Rod visual fields in cone-rod degeneration. Comparisons to retinitis pigmentosa.
Dark-adapted visual fields to short- and long-wavelength stimuli were obtained from 20 patients with cone-rod degeneration, 20 patients with retinitis pigmentosa, and ten normal subjects. Patients were selected because they retained rod electroretinographic (ERG) function over a sufficient range for the Naka-Rushton analysis of retinal illuminance versus amplitude functions. Patients with cone-rod degeneration retained a relatively normal field topography although overall sensitivity was reduced. The mean sensitivity loss was consistent with a small elevation in ERG semisaturation constant and minimally delayed rod b-wave implicit times. Rod visual fields from patients with retinitis pigmentosa retaining rod ERG function were consistent with log sensitivity profiles reported previously for type 2 patients. Sensitivity loss was greatest in midperipheral regions, with most patients showing least loss in the far periphery. Disproportionate loss in the midperiphery is consistent with a large elevation in the ERG semisaturation constant and prolonged rod b-wave implicit times.
Birch
D G
DG
Retina Foundation of the Southwest, Presbyterian Medical Center, Dallas, TX 75231.
Anderson
J L
JL
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D003623:Dark Adaptation; D004596:Electroretinography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010786:Photoreceptor Cells / Q000503:physiopathology*; D012162:Retinal Degeneration / Q000503:physiopathology*; D012174:Retinitis Pigmentosa / Q000503:physiopathology*; D014792:Visual Acuity; D014794:Visual Fields