Medical hypothesis discovery and innovation in ophthalmology

Abstract

Background: Keratoconus (KC) is a progressive, asymmetric, usually bilateral disorder characterized by central or paracentral corneal thinning. Epidemiological data from the United Arab Emirates (UAE) remain limited. This study estimated the five-year clinic-based period proportion of attendees with recorded KC and described their demographic and clinical characteristics at UAE tertiary eye centers.
Methods: Retrospective cross-sectional study including unique patients aged greater than or equal to 10 years at their first eligible encounter who attended Magrabi Health Centers in Abu Dhabi, Al Ain, or Dubai between January 2020 and December 2024. Unique clinic attendees were identified from electronic medical records; KC cases were identified using a prespecified set of recorded keratoconus diagnosis codes within the ICD-10-CM H18.6 category. Universal systematic KC screening was not conducted for all attendees. The clinical records of KC cases were reviewed for demographic and ocular characteristics. Severity was categorized using a study-specific composite classification informed by selected Amsler–Krumeich and Belin ABCD criteria and based on available keratometric, refractive, pachymetric, and corneal-scarring data.
Results: Among 15,431 unique clinic attendees, 1,027 had recorded KC, corresponding to a five-year clinic-based period proportion of 6.66% (95% CI, 6.27% to 7.06%). The proportion differed significantly by age group, sex, nationality, and location (all P < 0.001). The highest age-specific proportion was observed among the 21–30 age group (14.07%), followed by the 31–40 age group (13.49%). In the exploratory adjusted analysis, compared to attendees aged less than or equal to 20 years the 21–30 age group had the highest adjusted odds ratio (aOR) for recorded KC (aOR = 4.15; 95% CI, 3.34 to 5.15), followed by the 31–40 age group (aOR = 3.85; 95% CI, 3.10 to 4.79). Males (aOR = 1.62; 95% CI, 1.40 to 1.86) and non-Emiratis (aOR = 1.86; 95% CI, 1.63 to 2.13) also had higher adjusted odds of recorded KC. Compared with attendees in Abu Dhabi, those in Al Ain (aOR = 0.46; 95% CI, 0.35 to 0.60) and Dubai (aOR = 0.28; 95% CI, 0.23 to 0.34) had lower adjusted odds. Bilateral involvement occurred in 77.9% (800/1,027) of KC cases. Category I was the most frequent study-specific composite severity category among affected right eyes (54.2%; 499/921) and left eyes (56.8%; 515/906). Corneal scarring was present in 6.7% (62/921) and 7.6% (69/906) of affected right and left eyes, respectively.
Conclusions: The five-year clinic-based period proportion of attendees with recorded KC was 6.66%. Exploratory adjusted analysis suggested that recorded KC is associated with age, sex, nationality, and location. These findings provide clinic-based epidemiological data on KC in the UAE but should not be interpreted as population prevalence.