Comparison of the lubricant eye drops Optive®, Vismed® and Cationorm® on the corneal healing process in an ex‐vivo model of the anterior ocular segment, the Ex Vivo Eye Irritation Test (EVEIT) System.

Abstract

Purpose Evaluation of the impact of lubricant eye drops on the corneal healing process and corneal toxicity. Methods Optive and Cationorm were tested regarding corneal irritability and effect on corneal healing against Vismed and 0.01% benzalkonium chloride (BAK) as negative and positive control. Formulas were applied hourly over 3 days on rabbit corneas cultured on artificial anterior chambers (Ex‐Vivo Eye Irritation Test (EVEIT) system). Five corneae were used for each substance except for BAK (n=1). Initially, four corneal abrasions (2 ‐ 5.4 mm²) were induced. All defects were monitored by fluorescein stains and photographes. Results Optive and Vismed showed a complete corneal healing on day 2. In one cornea (Optive) erosion reoccurred on day 3. Erosion sizes of Cationorm treated corneae increased significantly from 12.20 mm² to a subtotal erosion of 51.89 mm² on day 3. Histology revealed epithelial loss and severe alterations of the superficial stroma for Cationorm. Glucose and lactate concentrations were about unchanged after application of Optive and Vismed. In contrast, Cationorm and BAK treated cornea showed a significant increase in lactate concentrations. Conclusion Vismed application led to a rapid corneal healing. Whether the toxicity seen for Optive in one cornea is a valid result should be examined in a long term application study. Cationorm shows considerable corneal toxicity that could be caused by its additive, cetalkonium chloride. Otherwise, Cationorms electrostatic properties lead to a drug film on the area of epithelial loss that could hinders epithelial cell migration and adhesion to heal the lesion. Commercial interest