STUDY OF CAUSES AND PREVALENCE OF AMBLYOPIA EX-ANOPSIA IN KHARTOUM EYE TEACHING HOSPITAL

Abstract

Amblyopia or sometimes-called “lazy eye” is a poor vision in an eye that did not develop normal vision during early childhood. The best time to correct amblyopia is to detect it early by screening methods and treat it during infancy or early childhood. This study was carried out in Khartoum Eye Teaching Hospital (K.E.T.H) in the period from October 1996 to December 1997. Data was collected in a period of four months from 1st of January 1997 – 30th of April 1997. A total number of 3000 patients with defective vision were traced from the retraction department. Out of this number 200 were found to be amblyopic, while the remaining number were patients with refractive errors correctable with glasses or other means of correction. Out of the 200, 50 patients showed diseases of the retina and optic nerve (organic amblyopia), while 150 were patients with amblyopia exanopsia. The objective of this study is to detect the prevalence of amblyopia exanopsia and its different causes among patients attending K.E.T.H, which will reflect roughly the percentage of amblyopia ex-anopsia among Sudanese patients. Amblyopia was found in 5% of the total number in this current study. Males (51.3%) were more affected than females (45.7%). The majority of amblyopic patients (54.6%) were found in the age group from 16-30 years; followed by the age group 5-15 years and this is considered a late presentation. Younger age groups are not included in this study because very young children are not brought to the hospital by their parents for visual assessment; so amblyopia is not studied in this age group. Unilateral amblyopia was common in our patients (85.3%) than bilateral amblyopia (14.7%). Also left-sided amblyopes were 52.8% while right-sided were 42.2%. In this study the leading cause of amblyopia ex-anopsia was anisometropia (46.3%), anisohypermetropia (54.2%) being more than anisomyopia (45.8%). A combination of anisometropia and strabismus was detected in a considerable number of patients. The next common cause is strabismus (27%), esotropia seen in 90% of strabismic patients while exotropia (10%). Strabismus represents the leading cause of amblyopia at the age group from 5-15 years (63.6%). Regarding the high refractive errors as a third cause of amblyopia ex-anopsia the majority of patients were astigmatic (56.25%), next comes high myopia (31.25%) which is also the main cause of bilateral amblyopia and lastly high hypermetropia (12.5%). Stimulus deprivation amblyopia group had the least number of patients with a percentage of 5.3% and we believe that these patients are brought late by their parents seeking medical advise and greater number is expected to be seen if survey studies are done.