Vision assessment in persons with intellectual disabilities

To investigate the degree of visual acuity in workers with intellectual disabilities and the impact of vision on their working conditions.

We recruited 224 workers (mean age 43.77 years, SD ± 12.96; range, 19-72 years) from a workshop for those with intellectual disabilities, to participate in a vision examination program. The assessment consisted of objective refraction, visual acuity, ocular motility, near-point of convergence, cover/uncover test, stereo acuity and colour perception. Individuals with vision deficits were fitted with spectacles following the screening program.

Within the past three years, 38.9 per cent of the participants received eye care, 14.3 per cent of participants had not received eye care in more than three years, and 6.7 per cent had not received any eye care. As many as 39.7 per cent of participants did not know whether they had ever received eye care. Entering visual acuity for far vision was 0.52 dec (-0.29 logMAR) and 0.42 dec (-0.38 logMAR) for near vision. Only 14.9 per cent, 11 of all participants aged ≥50 years, owned spectacles for near vision before the examination. After subjective determination of refraction, best corrected visual acuity for far vision was 0.61 dec (-0.22 logMAR) and 0.56 dec (-0.25 logMAR) for near vision (in both cases with p < 0.001). After the examination, 44.6 per cent (33) of all workers aged ≥50 years received a recommendation for reading or bifocal spectacles. In 46 per cent of workers, the threshold of stereopsis was higher than 63 arc seconds, and some form of colour vision deficiency was measured in 12.5 per cent of participants.

Workers with intellectual disabilities are often unaware of their visual deficits. We found that some of their abnormalities can be solved by appropriate optical means and that they could benefit from regular eye care. These workers should be encouraged to be tested and to improve their vision with appropriate lenses.