Background: The nematode infection of the retina is a rare disease with sight threatening prognosis. Untreated eyes usually become blind. There are different types of clinical progression: granuloma causing tractional detachment chronic inflammation called diffuse unilateral subacute neuroretinitis (DUSN) and rapid loss of vision named "ocular wipe-out syndrome". Efficient drugs are not available. The progression of the disease can be stopped by killing the nematode by means of photocoagulation. For parasites in the periphery of the fundus this is the therapy of choice. Photocoagulation of the nematode close to the posterior pole can cause severe damage to the visual functions. There is a need for a less detrimental treatment.
Patient and methods: We report on a 48-year-old woman with an intraretinal nematode inside the papillomacular bundle. At an early stage of the disease with normal visual acuity the eye was vitrectomized and a posterior vitreous detachment performed. It was intended to extract the worm out of the retina in toto. The retina over the parasite was incised parallel to the nerve fibers, a tiny hook inserted and the worm pulled out.
Results: Only one half of the parasite could be removed since the adhesion of the parasite to the retina was stronger than its own cohesion. Nevertheless the inflammation rapidly regressed. Finally a small area of pigment mottling persisted around the former location of the parasite corresponding to a relative scotoma in the visual field. Visual acuity remained unchanged at full vision.
Conclusion: We demonstrated that nematode larvae can be removed successfully from the central retina using vitrectomy techniques. By that means the damage to the visual functions can be limited. Near the posterior pole surgical extraction of the worm may be favorable compared to photocoagulation.