ETDRS subfields (inner to outer radius in mm and degrees of visual angle) | Mean cells/ mm2 in subfield | Ratio of Rods to Cones | |
---|---|---|---|
Cones/ mm2 | Rods/ mm2 | Rods : Cones | |
 | Ages 27-37 years | ||
Center (0 - 0.5 mm; 0 - 1.7°) | 57,001 | 20,013 | 0.35 |
Inner (0.5 - 1.5 mm; 1.7 - 5.2°) | 18,774 | 78,252 | 4.17 |
Outer (1.5 - 3.0 mm; 5.2 - 10.4°) | 10,138 | 130,750 | 12.90 |
Mean photoreceptor density in ETDRS grid | 13,354 | 116,037 | 8.69 |
 | Age 61-90 years | ||
Center (0 - 0.5 mm; 0 - 1.7°) | 54,897 | 15,016 | 0.27 |
Inner (0.5 - 1.5 mm; 1.7 - 5.2°) | 17,673 | 56,105 | 3.17 |
Outer (1.5 - 3.0 mm; 5.2 - 10.4°) | 9,512 | 96,265 | 10.12 |
Mean photoreceptor density in ETDRS grid | 12,582 | 85,106 | 6.76 |
RMDA test spot locations | Ages 27-37 years | ||
 5° superior | 15,530 | 82,357 | 5.30 |
 12° superior | 9,406 | 145,683 | 15.49 |
 | Ages 61-82 years | ||
 5° superior | 15,376 | 62,043 | 4.04 |
 12° superior | 8,835 | 116,683 | 13.21 |