CORNEA . . . CONT.

HERPES ZOSTER KERATITIS

CN V1 territory

Symptoms and Signs (see Colour Atlas OP18)

neuralgia-type pain (vesicular skin eruption ~ 2 weeks)

ocular tearing, pain and photophobia

corneal hypoesthesia

Hutchinson's sign: if tip of nose involved (nasociliary branch of V1), eye involvement likely (75% chance)

Complications

corneal keratitis, ulceration, perforation and scarring

uveititis

glaucoma secondary to trabeculitis

muscle palsies (rare) due to CNS involvement

occasionally severe post-herpetic neuralgia

Management

oral acyclovir, valcyclovir or famcyclovir +/– cycloplegic agent

topical steroids as indicated for keratitis, iritis (prescribed by an Ophthalmologist)

KERATOCONUS

bilateral central thinning and bulging (ectasia) of the cornea to form a conical shape

associated with Descemet's and Bowman's membrane folds

onset between 1st and 3rd decade

results in irregular astigmatism, corrects poorly with glasses

apical scarring

blurring of visual acuity is the only symptom

Management

contact lens initially if spectacle correction unsatisfactory

penetrating keratoplasty (corneal transplant) 90% successful

post-operative complications: endophthalmitis, graft rejection, graft dehiscence

ARCUS SENILIS

hazy white ring in peripheral cornea, < 2 mm wide, clearly separated from limbus

common, bilateral, benign corneal degeneration due to lipid deposition, part of the aging process

may be associated with hypercholesterolemia if age < 50 years

no associated visual symptoms, no complications

no treatment necessary

KAYSER-FLEISCHER RINGS

rare

pigmented ring 1-3 mm wide, located in the peripheral cornea

due to copper pigment deposition in Descemet's membrane

associated with Wilson's disease (hepatolenticular degeneration)

Management

penicillamine to chelate copper

THE UVEAL TRACT

uveal tract = iris, ciliary body, and choroid

vascularized, pigmented middle layer of the eye

UVEITIS

may involve one or all three parts of the tract

idiopathic or associated with autoimmune, infectious, granulomatous, malignant causes

should be managed by an Ophthalmologist

IRITIS

inflammation of iris

usually unilateral

Etiology

usually idiopathic

connective tissue diseases: juvenile rheumatoid arthritis (JRA), ankylosing spondylitis (AS), Reiter's syndrome, inflammatory bowel disease (IBD)

infectious: syphilis, Lyme disease, toxoplasmosis, TB, HSV, herpes zoster

other: sarcoidosis, trauma