Pattern reversal visual evoked response in retinitis pigmentosa

Purpose: To determine if the pattern reversal visual evoked response (PVER) can objectively evaluate visual function in retinitis pigmentosa (RP). Methods: We retrospectively reviewed the medical records of 29 patients (29 eyes) with RP, a visual acuity (VA) better than 20/100, and for whom an electroretinogram (ERG) and a PVER had been recorded. A steady-state PVER was measured using five check sizes: 160, 80, 40, 20 and 10 min of arc. The best-corrected VA was measured using the ETDRS chart. Visual fields (VFs) were measured using standard Goldmann perimetry. To quantify the VFs, we measured the field size (isopter IV-2) in four meridians and averaged them. Twenty-five eyes of 25 normal subjects served as controls. Results: The mean and median VAs were 20/40 (logMAR = 0.30 ± 0.20). The average VF (isopter IV-2) was 20°(median, 9°; range, 2°to 62°). All patients had a recordable PVER. Only 12 (41%) patients had a recordable ERGs, all subnormal. The PVER amplitudes showed a relatively good correlation with VA in the intermediate check sizes (40 min of arc, r = 0.611, P = 0.0004; 20 min of arc, r = 0.596, P = 0.0007). The PVER amplitude-check size function had a flattened inverted V shape in the RP patients and an inverted U shape in the normal subjects, with the mean amplitudes for the RP patients significantly smaller than the normals at all check sizes. Conclusion: The PVER is a useful method for objectively evaluating the visual function in RP patients whose central vision is still preserved.