Related Experiment Video
Updated: Jul 24, 2026

A Step by Step Protocol for Subretinal Surgery in Rabbits
Published on: September 13, 2016
A combination solution for routine pupillary dilation
David M Krumholz1, Joan K Portello, Mark Rosenfield
1Department of Clinical Sciences, State University of New York, State College of Optometry, New York, New York 10036, USA. dkrumholz@sunyopt.edu
Background:
This study investigated the ability of a combination drop containing reduced concentrations of tropicamide and phenylephrine to produce pupillary dilation adequate for routine fundoscopy.
Methods:
One eye of each subject (N = 28; age range, 21 to 40 years; median, 23 years) was dilated with 1 drop of a solution containing 0.5% tropicamide and 2.5% phenylephrine (0.5T/2.5P). The other eye was dilated with 1 drop of either of 2 mixtures: 0.5% tropicamide and 1.25% phenylephrine (0.5T/1.25P, N = 15; median age, 23 years), or 0.25% tropicamide and 1.25% phenylephrine (0.25T/1.25P, N = 13; median age, 23 years). A topical anesthetic was administered before instilling the mydriatic agents. Pupil diameter was measured from a flash photograph taken every 15 minutes for 3 hours. There was no significant difference in pupil diameter between eyes dilated with the 0.5T/1.25P test solution and the 0.5T/2.5P control solution for the first 75 minutes after instillation (P = 0.41). All pupils reached their maximum diameter 60 minutes after drop instillation; where no significant difference was observed between the 3 mydriatic solutions (P = 0.81). All pupils were at least 7 mm in diameter 30 minutes after drop instillation, and this size was maintained for at least another 75 minutes for all solutions.
Conclusions:
Combination preparations of reduced concentrations of tropicamide and phenylephrine can produce clinically adequate mydriasis.
Related Concept Videos
Direct-Acting Cholinergic Agonists: Pharmacological Actions
Direct-Acting Cholinergic Agonists: Therapeutic Uses
Open Angle Glaucoma: Treatment
Drugs such as carbonic anhydrase inhibitors, α2- and...
Ophthalmic Drug Delivery Systems

