Prevalence of Keratoconus and Corneal Ectasia: a systematic review and meta-analysis

Abstract

keratoconus is the most common type of corneal dystrophy, characterized by a conical corneal bulge with progressive reduction in corneal thickness and bulging and irregular astigmatism. It is an inherited disease. The disease begins in adolescence and can last for 20 years. More than 90% of cases are bilateral. Objectives: Considering that many studies have been conducted on the prevalence of corneal ectasias such as keratoconus and its causes in different parts of the world, there is a need for a study that summarizes the results of these studies and provides a clear view of this information for planning , Make effective decisions and interventions. Therefore, the aim of this study was to systematically and meta-analyze the prevalence of corneal ectasias such as keratoconus in different countries and to investigate the risk factors associated with it. Methods: To find related studies, valid databases were searched. The articles and documents obtained from the search were entered into the statistical community in several stages in terms of title, abstract, and the entire text of screening and final studies that met the inclusion criteria. The studies were evaluated by 2 experts and evaluated using the STROBE checklist. Relevant data were extracted from the studies using the designed table and finally the data were analyzed and reported using CMA software and Random Effect model.

Findings: Out of 4727 studies, after applying the inclusion and exclusion criteria, finally 38 articles were included in the study. The overall prevalence of keratoconus was 55.4 per 100,000. In the study of the causes and risk factors of keratoconus, a positive family history 1.02 times, allergies 1.13 times, rubbing the eyes 6.7 times, allergic eye diseases 4.49 times, asthma 2.39 times, eczema 1.64 times and diabetes 1.19 times increase the chance of developing keratoconus.