Study of Pupil Dilatation Characteristics in Patients from Southern India with a Single Drop of Topical Tropicamide-Phenylephrine

Abstract

Introduction: Dilatation of the pupil is essential for eye examinations and procedures, and when the characteristics are known it will help the clinical work flow. Tropicamide-Phenylephrine combination is the most commonly used dilating agent in ophthalmic clinical practice. Aim: To study the pupil dynamics and properties on dilatation with Tropicamide (0.8%) + Phenylephrine (5%) combination drops. Materials and Methods: This was a cross sectional observational study conducted on 132 eyes (right eye) from 132 patients. Baseline measurement of the pupil and pupil dynamics were noted after dilatation with a single drop of TropicamidePhenylephrine (5%). Pupil Diameter was measured with Optical Biometer at every 2 minutes till 44 minutes or till the patient achieved full dilatation. Data was analysed using t-test, MannWhitney U test and ANOVA was used to compare data between groups. Results: The average onset of dilatation in our study population was at 9.02±5.2 minutes (2 to 24 min) from the time of instillation of drops. The mean time taken for full dilatation was 33.02±5.09 minutes (22 to 42 min) with mean amplitude of 2.39±0.68 mm (0.9 to 4.2 mm). The rate of dilatation of the pupil was 0.07±0.022 mm/sec (0.03 to 0.14 mm/min). A 98.4% of patients maximally dilated in an average time of 33.03 minutes. Conclusion: Instillation of a single drop of TropicamidePhenylephrine combination drop was effective and provides adequate dilatation for all ophthalmological clinical situations.

Keywords

• optical biometer
• pharmacological dilatation
• pupil dynamics