Cysticercosis is the most common ocular tapeworm infection. Human infection is caused by Cysticercus cellulosae, the larval stage of the cestode Taenia solium, which is endemic to Mexico, Africa, Southeast Asia, eastern Europe, Central and South America, and India. Humans acquire the disease via fecal-oral transmission or consuming undercooked infected pork. The eggs mature into larvae, penetrate the intestinal mucosa, and spread hematogenously to the eye via the posterior ciliary arteries into the subretinal space.
Ocular cysticercosis usually affects individuals between the ages of 10 and 30 years, without sex predilection. Cysticercosis may involve any structure of the eye, orbit, or adnexa, but involves the subretinal space most often (Fig 11-37). Larvae may perforate the retina, gaining access to the vitreous cavity (Fig 11-38). Other presentations include a subconjunctival or eyelid nodule.
Figure 11-37 Subretinal Fundus photograph of cysticercosis.
(Courtesy of Preema Abraham, MD, and the Retina Image Bank, American Society of Retina Specialists.)
Figure 11-38 Multiple intravitreal cysts associated with cysticercosis.
(Courtesy of Vishal Agrawal, MD, FRCS, and the Retina Image Bank, American Society of Retina Specialists.)
Figure 11-39 Histopathology image of cysticercosis, showing the protoscolex, or head, of the larva (arrow).
Patients may be asymptomatic with relatively good vision or may complain of floaters, moving sensations, ocular pain, photophobia, redness, and very poor visual acuity. Larvae may be observed in the vitreous or subretinal space in up to 46% of infected patients. A globular translucent cyst is seen, with an invaginated or evaginated head, or scolex, that undulates in response to the examining light (Figs 11-38, 11-39). Exudative, rhegmatogenous, or tractional retinal detachment may be observed. Computed tomography may reveal intracerebral calcification or hydrocephalus in patients with neural cysticercosis.
The differential diagnosis includes conditions associated with leukocoria (retinoblastoma, Coats disease, retinopathy of prematurity, persistent fetal vasculature, toxocariasis, and retinal detachment) and DUSN.
Larvae death provokes panuveitis. Laser photocoagulation alone may also provoke severe inflammation. Hence, early removal of intraocular larvae, often with vitreoretinal surgical techniques, is advocated. Antihelminthics plus systemic corticosteroids may be utilized for extraocular disease.
Sharma T, Sinha S, Shah N, et al. Intraocular cysticercosis: clinical characteristics and visual outcome after vitreoretinal surgery. Ophthalmology. 2003;110(5):996–1004.
Wender JD, Rathinam SR, Shaw RE, Cunningham ET Jr. Intraocular cysticercosis: case series and comprehensive review of the literature. Ocul Immunol Inflamm. 2011;19(4):240–245.
Excerpted from BCSC 2020-2021 series: Section 9 - Uveitis and Ocular Inflammation. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.