Scars	Black
Degenerations	Black
Contact lens	Black dotted circle
Sutures	Black straight lines
Cornea! outline	Black
IOL	Black
Guttata	Black shade
Deep blood vessels	Dark red, straight lines ending at limbus
Superficial blood vessels	Bright red, wavy branching lines crossing limbus
Ghost vessels	Red dotted straight lines
Hyphema	Red
Rose Bengal stain	Red
Pterygium	Red
Epithelial edema	Blue circles
Descemet's folds	Blue wavy lines
Stromal edema	Blue shadows
Lens	Green
Vitreous	Green
Corneal filaments	Green
Fluorescein stain	Green
Epithelial defect	Green
Infiltrates	Yellow
Hypopyon	Yellow
Iris	Brown
Pigment	Brown
Keratic precipitates	Brown 3

   

• Contact lens wear may cause epithelial defects; predispose to Pseudomonas aeruginosa infection
• Pre-existing corneal disease - trauma, bullous keratopathy, exposure keratopathy, decreased corneal sensation
• Chronic blepharitis; chronic dacryocystitis
• Tear film deficiency; topical steroid usage; Vitamin A deficiency.

 

• Pain, photophobia, redness, foreign body sensation, lid edema, discharge
• Circum-corneal congestion
• Sharp epithelial demarcation with underlying dense suppurative stromal inflammation, surrounded by stromal edema
• Epithelial defect surrounded by infiltrate
• Endothelial inflammatory plaque
• Anterior uveitis with hypopyon
• P. aeruginosa produces stromal necrosis with a shaggy surface and adherent mucopurulent exudate
• Corneal perforation is a complication.

 

SUSPECTED ORGANISM	STAIN	MEDIA
Aerobic bacteria	1. Gram 2. Acridine orange	1. Blood agar 2. Chocolate agar 3. Thioglycollate broth
Anaerobic bacteria	1. Gram stain 2. Acridine orange	1. Anaerobic blood agar 2. Phenylethyl alcohol agar in anaerobic chamber
Mycobacteria	1. Gram 2. Acid fast 3. Lectin	1. Blood agar 2. Lowenstein-Jensen medium
Fungi	1. Gram 2. Acridine orange 3. Calcofluor white	1. Blood agar (25°) 2. Sabouraud agar 3. Brain-heart infusion (25°)
Acanthamoeba	1. Acridine orange 2. Calcofluor white	1. Non-nutrient agar with E. coli overlay 2. Blood agar 3. Buffered charcoal-yeast extract agar

         

• In the form of broad spectrum topical antibiotics
• Oral ciprofloxacin 750 mg BD in juxta-limbal keratitis
• Atropine 3% ointment BD - to prevent posterior synechiae and decrease pain from ciliary spasm.
  7

 

ORGANISM	ANTIBIOTIC	TOPICAL DOSE
GP cocci	Cefazolin Vancomycin	50 mg/ml 50 mg/ml
GN rods	Tobramycin Gentamicin Ceftazidime Fluoroquinolones	9-14 mg/ml 15 mg/ml 50 mg/ml 3 mg/ml
No/multiple organisms	Cefazolin + Gentamicin (or) Fluoroquinolones	50 mg/ml 15 mg/ml 3 mg/ml
GN cocci	Ceftriaxone Ceftazidime	50 mg/ml 50 mg/ml
Mycobacteria	Amikacin	20 mg/ml
* GP = gram positive
* GN = gram negative

 

DRUG	VIAL STRENGTH	HOW TO PREPARE
Cefazolin [50 rag/ml]	1 vial = 500 mg	Add 10 ml of AT to vial
Ceftazidime [50 rag/ml]	1 vial = 500 mg	Add 10 ml of AT to vial
Vancomycin [50 rag/ml]	1 vial = 500 mg	Add 10 ml of AT to vial
Gentamicin [15 mg/ml]	1 vial = 2 ml [40 mg/ml]	Add 2 ml from vial to 5 ml of 0.3% gentamicin eye drops
* AT = preservative free artificial tears

   

• Filamentary fungi - Fusarium sp., Aspergillus sp
• Yeasts - Candida species (immunocompromised individuals; pre-existing corneal disease).

 

• Hyphae grow along stromal collagen fibers
• Ineffective phagocytosis by host immune system because hyphae are large - instead digestion of host cells occurs
• Immunosuppression increases fungal growth
• Fungi enter anterior chamber by penetrating intact Descemet's membrane.

