Clinical reading-related oculomotor assessment in visual snow syndrome

Visual snow syndrome (VSS) is a complex neurological condition presenting with an array of sensory, motor, and perceptual dysfunctions and related visual and non-visual symptoms. Recent laboratory studies have found subtle, basic, saccadic-based abnormalities in this population. The objective of the present investigation was to determine if saccadic-related problems could be confirmed and extended using three common clinical reading-related eye movement tests having well-developed protocols and normative databases.

This was a retrospective analysis of 32 patients (ages 16-56 years) diagnosed with VSS in the first author's optometric practice. There was a battery of three reading-related tests: the Visagraph Reading Eye Movement Test, the Developmental Eye Movement (DEM) Test, and the RightEye Dynamic Vision Assessment Test, all performed using their standard documented protocols and large normative databases.

A high frequency of oculomotor deficits was found with all three tests. The greatest percentage was revealed with the Visagraph (56%) and the least with the RightEye (23%). A total of 77% of patients failed at least one of the three tests.

The present findings confirm and extend earlier investigations revealing a high frequency of saccadic-based oculomotor problems in the VSS population, now including reading-related tasks. This is consistent with the more general oculomotor/motor problems found in these individuals.