INTER-OCULAR TEMPORAL ASYNCHRONY (IOTA) - PSYCHOPHYSICAL MEASUREMENT OF INTER-OCULAR ASYMMETRY OF VISUAL LATENCY

Ocular pathology can be associated with inter-ocular asymmetry of cond uction latency. We describe a relatively low-cost psychophysical metho d of quantifying this asymmetry of delay, an 'inter-ocular temporal as ynchrony' (IOTA) system. Testing of 28 visually normal young adults ga ve IOTA results with a mean of 0.11 ms (SD +/- 2.4 ms). These results correspond to 95% confidence limits of - 4.6 ms and + 4.8 ms. Inter-oc ular differences in retinal illumination, induced by using monocular n eutral density filters in visually normal subjects, significantly affe cted IOTA in accord with an imposed perceptual delay in the 'filtered eye'. This demonstration that the IOTA technique is capable of detecti ng induced asymmetry of perceptual delay in visually normal subjects, along with the small measured confidence limits reported above, sugges ts that the apparatus should be capable of detecting inter-ocular asym metries in response latencies with ocular disease, which have been pre viously measured by other techniques. (C) 1997 The College of Optometr ists.