Prevalence and factors associated with keratoconus among high school students in Trinidad and Tobago: A cross-sectional population-based study

Background: This study aimed to determine the prevalence of keratoconus (KC) among high school students in Trinidad and Tobago (T&T) and identify associated factors. 

Methods: This cross-sectional study was conducted using multi-stratified random sampling. Data on family history, eye rubbing, demographics, and clinical measures (visual acuity, autokeratorefraction, retinoscopy, corneal topography, optical coherence tomography (OCT), and slit-lamp biomicroscopy) were analysed. KC diagnosis was based on clinical signs, topographic and Optical coherence tomography (OCT) findings, and slit-lamp indicators. 

Results: A total of 2,084 students participated (mean age±SD = 14.0 ± 1.60 years; 58.9 % female). The prevalence of KC was 2.88 % (95 % CI: 2.22–3.69 %). Most cases of KC were stage 1 (78.3 %), and only 3.3 % were previously diagnosed. KC was more common among males (53.3 %), people of East Indian descent (56.7 %), and those residing in the urban areas (36.7 %). Multivariable analysis adjusting for potential covariates revealed that family history of KC (OR 2.56, 95 % CI: 1.11–5.93), rural residency (OR = 2.82, 95 % CI: 1.50–5.31) and grade level (higher odds for Form 1 students OR = 12.34, 95 % CI: 1.64–93.07) were significantly associated with higher odds of KC whereas female sex (OR = 0.56, 95 % CI: 0.33–0.94) was associated with a lower odd of KC. 

Conclusion: The study found that about 3 % of high school students, mostly males, those with an East Indian background and people with a positive family history in T&T had KC. These findings highlight the need for early targeted screening for at-risk individuals and population-based studies to further explore risk factors and inform preventive strategies.