Causes of blindness and low vision in Bayelsa State, Nigeria: a clinic based study

Abstract

Background: No data are yet available on the causes of blindness and low vision in Bayelsa State of Nigeria.

Objective: The study is to provide baseline data on the causes of blindness and low vision in Yenagoa, Bayelsa State, Nigeria.

Methods: A prospective study was conducted among new consecutive patients presenting at the eye clinic of Niger Delta University Teaching Hospital.Patients with visual acuity of less than 6/18 in the better eye after optical correction or with pin hole as necessary were studied. Their visual acuity was determined using a snellen chart followed  by anterior and posterior segment examination using a Haagstreit slit lamp biomicroscope and direct or indirect ophthalmoscope respectively(Keeler).Other information obtained from patients included their age, sex and occupation. Main outcome measure:Visual acuity <3/60 in the better eye and visual acuity <6/18 in the better eye.

Statistical analysis: Statistical analysis was done using a scientific calculator.

Results: Over a period of one year,230 patients presented with visual impairement consisting of 124 blind cases and 106 cases of low vision.Their ages ranged from 3 to 90 years with a mean of 48 years.There were 118 males and 112 females giving a male:female ratio of 1:1.1. Cataract and glaucoma were the leading causes of blindness and low vision. Cataract was responsible for 63% of blindness and 49.8% of low vision while glaucoma accounted for 22% of blindness and 17.9% of low vision. The other causes of blindness in decreasing order includes maculopathy (4.3%), retinitis pigmentosa (3.4%), optic atrophy, phtisis bulbi, keratopathy (each 2.6%) and age related macular degeneration (0.9%).The other causes of low vision in decreasing order includes refractive error(15%), maculopathy(5.6), optic atrophy (3.8%), retinitis pigmentosa, retinopathy (each 2.8%) and age related macular degeneration (1.9%). Majority of blindness is avoidable (93.5%), and found in the fifth and sixth decades of life. 

Conclusion: Cataract and glaucoma are the predominant causes of blindness and low vision in the study population and majority of the blindness(93.5%) is avoidable. A more aggressive approach to clear cataract back log and improvement of early diagnosis and treatment of glaucoma are needed to combart blindness in this community.

Keywords: Blindness, low vision, cataract, glaucoma, Yenagoa, Nigeria