Comparative mydriatic efficacy between mixture containing 0.8% tropicamide 5% phenylephrine and 0.4% and tropicamide 2.5% phenylephrine: A prospective analytical study

Abstract

Background This study is conducted to know the efficacy of mydriasis of diluted commercially available combination drop of tropicamide and phenylephrine. The pupillary dilation achieved with 0.8% tropicamide and 5% phenylephrine is compared with that of 0.4% tropicamide and 2.5% phenylephrine. Methods In this prospective analytical study conducted in 100 patients, one eye of each patient was dilated with combination drop of 0.8% and 5% phenylephrine and the other eye was dilated with a diluted concentration of the same eye drops. The drops were instilled at an interval of 10 minutes for 3 times. Mydriasis was recorded at 10, 20, 30, 40 and 60 minutes and difference between the two eyes was observed. Results The combination of 0.4% Tropicamide and 2.5% phenylephrine has produced an adequate mydriasis (8mm) at 30 and 40 minutes interval with a statistically significant p value of 0.045 and 0.042 respectively. The proportion of patients who required an additional application of drops after 60 minutes interval was statistically insignificant (p= 0.498). The progression of the pupil dilation at 20, 30and 40 minutes was found to be statistically significant with p values of 0.020, 0.003 and 0.022 respectively. A statistically significant difference was found in the dilation between the diabetic group and non-diabetic group at 40 and 60 minutes (p<0.001). Conclusion The diluted mixture was effective enough to produce an adequate mydriasis for intraocular examination. During the process of attaining an adequate mydriasis it also showed a significant progression in the pupillary dilation. The use of this mixture would possibly reduce the occasional adverse effects of the combination drops of higher concentrations especially in patients with co-morbid systemic conditions.