Analysis of the relationship of the central tear meniscus area with the tear film symptomatology and stability

Abstract

Purpose: Tear film meniscus evaluation offers a non-invasive indication of the total volume of the tear. This study aimed to analyse the relationship between the central tear meniscus area with symptomatology and tear film stability. Material and methods: 120 participants who completed an OSDI questionnaire were enrolled in the study. After fluorescein installation, two videos were recorded by a digital camera attached to a slit-lamp. The first video recorded the lower central portion of the tear meniscus (6 o'clock) with a short light beam (3x5mm), and the second one recorded the complete ocular surface obtaining the Break-Up time (BUT) and Maximum Blink Interval (MBI). A self-design program (FWCapture) was used to acquire the videos while the participants were requested to keep the eye open for as long as possible three times. Images were extracted from each video by a masked observer. From de first video, the Central Tear Meniscus Area with fluorescein (CTMAF) was "manually" measured by using ImageJ software (command "<<freehand tool"). From the second video, BUT and MBI were determined by counting video frames and then converting in seconds; both parameters were averaged using only the two most similar measurements. Results: CTMAF showed a negative correlation with OSDI score (Spearman Rho: p <0.001, r=-0.372). There was a statistical difference in the CTMAF between OSDI subgroups (Kruskal-Wallis: p=0.001). CTMAF showed a positive correlation with BUT/MBI (Spearman Rho: both p <=0.003, r>=0.246). Conclusions: Tear film volume showed a relationship with the symptomatology and tear film stability.