Diseases of the Cornea

Keratitis Infectious Physical Bacterial (Streptococcus pneumoniae) Bacterial (Pseudomonas aeruginosa) Fungal Herpes simplex Physical Abrasion

Bacterial (Streptococcus pneumoniae) Streptococcus pneumoniae: lancet-shaped, encapsulated, gram + diplococci Serpingous, gray-white stromal infiltrate and hypopyon (pus) Distinct borders with overhanging edges; usually with overhanging defect or ulcer Suppuration not usually extend over the entire corneal surface Sterile hypopyon is common

Bacterial (Streptococcus pneumoniae)

Bacterial (Streptococcus pneumoniae) History of the patient: trauma or URTI for 5-7 days Pneumococcal ulcer manifests 24-48 hrs after inoculation of the abraded cornea Spread erratically from original site towards the center Advancing border shows active ulceration as the trailing border begins to heal  acute serpingous ulcer Superficial corneal layers involved first then the deep parenchyma

Bacterial (Streptococcus pneumoniae) Topical erythromycin Chloramphenicol 4th gen fluroquinolones (Moxifloxacin and Gatifloxacin) Oral cephalosporins and erythromycin Concurrent dacrocystitis and nasolacrimal duct obstruction should be treated

Bacterial (Pseudomonas aeruginosa) Gram (-) corneal ulcer Rapid evolution; marked tendency to spread Common among immunocompromised, soft contact lens with faulty hygiene, contaminated fluorescein solution or eye drops

Bacterial (Pseudomonas aeruginosa)

Bacterial (Pseudomonas aeruginosa) Begins as a gray or yellow mucopurulent discharge adherent to ulcer surface  bluish green Ulcer is diffused with uniform penetration  severe pain More discharge Opacification and edema around the ulcer Rapid stromal necrosis due to proteolytic enzymes Corneal perforation and severe intraocular infection

Bacterial (Pseudomonas aeruginosa) Moxifloxacin, Gatifloxacin, Ciprofloxacin, Tobramycin, Gentamycin Other fluoroquinolones, polymyxin B or carbenicillin

Fungal Keratitis Indolent or slow-type (usually months) Filamentous Gray white Feathery border Satellite infiltrates Deep: endothelial plaque Yeast Focal Dense suppuration similar to Pneumococcus

Fungal Keratitis Intense suppuration, progressive hypopyon Anterior chamber membranes Gray infiltrate with irregular edges Marked inflammation of the globe with superficial ulceration Endothelial plaque with corneal abscess

Fungal Keratitis

Fungal Keratitis Candida, Fusarium, Aspergillus, Penicillium, Cephalosporium Except Candida: Hyphal elements Candida: pseudohyphae or budding

Fungal Keratitis No effective topical agent Combination of anti-fungal tablets (Amikacin, Cefaxolin, Gentamicin, Neomycin, etc) Oral tablets (Amphotericin B with saline) dropped every 5 mins Debridement to remove dead tissue and to increase drug absoprtion Candida: Natamycin, Ketoconazole, Voriconazole, Amphotericin B

Herpes simplex Keratitis Discrete punctate epithelial keratitis  coalesce into branching or dendritic lesion (swollen, opaque epithelial cells) Terminal bulbs Ulcer in the center of dendrite due to lysis and desanquamation of infected cells Centrifugal spread (center to peripheral)  geographic ulcer

Herpes simplex Keratitis

Herpes simplex Keratitis Usually among young children Mild stromal edema and subepitelial infiltrates Irritation, photophobia, tearing If central cornea affected  reduction in vision Can have fever, blisters

Herpes simplex Keratitis Debridement Idoxuridine, Trifluridine, Vidarabine, Acyclovir Penetrating keratoplasty: only for inactive infections Control reactivation of HSV infection Aspirin for fever Avoid exposure to ultraviolet light Prophylactic antivirals

Corneal Abrasion Scraping of the superficial part that may heal in a matter of hours Acute pain after trauma Photophobia, tearing, blepharospasm (eyelid spasm), foreign body sensation, blurred vision Adjacent cells expand and fill the defect  basal epithelial cells undergoes mitosis Patching/bandage, topical antibiotics, cycloplegic

Corneal Abrasion

Glaucoma

Glaucoma (Acute angle closure) True emergency!! Route of aqueous humor: cilliary body  drains anteriorly from iris  pupil  canal of Schlemm Occlusion at the anterior chamber angle by the peripheral iris  increase IOP Pupillary block: from posterior to anterior chamber  peripheral iris balloon forward Plateau iris: peripheral iris lax  contact with the angle

Glaucoma (Acute angle closure) Ocular pain, headache Unilateral blurring of vision Iridescent vision (halos) Nausea and vomiting Redness

Glaucoma (Acute angle closure) Elevated IOP (60-80 mmHg)  on tonometry “rock hard” Deep circumlimbal conjunctiva and episcleral injection  ciliary flush Fixed, mid-dilated pupil Edematous or steamy cornea Shallow anterior chamber Thinning out or excavation of optic disc “glaucomatous cupping”  chronic cases

Glaucoma (Acute angle closure)

Glaucoma (Acute angle closure) Increased IOP  acute ischemic changes in iris  corneal edema  optic nerve damage Primary open-angle glaucoma IOP doesn’t increase >30 mmHg Retinal damage develops over a period of time Normal-tension glaucoma Retinal ganglion cells susceptible to changes in IOP Optic nerve ischemia

Glaucoma (Acute angle closure) Carbonic anhydrase inhibitors Hyperosmotic agents Oral glycerin IV mannitol Pilocarpine Supportive: corticostroids, analgesics

Uveitis

Uveitis (Iridocyclitis) Anterior chamber Inflammation of the iris, ciliary body, choroid Deep, dull pain Photophobia may be severe Ciliary body controls the opening and closing of the iris muscles Tearing

Uveitis (Iridocyclitis) Visual acuity not significantly impaired Reading difficulty Ciliary flush Mildly edematous cornea Sterile hypopyon if severe

Uveitis (Iridocyclitis) Hallmark: cells and flare Cells Leukocytes floating in aqueous Flare Protein from inflamed iris or ciliary body Keratic precipitates (clumps of white cells and inflamatory debris) in active inflammation Koeppe nodules (granulomatous nodules in iris) Busacca nodules (within iris stroma) Berlin’s nodules (anterior chamber angle)

Uveitis (Iridocyclitis)

Uveitis (Iridocyclitis) Underlying systemic disease TB, Ankylosing spondylitis, Behcet’s syndrome, JRA, syphilis Treatment Immobilize iris and ciliary body to decrease pain Cycloplegia (atropine, cyclopentolate) Topical steroids Treat underlying systemic disease