TOXOCARIASIS

It is an infestation caused by an intestinal round worm
of dogs (Toxocara canis) and cats (Toxocara catis).
The young children who play with dogs and cats or
eat dirt are infested by ova of these worms. These
ova develop into larva in the human gut, and then
produce the condition visceral larva migrans (VLM).
Ocular toxocariasis. It is ocular infestation by these
larva and is almost always unilateral. Clinically it can
present as follows:
1. Toxocara chronic endophthalmitis. It usually
presents with leucocoria due to marked vitreous
clouding. The condition is seen in children
between the age of 2-10 years and mimics
retinoblastoma.
2. Posterior pole granuloma. It presents as a
yellow-white, round, solitary, raised nodule, about
1-2 disc diameter in size, located either at the
macula or in the centrocaecal area. The condition
is usually seen in children between 5 and 15
years of age, presenting with unilateral loss of
vision.
3. Peripheral granuloma. It is situated anterior to
the equator and may be associated with vitreous
band formation. It may present from 6 to 40 years
of age.
Diagnosis is made on the basis of clinical picture and
ELISA blood test.
Treatment. It consists of periocular (posterior sub-
Tenon) injection of steroid and systemic steroids. Pars
plana vitrectomy may be required in unresponsive
patients with endophthalmitis and in patients with
vitreous band formation.