Coloured contact lens impact on visual function and ocular surface integrity: legit vs non-legit sources contact lenses

Background: The popularity of purchasing coloured contact lenses (CLs) from non-optometry sources, such as night markets and online platforms, has risen due to cosmetic appeal. The rapid growth of e-commerce platforms that lack regulatory oversight is a concern to the safety, effectiveness, and quality control of these lenses to the wearers. Therefore, this article aims to investigate the changes in visual function, including visual acuity (VA) and contrast sensitivity (CS), as well as ocular surface integrity, encompassing corneal topography, corneal endothe0m, and central corneal thickness (CCT), in wearers of coloured CLs purchased from either optometry or non-optometry sources. Methods: A pilot study with five participants meeting the inclusion criteria were enrolled in this study. Preliminary assessments were conducted per the usual contact lenses clinic routine in the IIUM Optometry Clinic. The CL fit on the eyes was observed and noted. A double-masked crossover approach was used to reduce bias and enhance validity. Participants were randomly assigned to wear each type of coloured CL for one month, with a two-week washout in between. Measurements of VA, CS, mean K-reading, corneal endothelial cell density (ECD), and CCT were taken before lens usage, after one week, and after one month. A comparison of these parameters between the two types of CLs was made. Results: There were no significant differences in any measurements between lenses from optometry and non-optometry sources across all three time periods (p>0.05). Conclusion: The pilot study's findings suggest comparable effects on visual function and ocular surface integrity between coloured CLs obtained from optometry and non-optometry sources worn daily for a month.