 

• Trivial injury with organic matter
• Windy and dry season; rural areas
• Agriculturists are more prone.

 

• Signs >>> symptoms
• Gradual onset, foreign body sensation, photophobia, blurred vision, discharge
• Slow progression, less painful.

 

• Yellow-white ulcer with dense suppuration
  Rx:

  • Topical Imidazole 1%
  • Topical Flucytosine 1%
  • Oral fluconazole 200 – 400 mg/day if severe
    9

 

• Gray stromal infiltrate with a dry texture and indistinct margins
• Surrounding satellite lesions
• Feathery finger-like lesions
• Immune ring infiltrates (Wessely ring)
• Endothelial plaque
• Hypopyon - thick and immobile - due to direct invasion of hyphae enmeshed in thick exudates
  Rx:

  • Topical natamycin 5%,
  • Topical amphotericin B 0.15%
  • Oral ketoconazole 200 – 600 mg/day if severe

 

• KOH mount – KOH dissolves epithelial cell walls; hyphae become visible
• Culture media – Sabouraud's dextrose agar, Potato dextrose agar

 

• Topical antifungals up to 6 weeks
• Cycloplegics
• Hypotensive agents
• Systemic antifungals [oral fluconazole 150 mg BD; if severe or if endophthalmitis occurs]
• Surgery –

  • superficial keratectomy - for good drug penetration
  • glues - if micro-perforation occurs
  • therapeutic keratoplasty - for non-healing ulcers, corneal perforation.
    10

 

• Caused by a ubiquitous free-living protozoan
• Cysts become trophozoites which produce enzymes ♦ tissue penetration and destruction
• Contact lens wearers at particular risk.

 

• Severe pain, blurred vision
• Symptoms >> signs
• Photophobia, foreign body sensation
• Conjunctival injection, chemosis
• Stromal ring infiltrate ♦ ring abscess - may be central/ paracentral
• Radial keratoneuritis - perineural infiltrates
• Sub-epithelial keratopathy
• Endothelial plaque, hypopyon
• Frank corneal necrosis
• Pseudo-dendritic keratitis
• Small white satellite lesions
• Slowly progressive stromal opacification; descemetocele
• Scleritis

 

• 10% KOH mount - amebic cysts are seen
• Calcofluor white - a chemofluorescent dye with special affinity for acanthamoeba cysts
• Gram's stain, Giemsa stain, Periodic Acid Schiff
• Culture on non-nutrient agar with E. coli overlay; buffered charcoal yeast extract.
  11

 

1. PHMB (polyhexamethylene biguanide) 0.02% + Propamidine isothionate (brolene) 0.1%
2. Chlorhexidine [monotherapy]
3. Neomycin + brolene
   Also used are:
4. Miconazole 1%
5. Clotrimazole 1%
6. Dipropamidine isothionate 0.15%

 

• Non-ulcerative, non-suppurative inflammation of corneal stroma, often with subsequent vascularization

 

• Congenital/acquired syphilis (90%)
• TB, leprosy, Lyme disease
• HSV, HZV, mumps, influenza, rubella
• Chromium deficiency, gold toxicity
• Onchocercariasis, cysticercosis, infectious mononucleosis
• Malaria, leishmaniasis, trypanosomiasis

 

1. PROGRESSIVE STAGE [from 1-2 weeks]

   • Pain, photophobia, lacrimation, blepharospasm
   • Circum-corneal congestion, cloudy cornea
   • Superficial peripheral vascularization
   • Anterior uveitis, choroiditis
   • Limbitis - raised inflamed sector of limbus from which deep blood vessels invade
2. FLORID STAGE [from 2-4 months]

   • increased inflammation, DM folds
   • deep vascularization
   • ground glass cornea - diffuse stromal cellular infiltration
   • Salmon patch - corneal clouding obscures the outline of the vessels — looks dull, pinkish red
3. REGRESSIVE STAGE [from 1-2 years]

   • clearing starts
   • blood vessels become non-perfused ♦ GHOST VESSELS - may refill later following inflammation - bleeding occurs
   • stromal thinning, scarring, flattening
4. INACTIVE STAGE

   • central deep stromal scar; ghost vessels seen
     13

 

• corneal decompensation, corneal guttata
• band keratopathy, lipid keratopathy
• Salzmann nodular degeneration, astigmatism
• glaucoma

 

