98th Annual Meeting DOG 2000

K 154

L- and M-cone driven ERGs in sector RP

H. P. N. Scholl, J. Kremers

Purpose: To study the dynamics of the long- (L-) and middle-wavelength-sensitive (M-) cone pathways in patients with sector retinitis pigmentosa (sector RP).

Methods: Two patients with sector RP participated in the study. ERG responses were measured to stimuli which modulated exclusively the L- or the M-cones or the two simultaneously (both in-phase and in counter-phase). S-cones were not modulated. (J. Kremers, T. Usui, H.P.N. Scholl, and L.T. Sharpe: Invest Ophthalmol Vis Sci 1999; 40: 920-930).

Results: The two sector RP patients exhibited a general reduction of the L-/M-cone driven ERG sensitivity. In patient 1, both the L- and the M-cone driven ERGs were reduced in amplitude and slightly delayed. Patient 2 exhibited markedly reduced L- and M-cone driven ERGs. The L-cone driven ERG was considerably delayed, whereas the M-cone driven ERG was temporally normal. In both patients, the phases of the L- and the M-cone driven ERGs were positively correlated with cone contrast.

Conclusions: In RP patients with widespread disease, we recently found reduced L-/M-cone driven ERG sensitivities and increased phase lags of the L-cone driven ERG, whereas the M-cone driven ERG was phase advanced. Their phases were not positively correlated with cone contrast. The two sector RP patients also showed a reduced ERG sensitivity. However, the temporal features of the L- and M-cone driven ERGs differed from those found in patients with widespread disease.

Universtity Eye Clinic, Schleichstr. 12-16, D-72076 Tübingen



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