A recent study has found that diquafosol ophthalmic solution may be more effective for treating dry eye compared to sodium hyaluronate solution, a conventional treatment for the condition. Dry eye is caused by abnormalities in tear film composition or tear volume, leading to inadequate aqueous coverage of the eye. This insufficiency can induce significant eye discomfort. Current treatments for dry eye include artificial tear, sodium hyaluronate, and corticosteroids, but each has its own imitations. As a result, there is high demand for a novel treatment method that can ameliorate this condition more successfully. The researchers in this study compared the effects of 3% diquafosol solution with 0.1% sodium hyaluronate solution in dry eye patients. Diquafosol is a P2Y2 receptor agonist. It activates this endogenous receptor on the ocular surface, promoting the secretion of water as well as the production of mucin, an essential component of tear film. Dry eye subjects were randomly assigned to receive the diquafosol solution or sodium hyaluronate solution, using a double blind model where both subjects and researchers were unaware of the treatment being administered to each subject. After a 2 week period during which baseline measurements were obtained and a placebo ophthalmic solution was given, the subjects entered a 4 week treatment period where they received either diquafosol or sodium hyaluronate, 1 drop at a time six times daily. Several parameters were used to evaluate the efficacy of diquafosol. Fluorescein staining score was used to determine whether diquafosol had a negative effect compared to sodium hyaluronate. The researchers found that both diquafosol and sodium hyaluronate treatment led to improvement in flourescein staining scores, with no significant difference in the amount of improvement. Therefore, it was concluded that diquafosol was non-inferior to sodium hyaluronate. Next, the changes in rose bengal staining scores were observed. This test measures the amount of ocular surface that is not fully covered by mucin. At the end of the 4 weeks, diquafosol treatment led to a significantly better improvement in rose bengal staining score compared to sodium hyaluronate administration. Subjective parameters were also evaluated, yielding mixed results. For example, diquafosol decreased perceived heaviness of the eye compared to sodium hyaluronate, but subjects who received sodium hyaluronate had a greater decline in eye discharge. Additionally, a higher percentage of subjects in the diquafosol group experienced adverse events, which included eye irritation, blepharitis, and eye pruritis. However, the researchers deemed these events to be mild and therefore not indicative of problems with the diquafosol treatment. With these results, the researchers concluded that diquafosol may be a more effective treatment for dry eye over sodium hyaluronate via its mucin-producing mechanism, pointing to the rose bengal staining score improvement as the primary statistic to indicate this superiority. It is interesting to note, however, that certain previous studies have yielded opposite results. Clearly, further studies must be conducted to fully understand the effects of diquafosol.
Diquafosol may be better than sodium hyaluronate for treating dry eye
- by Dr. Paul Krawitz
- 15 October, 2012