Comparative Assessment of Tear Break-Up Time, Schirmer Test Values, and Oxidative Stress Biomarkers among Different Types of Soft Contact Lens Users

Abstract

Background: Soft contact lenses are widely used for vision correction and cosmetic purposes. Their long-term use may affect tear film stability affecting the ocular surface health. Oxidative stress may act as a possible mechanism behind contact lens-related dry eye symptoms.

Objective: To compare Tear Break-Up Time (TBUT), Schirmer test values, and oxidative stress biomarkers among different types of soft contact lens users and healthy controls.

Methods: This comparative cross-sectional study was conducted at LRBT Tertiary Teaching Eye Hospital, Lahore, Pakistan, during July to December 2025. A total of 150 participants were enrolled through consecutive sampling. The participants were divided into daily disposable lens users (n=50), monthly replacement lens users (n=50), and healthy controls (n=50). TBUT, Schirmer I test, and tear oxidative stress biomarkers were measured and compared among groups.

Results: Significant differences were observed among the study groups. Mean TBUT was 10.2±2.1 seconds in daily disposable users, 8.1±1.9 seconds in monthly replacement users, and 13.4±2.3 seconds in controls (p<0.001). Mean Schirmer values were 15.3±3.1 mm, 12.8±2.7 mm, and 19.6±3.4 mm, respectively (p<0.001). MDA levels were highest in monthly replacement users (4.82±0.91 nmol/mL) and lowest in controls (2.41±0.63 nmol/mL) (p<0.001). SOD and TAC levels were significantly lower among contact lens users (p<0.001). MDA showed a significant negative correlation with TBUT and Schirmer values.

Conclusion: Soft contact lens wear is associated with reduced tear film stability, decreased tear secretion, and increased oxidative stress. Monthly replacement lenses showed greater adverse effects than daily disposable lenses.