S-cone function in patients with retinitis pigmentosa.
OBJECTIVE
To determine whether short-wavelength-sensitive (S-) cones are more severely damaged in patients with retinitis pigmentosa than long-wavelength-sensitive (L-) and middle-wavelength-sensitive (M-) cones. To determine whether there are differences in the amount of S-cone damage in patients with dominant versus nondominant inheritance patterns. To accomplish these goals with methods that provide information not furnished by previous studies with two-color increment thresholds.


METHODS
Acuity mediated by the S-cones was measured in 56 patients with retinitis pigmentosa, and the electroretinogram (ERG) generated by the S-cones was measured in 11 of these patients. Mixed L- and M-cone acuity, mixed L- and M-cone ERGs, and clinical full-field rod and cone ERGs were obtained for all patients. Data for both dominant and nondominant patient groups were compared with data from age-matched normal subjects.


RESULTS
Only the nondominant group had reduced S-cone acuity, and 43% of patients in this group had selective reduction of S-cone acuity. In this particular sample the dominant and nondominant groups were comparable in clinical full-field ERG parameters and mixed L- and M-cone acuity, so the difference in S-cone acuities is not due to the dominant group having less advanced retinal degeneration. All 11 patients tested had reduced S-cone ERGs, 6 with significantly greater loss in the S-cone ERG than in the mixed L- and M-cone ERG.


CONCLUSIONS
These data provide evidence that retinitis pigmentosa can produce greater loss of S-cones than L- and M-cones, and that this selective loss is primarily seen in patients with nondominant forms of retinitis pigmentosa.
Swanson
W H
WH
Retina Foundation of the Southwest, Dallas, TX 75231-3303.
Birch
D G
DG
Anderson
J L
JL
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D003118:Color Perception / Q000502:physiology; D004596:Electroretinography; D005260:Female; D006801:Humans; D008027:Light; D008297:Male; D008875:Middle Aged; D017949:Retinal Cone Photoreceptor Cells / Q000503:physiopathology*; D012174:Retinitis Pigmentosa / Q000235:genetics / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology