Cornea Part 2 Flashcards
Describe corneal guttate
Irregular warts or excrescences on the descemet’s membrane
Describe bullae
Blister of serous fluid that can rupture and cause infection (very painful). Associated with Fuch’s syndrome.
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
Recurrent corneal epithelial erosion
What are the symptoms of recurrent corneal epithelial erosion?
Severe pain (especially middle of the night / when waking up) Photophobia Red eye (hyperaemia)
What could cause recurrent corneal epithelial erosion?
Previous injury / trauma
Corneal dystrophy
Epithelium could then become easily detached eg. By eyelids
Surrounding area then has poor wet ability
Signs of recurrent corneal epithelial erosion ?
Epithelial defect
Fluorescein pooling around area of previous defect
Occasionally micro cysts, punctate / fingerprint opacities seen after the defect has healed
Location / laterality of corneal dystrophies vs degenerations?
Dystrophy typically central and bilateral and symmetrical
Degeneration typically peripheral and often unilateral and asymmetrical
Onset age of corneal degenerations / dystrophies?
Dystrophies 1st to 2nd decade
Degeneration around 5th decade or later
Vascularisation in dystrophy vs degeneration?
None in dystrophy, common in degeneration
Family history links between corneal dystrophies vs degenerations?
Common links with dystrophies, uncommon with degenerations
Define corneal degeneration
Corneal tissue changes that can cause deterioration or impairment of vision - often associated with aging or systemic diseases
Difference between involutional and non-involutional
Involutional = associated with ageing and common
Non-involutional = associated with systemic conditions and less common
Some examples of corneal degenerations?
Arcus
Vogts limbal girdle
Lipid keratopathy
Band keratopathy
Keratopathy = non-inflammatory corneal disease
Describe Vogt Limbal Girdle
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
Describe lipid keratopathy
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
Describe band keratopathy
Age related deposition of calcium salts in the bowmans later, epithelial basement membrane and anterior stroma
Aetiology of band keratopathy?
Age related changes
Secondary to anterior uveitis, silicone oil in anterior chamber, chronic corneal oedema, chronic keratitis
Hereditary
Rare metabolic disorder: metastatic calcification
Signs and symptoms of band keratopathy
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
Describe Francois central cloudy dystrophy and crocodile shagreen
NOT dystrophies, are actually both degenerations
Almost distinguishable from each other
Asymptomatic and signs are:
Central greyish polygonal or rounded stroma opacities
No treatment.
How would we manage degenerations?
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
Describe arcus (what is it?)
Peripheral corneal opacity due to lipid deposits in peripheral cornea
Most common corneal opacity
Asymptomatic
Describe the visible signs of arcus
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
Associations with arcus?
Aging
Dyslipidaemia (younger px’s)
Generally describe corneal dystrophies
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
Examples of corneal dystrophies?
Cogan dystrophy
Reis-buckler corneal dystrophy
Granular corneal dystrophy
Fuchs dystrophy
Describe Cogan epithelial basement membrane dystrophy
Recurrent epithelial erosions / lesions Eg map, dot, fingerprint dystrophy Most common corneal dystrophy Mostly sporadic Bilateral and asymmetrical Often no symptoms
Describe Reis-Bucklers corneal dystrophy
Bowmans later dystrophy
Sub epithelial opacities that are denser in the centre
Can cause recurrent erosion in childhood and vision impairment
Describe granular corneal dystrophy
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
Describe Fuch’s endothelial corneal dystrophy
Bilateral acceleration of endothelial cell loss
Mostly sporadic
Associated with open angle glaucoma
Corneal guttata Interruption to endothelial mosaic Stromal oedema Bullae Peripheral vascularisation
How would we manage dystrophies?
Monitor and only treat if affecting vision or causing discomfort.
Manage symptoms eg irritation with lubrication
Treatment if necessary (ophthalmologist)
Excimer laser
Keratoplasty
Define ectasias
A group of abnormalities that cause irregularities in corneal shape
Normally progressive and reduce vision
Examples of ectasias?
Keratoconus
Keratoglobus
Pellucid marginal degeneration
Describe keratoconus
A progressive corneal disorder with peripheral and central corneal thinning together with asymmetrical astigmatism and the development of an atypical protrusion (come shape)
Aetiology of keratoconus?
Spontaneous
Secondary to some other systemic conditions
Associations:
Down’s syndrome, marfans, retinitis pigmentosa, vernal keratoconjunctivitis
Signs of keratoconus?
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
How would you manage keratoconus?
Manage the rx with spectacles, soft and rgp specialist lenses
Routine referral
Stop rubbing eyes
Referral-
Intracorneal ring
Corneal cross linking
Keratoplasty
Describe pellucid marginal degeneration
Progressive peripheral corneal thinning disorder often misdiagnosed with keratoconus
Normally bilateral
Signs of pellucid marginal degeneration
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
Management of pmd
Manage rx with specs, specialist cls
Routine referral
Surgical intervention as last resort
Describe abnormalities of the cornea and globe
Generally congenital birth defects that have resulted in malformed cornea. Can affect clarity or refractive power of cornea
Examples of abnormalities of cornea and globe
Microcornea Microophthalmos Nanophthalmos Anophthalmos Megacornea Sclerocornea Cornea Plano Keratectasia Posterior keratoconus
How would we manage abnormalities of the cornea and globe?
As they are congenital usually the hospital will manage (if required)
