Studies On Color Pattern Reversal Visual Evoked Potential Of Primary Glaucoma

Objective To investigate the sensibility of color pattern reversal visual evoked potential (CPR-VEP) to the visual function damage of glaucoma at different temporal frequency and color stimulation.MethodsCPR-VEP were recorded in 17 eyes of 12 primary open angle glaucoma (POAG) patients ,56 eyes of 41 primary angle closure glaucoma (PACG) and 20 eyes of 13 age-equivalent normal persons at an ascending series of temporal frequency (1Hz,2Hz,4Hz,8Hz,16Hz,32Hz) and 3 colors stimulation (black/white, red/green and blue/yellow). P₁₀₀ amplitudes and incubation periods of them were compared respectively.Results1.The normal control group: With black / white stimulation, the P₁₀₀ wave amplitudes were reduced with the temporal frequency increasing ; red / green and blue / yellow stimulation at 2 Hz and 8 Hz had higher volatility . The P₁₀₀ wave amplitudes were hightest with black/white stimulate, second with blue/yellow stimulate , the P₁₀₀ wave amplitudes relatively high only at high Temporal Frequency with red/green stimulate.The P₁₀₀ wave incubation periods were extended with the temporal frequency increasing with different colors stimulation , but slightly shortened at 16Hz with black / white and blue / yellow stimulation.2.The POAG group: the P₁₀₀ wave amplitudes were reduced with the temporal frequency increasing except with blue / yellow stimulation at 2 Hz. The P₁₀₀ wave incubation periods were extended with the temporal frequency increasing with different colors stimulation except with red / green stimulation at 8 Hz and blue / yellow stimulation at 32 Hz.3. The PACG group: the P₁₀₀ wave amplitudes were reduced with the temporal frequency increasing except at 8 Hz. The P₁₀₀ wave incubation periods were extended with the temporal frequency increasing with 3 colors stimulation except at 32 Hz and blue / yellow stimulation at 8 Hz.4. The P₁₀₀ amplitudes: PACG group> NC group> POAG group; the P₁₀₀ wave incubation periods of the POAG group and the PACG group were extended than the NC group.Compared with NC group,POAG group had lower P₁₀₀ wave amplitudes and longer P₁₀₀ wave incubation periods, the difference was significant with blue / yellow stimulation at 16 Hz. PACG group had higher P₁₀₀ wave amplitudes and longer P₁₀₀ wave incubation periods compared with NC group, the difference of P₁₀₀ wave amplitudes were significant at 8 Hz which were the most significant with blue / yellow stimulation, the P₁₀₀ wave incubation periods at 16 Hz. The difference of the P₁₀₀ wave amplitudes between PACG group and POAG group were significant at 8 Hz with blue / yellow stimulation.Conclusions The change of CPR-VEP P₁₀₀ wave could be used to objectively assess the visual function damage of PG CPR-VEP with blue/yellow stimulation at 8Hz and 16Hz temporal frequencies may be more useful to the early diagnosis of glaucoma.