The patients with POAG had early visual field loss as estimated by
the global MD index
17 18 (median MD = −3.1 ±
2.40 dB).
On average, the patients with POAG were 29 days older, (normal–POAG
range, −1.41 to +1.42). The differences were not statistically
significant (P = 0.44, Wilcoxon matched-pairs test).
Pupil size was measured at the beginning of each visual field
examination. The pupil diameter in the POAG-affected eye was, on
average, 0.16 mm larger than that of the paired normal eye
(normal–POAG range, −1 to +1). This difference did not reach
statistical significance (P = 0.26, Wilcoxon
matched-pairs test). The POAG-affected members had a slightly higher
acuity than the normal members (P = 0.044, Wilcoxon
matched-pairs test). The POAG-affected members also had higher IOPs
(P < 0.0001, Wilcoxon matched-pairs test). The mean
IOP for the POAG-affected members was 18.8 mm Hg (range, 12–28 mm Hg),
whereas the normal subjects had a mean IOP of 15.1 mm Hg (range, 10–22
mm Hg).
The average difference in sensitivity between the POAG-affected and
normal members of each pair (
n = 38) is shown in
Table 1 for each of the 10 most sensitive locations. The number of
cases in which the normal member of each pair had a higher sensitivity
than the POAG-affected member is also shown in
Table 1 , along with the
number of cases in which the POAG-affected and normal members of each
pair did not have the same sensitivity (non-ties), as well as the
probability that this would occur by chance.
Figure 1 shows an example, taken from the seventh most sensitive location, of
the distribution of sensitivity differences for the 38 matched pairs.
This distribution, which is typical in the most sensitive locations, is
significantly nonnormal (Shapiro–Wilks test,
P <
0.04). Non parametric statistics were used for the paired comparisons.