Pattern reversal visual evoked response in retinitis pigmentosa.

Abstract

To determine if the pattern reversal visual evoked response (PVER) can objectively evaluate visual function in retinitis pigmentosa (RP). 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. The mean and median VAs were 20/40 (logMAR = 0.30 +/- 0.20). The average VF (isopter IV-2 ) was 20 degrees (median, 9 degrees: range. 2 degrees to 62 degrees). 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. The PVER is a useful method for objectively evaluating the visual function in RP patients whose central vision is still preserved.