Wednesday, 27 September 2017

Prevalence and Causes of Visual Impairment among Patients in Juaben Hospital Eye Clinic, Ghana

Visual impairment (VI) is a global health problem which affects all aspects of life. It presents educational, occupational and social challenges, with the affected persons being at risk of behavioral, psychological, and poor social integration. It does not only have significant effects on the lives of those affected but it also presents a large social and economic cost to the country. The World Health Organization (WHO) defines visual impairment (VI) as presenting visual acuity (PVA) that is worse than 6/18, but better and equal to 3/60 or a corresponding visual field (VF) loss of less than 20 degrees around the central fixation in the better eye with presenting optical correction if any. Blindness is defined as PVA of worse than 3/60, or a corresponding VF loss of less than 10 degrees around the central fixation in the better eye with presenting optical correction if any.

 Previously, estimates of VI were based on corrected vision, but in order to assess the magnitude of VI caused by uncorrected refractive errors (URE), estimates need to be based on presenting visual acuity. The estimated number of people visually impaired in the world is 285 million, of whom 39 million are blind. Age and gender affect VI and it has been reported that prevalence increases with age and women have a significantly higher risk of developing VI than men in every region of the world. It is estimated that globally, up to 75% of all blindness is avoidable (either preventable or treatable). Without intervention, the number of blind people might reach 76 million by 2020 because of a number of factors, primarily the rapid aging of populations in most countries. 

The principal causes of VI globally are uncorrected refractive errors (URE) and cataracts, 43% and 33 % respectively. Other causes are glaucoma, 2%, age related macular degeneration (ARMD), diabetic retinopathy, trachoma and corneal opacities, all about 1%. A large proportion of causes, 18%, are undetermined. The causes of blindness are cataract, 51%, glaucoma, 8%, ARMD, 5%, childhood blindness and corneal opacities, 4%, uncorrected refractive errors and trachoma, 3%, and diabetic retinopathy 1%, the other causes are 21%. There is inadequate data on the prevalence rate of VI and blindness in Ghana.The paucity of reliable information on this contributes to problems in designing and evaluating eye care services in Ghana. The purpose of this study is to provide useful information on the prevalence and causes of VI and blindness and their relationship with age and gender among patients who reported at the Juaben Hospital Eye Clinic.

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