ASCRS 2025: Amar Shah, MD, on why hyperosmolar tear film before and after cataract surgery matters

Amar P. Shah, MD, of Mid Ohio Eye, presented new findings on tear film hyperosmolarity and its implications for cataract surgery outcomes during the 2025 American Society of Cataract and Refractive Surgery Annual Meeting, held April 25–28 in Los Angeles, California. “One central feature of dry eye disease is hyperosmolarity of the tear film,” Shah emphasized, highlighting its role in initiating inflammatory cascades, cellular damage, and tear film instability.

For cataract patients, this is more than a dry eye concern—it has direct surgical relevance. A hyperosmolar tear film can compromise preoperative measurements, potentially skewing keratometry and biometry values and leading to inaccurate IOL power calculations. Even with precise biometry, patients may experience visual fluctuations postoperatively due to tear film–induced light scatter. “It might be going from blurry to clear and bouncing all over the place,” Shah explained.

Shah’s study identified 3 key findings:

1. Postoperative Emergence of Hyperosmolarity: Remarkably, 30% of patients with normal preoperative osmolarity became hyperosmolar 1 month postoperatively. “All of a sudden 1 month after surgery, when they should be kind of healed, they're hyperosmolar,” he noted.
2. Limited Resolution in Hyperosmolar Patients: Only 50% of preoperatively hyperosmolar patients normalized postoperatively, despite standard regimens of antibiotics, steroids, and NSAIDs. Shah remarked, “The fact that still half of patients in that group were hyperosmolar was telling.”
3. Persistent Hyperosmolarity: Across all patients, nearly 40% remained hyperosmolar 1 month postoperatively, underscoring the need for greater preoperative attention to ocular surface health.

These findings suggest that osmolarity testing could play a more routine role in cataract evaluations. “It’s an additional piece of evidence that could potentially identify patients that may be at risk for ocular surface issues,” Shah said. While surgery was not delayed based on osmolarity in the study, Shah suggested elevated values could justify treatment before proceeding. Furthermore, tear osmolarity could be a valuable diagnostic tool in postoperative patients with unexplained visual dissatisfaction.

He noted that the data support a paradigm shift: integrating tear film osmolarity into pre- and postoperative workflows could significantly enhance refractive accuracy and patient satisfaction.