• Topical steroids - to reduce corneal inflammation and iritis
• Penicillin G given in ♦

  • Primary and secondary syphilis ♦ 1.2 million units i.m
  • Tertiary syphilis ♦ 2.4 million units i.m weekly × 3 wks
• Penetrating keratoplasty - for corneal scarring
  14

   

• present with watering, discomfort, decreased vision, pain
• opaque epithelial cells break down to form linear, branching, dendritic ulcer with terminal bulbs (ulcer bed stains with fluorescein; margin stains with Rose Bengal)
• centrifugal enlargement ♦ geographical/ameboid ulcer
• decreased corneal sensation

1. debridement of dendritic (not geographic) ulcer
2. acyclovir ointment 3% (5 times per day); check for response in a week; if no response, change the antiviral agent to -

   • trifluorothymidine 1% (6 X/day) or
   • ganciclovir gel 0.15% (5 X/day) [5 times per day]

 

• exaggerated hypersensitivity reaction to viral antigens
• infection of keratocytes and endothelium

• gradual onset of blurred vision and haloes; no pain
• central, disc-like zone of epithelial edema overlying an area of stromal thickening, with KPs and DM folds
• ring of stromal precipitates - WESSELY RING ♦ marks the junction between viral antigen and host antibody
• mild anterior uveitis; raised IOP
• decreased corneal sensation

• Topical prednisolone acetate 1% + antiviral cover initially [if steroids used > 4 times/day]
• If topical prednisolone acetate 0.25% used - no need for antiviral cover
• Gradually taper steroids over several weeks

 

• active viral invasion and tissue necrosis
• can have an intact epithelium or epithelial disease
• cheesy/necrotic stroma
• profound interstitial opacification
• anterior uveitis, KPs
• scarring, vascularization, lipid keratopathy, perforation
• Rx:

  • epithelial disease is treated with topical antivirals
  • severe stromal keratitis associated with anterior uveitis is treated with steroids (cautiously) + topical antivirals + topical antibiotics
    16

 

	HERPES SIMPLEX	VARICELLA-ZOSTER
Dermatomal distribution	Incomplete	Complete
Pain	Less	More
Dendrites	Large with central ulceration and terminal bulbs	Small, medusa-like dendrites without central ulceration or terminal bulbs
Dendritic mucous plaques	Don't occur	Occur late
Skin scarring	Rare	Frequent
Postherpetic neuralgia	Rare	Common
Iris atrophy	Patchy	Sectoral
Bilateral involvement	Rare	Never
Recurrent lyric epithelial keratitis	Common	Never
Corneal hypoesthesia	Sectoral/diffuse	Frequent

 

• Non-inflammatory ectasia of cornea resulting in visual impairment, owing to a high degree of irregular myopic astigmatism
• Adolescence; bilateral/unilateral

 

1. Developmental delay in separation of lens fibers from cornea
2. Degeneration of elastic fibers
3. Secondary to disease process or malnutrition
4. Endocrinological - because of association with hypothyroidism and pregnancy

 

• Decreased visual acuity; ghost images; glare
• Can present with irritation and frequent rubbing of the eye

 

• Central/eccentric cone
• Fleischer ring - a line running along the base of the cone due to iron deposition superficial to the Bowman's membrane (complete/incomplete; pigmented/yellow/brown)
• Prominent corneal nerves
• Stromal thinning increases gradually from base of the cone to the apex
• Vogt's striae - thin vertical stress lines in the deeper stroma which disappear on digital pressure
• Endothelial reflex because of increased concavity
• Acute Hydrops - in the center of the cone due to rupture of the descemet's membrane and influx of fluid into the stroma
• Scarring following rupture
  18
• Munson sign - on looking down, the angular curve is assumed by the lower lid margin
• Axenfeld sign - loss of sensitivity at the apex of the cone
• Benedict sign - conical reflection on the nasal cornea when torch light thrown from temporal side

 

• Keratometry - non-alignment of the mires
• breaking/doubling of the right lower circle.
• Placido's disc - irregularities in reflection of illuminated rings near the corneal center; distortion of the horizontal axis
• Direct ophthalmoscopy - oil drop sign
• Retinoscopy - scissors reflex; 2 shadows move in opposite direction
• Orbscan detects early keratoconus; bow-tie pattern; called Forme Frustae keratoconus

 

