B1. Corneal Degeneration & Dystrophy Flashcards
what is the difference between dystrophy and degeneration?
dystrophy: A disorder in which an organ or tissue of the body wastes away/weaken
Hereditary condition
NOT due to arrested development
Usually bilateral, only involves central acornea and retina
young onset
no vascularisation
degeneration:
Acquired loss of function associated with
Ageing
Inflammation
Infection
Vascular disease
Vitamin deficiency
Can be any part of the eye, often unilateral
40 or more years old
common vascularisation
what are the SSX of band keratopathy? is it a degeneration or a dystrophy? Mx?
degeneration
Symptoms:
Decreased vision (if blocking pupil)
Irritation, pain, FB sensation
Signs:
Early: white granular crescent at limbus
Later: spread centrally to form a band of chalky plaque
what are the SSX of crocodile shagreen? is it a degeneration or a dystrophy? any MX?
degeneration
Symptoms:
Asymptomatic
Signs:
Greyish-white polygonal opacities in stroma with clear spaces in between
no Mx
MX for band keratopathy?
Lubrication for mild sx
Chelation
Monitor 3-6 mths
background and cause for band keratopathy?
Background
Deposition of calcium in Bowman’s membrane
Due to:
Chronic anterior uveitis
Age-related
Systemic hypercalcemia
Hereditary
what are the 7 corneal dystrophies? classify the further by which layers of the cornea they affect
Epithelial basement membrane dystrophy (EBMD)
Meesman dystrophy (epithelial)
Reis-Buckler’s dystrophy (bowmans layer)
Granular dystrophy (stromal)
Lattice dystrophy (stromal)
Macular dystrophy (stromal)
Fuch’s dystrophy (endothelial)
what is the background and etiology of EBMD?
Background
Seen in 20-30yo, 10% of px recurrent erosions in 30’s
Etiology
Thickening of basement membrane into epithelium with protein deposits -> weak epithelial adhesion -> epithelial erosion
SSx of EBMD?
Signs:
Dot-like opacities
Microcysts
Maps
Fingerprints
Symptoms:
May range from no symptoms to irritation, photophobia, reduced VA
Mx for EBMD?
Management
Lubricants
Bandage CL
Topical hypertonic saline (5% NaCl)
what is the background of meesman dystrophy?
Background
Juvenile epithelial dystrophy
Presents before 2nd birthday
SSx of meesman dystrophy?
Signs
Small whitish intraepithelial cysts
Possible epithelial erosions
Symptoms
May range from no symptoms to irritation, photophobia, reduced VA (Same as EBMD)
Mx of meesman dystrophy?
Symptomatic relief, lubricants.
what is the background of reis-bucklers dystrophy?
Background
Onset is in early infancy
Autosomal dominant
SSx of reis bucklers dystrophy?
Hazy white, round, polygonal opacity in Bowman’s, progress to reticular pattern
Severe recurrent corneal erosions in childhood
Mx for reis bucklers dystrophy?
Excimer laser keratectomy
Lamellar keratoplasty
etiology for all stromal dystrophies?
primarily affects stroma but over time they often extend into the anterior corneal layers and some may affect Descemet’s membrane and the endothelium.
What gene type is lattice dystrophy? SSx? Mx?
Classic form - TGFB1 type
autosomal dominant
recurrent erosion occurs at the end of first decade
SSx:
‘glass-like’ filamentous lesions
generalized stromal haze may progressively impair vision
Treatment: penetrating or deep lemallar keratoplasty
What gene type is granular dystrophy? SSx? Mx?
Classic form - TGFB1 type
autosomal dominant
recurrent erosion uncommon
SSx
glare and photophobia
Discrete crumb-like opacities are seen in the central anterior stroma
gradual increase in number and size, with deeper and outward spread
corneal sensation impaired
Treatment: penetrating or deep lemallar keratoplasty
What gene type is macular dystrophy? SSx? Mx?
gene CHST6, autosomal recessive
early (end of first decade) visual deterioration
recurrent erosion very common
dense greyish-white spots centrally in anterior stoma and peripherally in posterior stroma
eventual involvement of full-thickness stroma
Treatment: penetrating keratoplasty
what is the background of fuchs dystrophy?
Slow progressive disease in old age
Usually women are affected
Bilateral endothelial cell loss
Increased prevalence of open-angle glaucoma
6 SSx of fuchs dystrophy?
Symptoms
- Gradually worsening blurring, particularly in the morning due to corneal edema
- Onset usually middle age or later
Signs
- Cornea guttata – presence of irregular warts on Descemet’s membrane secreted by abnormal endothelial cells
- Specular reflection shows tiny dark spots, progressing to “beaten metal” appearance
- Endothlial decompensation leading to central stromal edema and blurred vision
- Edema in advanced cases forms bullae (bullous keratopathy), rupture of bullae can lead to pain and exposed nerve fibres
Mx for Fuch’s dystrophy?
Non-urgent referral.
hypertonic saline eye drops and/or ointments. Use of the hypertonic saline may stabilize or improve vision by drawing extra water out of the cornea.
Any activity that helps to evaporate fluid off the cornea will help shorten the time to visual recovery. Such activities may include pointing car vents toward the face or blowing air by the eyes using a hair dryer at arm’s length.
Bandage contact lenses can also be quite helpful in management of painful ruptured bullae in more severe disease.
As Fuchs’ dystrophy progresses, medical treatment may fail and surgical management becomes necessary.
