Frequency doubling perimetry in resolved optic neuritis.Invest Ophthalmol Vis Sci. 2000 Aug; 41(9):2558-60.IO
To study the visual field with frequency doubling technology (FDT) in patients with recovered optic neuritis and to detect loss of magnocellular projecting cells (M cells) in the extrafovea.
Fourteen patients who had undergone one attack of optic neuritis and recovered normal vision (1.0 or better) and critical fusion frequency were examined with conventional Humphrey automated perimetry central 30-2 and FDT c-20 threshold tests. After 1 year, 12 patients were reexamined with central 30-2 and FDT c-20 tests. The visual fields examined by both perimeters were divided into three zones. The mean sensitivity in each zone in involved eyes, uninvolved eyes, and involved eyes after 1 year was compared with that in healthy eyes.
Conventional automated perimetry showed depression toward the fovea. However, FDT demonstrated general depression, especially midperipheral deficits. After 1 year, the midperipheral deficits with frequency doubling perimetry (FDP) improved, as did central depression, as observed with central 30-2 tests.
FDT was developed to detect early glaucomatous damage, which was thought to be caused by a loss of M cells. Our study suggested that patients with resolved optic neuritis also had a loss of M-cell function in the extrafoveal area, as observed by field damage and its recovery.