Diseases of the Cornea. Keratitis Infectious – Bacterial (Streptococcus pneumoniae) – Bacterial...

Diseases of the Cornea

Keratitis

• Infectious– 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


• 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


• 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


• 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


• 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


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


• 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


• Ocular pain, headache• Unilateral blurring of vision • Iridescent vision (halos)• Nausea and vomiting• Redness


• 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


• 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


• 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


• Visual acuity not significantly impaired• Reading difficulty• Ciliary flush • Mildly edematous cornea• Sterile hypopyon if severe


• 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)


• 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

Diseases of the Cornea. Keratitis Infectious – Bacterial (Streptococcus pneumoniae) – Bacterial...

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Transcript of Diseases of the Cornea. Keratitis Infectious – Bacterial (Streptococcus pneumoniae) – Bacterial...