[The characteristics of luminance of color visual evoked potential in macular diseases]

To objectively evaluate the luminance channel damage of macular diseases by color pattern reversal visual evoked potential (CPR-VEP).

CPR-VEP was performed in 38 eyes with age-related macular degeneration (ARMD) dry type, 24 eyes with ARMD wet type, 20 eyes with Stargardt's disease and 54 normal eyes. Color pattern stimuli were obtained with color monitor controlled by computer program. Color pattern reversal rate was 2 Hz and its spatial frequency was 0.53 cycle/degree. The color graphic system could present white/black (W/B), red/black (R/B), green/black (G/B), blue/black (B/B), yellow/black (Y/B).

In normal eyes, CPR-VEP P(1) latency was negatively correlated with luminance, whereas P(1) amplitude positively correlated with luminance; there were linear regressions between the mean luminance and P(1) latency and between the mean luminance and P(1) amplitude. Also in ARMD dry type, the CPR-VEP showed that the characteristics of the luminance channel were similar to that in the normal eyes. However, these phenomena did not exist in ARMD wet type and Stargardt's disease.

In ARMD dry type, there is no damage of luminance channel, but in ARMD wet type and Stargardt's disease, there is severe damage of luminance channel and the patients can not discriminate luminance difference.