Refractive errors in patients attending a private hospital in Jos, Nigeria

This study was carried out to determine the prevalence and pattern of refractive error in patients presenting to a private hospital.

Records of all patients who presented at the hospital from 2000 to 2009 with visual acuity (VA) of 6/9 or less and showed improvement in distance vision of one or more lines with refraction were reviewed. The eye with the better presenting visual acuity was used for classifying the patient. The spherical equivalent refraction was used with the formula (sphere plus cylinder/2).

Two thousand eight hundred ninety eight patients were seen at the hospital for various eye problems. Six hundred one (20.7%) patients with distant VA which improved with refraction were considered for this analysis. Two hundred twenty one (36.8%) of patients with refractive error were visually impaired (VA <6/12-3/60). Blindness (<3/60 - none perception of light) was seen in 91 (15.1%) of the patients, seven of whom were aphakic. Best corrected visual acuity increased the number of patients with normal visual acuity from 289 (48.1%) to 579 (96.3%). Overall visual impairment (VI) (<6/12-3/60) was reduced from 221 (36.8%) to 22 (3.6%). Severe visual impairment and blindness were completely eliminated just with refractive correction. Of those with refractive error, there were 35.8% with myopia, 29.5% with hypermetropia and 34.8% with astigmatism. Males had slightly more myopia and astigmatism, and female more hypermetropia though the difference was not statistically significant. Refractive error was seen more among the students 207 (34.4%) and civil servants 189 (31.4%) and least among the artisans 7 (1.2%). Anisometropia of ≤ 1 D, >1-2 D, >2-3 and > 3 D were found in 76.5%, 11.8%, 5% and 5.0% respectively.

The study shows that refractive error is a common cause of VI and myopia is the most common type. It confirms that most of the refractive error can be corrected with off-the-shelf spectacles.