Spatial and Temporal Integration Abnormalities in X-Linked Retinoschisis.

Abstract

PurposeTo evaluate spatial and temporal integration across the visual field in individuals with juvenile X-linked retinoschisis (XLRS).MethodsNine subjects with XLRS and 10 visually normal individuals participated. Luminance thresholds were measured at 15 locations along the horizontal visual field meridian. Locations were grouped into four regions for analysis: foveal, parafoveal (2°), perifoveal (5°–10°), and peripheral (10°–60°). For spatial integration measurements, stimulus duration was 100 ms, and size ranged from 0.01 to 2.32 deg2 (Goldmann I–V). For temporal integration measurements, stimulus size was 0.15 deg2 (Goldmann III), and duration ranged from 12 to 800 ms. The effect of stimulus size and duration on the subjects' threshold was described using integration models.ResultsLuminance thresholds for the XLRS group were more elevated for small targets (2.0×–12.6×) than for large targets (1.25×–3.2×) compared to controls for all locations. Likewise, thresholds for the XLRS group were more elevated for short durations (6.3×) than for long durations (4.0×) in the fovea and parafovea but were similarly elevated at all durations (2.0×–2.5×) in the perifovea and periphery. For both the size and duration experiments, thresholds measured in the fovea, parafovea, and perifovea of XLRS subjects were highly similar to those measured from the peripheral field of the controls.ConclusionsSpatial and temporal integration characteristics of the XLRS fovea, parafovea, and perifovea are similar to those of the normal periphery. The results also indicate that scaling stimulus size equates thresholds for the XLRS and control subjects throughout the visual field, but scaling duration does not.