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Tear Clearance Rate Assessment with a Modified Slit Lamp Biomicroscope
1Visual Optics Group, Cathedral of Optics and Photonics, Department of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wrocław, Poland. Izabela.garaszczuk@pwr.edu.pl.
Summary
A new slit lamp biomicroscope method accurately measures tear clearance rate (TCR), a key indicator for diagnosing dry eye disease (DED). This accessible technique shows strong correlations with established DED diagnostic markers.
Area of Science:
- Ophthalmology
- Biomedical Engineering
- Clinical Diagnostics
Background:
- Tear clearance rate (TCR) is a traditional marker for dry eye disease (DED).
- Conventional TCR assessment via fluorophotometry requires specialized equipment and expertise, limiting its clinical use.
- There is a need for a more accessible and clinically feasible method to evaluate TCR.
Purpose of the Study:
- To develop and validate a clinically accessible method for assessing TCR using a modified slit lamp biomicroscope.
- To evaluate the feasibility of this new method in distinguishing between dry eye patients and healthy controls.
- To correlate TCR measurements with established DED diagnostic parameters.
Main Methods:
- A cross-sectional study involving 95 participants (65 with DED, 30 controls).
- Fluorescein dye instilled, and tear fluorescence intensity decay recorded over 5 minutes using a smartphone-equipped slit lamp biomicroscope with narrow-band filters.
- Custom software quantified fluorescence intensity and calculated TCR; symptom questionnaires (OSDI, DEQ-5), tear osmolarity, and other ocular surface parameters were also assessed.
Main Results:
- The modified slit lamp biomicroscope method successfully differentiated between DED and control groups.
- TCR₀.₅₋₂ (fluorescence decrease between 0.5 and 2 minutes) showed the strongest discriminatory power (6.9% vs. 13.8%, p < 0.01).
- Early-phase TCR correlated significantly with DED severity, OSDI, DEQ-5, ocular surface staining, and non-invasive tear film break-up time (NIKBUT).
Conclusions:
- A modified slit lamp biomicroscope enables clinically feasible assessment of TCR.
- This method effectively distinguishes between individuals with and without DED.
- The findings support the use of this accessible technique as a valuable tool in DED diagnosis and management.
