Table 2.
Baseline visual acuity (VA) and low luminance deficit (LLD), and rate of visual acuity loss
| Category at baseline |
# eyes |
# (%) with moderate VA loss at 2 years |
# (%) with severe VA loss at 2 years |
Relative risk of at least moderate VA loss at 2 years |
Relative risk of severe VA loss at 2 years |
Mean VA at baseline (logMAR) |
Mean logMAR VA loss at 2 years [95% CI] |
Mean VA at 2 years (logMAR ) |
Mean final logMA R VA loss* [95% CI] |
Mean final VA (logMAR) |
|---|---|---|---|---|---|---|---|---|---|---|
|
1 VA >=20/50 |
52 | 21 (40%) | 9 (17%) |
1 | 1 | 20/33 (0.22) |
0.28 [0.20– 0.36] |
20/63 (0.50) |
0.65 ([0.55– 0.76]) |
20/148 (0.87) |
| VA 20/51–20/199 | 30 | 4 (13%) p=0.008 |
1 (3%) p=0.04 |
0.33 [0.13– 0.87] |
0.19 [0.03– 1.42] |
20/89 (0.65) |
0.08 [− 0.01to 0.17] p=0.001 |
20/107 (0.73) p=0.001 |
0.37 [0.23– 0.50] p=0.002 |
20/205 (1.01) p=0.14 |
| VA <=20/200 | 9 | 1 (11%) p=0.07 |
0 (0%) p=0.08 |
0.28 [0.04– 1.80] |
undef | 20/264 (1.12) |
−0.04 [− 0.26 to 0.17] p=0.002 |
20/235 (1.07) p=0.0001 |
−0.01 [−.0.26 to 0.24] p=0.000 1 |
20/258 (1.11) p=0.13 |
|
2 VA >=20/50 AND better LLD |
21 | 4 (19%) | 1 (5%) | 1 | 1 | 20/30 (0.18) |
0.16 [0.04– 0.27] |
20/43 (0.33) |
0.46 [0.29– 0.63] |
20/87 (0.64) |
| VA >=20/50 AND worse LLD |
31 | 17 (55%) p=0.008 |
8 (26%) p=0.03 |
2.88 [1.13– 7.35] |
5.42 [0.73– 40.21] |
20/36 (0.25) p=0.02 |
0.36 [0.27– 0.45] p=0.009 |
20/81 (0.61) p=0.002 |
0.78 [0.64– 0.93] p=0.005 |
20/214 (1.03) p=0.002 |
|
3 20/25 < VA <=20.50 AND better LLD |
18 | 4 (22%) | 1 (6%) | 1 | 1 | 20/32 (0.21) |
0.17 [0.04– 0.30] |
20/48 (0.38) |
0.47 [0.28– 0.66] |
20/96 (0.68) |
| 20/25 < VA <=20.50 AND worse LLD |
29 | 17 (59%) p=0.02 |
8 (28%) p=0.06 |
2.64 [1.05– 6.60] |
4.97 [0.68– 36.47] |
20/36 (0.26) p=0.02 |
0.37 [0.27– 0.48 p=0.02 |
20/86 (0.64) p=0.005 |
0.80 [0.65– 0.95] p=0.01 |
20/230 (1.06) p=0.004 |
|
4 VA 20/51-20/199 AND better LLD |
27 | 3 (11%) | 0 (0%) | 1 | 1 | 20/89 (0.65) |
0.05 [− 0.01 to 0.12] |
20/103 (0.71) |
0.32 [0.21– 0.44] |
20/191 (0.98) |
| VA 20/51–20/199 AND worse LLD |
3 | 1 (33%) p=0.34 |
1 (33%) p=0.03 |
3.00 [0.44– 20.53] |
undef | 20/80 (0.60) p=0.58 |
0.34 (0.14– 0.55] p=0.01 |
20/174 (0.94) p=0.14 |
0.74 [0.38– 1.10] p=0.03 |
20/438 (1.34) p=0.09 |
logMAR = logarithm of the minimal angle of resolution, CI = confidence interval, VA = visual acuity, LLD = low luminance deficit.
The p values are from comparisons of the rates of at least moderate and severe VA loss based on the Chi square test. The p values for the continuous variables (mean VA loss, mean VA) are based on Student’s t test.
Mean total follow-up was 4.9 years for the best VA group, 5.2 years for the intermediate VA group, and 4.3 years for the worst VA group (p=0.25)The top grouping of three rows include the data on VA loss for each VA group. The p values reflect the given row relative to the good VA group.The second grouping of two rows presents the data for the good VA group, stratified into better and worse LLD. The third grouping of two rows compares the data for the eyes with acuities worse than 20/25 but equal to or better than 20/50, stratified into better and worse LLD. The fourth grouping of two rows presents the data for the intermediate VA group, stratified into better and worse LLD. All subjects with VA of 20/200 or worse had baseline LLD in the better LLD category.