Foveal cone pigment density difference and reflectance in retinitis pigmentosa
P. E. Kilbride, M. Fishman, G. A. Fishman and L. P. Hutman
Cone pigment density difference refers to a change in light absorption by
cones before and after bleaching of their visual pigments. With a
television ophthalmoscope image processor, we measured the foveal cone
pigment density difference in patients with retinitis pigmentosa (RP), good
central vision, and no clinically apparent foveal lesion. Foveal
reflectance was obtained at 12 different wavelengths of illumination.
Compared with similar-aged normal subjects, most patients with dominantly
inherited RP had normal or minimally reduced cone pigment density
difference within the central fovea, relatively lower than normal density
difference at the foveal margin, and increased foveal reflectance. Compared
with these normal subjects, patients with recessively inherited RP had
significantly reduced cone pigment density difference within the central
fovea, relatively more normal density difference at the foveal margin, and
normal foveal reflectance.
