Figure 4: Mechanism of the development of corneal epithelial disorder suggested by the clinical history of this patient. The cytotoxicity of the surfactant may have added to the cytotoxicity of the main component and BAC in Lataronrost eye drops similar to that of Xalatan eye drops. Its use in combination with Timoptol XE eye drops, which decreases corneal sensitivity and lacrimal secretion, may have induced corneal disorder.