Visual function among commercial vehicle drivers in the central region of Ghana.

Aim: To determine the relationship between some visual functions: colour vision defects, abnormal stereopsis, visual acuity and the occurrence of road traffic accident (RTAs) among commercial vehicle drivers in the central region of Ghana, and to assess their knowledge of these anomalies.
Method: A descriptive cross-sectional study employing a multi-stage random sampling approach was conducted in the major commercial towns within the central region of Ghana. Participants were taken through a comprehensive eye examination after the administration of a structured questionnaire.
Results: 520 male commercial vehicle drivers were enrolled for this study with a mean age of 39.23 years ±10.96 years and mean visual acuity of 0.02±0.08 logMAR. Protans were more likely to be involved in RTAs (χ(2)=6.194, p=0.034). However, there was no statistically significant association between abnormal stereopsis (OR=0.89 95% CI: 0.44-1.80, p=0.56), poor vision due to refractive error (χ(2)=3.090, p=0.388) and the occurrence of RTAs. While 86.9% were aware of abnormal stereopsis, only 45% were aware of colour vision defects. There was a statistically significant association between stereopsis anomaly and colour vision defect (r=0.371, p<0.005).
Conclusion: The study found an association between protanopia and RTAs but none between stereopsis anomalies, refractive errors and the occurrence of RTAs. Drivers were less knowledgeable on colour vision defects as compared to stereopsis anomalies.
(Copyright © 2015 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.)