Comparison of Three Lubricant Eye Drop Solutions in Dry Eye Patients

Purpose: Lubricant eye drops that restore physiological osmolarity represent a promising strategy for dry eye syndrome as hyperosmolarity plays a central role in this disease. This preliminary study compared three lubricant eye drop solutions with different osmolarities and compositions in subjects with this condition.

Methods: Subjects with dry eye syndrome undergoing treatment with benzalkonium chloride-containing lubricant eye drops were randomized to Carnidrop (n = 9), Optive (n = 9), or Blu Sal (n = 9). Fluorescein break-up time (FBUT) and Ocular Protection Index (OPI) were measured at baseline, 15 min, and 60 min after instillation to evaluate the stability and quality of the tear film.

Results: At 15 min, a significant increase in FBUT vs. baseline was reported with Carnidrop (from 2.0 ± 0.8 to 4.8 ± 2.0; p = 0.004) but not in patients who received Optive or Blu Sal. At 60 min, FBUT was significantly increased vs. baseline with Carnidrop (from 2.0 ± 0.8 to 6.0 ± 2.8, p = 0.001) and Optive (from 2.9 ± 2.8 to 4.3 ± 2.9, p = 0.004) but not with Blu Sal. At 15 min, OPI was significantly increased from baseline in only the Carnidrop group (from 0.4 ± 0.2 to 1.0 ± 0.4, p = 0.003). This increase was significantly greater with Carnidrop than with Blu Sal (p = 0.003). At the 60 min evaluation, OPI remained significantly increased from baseline in only the Carnidrop group (p = 0.003).

Conclusions: Carnidrop produces a larger increase in FBUT and OPI than Optive and Blu Sal in subjects with dry eye syndrome over a 1 h period, possibly because of its hypo-osmolarity and high osmolyte (in particular L-carnitine) content. The instillation of compounds that improve the quality and stability of the tear film, which are impaired in dry eye syndrome, could be effective in the treatment of this condition.