Steady and Transient Glare Effects as a Function of Retinal Eccentricity for a Patient With Retinitis Pigmentosa

BEATRIZ MATEZANZ; ISABEL ARRANZ; CRISTINA DE LA ROSA; SANTIAGO MAR; LUIS ISSOLIO; JOSÉ MENÉNDEZ; JUAN ANTONIO APARICIO

Fort Lauderdale

Congreso; ARVO; 2010

ARVO

Purpose: This work provides information on the functionality of cones and rods in the first 15º temporal retinal eccentricity in terms of their adaptation ability to a mesopic level of illumination, for a subject with simple retinitis pigmentosa (RP).Method: A two-maxwellian view system has been designed which allows to measure detection thresholds at several retinal eccentricities, in dark adaptation (DA), steady light adaptation (LA) and transient light adaptation SOA300 (detection field is shown 300 ms after beginning of transient adaptation field). A circular adapting beam 1.05º and a detection beam (24’ wide and 40 ms of duration) enter subject’s eye. Neutral density filters in steps of 0.1 log units allow controlling the luminance of both beams. Shutter systems allow controlling beams duration and delaying between them. One subject with RP participated in this study, with central visual fields of 12º and corrected visual acuity of 20/30 in her right eye. Two ocularly healthy individuals comprised the control group.Results: In DA, luminance thresholds for the patient with RP were at least 100 times greater than those found in normal subjects and increase from fovea to periphery opposite to the behaviour found in the control group. This may be probably due to the fact that damage on rods is already extended all along the retina. However, for SOA300 and LA adaptation, thresholds for all the 12º of useful temporal field of view in the patient with RP are similar to those obtained for the control subjects. In fact the speed of adaptation, measured as closeness between thresholds measured in LA and SOA300 conditions, are functionally similar to those obtained for normal subjects at the different eccentricities considered.Conclusions: A device has been built which provides psychophysical information about functional behaviour of rods and cones at different retinal locations. This information may be useful in patients with retinitis pigmentosa at very different stages of their ocular disease.