Clinical Determinants and Adverse Reactions to Tropicamide/Phenylephrine in Hospitalized Patients.

This study is examining what factors — such as age, existing health conditions, and medications — predict who will have an adverse reaction to eye drops containing tropicamide and phenylephrine, which are routinely used to dilate the pupils before eye surgery. **You may be eligible if...** - You are older than 18 years - You have signed the informed consent form - You are a patient at the Instituto de Oftalmología Conde de Valenciana in Mexico City and are scheduled for a surgical procedure - Your doctor has prescribed two drops of tropicamide/phenylephrine (8 mg/50 mg/mL) for pupil dilation - You have any type of underlying medical condition **You may NOT be eligible if...** - You have a known allergy to any component of the eye drop formulation Talk to your doctor to see if this trial is right for you.