Short-term effect of non-preserved cationic oil in-water ophthalmic emulsion on tear meniscus parameters of healthy individuals in a prospective, controlled pilot study

Abstract Background: This study investigated the effect of instilling a single drop of non-preserved cationic oil-in-water ophthalmic emulsion (Cationorm®) on the lower (LTM) and upper tear meniscus (UTM) parameters of normal eyes. Methods: In this prospective, single-center, non-randomized, controlled pilot study, optical coherence tomography was used to estimate the UTM and LTM height, depth, and cross-sectional area in participants without a history of dry eye disease. In the right eye (study eye), we instilled one drop of Cationorm® in the lower conjunctival sac. Scans of the tear menisci were acquired at baseline, before the instillation, and at ۵, ۱۵, and ۳۰ min thereafter. Control scans of the left eye (control eye) were obtained at the same timepoints. The tear meniscus parameters of the study eye were compared with the control eye at each timepoint. Results: Twenty subjects (۱۱ male and ۹ female; mean ± standard deviation of age: ۳۷.۸ ± ۱۰.۹ years) were included in the study. Compared to the control eye, instillation of a single drop of Cationorm® resulted in significantly higher LTM parameter values and a higher UTM cross-sectional area up to ۳۰ min after instillation (all P < ۰.۰۵). The UTM height and depth were significantly greater in the study eye than in the control eye up to ۵ min (P < ۰.۰۰۱ and ۰.۰۰۷, respectively) and ۱۵-min (P = ۰.۰۴۵, and ۰.۰۰۲, respectively) after Cationorm® instillation. In the study eye, Cationorm® resulted in a significant increase in LTM parameter values up to ۳۰ min post-instillation (all P < ۰.۰۰۱). The UTM height was significantly greater up to ۱۵ min post-instillation than at baseline. The UTM depth and area increased significantly from baseline to ۵ min after instillation (P = ۰.۰۴۳, and ۰.۰۰۲, respectively). Conclusions: Cationorm® seems to have a prolonged residence time on the ocular surface of healthy subjects as indicated by LTM parameters and to a lesser extent by UTM parameters.