Development of an algorithmic approach for the early detection and management of keratoconus.

Abstract

Empirical evidence, supported by anecdotal evidence suggests that some Keratoconic pre-pubescent children present for their first clinical examinations with advanced signs of KC and visual impairment that cannotr be corrected with readily accessible optical aids. This is evidenced by higher prevalences of KC reported in some African communities. This negatively impacts on the lives of these children and hinders the practitioner’s capacity to successfully manage the patient and provide good functional vision, often resulting in visual impairment. The study set out to verify this observation and to offer a potential solution to the problem that is the late presentation of young subjects with KC residing in Harare. Method: A questionnaire, Visual acuity check, retinoscopy and anterior segment assessment were used to award subjects attending primary school in urban Harare aged 6-12years a keratoconus risk score as per scoring sheet developed. A comprehensive exam including refraction, slit lamp exam and keratometry were then performed on the high-risk subjects for the diagnosis of clinical KC. Topography, contrast sensitivity measurement and pachymetry map analysis were then performed for the diagnosis of pre-clinical KC. Results: 1159 subjects were recruited, 57% were female, 99% of African ethnicity and Christian background. Prevalence of clinical KC was found to be 630: 100 000 and pre-clinical KC was found to be 1360:100 000. Anterior surface abnormalities were present in 30% of the subjects considered to be high risk for the development of KC. The age range of the subjects diagnosed with clinical KC was 8-12years. VKC, reduced VA, itchy eyes and eye rubbing were the most frequently encountered symptoms. Conclusion: The odds of having KC are increased if the child is aged between 8 and 12 years and of African ethnicity, regardless of gender. Increased probability of developing KC was found in the presence of VKC, reduced VA, itchy eyes and frequent eye rubbing.. The early detection and management algorithm developed will allow for the timely diagnosis of KC and in turn offer improved prognosis as the earlier management of the condition will be possible with all treatment options still viable.