Table 1.
Visual characteristics of the 11 observers with AMD. The PRL is only given for the tested eye (PRL was not determined for observer C).
| Observer ID | M/F | Age | Yrs since onset | Acuity (logMAR) | PRL ecc. (deg) | PRL directiona | Letter-size threshold (deg) | Nominal critical spacing (multiples of letter size) | Absolute critical spacing (deg) | ||
|---|---|---|---|---|---|---|---|---|---|---|---|
|
| |||||||||||
| OD | OS | OD | OS | ||||||||
| A | M | 72 | 0.5 | 0.80 | prosthesis | 4.98 | 288° | 0.54 | 1.25 | 0.68 | |
| B | F | 75 | 5 | 0.74 | 0.92 | 5.17 | 94° | 0.81 | 1.35 | 1.09 | |
| C | F | 72 | 4 | 0.62 | 0.64 | - | - | 0.55 | 1.39 | 0.74 | |
| D | M | 84 | 8 | 0.56 | 0.70 | 6.16 | 291° | 0.73 | 1.45 | 1.06 | |
| E | M | 84 | 3 | 0.48 | 0.48 | 2.45 | 298° | 0.52 | 1.53 | 0.79 | |
| F | F | 82 | 9 | 0.50 | 0.52 | 3.49 | 288° | 0.45 | 1.64 | 0.73 | |
| G | F | 73 | 7 | 0.66 | 0.48 | 2.49 | 209° | 0.67 | 1.80 | 1.21 | |
| H | M | 86 | 12 | 0.70 | 0.74 | 6.69 | 259° | 0.64 | 2.23 | 1.43 | |
| I | F | 89 | 15 | 1.04 | 1.06 | 6.50 | 202° | 0.85 | 2.28 | 1.93 | |
| J | F | 74 | 6 | 0.54 | 1.12 | 2.87b | 161° | 0.34 | 3.02 | 1.04 | |
| K | F | 78 | 3 | 0.40 | 0.32 | 4.54b | 143° | 0.39 | 4.07 | 1.58 | |
a
The direction of the PRL was specified with respect to the fovea (which in all cases, fell within the central scotoma), counter-clockwise from the horizontal 3 o’clock position (0°).
b
Both observers J and K showed some residual foveal function. Depending on the size of the fixation cross (<1°), the two observers could switch to using their fovea for fixation. They also reported a drastic decrease in vision in dim light, consistent with the shift to a peripheral PRL for visual tasks when the lighting is not sufficient to support foveal vision.