• Vernal keratoconjunctivitis, atopic keratoconjunctivitis [due to constant rubbing of eye]
• Retinitis pigmentosa; Leber's congenital amaurosis
• Retrolental fibroplasia
• Macular coloboma
• Ectopia lentis, blue sclera
• Cataract, retinal detachment, optic atrophy
• Xeroderma pigmentosa
• Addison's disease
• Syndromes - Down's, Ehlers-Danlos, Marian's, Crouzon's, Apert's.
  19

 

KERATOCONUS	KERATOGLOBUS	PELLUCID MARGINAL DEGN
Most common	Rare	Less common
Bilateral [usually]	Bilateral	Bilateral
Onset at puberty	Onset at birth	20 – 40 years
Inferior paracentral thinning	Thinning greatest in periphery	1-2 mm band of thinning inferiorly
Protrusion at apex	Generalized protrusion	Protrusion superior to band of thinning
Fleischer ring present	Absent	Sometimes present
Scarring common	Mild scarring	Only after hydrops
Striae are common	Sometimes	Sometimes
* DEGN - degeneration

 

1. Spectacles
2. Contact lenses - RGP [rigid gas permeable]

   • Gas-permeable with large diameter - for oval/globus cones
   • Aspherical - for nipple cones
   • Small, steep lenses - for severe nipple cones
   • Semi-rigid/hard - for steep oval cones
   • Piggy bag lenses
   • Scleral contact lenses [Boston lenses]
3. Surgery -

   • Anterior lamellar keratoplasty
   • Epikeratoplasty
   • Deep lamellar keratoplasty
   • Penetrating keratoplasty (use same sized donor button)
     20
   • Thermokeratoplasty - heat is applied to the tip of the cornea for 1 min which causes shrinkage of collagen and flattening of the cornea
   • Intacts [intra-stromal rings]

   • Rx of acute hydrops:

     • hypertonic saline drops
     • C3F8 (14%) injection into the anterior chamber

 

• Increased curvature of the posterior corneal surface with normal curvature of the anterior corneal surface
• May be focal/generalized; central/eccentric
• Unilateral; present from birth
• Associated with posterior corneal opacity, anterior lenticonus, aniridia, iris atrophy, ectropion uveae
• Amblyopia and strabismus may be present
• Associated features: hypertelorism, webbed neck, short stature, mental retardation, abnormal development of bridge of the nose
  21

 

• A dystrophy is a bilateral, symmetric, inherited condition that appears to have little or no relationship to environmental or systemic factors.

  Degeneration	Dystrophy
  Opacity often peripheral	Central opacity
  May be asymmetric	Bilateral and symmetric
  Presents later in life	Presents early in life
  Associated with aging	Hereditary
  Progression can he very slow or rapid	Progression usually slow

  
  22
• Cogan microcystic/epithelial basement membrane/map-dot-fingerprint dystrophy

  • dot-like opacities; epithelial microcysts
  • map-like patterns; whorled fingerprint-like lines
  • not familial/progressive
  • cause recurrent bilateral corneal erosions
• Meesmann dystrophy - tiny intraepithelial cysts in the interpalpebral area; do not reach limbus
• Reis-Buckler dystrophy - gray-white, round and polygonal opacities in the center of the cornea; decreased corneal sensation; visual disturbance due to scarring
• Thiel Behnke dystrophy - similar to Reis-Buckler type; opacities for a honey-comb pattern
• Crystalline dystrophy - scintillating subepithelial crystalline opacities in the center of a generally hazy cornea
• Lattice type 1 - fine, spidery, branching lattice lines spreading outward, sparing the periphery
• Lattice type 2 - short, fine, sparse lattice lines; associated with progressive bilateral cranial and peripheral neuropathies
• Lattice type 3 - thick ropy lines from limbus to limbus with minimal intervening haze
• Granular - small, white, crumb-like deposits in the central anterior stroma; not reaching limbus
• Avellino - fine ring /disc-like opacities [dense centrally] with deep linear opacities
• Macular - grey-white, dense, focal, poorly delineated spots with diffuse stromal clouding; eventually full thickness stroma is involved with stromal thinning
• Gelatinous - in familial sub-epithelial amyloidosis; grey sub-epithelial nodules giving a mulberry - like appearance; presents with photophobia, watering, decreased vision
  23
• Fuch's endothelial dystrophy–

