Abstract
Purpose :
Cortical/cerebral visual impairment (CVI) is the most common cause of visual impairment among children in developed countries. Currently, there is no standardized, objective, and quantitative assessment tool to evaluate the multiple aspects of vision affected in CVI. Eye tracking is a novel technology that could be used for this purpose.
Methods :
We prospectively recruited five children with CVI and six age-matched controls (age range 2-12 years). All children underwent complete ophthalmologic exam. In children with CVI, visual acuity was graded clinically on a previously published 6-level scale. The EyeLink® system tracked eye position remotely at 500 Hz while subjects viewed stimuli on a computer monitor. Grating acuity, contrast sensitivity, and color saturation threshold were assessed using forced preferential looking. Characteristics of saccades (latency and velocity) and fixations (duration) were calculated by the EyeLink® software.
Results :
Among children with CVI, grating acuity threshold by eye tracking strongly correlated with clinical visual acuity (r=0.87, p=0.05). Compared to controls, children with CVI had significantly worse grating acuity threshold (mean 8.6 ±7.6 vs. 20±0 cycles per degree, p=0.01) and contrast sensitivity threshold (31±19% vs. 7.0±3.5%, p=0.05). Color saturation threshold was not significantly different between groups (22±16% [CVI] vs. 12±4.1% [controls], p=0.30). Latency to first saccade was longer in CVI patients (392±84 vs. 279±40 ms, p=0.01), but average and peak saccade velocity did not differ (p>0.80). Children with CVI had longer fixation duration (492±93 vs. 351±45 ms, p=0.05) and fewer fixations (3.7±0.83 vs. 6.9±0.74, p=0.0043) and saccades (4.8±0.44 vs. 7.1±0.65, p=0.0043) per trial.
Conclusions :
Eye tracking shows promise as a quantitative measure of vision in children with CVI. Visual function and oculomotor findings are consistent with previously published qualitative data. Further research is necessary to establish the reliability and validity of this technique, which could potentially serve as an outcome measure in clinical trials of treatments for CVI.
This is a 2020 ARVO Annual Meeting abstract.