congenital anomalies of uvea
TRANSCRIPT
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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