Q

What are some associations with retinoblastomas?

A
  • Pineal tumours
  • Secondary malignancies are biggest cause of death. These are osteosarcomas and rhabdomyosarcomas
42
Q

How is retinoblastoma managed?

A

SCREENING OF SIBLINGS, PARENTS AND GENETIC COUNSELLING

- Chemotherapy: Useful in bilateral tumours

- Enucleation: may be needed with large tumours, optic nerve invasion or extrascleral extension.

- External beam radiotherapy: may cause secondary non-ocular cancers in the radiation field, esp. if carrying the RB-1 germline mutation

- Ophthalmic plaque brachytherapy more focal and shielded radiation field, and may carry less risk, but is limited to small–medium retinoblastomas in accessible locations.

- Cryotherapy and transpupillary thermotherapy (TTT): small tumours

43
Q

What are the two most common causes of infectious blindness?

A
  • Trachoma
  • Onchocerciasis

Majority of these cases are in Africa

44
Q

What is the pathophysiology of onchocerciasis (river blindness)?

A

- Onchocerca volvulus transmitted by black flies of the Simulium species

- Fly bites result in nodules from which microfilariae are released, to invade conjunctiva, cornea, ciliary body, and iris

  • Microfilariae cause inflammation then fibrosis. If in the cornea, corneal opacities occurs. Chronic iritis causes synechiae ± cataracts and a fixed pupil
45
Q

How is onchocerciasis treated?

A

- Microfilariae: Ivermectin every 6-12 months for 10-15 years. Give PO steroids for 3/7 first if severe disease

- Macrofilariae (adults): Doxycycline daily for 4 weeks

Best treatment is to give both but compliance issue with Doxycycline

46
Q

What is Bell’s phenomenon and how is it managed if there is lagopthalmos present too?

A

• Lubricant ointment: lacrilube or simple eye ointment

• No patching: cross taping if needed

Reassure Bell’s palsy patient that symptomd should start to improve after 3/52

47
Q

What are the stages of diabetic eye disease?

A
48
Q

What are some differentials for diplopia?

A
49
Q

What are some differentials for gradual change in vision?

A
50
Q

What are some differentials for painful sudden loss of vision?

A
51
Q

What is punctate staining and what is it a sign off?

A

On fluoroscein staining lots of little drops

Usually means dry eye

52
Q

Which type of chemical injury to the eye is more severe and why?

A

ALKALI

Alkali: liophillic so penetrate through tissues, tissues then release proteolytic enzymes breaking things down further

Acid: causes damage by denaturing and precipitating proteins, coagulated proteins act as a barrier to prevent further penetration

53
Q

What percentage of world blindness is due to cataracts?

A

Around 51% according to WHO

54
Q

What is the commonest cause of registration as blind in the UK?

A

AMD

55
Q

What is the pathophysiology of trachoma?

A
  • Chlamydia trachomatis (serotype A, B, C) spread by flies, where it is hot, dry, and dusty and the people are poor, living near cattle
  • Most common infectious cause of blindness
  • Scarring on the inner eye lids which directly damages the cornea, and in later stages the eye lid is distorted causing entropion; eyelashes scratch the cornea, which ulcerates
56
Q

How is trachoma managed?

A

SAFE

Surgery: lid surgery (bilamellar tarsal rotation operations) to prevent ectropion and scarring

Antibiotics: PO azithromycin and tetracycline 1% eye ointment 12-hrly for 5days each month for 6 months.

Facial Cleanliness: prevent transmission and reinfection between family etc

Enivronmental Improvement: improved sanitation

57
Q

What investigations are done to diagnose AMD?

A

- Slit lamp

- Colour fundus photography

- OCT

- Fluorescein angiography if neovascular AMD

58
Q

What is the treatment for endopthalmitis following cataracts surgery?

A

Intravitreal Vancomycin

(C) - Y4 Neurology and Special Senses (23 decks)

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