Pupil perimetry and Humphrey field analysis in Leber hereditary optic neuropathy compared with optic neuritis

Leber's hereditary optic neuropathy (LHON) and optic neuritis share some common features, but probably have a different pupillary reaction. In the present study, we hypothesized that pupil perimetry is a means by which we can confirm this difference. Data from pupil perimetry (PPM) and Humphrey field analyzer (HFA) measurements in 10 patients with LHON and 11 patients with optic neuritis were collected and assessed by both qualitative and quantitative methods. Four examiners compared the gray-tone results for PPM and HFA to qualitatively determine the presence of any difference. Quantitative analysis was conducted in five zones: the central four points and the superotemporal, superonasal, inferotemporal, and inferonasal quadrants. The constriction amplitudes of PPM and threshold HFA were divided into 11 grades and the differences between the grades were calculated. The differences for each zone were then compared between the LHON and the optic neuritis groups. Qualitative comparison showed that pupil perimetry provided better results than Humphrey perimetry in six cases of LHON and in two cases of optic neuritis. Quantitative analysis showed that the difference in the grades between the two perimetry methods at the central four points was significantly less in the optic neuritis group than in the LHON group. This suggests that optic neuritis has a nonselective, larger, and deeper depression of central visual function than LHON, and is probably a reflection of the damage pattern of the W-ganglion cells.