  • Middle-aged women
  • Increased incidence of POAG
  • Central corneal guttata which spread to the periphery
  • Blurred vision especially in the morning which clears during the day
    Stage I - cornea has a beaten metal appearance
    Stage II - endothelial decompensation leads to stromal edema
    Stage III - epithelial edema leading to bullous Keratopathy
    Rx - Topical NaCl; bandage contact lens; PKP
• Posterior polymorphous dystrophy–

  • Endothelium displays features of epithelium
  • Vesicular/band-like/geographical endothelial patterns
  • Associated with peripheral anterior synechiae, glaucoma, ectropion uveae
• Congenital Hereditary Endothelial Dystrophy

  • Focal/generalized absence of endothelium
  • Diffuse bilateral comeal edema
  • Blue grey/ground glass appearance/total opacification
• D/D - birth trauma, buphthalmos, sclerocornea.

 

• Observation till asymptomatic or manageable vision
• PKP when vision deteriorates
  24

   

1. Optical -

   • irregular astigmatism e.g. Keratoconus
   • superficial corneal irregularities
   • anisometropia for binocular single vision
2. Promote epithelial healing -

   • persistent epithelial defects
   • recurrent corneal erosions
3. Pain relief -

   • bullous keratopathy
   • wet filamentary keratitis
   • trichiasis
   • Thygeson's SPK
4. Preservation of corneal integrity -

   • descemetocele
   • corneal wound apposition
5. Miscellaneous -

   • ptosis props to support the upper lid in patients with ocular myopathies
   • prevent symblepharon in eyes with cicatrizing conjunctivitis
   • drug delivery [hydrogel lenses soaked in topical medication]

 

1. Conjunctival -

   • Allergic conjunctivitis - perilimbal injection, fine papillary conjunctival reaction
   • Giant papillary conjunctivitis - increased mucus, Trantas dots, limbitis
   25
2. Corneal-

   • Epithelial edema - due to corneal hypoxia (excessive usage: e.g. Overnight wear)
   • Corneal vascularization at the superior limbus
   • Sterile corneal infiltrates - epithelial, sub-epithelial, stromal
   • Corneal warping - severe astigmatism
   • Microbial keratitis - Pseudomonas aeruginosa, Acanthamoeba
     26

 

1. AGE RELATED:

   1. Arcus senilis -

      • occurs hi elderly individuals
      • a ring of lipid deposition in the peripheral cornea [1 mm band]
      • separated from the limbus by a clear zone
      • also seen in Type II hyperlipoproteinemia [presents early]
      • usually bilateral; unilateral in ocular hypotony and carotid artery disease
   2. Vogt white limbal girdle -

      • narrow bilateral crescentic lines
      • chalk-like flecks in the interpalpebral fissure along the nasal and temporal limbus
   3. Cornea farinata -

      • bilateral minute flour-like deposits in the deep stroma
   4. Crocodile shagreen -

      • grayish white, polygonal stromal opacities separated by relatively clear spaces
      • in the anterior 1/3 or posterior 2/3
   5. Corneal guttata -

      • focal accumulation of collagen on the posterior surface of the descemet's membrane
      • warts or excrescences in the center of the cornea
      • called Hassal-Henle bodies if in the periphery
2. LIPID KERATOPATHY:

   • Primary - occurs spontaneously in an avascular cornea
   • Secondary - occurs following previous ocular disease/ injury which results in vascularization
     27
   • Yellowish stromal deposits of cholesterol, fats, Phospholipids occurs
   • If associated with corneal vascularization, it is progressive
     Rx-

     • control underlying disease [inflammation or vascularization]
     • argon laser photocoagulation to arterial feeder vessels
     • needle point cautery to feeder vessels
     • PKP if severe
3. BAND KERATOPATHY:

   • Deposition of calcium salts in the sub-epithelial space and anterior portion of the Bowman membrane
   Causes:
   1. Ocular

      • chronic anterior uveitis
      • interstitial keratitis, severe superficial keratitis
      • phthisis bulbi
      • silicon oil instillation in an aphakic eye
   2. Age related band keratopathy
   3. Metabolic

      • hypercalcemia caused by hyperparathyroidism, Vitamin D toxicity, milk-alkali syndrome, sarcoidosis
      • hyperphosphatemia with normal serum calcium [in some renal failure patients]
   4. Hereditary transmission ♦ primary hereditary band keratopathy
   Clinical Features
   • Peripheral interpalpebral calcification separated from the limbus by a clear zone
   • Gradual central spread ♦ band like chalky plaque
   • Nodular elevated lesions in advanced stages
   • Discomfort due to epithelial breakdown
     28
     Rx-

