Date of Award
Master of Science in Vision Science
Background: The purpose of this study was to asses the efficacy of a humanitarian eye clinic and with this data determine the prevalence of legal blindness and visual impairment due to refractive error in Ghana, Africa.
Methods: A humanitarian eye clinic was established for 5 days in surrounding villages of Kumasi, Ghana. 1125 patients were evaluated for refractive error and ocular health. An entering visual acuity was taken both at distance and near and an exiting visual acuity was taken after a spectacle correction was dispensed, at both distance and near.
Results: Out of the 1125 patients, a total of 923 records were complete. 182 distance spectacle corrections and 264 near corrections were dispensed within the usable study sample. Hyperopia and presbyopia were the foremost causes of reduced entering acuity in the patient population. The most prevalent ocular disease was cataracts, totaling 145 patients. Of this population, 50 (34.5%) demonstrated improved acuity with spectacle correction. Average entering acuity of the patients with cataracts was 20/87.5, exiting with a mean of 20/78.4. The mean of the reduced distance entering acuity group was 20/59.2, with a mean exiting acuity of 20/29.7 after spectacle correction. The mean of the reduced near entering acuity group was 20/62.0, with a mean exiting acuity of 20/24.9 after spectacle correction. Of the 923, 68 (7%) patients had an entering distance acuity that met the criteria for legal blindness, while 53 (6%) exited with legal blindness after spectacle correction. Eighty-six (9%) patients entered as visually impaired in the distance and only 49 (5%) exited as visually impaired. Those with 20/70 or worse vision at near made up 196 (21%) patients, while only 73 (8%) exited as visually impaired.
Conclusion: With the provision of spectacle corrections at near and far, the prevalence of preventable visual impairment and blindness was markedly reduced in this underserved population. These results, especially the improvements in near vision, add to the mounting body of evidence that uncorrected refractive error accounts for a larger proportion of visual impairment in underserved populations worldwide than ocular disease conditions.
Bement, Ashley; Sundstrom, Erin; and Dreher, Carla, "The prevalence of legal blindness and visual impairment due to refractive error from a humanitarian vision clinic in Ghana, Africa" (2007). College of Optometry. 1528.