Abstract
Purpose :
People with albinism (PwA) are known to have a variety of visual impairments, however, little is known whether these functions are disrupted across earlier and later stages of the visual pathway. We investigated a battery of 11 distinct perceptual functions within each observer and compared the data with age- (±5 years) and gender-matched controls.
Methods :
10 self-reported PwA and 12 controls were recruited. The self-administered, response-adaptive AIM and FInD psychophysical methods were deployed and measured in OS,OD,OU near visual acuity, spatial-Contrast-Sensitivity-Function(CSF), and temporal Contrast-Sensitivity(tCS; 0.5c/°; horizontal grating; 0,1,2,4,8Hz), and OU in glare acuity, threshold-versus-contrast (TvC: 2c/° vertical grating), cone-isolated color detection, color discrimination, stereoacuity across spatial frequencies (1c/°, 2c/°, 4c/°, 8c/°), horizontal, circular, and expanding pattern and motion coherence, and equivalent-noise motion detection. Thresholds were determined by AIM and FInD and compared using N-ANOVAs, t-tests, planned comparisons, correlations across outcomes, and agglomerative hierarchical cluster analysis for each group.
Results :
We found significant differences between groups in earlier visual functions, i.e. reduced near acuity with and without glare, reduced CSF-acuity and lower CSF area under the curve. Most PwA did not perceive stereo-depth. Main effects for group, temporal frequency, and eyes (3-WayANOVA:p<0.05) and an interaction between group and frequency were found for tCS(p<0.001), which was due to a lack of interocular spatio-temporal contrast summation in PwA. No significant main effects or interactions were found in either color test, pattern and motion coherence tests (2 way/ANOVAs p>0.05). The TvC task identified elevated internal noise in PwA compared to controls (p<0.01). Correlations between outcomes revealed a different pattern between groups and preliminary hierarchical clustering revealed different functional clusters between groups.
Conclusions :
AIM and FInD successfully interrogated visual deficits in PwA. Overall, PwA showed impaired performance in achromatic and binocular functions, and had higher intrinsic noise levels. Chromatic vision and pattern and motion coherence were comparable between groups. Preliminary results of predictive clustering and correlation between outcomes revealed a difference in functional outcome clusters between groups.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.