     • Chelation with a neutral solution of EDTA (sodium edetate) 150 mg/ml after large chips of calcium are removed with forceps and the epithelium is scraped off [mix a 20 ml vial with 100 ml of sterile ophthalmic irrigation solution and warm it]
     • Excimer laser keratectomy
   • SPHEROIDAL DEGENERATION

     • Also called corneal elastosis; Labrador keratopathy; climatic droplet keratopathy [due to increased exposure to UV light]
     • Amber-colored spheroidal granules in the superficial stroma, in the interpalpebral strip
     Rx-
     • corneal epithelial debridement
     • superficial keratectomy
   • SALZMANN NODULAR DEGENERATION

     • Secondary to chronic keratitis as in trachoma, phlyctenulosis
     • discrete, elevated, gray superficial lesions
     • stromal opacities form nodules which elevate the epithelium
     • located over scarred cornea or at the edge of a scar in a clear cornea
     Rx-
     • superficial keratectomy or debridement
       29

   

• Traumatic/inflammatory/toxic/nutritional insult ♦ causes blood vessels to gain access into a swollen and edematous tissue
• The normally present vasoinhibitory factors are abolished in pathological state

 

1. Superficial vascularization–

   • Originates from the superficial limbal plexus
   • From branches of anterior ciliary arteries
   • Confined to a segment or extend around the limbus
   • Preceded by edema, exudation or epithelial disturbance
   • When extensive - called pannus
2. Interstitial vascularization–

   • Straight non-anastomozing blood vessels from anterior ciliary arteries
   • Seem to disappear from view
   • Invade the cornea at the level of the pathological process
3. Deep vascularization–

   • Retrocorneal pannus
   • Proliferation of deep blood vessels by budding from anterior ciliary arteries

 

• Radiation ♦ given at the onset of superficial vascularization; obliterative end arteries develop due to trauma to the endothelium
• Peritomy is done 3-4 mm from limbus
• Argon laser photocoagulation
• Sodium chromoglycate 4% drops
• Superficial keratectomy or PKP
  30

 

• Inflammatory or degenerative in growth of fibrovascular tissue from the limbus
• Growth of tissue between epithelium and Bowman's layer
• An inflammatory pannus disrupts the Bowman's layer; a degenerative pannus leaves it intact

 

1. Infiltration - superficial corneal layers are infiltrated by polymorphonuclear leucocytes (PMNs) and lymphocytes
2. Progressive - new vessels emerge from the limbal plexus to form a grey vascular mass beneath the epithelium
3. Stationary - resolution of exudates followed by shrinkage of blood vessels
4. Sclerotic - cicatricial tissue or obliterated remnants of blood vessels

 

• Progressive - a leash of vessels in front of which there is a zone of infiltration and haziness
• Regressive - vessels extend beyond the area of infiltrated cornea

 

• Superior limbic keratoconjunctivitis; phlyctenulosis
• Vernal keratoconjunctivitis; atopic conjunctivitis
• Herpes simplex keratitis; trachoma
• Contact lens wear; toxic/chemical keratitis
  31

 

• Chronic painful peripheral corneal ulceration (serpigenous ulcer) progressing circumferentially and centrally
• Infection or collagen vascular disease is absent

 

• autoimmune reaction
• helminthiasis
• chronic hepatitis C
• corneal injury; surgery; burns
• HSV/HZV

 

• Pain, photophobia, lacrimation
• Decreased vision, blepharospasm
• Starts as a peripheral infiltration in the interpalpebral fissure area near the limbus
• Marginal furrow ulcer with overhanging edge and sloping peripheral border
• The infiltration breaks into a circumferential ulcer

 

	Type 1	Type 2
Prevalence	Common form	Atypical form
Pathogenic factors	Trauma	Trauma, helminthiasis
Age	> 40 years	20-30 years
Sex	Female > male	Male > female
Pain	Moderate - severe	Variable
Course	Slowly progressive	Rapid
Response to treatment	Moderate	Poor
Perforation	Rare	In 1/3 of cases
Laterality	75% unilateral	75% bilateral

 

• Total count/differential count; platelet count; ESR; Hemoglobin%
• Rheumatoid factor; ANA; pANCA; cANCA

 

