CORNEA Dr. S. DILEEP KUMAR

ANATOMY Diameter – 11.7 microns to 11 microns Thickness 0.5mm in centre 0.7 periphery Radius of curvature ant- 7.8mm post - 6.5mm R.I Dioptric power – 45D

HISTOLOGY Has got 5 layers 1.Epithelium- stratified sq epi has 5-6 layers if damaged replaced within 7days 2.Bowman’s membrane- condensed collagen fibres resist entry of organisms can not regenerate

STROMA – Collagen fibres in hydrated matrix of proteoglycans DESEMENT’S MEMBRANE – can regenerate ENDOTHELIUM – 3000 cells/ mm2 Na channel – active pump

NERVE SUPPLY – Ant ciliary N of ophthalmic division of 5 th C.N PHYSIOLOGY – Regular arrangment of corneal lammellae – LATTICE THEORY OF MAURICE. Dehyration state maintaned by epi & endo by active Na channel pump

CORNEAL ULCER DEF: Discontinuation of normal epi associated with surrounding corneal infiltration / edema ETIO: Corneal abrasion Epi drying – xerosis Necrosis of epi Desquamation of epi – edema Epi damage due to trophic changes

SOURCE OF INFECTION: endogenous, exogenous, local STAGES: 1.Stage of progressive infiltration 2.Stage of active ulceration 3.Stage of regression 4.Stage of cicatrization- nebular,macular, leucoma

CLINICAL FEATURES : Symptoms – pain, watering, redness, photophobia, blurred vision. Signs – lid swollen, conj congestion, chemosis, yellowish-white area of ulcer, AC – hypopyon sterile or non sterile

COMPLICATIONS : Cornea – scarring, fistula, desmatocele, perforation. AC - secondary glaucoma Iris – toxic iritis, prolapse of iris Lens – subluxation / dilocatrion, ant subcapsular cataract Uvea – purulent uveitis, endophtalmitis, panophtalmitis Intraocular hemorrahge

MANAGEMENT : Evaluation clinically – history slit lamp examination Lab investigations - routine Microbilogical evaluation gram, gemsa, KoH culture –blood agar sabouraud’s

Treatment : Topical antibiotic : Gentamycin – 14mg /ml Cephazoline – 50 mg / ml Subconj injection – GM -40 mg cepha 125mg Systemic Non specific Rx- Cycloplegic – relieve pain, prevent post synneche, increases antibiotic circulation,decreases exudation decreases hyperemia. Analgesics & vitamins

Non healing ulcer : Cause : wrong diagnosis Local – chr dacrocystistis, increased iop, trichiasis, retained FB General – DM, AIDS Rx Remove the cause Mechanical debriment Chemical cautery Peritomy

Rx for impending perforation -Rest -Pressure bandage -Decrease iop -Tissue adhesive -Conj flap -Bandage soft contact lens -Penetrating K.P

CORNEAL ULCER Etiological classification: 1.Infective :bacterial/fungal/viral 2.Non infective : Allergic/Trophic/Traumatic/Idiopathic *hypopyon corneal ulcer- pnuemococcus

HYPOPYON CORNEAL ULCER 1.Etiology: psuedomonas pyocyanea & pneumococcus 2.Clinical features: 3.Investigations : routine, microbilogical 4.Treatment : 1.Rx of uncomplicated ulcer 2. Rx of non healing ulcer 3. Rx of impending perforation 4. Rx of perforated ulcer 5. Complications:

FUNGAL CORNEAL ULCER Etio – aspergilluis fusarium, c. albicans Clinical features- Symptoms – pain watering & photophobia are less. Fungal hypahae can be seen. Signs – feathery borders surounded by yellow line which gradually deepens. Immune ring can be seen (wesseley) inflitrats can be seen

CORNEAL OPACITY Definition: Etiology : congenital, healed corneal wounds, healed corneal ulcers Clinical features: Types : Nebular, macular, leucomatous, adherent leucoma,irido-corneal scar, Ant. Staphyloma. Treatment : site/size conservative-tatooing/optical iridectomy surgical- keratoplasty

KERATOCONUS Def : Etiopathogenis : Clinical features : munson’s sign/S/L-ectasia, stromal thinning, fleisher’s ring,volk lines/placido disc/keratometry/retinoscopy(scirrors reflex)/D.D ophthalmoscopy(oil droplet) Morphological classification : Nipple, oval & globus Associations : Complications : Acute hydrops Treatment : contact lenses/penetrating keratoplasty/intacs

KERATOPLASTY Also called corneal grafting or corneal transplantation Types : penetrating(full thickness)/lamellar(partial thickness) Indications : optical/therapuetic/tectonic/cosmetic Donor tissue- removed within 6hr after death Methods of corneal preservations: short term/intermediate/long term storage

Surgical technique : exision of donor corneal button/ excision of recipient corneal button/ suturing of corneal graft into tht host. Complications : early- flat A.C/iris prolapse/infection/epithelial defects & pri. Graft rejection. Late- graft rejection/recurrence of disease/astigmatism

PANNUS Definition: infiltration of the cornea asso. With vascularization in upper part. Types – progressive/ regressive(pannus siccus)