Abstract
Abstract: :
Purpose: To compare a standard clinical measure of visual field sensitivity (Humphrey Visual Field Analyzer) to perimetry, measured using higher-level psychophysical tasks (acuity and contrast sensitivity), and to perimetry measured with the multifocal ERG (mfERG) technique in patients with retinitis pigmentosa (RP). Methods: Luminance sensitivity, letter acuity, and grating contrast sensitivity were measured at 13 locations within the central 10 degrees. Targets were presented along the horizontal and vertical meridians on a CRT display (mean luminance 150 cd/m2) for a duration of 375 msec. mfERGs were recorded using a standard protocol and a 103-hexagon array. Humphrey visual field thresholds were also measured at the same retinal locations. Data from a group of six patients with RP were compared to the results from six age-similar control subjects. For the patients, log losses in sensitivity from the average control values at the corresponding locations were calculated. Results: For this group of patients with RP, sensitivity on all of the tasks decreased as a function of eccentricity, as expected. Overall, luminance sensitivity and contrast sensitivity showed the least sensitivity loss (median = 0.18 and 0.17 log units, respectively). The mfERG amplitude measure was most affected (median = 0.52 log units) and spatial resolution showed an intermediate amount of loss (0.25 log units). Conclusion: These results suggest that perimetric measures of acuity and contrast sensitivity may prove to be useful additions to standard clinical field and mfERG measures for following disease progression.
Keywords: 624 visual fields • 562 retinal degenerations: hereditary • 393 electrophysiology: clinical