CONGENITAL ANOMALIES OF UVEA

P.NAGEENAROLL .NO. 73

There are various types of congenital anomalies of uveal tract:

Heterochromia of iris Corectopia Polycoria Congenital aniridia Persistent pupillary membrane Congenital coloboma of uveal tract Albinism

HETEROCHROMIA It refers to variations in the iris colour.

It is usually of two types:1) HETEROCHROMIA IRIDIUM- Colour of one iris differs from other.2) HETEROCHROMIA IRIDIS- One sector of iris differs from others. These conditions are due to absence of pigment in

iris

DIFFERENTIAL DIAGNOSIS: SIDEROSIS MALIGNANT MELANOMA OF IRIS HETEROCHROMATIC CYCLITIS

CORECTOPIA It refers to abnormally eccentric placed

pupil. More usually shifted to the nasal side.

CONGENITAL ANIRIDIA(IRIDEMIA) Congenital absence of iris. TRUE ANIRIDIA- Complete absence of iris.( extremely

rare) CLINICAL ANIRIDIA- Presence of peripheral rim of iris .

Zonules of lens and ciliary processes are often present.

COMPLICATIONS: Secondary glaucoma, cataract & dry eye.

PERSISTENT PUPILLARY MEMBRANE It is due to remnants of anterior

vascular sheats of lens. Characterised by stellate shaped shreds of the

pigmented tissue coming from the anterior surface. These may be either freely floating or attached to ant. chamber .

Sometimes there may be a supporting stroma consisting of pigment cells. Central brown dots may be retained on the pupil.

CONGENITAL COLOBOMA Absence of tissue of iris, ciliary body & choroid.PATHOGENESIS: Defective closure of embryonic cleft. This leads

to maldevelopment of uveal & retinal tissues.

TYPES OF COLOBOMAS:1) Typical coloboma- It is situated in the inferonasal quadrant &

occurs due to defective closure of cleft. 2) Atypical coloboma- Found in other positions.

FEATURES OF COLOBOMA:• Oval or comet shaped defect with rounded

apex towards disk.• Few vessels are seen over the

surface( both retinal & choroidal) .• Surface may be irregularly

depressed( ectatic coloboma).• Central vision is very poor & there may be

a scotoma corresponding to the coloboma.• High risk of retinal detachment & laser

delimitation.

ALBINISM Hereditary condition in which there is

defective development of pigment throughout the body.

It is of 3 types:1) OCULAR- Further subdivided on the basis of

tyrosinase test.2) OCULOCUTANEOUS3) CUTANEOUS Partial albinism in which there is

absence of pigment in the choroid & retina.

FEATURES:Iris looks pink & dazzling glare. Nystagmus, photophobia & defective vision. Occasionally strabismus. Greater clarity of retinal & choroidal vessels

on ophthalmoscopy. Vessels are seperated by glistening white

spaces. TREATMENT: Use of tinted glasses as protection from

glare.

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