Causes of Low Vision among Children & Adult Patients Presenting At Low Vision Clinic of Mayo Hospital, Lahore.

Abstract

Objectives: To study the causes of low vision among children and adult patients presenting at low vision clinic of Mayo Hospital, Lahore. Materials & Methods: A cross sectional study was conducted on the patients presenting at Low Vision Clinic of Mayo Hospital Lahore, from September, 2008 to November, 2008, with non probability convenient sampling method. The visual acuity of each eye was assessed using Log MAR chart, Fein bloom chart and Lea symbols. Refraction was performed in all cases. All the patients after refraction were prescribed spectacles, telescopes, stand magnifier, filters and near spectacles necessary. Visual field was tested by simple confrontation method. Color vision was tested by Ishihara chart. Contrast sensitivity was also measured by contrast sensitivity chart. Posterior segment examination to investigate the cause of Low Vision was undertaken after dilating the pupil. Results: 48% of patients had low vision due to retinitis pigmentosa and nystagmus 24% each. Third major cause of low vision was age related macular degeneration which affected 9% of adult population. Some other causes of low vision included maculopathy 8%, refractive errors 7%, diabetic retinopathy 4%, glaucoma, pseudophakia, corneal opacity 2% each, phthisis bulbi 1% and 16% others. Conclusion: Retinitis pigmentosa and nystagmus were the major causes of low vision affecting 48% of patients. Age related macular degeneration and diabetic retinopathy were affecting only the adult population. 59% of the patients having unavoidable cause of low vision, where as 24% have avoidable causes of low vision.  16% of patients have other causes of low vision. Child population comparatively needs more specialized curative services because of concept of disability adjusted life years.