Identifying live nematodes in diffuse unilateral subacute neuroretinitis by using the scanning laser ophthalmoscope

To describe use of the scanning laser ophthalmoscope (SLO) to identify live nematodes in patients with diffuse unilateral subacute neuroretinitis.

Infrared, red, and blue illumination (780, 633, and 488 nm, respectively) in an SLO were used to image and evaluate functional retinal status in patients with late-stage diffuse unilateral subacute neuroretinitis. An examination to identify live nematodes was performed in the affected eyes.

Using blue illumination, the ocular fundus appeared dark and provided a high-contrast background for the white image of the worm. The red laser was used to perform red-on-red perimetry. We also used perimetry stimulus to stimulate the worm's movement and pinpoint its location. We precisely defined the relation between the fixation point and the worm to plan accurate laser treatment. The infrared laser is safe and comfortable for prolonged examination. Using the SLO, several physicians simultaneously visualized the ocular fundus. Video output from the SLO provided temporal information, excellent for enhancing detection of worms, which was displayed dynamically on video.

Although examination with a fundus contact lens by skilled ophthalmologists is the method of choice, the SLO provides a new examination modality with distinct advantages for identifying live worms in young patients with diffuse unilateral subacute neuroretinitis.