Chronic use of contact lenses and its long-term effects on corneal health

Background: The use of contact lenses made from soft hydrogel and silicone hydrogel materials can lead to multiple eye problems especially concerning corneal health. This research aims to determine the long-term effects of soft hydrogel and silicone hydrogel contact lenses on corneal thickness and shape together with tear film production and neovascularization. Objective: The research objective was to analyze the prolonged contact lens use effects on corneal health throughout twelve months by measuring corneal thickness and shape together with tear production and neovascularization presence. Materials and Methods: A prospective observational study took place at Tikrit Teaching Hospital in Iraq between April 2024 and December 2024. A total of 200 participants were divided into two groups (Group A received Soft Hydrogel contact lenses and Group B received Silicone Hydrogel contact lenses). Participants received ocular examinations at the start and at four time points (3, 6, 9 and 12 months) that included Optical Coherence Tomography (OCT) measurements of corneal thickness as well as corneal topography analysis and slit-lamp examination and tear film assessment. Results: The corneal thickness of Group A (Soft Hydrogel) decreased while corneal irregularity and neovascularization increased compared to Group B (Silicone Hydrogel). The tear production of Group A decreased more dramatically than Group A while the participants experienced more severe dry eye symptoms. Conclusion: Soft hydrogel lenses led to major corneal changes and complications that resulted in reduced thickness and irregularity and neovascularization. The higher oxygen permeability of Silicone hydrogel lenses resulted in fewer adverse effects which makes them the preferred choice for extended contact lens use.