Preoperative dry eye represents a risk of suboptimal refractive results following cataract or refractive surgery. Because of this, identifying at-risk individuals in the standard population is essential to optimizing outcomes, especially when refractive surgery is still gaining popularity to treat vision problems.

Tear osmolarity is an objective measure of dry eye; however, minimal literature is available to provide an understanding of incidence of hyperosmolarity in the population and its relationship with subjective dry eye parameters and clinical variables.

A retrospective study, presented recently at the ARVO annual meeting, offers an analysis of the largest current sample of osmolarity in a normal population and post-refractive patients.

In all, 1404 patients undergoing screening for refractive surgery from 2017 to 2020 were reviewed. Routine exam included dry eye testing with osmolarity and the Ocular Surface Disease Index (OSDI) questionnaire, and patients were instructed to refrain from topical eye drops for a minimum two hours before the appointment.

Results indicated normal tear film homeostasis by osmolarity testing in 82.3% of eyes; post-refractive surgery patients indicated higher mean OSDI values compared to the remainder of the population.

The researchers concluded that significant correlation exists between osmolarity scores and OSDI classification for the general population. Contact lens use correlated inversely with osmolarity and OSDI scores, while artificial tears correlated with OSDI scores in the post-refractive group only.

The authors noted that osmolarity and OSDI scores indicate that the majority of the standard population fall within normal ranges. “The impact of our findings may resonate” with surgeons and comanaging optometrists, “as a reasonable percentage of individuals will be diagnosed with tear film hyperosmolarity and represent a risk for reduced postoperative outcome and ocular comfort,” they concluded in their presentation.