An eye with the more demonstrable structural deterioration, as shown by reduced RNFL thickness and GCC area, and retinal ganglion cell dysfunction as shown by decreased PhNR/b-wave amplitude ratio was associated with the worse visual fields outcome. RNFL thickness and GCC area measurements using OCT and PhNR/b-wave amplitude ratio could be a useful prognostic indicator in the preoperative assessment of chiasmal compression.

Visual field recovery and changes of RGCs after chiasmal decompression have similar aspects and are significantly correlated. However, prolonged retrograde degeneration progressed for some period, even after surgical decompression and visual field recovery preceded demonstrable retinal regeneration.

We compared the best-corrected Snellen acuity (SA) and the pattern reversal visual-evoked response (PVER) acuity in normal subjects and patients. Forty-two eyes of 42 normal subjects were controls; 457 eyes of 329 patients comprised the patient group. A steady-state stimulus with five check sizes ranging from 160 to 10 min in 1.0-octave steps was used. The PVER acuity was derived from the best-fit linear function relating the amplitude to the log-adjusted check size. Three intercepts of 0, 1 and 2 μV were used in both groups, and the PVER acuities were called P°, P¹ and P². The SAs in normal subjects ranged from 20/15 to 20/20 (mean, 20/18.3) and in patients from 20/15 to 20/1,600 (mean, 20/56.9). In normals, the P° showed the best agreement with the SA (mean acuity difference, +0.34 octave). The SA and P° agreed within ± 2.0 octaves in 33/42 (78.6%) eyes. In patients, the P° also showed the best agreement with the SA; 306/457 (67.0%) eyes showed an acuity difference within ± 2.0 octaves. Unlike normals, 83/ 457 (18.2%) eyes showed an acuity difference > -3.0 octaves. These eyes mostly had optic nerve disease with a flattened PVER amplitude-check size function curve. The P° seems to correlate better with SA than P¹ and P², but this analytical method may be less effective in the presence of certain pathologic conditions.