Table 3. Comparison Of LogCS, Color Confusion Index, and Time Since Diagnosis of HIV Infection vs Average Retinal Nerve Fiber Layer Thickness Grouped by Thickness for 102 Eyes of 57 Study Participants.
| Normal RNFLa (n = 74) | Thick RNFLa (n = 10) | P Valueb | Thin RNFLa (n = 18) | P Valuec | |
|---|---|---|---|---|---|
| RNFL thickness (μm) | |||||
| Mean ± SD | 104.4 ± 6.4 | 121.4 ± 5.1 | 82.5 ± 4.6 | ||
| Median (range) | 104.0 (93.3 to 116.5) | 119.7 (117.3 to 134.7) | 83.1 (75.0 to 90.0) | ||
| LogCS | .43 | .009 | |||
| Mean ± SD | 1.87 ± 0.12 | 1.84 ± 0.14 | 1.78 ± 0.19 | ||
| Median (range) | 1.90 (1.45 to 1.95) | 1.90 (1.50 to 1.95) | 1.85 (1.25 to 1.95) | ||
| C-index | .47 | .42 | |||
| Mean ± SD | 1.72 ± 0.71 | 1.53 ± 0.60 | 1.95 ± 0.88 | ||
| Median (range) | 1.58 (0.96 to 4.07) | 1.31 (0.96 to 2.45) | 1.72 (0.96 to 3.50) | ||
| Time since diagnosis of HIV infection (months) | |||||
| Mean ± SD | 187.3 ± 94.7 | 159.5 ± 76.6d | 216.4 ± 81.2d | ||
| Median (range) | 202 (3 to 359) | 167 (29 to 243) | 209.5 (75 to 332) | ||
C-index = color confusion index; CS = contrast sensitivity; HIV = human immunodeficiency virus; RNFL = retinal nerve fiber layer; SD = standard deviation.
Study participants were included in the normal subgroup if their measurements fell within 1 standard deviation of the mean value (104.68 ± 12.61 μm) of parapapillary RNFL measurements in 4 quadrants (superior, temporal, inferior, nasal) for a population of HIV-negative individuals described by Rao and associates.24 Participants with values above or below that range were included in the thick and thin subgroups respectively.
Based on Kruskal-Wallis test for the comparison of the thick RNFL subgroup to normal RNFL subgroup.
Based on Kruskal-Wallis test for the comparison of the thin RNFL subgroup to normal RNFL subgroup.
P value = .18 for the comparison of time since diagnosis of HIV infection between eyes with thin and thick RNFL.