Conventional Humphrey automated perimetry showed general
depression in patients with resolved optic neuritis, especially within
central depression in a 5° field. The findings corresponded with
those reported by Wall.
2 FDT demonstrated general
depression in resolved optic neuritis, especially depression in the
extrafoveal area. The area outside 10° of eccentricity showed an
abnormality with the Humphrey field analyzer.
2 This
perimeter could not separate the function of P and M cells. M-cell
function was related to high temporal frequency. Sensitivity up to
10° field at temporal frequency was abnormal at up to 2.5° at 23 Hz
in optic neuritis.
4 The area outside 10° at high
temporal frequency had not previously been examined in optic neuritis;
however, FDT could cover up to 20° at high temporal frequency.
Glaucomatous visual field defects were specifically detected by
FDT.
5 6 Early glaucomatous damage was correlated with a
loss of large retinal ganglion cells (M cells)
8 and
nonlinear units (M
Y cells).
9 Patients in the present study had normal intraocular pressure
throughout the course and no glaucomatous cupping after resolution.
Visual field defects in optic neuritis were thought to include losses
of both P and M cells. Both P and M cells were found in the extrafoveal
area and in the fovea.
10 Central depression detected by
conventional automated perimetry led to a loss of P
cells,
1 and deficits in the midperiphery detected by FDT
led to a loss of M
Y cells, because of
dissociation of field damage pattern and its long-term recovery
observed between both perimeters. Central (R1) depression was detected
by conventional automated perimetry, but mean sensitivity in R3 was not
significantly decreased. On the other hand, midperipheral deficits (R2
and R3) were found by FDT, but the central area (R1) was near normal.
Midperipheral deficits by FDT tended to recover after 1 year, whereas
the field in R3 observed by conventional automated perimetry remained
unchanged. FDT takes approximately 5 minutes per eye to perform and
could be useful as a follow-up study of the midperipheral visual field
of patients with optic neuritis after recovery.
One third of the uninvolved eyes showed abnormal visual fields in the
recovery stage.
7 The visual field in uninvolved eyes by
conventional automated perimetry and FDT showed slight general
depression but was not significantly different in any zone.