Cornea Part 2

Question 1

Describe corneal guttate

Answer 1

Irregular warts or excrescences on the descemet’s membrane

Question 2

Describe bullae

Answer 2

Blister of serous fluid that can rupture and cause infection (very painful). Associated with Fuch’s syndrome.

Question 3

What is the name for abnormally weak attachment between the epithelium and bowman’s membrane? When the epithelium can easily become detached eg. because of movement of the eyelids

Answer 3

Recurrent corneal epithelial erosion

Question 4

What are the symptoms of recurrent corneal epithelial erosion?

Answer 4

Severe pain (especially middle of the night / when waking up)
Photophobia 
Red eye (hyperaemia)

Question 5

What could cause recurrent corneal epithelial erosion?

Answer 5

Previous injury / trauma
Corneal dystrophy

Epithelium could then become easily detached eg. By eyelids
Surrounding area then has poor wet ability

Question 6

Signs of recurrent corneal epithelial erosion ?

Answer 6

Epithelial defect
Fluorescein pooling around area of previous defect
Occasionally micro cysts, punctate / fingerprint opacities seen after the defect has healed

Question 7

Location / laterality of corneal dystrophies vs degenerations?

Answer 7

Dystrophy typically central and bilateral and symmetrical

Degeneration typically peripheral and often unilateral and asymmetrical

Question 8

Onset age of corneal degenerations / dystrophies?

Answer 8

Dystrophies 1st to 2nd decade

Degeneration around 5th decade or later

Question 9

Vascularisation in dystrophy vs degeneration?

Answer 9

None in dystrophy, common in degeneration

Question 10

Family history links between corneal dystrophies vs degenerations?

Answer 10

Common links with dystrophies, uncommon with degenerations

Question 11

Define corneal degeneration

Answer 11

Corneal tissue changes that can cause deterioration or impairment of vision - often associated with aging or systemic diseases

Question 12

Difference between involutional and non-involutional

Answer 12

Involutional = associated with ageing and common

Non-involutional = associated with systemic conditions and less common

Question 13

Some examples of corneal degenerations?

Answer 13

Arcus
Vogts limbal girdle
Lipid keratopathy
Band keratopathy

Keratopathy = non-inflammatory corneal disease

Question 14

Describe Vogt Limbal Girdle

Answer 14

Crescent limbal bands that happen at 3 and/or 9 o’clock

Asymptomatic with no known aetiology

Two types:
Type 1 = Swiss cheese hole pattern distinct from the limbus

Type 2= (most common) solid opacification area with no clear limbal zone

Question 15

Describe lipid keratopathy

Answer 15

Lipid deposits in the stroma

Causes:
Age related changes
Secondary to anterior uveitis, chronic corneal oedema, chronic keratitis, silicone oil in anterior chamber
Hereditary
Rare metabolic disorder: metastatic calcification

Primary: (rare) spontaneous occurrence of crystallised lipids in the stroma, no vascularisation

Secondary: (common) secondary to corneal disease with vascularisation eg. HSK or HZK

Question 16

Describe band keratopathy

Answer 16

Age related deposition of calcium salts in the bowmans later, epithelial basement membrane and anterior stroma

Question 17

Aetiology of band keratopathy?

Answer 17

Age related changes

Secondary to anterior uveitis, silicone oil in anterior chamber, chronic corneal oedema, chronic keratitis

Hereditary

Rare metabolic disorder: metastatic calcification

Question 18

Signs and symptoms of band keratopathy

Answer 18

Calcified plaque of opacification

Clear margins between limbus and edge of band

Gradual spread of band / plaque

Advanced lesions can become nodular

Symptoms: reduction in vision

Question 19

Describe Francois central cloudy dystrophy and crocodile shagreen

Answer 19

NOT dystrophies, are actually both degenerations

Almost distinguishable from each other

Asymptomatic and signs are:
Central greyish polygonal or rounded stroma opacities
No treatment.

Question 20

How would we manage degenerations?

Answer 20

Optom - monitor and manage underlying causes
Only treat if affecting vision or causing discomfort

Refer to GP for underlying systemic causes and ophthalmologist is vision impaired.

Treatment may include scrapping / lasers treatment
Keratoplasty in extreme cases

Question 21

Describe arcus (what is it?)

