Abstract:
In dry eye disease, patient–reported severity of symptoms may not agree with objective findings; however relief of patient symptoms is an important treatment objective along with preservation of ocular surface health. In a clinical trial of a new dry eye treatment, specific symptoms and signs are selected on the basis of the known or proposed mechanism of action of the agent tested. This study investigates the usefulness of several different subjective and objective variables used to assess the safety and efficacy of two emulsion–based artificial tears for dry eye treatment.
A new multi–dose emulsion–based artificial tear formula was evaluated in comparison to an existing unit–dose emulsion in a parallel, multi–center, randomized, investigator–masked clinical study. Entry criteria included presence of dry eye symptoms, current need for artificial tears, and reduced Schirmer or Tear Break–up (TBUT) scores. After entry, subjects were instructed to use one of the two formulas as needed, but at least 2 times a day. After 7, 30, 60, and 90 days, signs and symptoms of dry eye disease were measured.
158 subjects were enrolled in the study, of which 132 completed the 90–day visit. The figure illustrates the results as % change from baseline for the multi–dose emulsion (the unit–dose was similar). By day 90, there were significant decreases in symptoms of dryness, OSDI score, and conjunctival staining (p<0.001), and a significant increase in TBUT (p<0.001), with an improvement in Schirmer score and corneal staining (not shown) at some time points.
Treatment with an emulsion–based artificial tear produced consistent reduction in symptoms as measured with two methods. Signs also improved, with TBUT and conjunctival staining having the most consistent improvement across treatments and time points. This result is supportive of the proposed mechanism of action of these emulsions, in stabilizing the tear film through enhancement of the lipid layer. Further, these data stress the importance of selection of appropriate outcome variables for different types of dry eye treatments.
Keywords: clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled • cornea: tears/tear film/dry eye • clinical research methodology