UVEAL TRACT DISORDERS

Uveal tract, the inner vascular coat of eye, includes three structures—iris, ciliary body and choroids. Uveitis, i.e. inflammatory disorders of uveal tract may be infective or non-infective in origin (Table 26.7) and include anterior

Anterior uveitis (iridocyclitis)

• Infections: Viruses, e.g.

• Trauma: Foreign body, blunt/penetrating injury

• Autoimmune: Rheumatoid arthritis, Kawasaki disease

• Others: Drugs, Stevens-Johnson syndrome

• Idiopathic

Posterior uveitis (choroidoretinitis)

• Intrauterine (TORCH) infections

• Postnatal infections, e.g.

- Viral : HSV, HIV, CMV, Rubella

- Granulomatous : TB, Brucellosis, sarcoidosis

- Parasitic : Toxoplasmosis

• Idiopathic

Panophthalmitis

• Septicemia

• Penetrating eye injuries

Sympathetic ophthalmitis

• Reactive (injury to other eye)

uveitis (Iridocyclitis), posterior uveitis (Chorioretinitis), panopthalmitis and sympathetic ophthalmitis.

Acute iridocyclitis is usually infective in origin (Table 26.7) and presents with intense eye pain, lacri­mation, photophobia. Important ocular signs include circumciliary congestion, aqueous flare (proteins/cells in anterior chamber), keratic precipitates (kp) on posterior surface of cornea, muddy iris and small, irregular, sluggishly reactive pupil.

Prompt diagnosis and therapy with systemic anti­biotics, intra-ocular antibiotics (in some cases) and topical cycloplegic agents are necessary to prevent complications like: (a) synechiae formation with glaucoma, (b) corneal degeneration, e.g. band keratopathy, (c) lenticular opacities, and (d) impairment of vision.

Chronic iridocyclitis is usually seen in autoimmune rheumatoid disorders, e.g. JRA, SLE, etc. and may be entirely asymptomatic till visual loss. Systemic steroids or immunosuppressive therapy is necessary to prevent and treat these cases.

Chorioretinitis is often chronic and asymptomatic, till diagnosed on routine ophthalmic examination or development of secondary complications. Intrauterine infections are most common cause of chorioretinitis in children, though ocular finding may not be present at birth and appear at a later age.

Chorioretinitis in CMV is typically diffuse except at macula, while macular involvement is characteristic of congenital toxoplasmosis. Complications of posterior uveitis include retinal detachment, glaucoma and phthisis

Panophthalmitis is an acute suppurative condition involvi ng nearly all ocular tissues, usually after perforating eye injury or septicemia. It is an ocular emergency, presenting with intense pain, inflammation and visual loss. Intensive antibiotic therapy with enucleation or evisceration of orbit is necessary to

prevent sympathetic ophthalmitis and loss of vision in other eye.

Sympathetic ophthalmitis affects the normal eye after many weeks/ years of the injury to one eye and considered as a hypersensitivity phenomenon. Loss of vision in uninjured eye develops rapidly, which may be prevented by enucleation of injured eye before the development of sympathetic ophthalmitis.

Developmental disorders of uveal tract mainly involve the iris and include:

Aniridia, i.e. congenital absence/hypoplasia of iris, is almost always bilateral. Although most of these cases are familial, sporadic aniridia is of main interest due to frequent association with Wilms tumor, urogenital abnormalities and mental retardation. Other ocular defects, e.g. glaucoma, cataracts and macular or optic nerve hypoplasia are common in these cases.

Coloboma of iris is a development defect, usually located inferiorly (key-hole iris). Although it is unlikely to affect vision, these cases should be investigated for other ocular abnormalities.

Heterochromia iridum (different colors of two iris) or H. iridis (different colors in same iris) may be an isolated familial condition or associated with Waardenburg syndrome, i.e. partial albinism with white forelock, deafness and heterochormia. Pink iris is seen in albinism and blue in partial albinism.

Other iris abnormalities include Lisch nodules, i.e. discrete nodules over iris in neurofibromatosis and Brush-field spots, i.e. sand-grain like deposits in Down syndrome.

26.2.8