Table 1.
Distribution of clinical characteristics in patients with USH2A mutations
| Characteristic | RP (n=75) | USH2 (n=88) | P value (t-test) |
| Female/male | 35/40 | 35/53 | 0.374 |
| Mean age ±SD (range), years | 45.85±14.96 (2–78) | 40.21±15.32 (6–80) | 0.647 |
| Mean onset age ±SD (range), years | 23.37±15.72 (0–64) | 15.34±12.62 (0–46) | 0.01 |
| Mean BCVA ±SD (range) | 0.35±0.30 (0.0001–1) | 0.38±0.32 (0.0001–1) | 0.495 |
| Age, ≤50 years | 0.43±0.30* | 0.46±0.31* | 0.499 |
| Age, >50 years | 0.22±0.257 | 0.11±0.22 | <0.05 (0.033) |
| Duration, ≤10 years | 0.54±0.30† | 0.56±0.29† | 0.755 |
| Duration, 10–20 years | 0.44±0.26 | 0.47±0.36 | 0.705 |
| Duration, >20 years | 0.24±0.27 | 0.25±0.25 | 0.856 |
| Mean duration ±SD (range), years | 23.27±16.13 (3–78) | 24.50±15.25 (2–70) | 0.651 |
| Mean MD ±SD (range), dB | −25.06±6.06 (−33.60 to −4.24) |
−26.11±4.67 (−33.25 to −9.6) |
0.362 |
| Age, ≤50 years | −23.73±6.45* | −26.59±3.61 | <0.01 (0.007) |
| Age, >50 years | −27.67±3.27 | −27.29±7.46 | 0.835 |
| Duration, ≤10 years | −20.71±7.45‡ | −26.26±3.28 | <0.01 (0.006) |
| Duration, 10–20 years | −25.55±3.95 | −25.65±4.78 | 0.968 |
| Duration, >20 years | −27.42±3.95 | −27.34±4.61 | 0.910 |
| Mean CFT (µm) | 223.78±55.46 | 210.28±39.31 | 0.132 |
| Age, ≤50 years | 232.39±49.93* | 210.75±39.63 | <0.05 (0.015) |
| Age, >50 years | 204.53±43.62 | 203.25±39.66 | 0.761 |
| Duration, ≤10 years | 256.67±52.76§ | 224.00±33.03 | <0.05 (0.04) |
| Duration, 10–20 years | 223.71±38.70 | 206.05±44.63 | 0.116 |
| Duration, >20 years | 220.95±51.83 | 204.60±35.07 | 0.268 |
*Best Snellen corrected visual acuity (BCVA), visual field (VF) and central foveal thickness (CFT) of patients younger than 50 years old had significant differences with that of patients older than 50 years (p<0.001, p<0.01, p<0.05).
†BCVA of patients with duration ≤10 years was better than that of patients with duration >20 years (p<0.001) but there was no difference from patients with duration 10–20 years (p=0.079).
‡VF of patients with duration ≤10 years was better than that of patients with duration >10 years (p<0.05), but there was no difference in mean deviation (MD) between patients with retinitis pigmentosa (RP) with duration 10–20 years and >20 years (p>0.05).
§CFT of patients with duration ≤10 years was thicker than that of patients with duration >10 years (p<0.05), but there was no difference in CFT between patients with RP with duration 10–20 years and >20 years (p>0.05).
BCVA, best Snellen corrected visual acuity; CFT, center foveal thickness; MD, mean deviation; RP, retinitis pigmentosa; SD, standard deviation; USH2, Usher syndrome type IIa.