Ocular and visual status among children in special schools in Hong Kong

Title Ocular and visual status among children in special schools in Hong Kong
Author, Co-Author Zhang Ning, Carly Lam, Long Qian Liu, Xiao Ming Chen
Topic Binocular Vision/Pediatrics
Program Number
Ballroom A-B
Abstract Purpose: This study aims to identify any visual problems in children with special needs in Hong Kong.

Methods: 234 children (6-17 years) with mild or moderate learning disability from 4 special schools in Hong Kong were examined. The parents were asked to complete a form on the medical history and vision habits of their children. Visual acuity, refractive errors (objective and subjective refraction), binocular vision (NPC, stereopsis), colour vision, ocular motility, pursuit and saccadic eye movement, accommodation (AA) and ocular health of the children were assessed at the children’s respective schools.

Results: Majority of the children had one or more of the following conditions: autism, mental retardation and development delay (62.4%, 48.29% and 17.52%). 24% of the children never had an eye examination; 50% had undertaken eye examinations but less frequent than annually. Prevalence of myopia, hyperopia and astigmatism were 34.5%, 3.5% and 17%; 31.3% of the children needed spectacles correction (criteria adopted from Coulter et al. (2015) for special needs children. Those who had glasses (n=35), 23% did not reach visual acuity of log MAR 0.3. 26% (56/215) had abnormal NPC (> 6 cm), 3.4% (5/147) had binocular AA less than 10D, 29% (57/197) had stereo acuity worse than 100 minute of arc, 3.6% (8/216) failed the colour vision test, and 7.7% (17/220) of the children had strabismus, mostly exotropia. 5.5% (12/219) had ocular anomalies, which affected vision. Overall, 33.8% were referred for further management.

Conclusions: The special needs children in Hong Kong share a similar visual anomalies profile to special needs children elsewhere. Prevalence of uncorrected refractive error and anomalies in other visual functions were higher in these children than normal children. They will benefit from early vision screening, comprehensive eye examination, refractive errors correction to enhance their vision and hence their ability to learn in their educational environment.
Affiliation of Co-Authors School of Optometry, The Hong Kong Polytechnic University, Department of Ophthalmology, West China Hospital, Department of Ophthalmology, West China Hospital