Study of electroretinogram components using pattern inversion in the early diagnosis of glaucoma
Current electrophysiological techniques that help guide the diagnosis of glaucoma include pattern-electroretinogram (PERG) and pattern-visual evoked potential (PEVP) recordings. However, PERG has been recognized over the last decade as a good indicator of retinal ganglion cell function. One hundred seventy one eyes corresponding to 89 subjects were studied using both PERG (gold foil electrodes) and PEVP recordings. Two groups respectively including 32 subjects with ocular hypertension (OHT) and 27 subjects with simple chronic glaucoma (SCG) were compared with a control group composed of 30 healthy age-matched subjects. In regard to PERG recordings, the amplitudes of the P50 and N95 components were measured, but statistically significant differences were shown only for the N95 amplitudes both SCG (P < 0.01) and OHT (P < 0.05) groups. The amplitude and latency of the PEVP P100 component were analyzed. P100 latency was significantly delayed (P < 0.05) in SCG patients only. These findings suggest that the amplitude of the N95 component is the most sensitive electrophysiological parameter for early glaucoma detection.