Figure 24-2 Intermediate uveitis with inferior snowbank formation, right eye.

Posterior Uveitis

Toxoplasmosis

Toxoplasmosis is the most common cause of posterior uveitis in children. It is discussed in Chapter 28.

Toxocariasis

Ocular toxocariasis is caused by the nematode larvae of a common intestinal parasite of dogs (Toxocara canis) or cats (Toxocara cati). This disease primarily affects children, as it is contracted through the ingestion of ascarid ova in soil contaminated by dog or cat feces. Visceral larva migrans (VLM) is an acute systemic infection produced by these organisms; it commonly occurs at approximately age 2 years. If symptomatic, it is associated with fever, cough, rashes, malaise, and anorexia. Laboratory testing reveals eosinophilia. VLM and ocular toxocariasis, for unknown reasons, seldom occur in the same patient.

Ocular toxocariasis is usually unilateral and is not associated with systemic illness or an elevated eosinophil count. The average age of onset is 11.5 years. The 3 major retinal forms of the disease include posterior pole granuloma, peripheral granuloma with macular traction (Fig 24-3), and