• Topical steroids; oral steroids
• Topical cycloplegics
• Bandage contact lens
• Peritomy - resection of 4 mm perilimbal conjunctiva adjacent to the ulcer
• Lamellar corneal transplant and conjunctival flaps
• Systemic immunosuppressives
• Glue if corneal perforation
• PKP - if extreme peripheral corneal thinning
  33

     

• Endothelial damage during cataract surgery
• Pseudophakic bullous keratopathy due to AC IOL touching endothelium or raised IOP following surgery
• Aphakic bullous keratopathy due to vitreous in anterior chamber, which touches the endothelium
• Congenital Hereditary Endothelial Dystrophy (CHED)
• Fuch's endothelial dystrophy
• Posterior polymorphous dystrophy
• Chandler syndrome (ICE syndrome)
• Acute angle closure glaucoma
• Herpetic disciform keratitis
• Corneal transplant rejection

• Choose the type of cataract surgery depending on the type of cataract (phacoemulsification for a hard cataract will cause more endothelial damage)
• Use viscoelastics liberally during surgery - to protect endothelium from instrument touch
• Wash out all viscoelastic at the end of surgery to prevent post-operative rise of IOP
• Try to avoid the use of AC lOLs if there already is endothelial compromise
• Look for cornea guttata and Fuch's endothelial dystrophy in pre-operative evaluation ♦ in which case use BSS (balanced salt solution) or sodium hyaluronate
  34

 

• Hypertonic saline 5% eye drops or 6% eye ointment [draw out water from the cornea by osmosis]
• A thin, high water content bandage contact lens - for pain relief
• Control IOP if it is high
• Remove AC lOLs and iris-clipped if they are the cause for bullous keratopathy
• Anterior stromal puncture ♦ with a 25-g needle, multiple small superficial punctures are made in the cornea, at/below Bowman's layer; place bandage contact lens for 1-2 weeks to allow the epithelium to adhere to cornea
• Excimer laser phototherapeutic keratectomy
• Penetrating keratoplasty
  35

   

• Optical - for visual rehabilitation
• Tectonic - for re-enforcing altered corneal structure (descemetocele)
• Therapeutic - tissue substitution for refractory corneal disease (corneal ulcer)

 

• Keratoconus with apical scarring; rapid progression
• Aphakic/pseudophakic bullous keratopathy
• Corneal scarring
• Fuch's endothelial dystrophy
• Failed graft ♦ primary graft failure; graft rejection/infection
• Herpes simplex keratitis causing stromal necrosis
• Ocular trauma - normal posterior segment
• Congenital corneal opacities — Peter's anomaly, sclerocornea
• Stevens-Johnson syndrome
• Corneal dystrophies
• Chemical burns

 

ABSOLUTE	RELATIVE
– Death of unknown cause – AIDS, rabies – Hepatitis, septicemia – CMV encephalitis – Congenital rubella – Reye's syndrome – Leukemia – Hodgkin's disease – Intrinsic eye disease – Creutzfeldt-Jakob disease	– Multiple sclerosis – Parkinsonism – Syphilis – Chronic lymphocytic leukemia – Chronic immunosuppression

 

• Epithelium - edema, abrasions, foreign body
• Stroma - edema, DM folds
• Breaks in DM
• Endothelium - specular microscopy

 

1. Short term storage - Moist chamber technique

   • Whole globe preservation at 4°C with saline humidification for up to 48 hrs
   • Disadvantages: endothelium undergoes autolysis; difficult to screen for HIV and HBsAg; HLA typing can't be done in aqueous environment
2. Intermediate term storage media (2 wks)

   	MKM	CSEM	CSM	DM	OM	K-SOL
   TC199	+	+	-	-	+	+
   HEPES	+	-	+	+	+	+
   Dextran	+	-	-	+	+	-
   Chondroitin sulphate	-	+	+	+	+	+
   Gentamicin sulphate	-	-	+	+	+	+
   NEAA	-	-	+	+	+	-
   MEM	-	-	+	+	+	-
   Mercaptoethanol	-	-	+	+	-	-
   Sodium bicarbonate	-	-	-	-	+	-
   Sodium pyruvate	-	-	-	-	+	-

   • Storage up to 2 weeks
   • MKM = Mc-Carey Kaufman Medium
   • In modified MK medium, 0.025 M of HEPES is used instead of bicarbonate buffer
   • CSEM = chondroitin sulphate enriched medium
   • CSM = corneal storage medium
     37
   • DM = dexsol medium
   • OM = optisol medium
   • K-SOL = K sol medium
   • NEAA = non-essential amino acids
   • MEM = minimum essential medium
   • TC 99 = Technichium 99
3. Long Term Storage
   1. Organ Culture Method
   Eagle's MEM + Earle's Salts + L-Glutamine + Decomplemented Calf Serum is used

