Exploratory Pilot Study on the Tolerability and Ocular Surface Effects of Liposomal Ozonated Oil Compared with Standard Prophylaxis in Cataract Surgery. The CAREST Study

Purpose: To obtain preliminary data on the tolerability and ocular surface outcomes of liposomal ozonated oil compared with standard prophylaxis in cataract surgery. Patients and Methods: This open-label, prospective, contralateral-eye controlled pilot study included 60 eyes from 33 adult patients undergoing bilateral cataract surgery. For each patient, one eye was treated with liposomal ozonated oil (one drop, four times daily) from 3 days before surgery until 21 days postoperatively, while the contralateral eye received standard treatment. The study outcomes included treatment tolerability, postoperative infectious complications, ocular signs and symptoms, Tear Break-Up Time (TBUT), Ocular Surface Disease Index (OSDI), visual acuity, anterior chamber reaction (Tyndall effect), and patient-reported discomfort. Assessments were performed at postoperative day 21, with exploratory follow-up evaluations at month 3. Results: No postoperative infectious complications were observed in either treatment group. No significant between-group differences were observed in most evaluated ocular surface parameters at postoperative day 21 and month 3. At postoperative day 21, fewer patients in the liposomal ozonated oil group reported foreign body sensation and a higher proportion had TBUT > 10 seconds, although these differences were not statistically significant. At month 3, foreign body sensation was reported more frequently in the liposomal ozonated oil group, whereas no other significant between-group differences were observed. The majority of patients showed no anterior chamber reaction at postoperative day 21 (96.67%), and all patients reported good tolerability and no discomfort. Conclusion: Liposomal ozonated oil was well tolerated and showed comparable clinical outcomes to standard prophylaxis following cataract surgery. The findings of this pilot study suggest potential benefits for ocular surface outcomes that warrant confirmation in adequately powered studies with larger sample sizes and longer follow-up. No infectious complications occurred in either treatment group; however, the absence of events and the limited sample size preclude conclusions regarding its potential role in infection prevention. Clinical Trial Registration: The study was registered in the Spanish Registry for Post-Marketing Clinical Investigations with Medical Devices (NEOPS; Spanish Agency of Medicines and Medical Devices, AEMPS) under registration code 22– 0061.e (September 6, 2022). Keywords: cataract surgery, liposomal ozonated oil, ocular infections, OSDI, TBUT