Effectiveness of Dry Eye Therapy Under Conditions of Environmental Stress

Abstract

Purpose: Dry eye is often characterized by increased tear evaporation due to poor tear film quality, especially of the lipid component of the tear film. Using an environmental chamber to induce environmental stress, this study compared the effect of three lubricant eye drops on various aspects of tear physiology in a crossover design (evaporation was the principal outcome measure). Methods: Three eye drop formulas were tested: 0.5% carmellose sodium (Drop C), 0.5% carmellose sodium with added lipid (Drop C-L) and 1.0% glycerine with added lipid (Drop G-L). Nineteen control and 18 dry eye subjects used each product for 2 weeks, three times per day, in a random order, with a minimum 1-week washout between treatment periods. Tear evaporation, break up time, osmolarity, tear structure (by interferometry) and patient symptoms were assessed with the subjects adapted for 10 min in an environmental chamber controlled at 20% relative humidity and 22 °C. The treatment effects were analyzed using general linear model repeated measures analyses of variance. Results: In dry eye subjects, evaporation, break up time, osmolarity and symptoms improved for all formulas (p < 0.05). Normal subjects showed some improvements: evaporation with C-L, osmolarity with C and symptoms with C-L and G-L. Change in evaporation was greater for both C-L and G-L versus C (p < 0.05), and there was a trend for C-L to reduce evaporation more than G-L (p < 0.11). There were no significant treatment effects on tear film structure. Conclusion: Overall, the eye drop formula containing both carmellose sodium and lipid (C-L) produced a greater treatment effect on tear evaporation than the other formulations containing only one of these ingredients. This study also demonstrates the utility of a controlled environmental chamber in showing the difference in performance between dry eye treatments.

Efficacy, Safety, and Acceptability of a Lipid-Based Artificial Tear Formulation: A Randomized, Controlled, Multicenter Clinical Trial

“…In a direct comparison of the lipidcontaining formula ADV2 with an aqueous-only eye drop, a similar reduction in dry eye symptoms was reported, but with a greater reduction in tear film evaporation after 2 weeks of dosing, 24 suggesting that the formulation of ADV2, with a reduced lipid content for improving tolerability while maintaining the benefits of the lipid, was effective. Those findings are consistent with the results from the present study demonstrating improvements in all groups in TBUT, a marker of tear film stability that may directly relate to Table I for treatment and formulation information.…”

Over the counter (OTC) artificial tear drops for dry eye syndrome

“…Twenty trials were reported as being double-masked (Baeyens 2012; Bron 1998a; Christensen 2009; Cohen 2014; Johnson 2008; Nelson 1988; Tomlinson 2013), single-masked (Foley-Nolan 1995), masked (Simmons 2007), masked-observer (Lee 2011) or investigator-masked trials (Aguilar 2014; Benelli 2010; Brodwall 1997; Bron 1998b; Donshik 1998 Trial 2; Donshik 1998 Trial 3; Khanal 2007; Kislan 2008; Simmons 2004a; Xiao 2008), but insufficient details were provided as to how masking was performed. Iester 2000 did not report masking.…”

Artificial tears potpourri: a literature review

“…Allergan funded a project studying the efficacy of Refresh Tears ® , Refresh Ultra ® , and Refresh Optive ® in relieving the signs and symptoms of dry eye 43. A total of 37 participants completed the study; 18 with a history of dry eye and 19 controls without a history of dry eye.…”