Answer 21

Peripheral corneal opacity due to lipid deposits in peripheral cornea
Most common corneal opacity

Asymptomatic

Question 22

Describe the visible signs of arcus

Answer 22

Stromal lipid deposits:

• superior then inferior, creates a band around cornea
• central border is diffuse then peripheral border is sharp with a distinct edge from the limbus

Question 23

Associations with arcus?

Answer 23

Aging

Dyslipidaemia (younger px’s)

Question 24

Generally describe corneal dystrophies

Answer 24

A group of corneal opacifying disorders that can affect one or more of the corneal layers

Mostly inherited rare group of disorders
Not associated with systemic disease
Can cause significant sight loss
Slow progressing

Question 25

Examples of corneal dystrophies?

Answer 25

Cogan dystrophy Reis-buckler corneal dystrophy Granular corneal dystrophy Fuchs dystrophy

Question 26

Describe Cogan epithelial basement membrane dystrophy

Answer 26

``` Recurrent epithelial erosions / lesions Eg map, dot, fingerprint dystrophy Most common corneal dystrophy Mostly sporadic Bilateral and asymmetrical Often no symptoms ```

Question 27

Describe Reis-Bucklers corneal dystrophy

Answer 27

Bowmans later dystrophy Sub epithelial opacities that are denser in the centre Can cause recurrent erosion in childhood and vision impairment

Question 28

Describe granular corneal dystrophy

Answer 28

Classic central stromal granular dystrophy Severe appearance Discrete white central anterior stromal opacities that increase in number and size Causing blurring of vision and glare / photophobia

Question 29

Describe Fuch’s endothelial corneal dystrophy

Answer 29

Bilateral acceleration of endothelial cell loss Mostly sporadic Associated with open angle glaucoma ``` Corneal guttata Interruption to endothelial mosaic Stromal oedema Bullae Peripheral vascularisation ```

Question 30

How would we manage dystrophies?

Answer 30

Monitor and only treat if affecting vision or causing discomfort. Manage symptoms eg irritation with lubrication Treatment if necessary (ophthalmologist) Excimer laser Keratoplasty

Question 31

Define ectasias

Answer 31

A group of abnormalities that cause irregularities in corneal shape Normally progressive and reduce vision

Question 32

Examples of ectasias?

Answer 32

Keratoconus Keratoglobus Pellucid marginal degeneration

Question 33

Describe keratoconus

Answer 33

A progressive corneal disorder with peripheral and central corneal thinning together with asymmetrical astigmatism and the development of an atypical protrusion (come shape)

Question 34

Aetiology of keratoconus?

Answer 34

Spontaneous Secondary to some other systemic conditions Associations: Down’s syndrome, marfans, retinitis pigmentosa, vernal keratoconjunctivitis

Question 35

Signs of keratoconus?

Answer 35

Increasing asymmetric astigmatism Scissoring reflex in ret Vogt striae (deep stromal stress lines) Cone configuration Munsen’s sign (lower lid bulges when looking down Flieshers ring (iron deposits round base of cornea) Acute hydrops (rupture of stressed descemets membrane) Steep k readings Asymmetrical displaced apex seen during topography Oil drop reflex in ophthalmoscopy

Question 36

How would you manage keratoconus?

Answer 36

Manage the rx with spectacles, soft and rgp specialist lenses Routine referral Stop rubbing eyes Referral- Intracorneal ring Corneal cross linking Keratoplasty

Question 37

Describe pellucid marginal degeneration

Answer 37

Progressive peripheral corneal thinning disorder often misdiagnosed with keratoconus Normally bilateral

Question 38

Signs of pellucid marginal degeneration

Answer 38

``` Bilateral thinning of inferior cornea Cornea above the thinned area is flat Pinhole va is unaffected Does NOT show: - Vogt straie - acute hydrops - fleischers ring ```

Question 39

Management of pmd

Answer 39

Manage rx with specs, specialist cls Routine referral Surgical intervention as last resort

Question 40

Describe abnormalities of the cornea and globe

Answer 40

Generally congenital birth defects that have resulted in malformed cornea. Can affect clarity or refractive power of cornea

Question 41

Examples of abnormalities of cornea and globe

Answer 41

``` Microcornea Microophthalmos Nanophthalmos Anophthalmos Megacornea Sclerocornea Cornea Plano Keratectasia Posterior keratoconus ```

Question 42

How would we manage abnormalities of the cornea and globe?

Answer 42

As they are congenital usually the hospital will manage (if required)