Pattern-reversal electroretinograms and visual evoked potentials in retinitis pigmentosa

Objective To analyze pattern electroretinograms (PERGs) and pattern visual evoked potentials (PVEPs) in retinitis pigmentosa (RP) patients. Methods PERGs and PVEPs were recorded in 106 eyes of 53 RP patients. A RETIport system was used for stimulation and recording. Results Reproducible PERGs were found in 17 (32%) of the patients, from only one eye in 4 of the 17 patients. We failed to record a normal PERG in any patient. All 53 patients gave reproducible PVEPs. The patients could be divided into three groups according to the waveform of the response. In the first group (n = 17), all patients produced PVEPs with a characteristic, triphasic shape, but with smaller amplitudes. In the second group (n = 16), the PVEPs displayed doubled P100 peaks, with components separated by about 50 ms. The recordings in the third group (n = 20) were broad in shape and characterized by a greatly increased N70-N170 latency difference and decreased amplitudes. Conclusions In the population of RP patients, different types of PVEP waveform alterations can be observed. The appearance of both the responses with decreased amplitude and those with broad, doubled P100 waves might reflect differences in central retinal degeneration. The significance and pathological background of these PVEP alterations need further investigations.