Dynamic distribution of artificial tears on the ocular surface

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Corneal Science

Background:

• Dry eye disease affects millions globally, necessitating effective artificial tear formulations.
• Artificial tears aim to supplement or replace natural tear film components.
• Understanding the rheological properties of artificial tears is crucial for optimizing their efficacy.

Purpose of the Study:

• To investigate the impact of artificial tear viscosity on key ocular surface parameters.
• To quantify changes in tear film thickness, tear menisci, and tear volume using optical coherence tomography (OCT).
• To compare the short-term effects of different artificial tear formulations.

Main Methods:

• Healthy participants (n=20) underwent OCT imaging of the tear film and menisci.
• Various artificial tears with differing viscosities (1-70 cP) and an isotonic control were instilled.
• Measurements of tear film thickness, tear meniscus dimensions, and tear volume were taken at multiple time points post-instillation.

Main Results:

• All tested artificial tears and saline increased tear film thickness, tear menisci height, radius, area, and estimated tear volume immediately after instillation (P < .001).
• Tear film thickness remained elevated for 5 minutes, while other parameters returned to baseline within 5 minutes.
• More viscous artificial tears led to greater increases in tear film thickness and lower tear meniscus variables at the time of instillation (P < .05).

Conclusions:

• Optical coherence tomography is effective in evaluating the dynamic effects of artificial tears.
• All tested artificial tear preparations, including saline, transiently improve tear film parameters.
• Artificial tear viscosity is a significant factor influencing immediate post-instillation ocular surface hydration.