Degenerative changes in
cornea
Age related corneal degeneration
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Arcus senilis
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It is the most common peripheral corneal opacity, frequently occur with
predisposing systemic conditions in elderly individuals,occusionaly arcus
associated with familial or non familial dyslipoprotaneamia,it is most frequently
bilateral ,unilateral condition is rare and my occur in association with carotid
disease and ocular hypotony
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Sign
Lipid stromal deposit ,form a band in peripheral cornea separated from limbus by
clear corneal zone
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Corneal guttata
Consist of focal accumulation of collagen on the posterior surface of descement
membrane, the lesion appear as warts or excencesrese and are secreted by
abnormal endothelial cells
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Keratoconus
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It is progressive disorder, in which cornea assume irregular conical
shape,,onset around puberty with slow progressive visual impairment
Both eyes are affected in almost all cases, although involvement
commonly asymmetrical
The role of inheritance are not clear,offsprings are affected in about 10%
of the cases
AS. Transmission are proposed
Association
Systemic disorder,: down ,ehler danlos,marfan syndroms,osteogenesis
imperfecta and mitral valve prolapse
Ocular association: vernal keratocongectivitis,aniridia,ectopia
lentis,retinitis pigmentosa,rigid contact lens wear and constant eye
rubbing
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Presentation
Unilateral visual impairment due to progressive myopia and astigmatism
which subsequently become irregular
Patient report frequent changes of spectacle
As a result of asymmetrical nature of the disease the fellow usually have
normal vision with negligible astigmatism which however increase as the
condition progress
Sign
1-early
apical corneal protrusion
Retinoscopy show irregular seizer reflex
Slit lamp show very fine vertical deep stromal striae called vogt lines
Corneal topography is the most sensitive method for detection of early
keratoconus
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2-Late sign
Progressive corneal thinning
Progressive visual deterioration
Bulging of lower lid in down gaze (munson sign)
Epithelial iron deposit (fleischer ring) my surround the base of the cone
• 3-Acute hydropes
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Caused by acute influx of aqueous humor into the cornea as aresult of
rupture of descement membrane, causing
Sudden drop of V.A.
Discomfort and watering
Breaks usually heals within 6-10 wks and corneal edema resolved leaving
variable amount of stromal scar
Treatment of acute phase is with hypertonic saline, patching or soft
bandage contact lens
Permanent treatment:keratoplasty
• Treatment of keratoconus
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Spectacles. in early cases to correct mild irregular astigmatism
Rigid contact lens. when astigmatism cannot corrected by spectacles
Keratoplasty. In advanced progressive cases
• Contact lens
• Therapeutic indication
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1-optical:
A. irregular astigmatism
B. superficial corneal irregularity
C. anisometropia, which my fallow cataract surgery
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2-promotion of epithelial healing
A. persistent epithelial defect ,to protect the regenerated epithelium from
constant rubbing by blinking
B. recurrent corneal erosion
3- pain relief
A. bulbous keratopathy which condition occur as aresult of loss of
endothelial cell leading to development of corneal edema which when
rapture cause sever pain with blinking as following complicated cataract
surgery
B. wet filamentary keratitis as in brain stem stroke
C. Protection of corneal epithelium from aberrant lashes
3-preservation of corneal integrity
A. descematocele which sever corneal thinning which intended to rupture
B. splinting and apposition of small corneal wound till healing
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4-miscelenous indication
A.Ptosis prop as in patient with ocular myopathy
B. maintenance of fornices in eyes with cicatrizing conjunctivitis
C. drug delivery
Complication
Conjunctival
allergic conjunctivitis
Giant papillary conjunctivitis
Corneal complication
Epithelial edema due to hypoxia
Corneal vascularization due to hypoxia
Sterile corneal infiltrate
Microbial keratitis
Corneal warping, sever and permanent astigmatism my be caused by chronic
corneal hypoxia