   • Stored at 34°C for 35 days, endothelial side up
   • If no growth after 10 days in any microbiological medium - cornea is fit for transplant
   2. Cryopreservation

   • Can preserve indefinitely
   • Corneo-scleral button passed through a series of solutions containing increasing concentration of DSMO (Dimethyl sulphoxide) up to 7.5%
   • Placed in each solution for 10 min.
   • Frozen up to −80°C; stored at −160°C
   • Disadvantages are - Intracellular microcrystal formation; number of endothelial cells decreases
   • Used for lamellar transplant

   

1. PRIMARY GRAFT FAILURE

   • Irreversible graft edema in immediate post-op period
   • No period of graft clarity
   • Due to endothelial damage
   38Causes:
   • Donor tissue with endothelial cell count < 1500/mm³
   • Improper preservation
   • Trauma during surgery, stretching of cornea; shallowing of AC; instrument touch
2. GLAUCOMA

   • Acute rise in IOP, with/without optic nerve damage or field loss
   Causes:
   • retention of visco-elastic
   • angle closure
   • distortion of Trabecular Meshwork
   • inflammation
   • steroid induced
3. EPITHELIAL DEFECTS

   • Increased chance of rejection, infection, ulceration, perforation
   Causes:
   • Storage
   • Injury during surgery
   • Post-operative lid movement
   • Trichiasis

 

1. GRAFT REJECTION

   • Epithelial rejection:

     • elevated rejection line which stains with fluorescein/Rose Bengal
     • represents zone of destruction of donor epithelial cells
     • occurs usually 3 months following surgery
   • Subepithelial infiltrates: KAYE's DOTS

     • Randomly distributed in Bowman's membrane
     • Usually occurs 10 months following surgery
       39
2. Stromal rejection:

   • sudden onset of peripheral full thickness haze with circum-corneal congestion
   • Associated with endothelial rejection
3. Endothelial rejection:

   • Khoudadoust line
   • diffuse KPs
   • linear arrangement of endothelial precipitates
   • edematous cornea
   Risk factors for rejection -
   • Vascularization
   • Previous graft failure
   • Large, eccentric, bilateral grafts
   • Younger patients
   Treatment of graft rejection -
   • Topical hourly steroids
   • Systemic steroids
   • In severe rejection, pulsed I.V. methyl prednisolone followed by oral prednisolone
4. GRAFT INFECTION:

   • bacterial, viral, fungal, acanthamoebic infection
   • due to steroid usage
   • Infectious crystalline keratopathy - caused by Streptococcus viridans
5. WOUND DEHISCENCE:

   • following high IOP, early suture removal or trauma

 

• recurrence of disease - especially herpetic keratitis and corneal dystrophies
• late graft failure ♦ decompensation due to decreased endothelial cells
• astigmatism if donor button is slightly larger
  40

 

• Partial thickness graft of cornea
• Anterior lamellar and deep lamellar keratoplasty

 

• Corneal opacity involving superficial 1/3 of stroma, not caused by recurrent disease
• Marginal corneal thinning e.g. pterygium, Terrien marginal degeneration, limbal dermoids
• Localized thinning or descemetocele
• Keratoconus

 

• All opaque corneal tissue is removed to the descemet's membrane level
• Endothelium is not transplanted – so less chances of rejection

 

• Disease involving anterior 95% of corneal thickness with endothelium being normal and no breaks/scars in descemet's membrane
• Chronic inflammatory disease like atopic keratoconjunctivitis

 

• Less astigmatism
• Structurally stronger globe
• No risk of endothelial rejection
• Increased availability of graft material

 

• Corneal perforation during dissection
  41

 

	CORNEA	LENS
MYOPIA	– PRK – LASIK – Radial keratotomy – Intrastromal plastic rings	– Clear lens extraction – Phakic IOL: iris clipped lenses and implantable contact lenses
HYPEROPIA	– PRK – LASIK – Laser thermo-keratoplasty	– Clear lens extraction – Phakic IOL
ASTIGMATISM	– Arcuate keratotomy	– Toric IOL implantation
PRESBYOPIA	– Conductive keratoplasty	– Multifocal IOL