Impact of Dim Light Exposure during Study on Tear Film Break-Up Time (TBUT) in Medical Students

Abstract

Background: Tear Film Break-Up Time (TBUT) is a key parameter that is used for assessing the stability of tear film.

Objectives: To determine impact of exposure to dim light while studying on TBUT in medical students.

Methods: This cross-sectional analytical study was conducted on undergraduate medical students (18–26 years) at Al Tibri Medical College and Hospital, Karachi, over six months (Jan 2021–June 2021). Using non-probability consecutive sampling, students studying ≥2 hours/day were included. Lighting was measured with a lux meter (<300 lux = dim, ≥300 lux = adequate). TBUT was assessed via fluorescein and slit lamp, and data were analyzed with SPSS using t-tests and chi-square tests (p<0.05).

Results: From 357 students, 41.7% studied under dim light and 58.3% under adequate light. Mean TBUT was significantly lower in the dim light group (8.2 ± 2.1 sec) compared to adequate light (11.4 ± 2.6 sec, p<0.001). Abnormal TBUT (<10 sec) was more prevalent in dim light (69.8%) versus adequate light (29.8%), indicating a strong association between dim light exposure and tear film instability.

Conclusion: Dim light exposure during study significantly reduced TBUT and increased tear film instability in students. A future interventional or longitudinal research ought to be carried out for confirming causality.

Keywords: Tear Film, Dry Eye, Dim Light, Tear Film Break Up Time.