This study evaluated pupil dilation after administration of fixed combination tropicamide-phenylephrine (TR/PH) vs. placebo. Participants attended 3 visits. At each visit, after baseline measurements, either the study drug or placebo was administered to both eyes, then pupil dilation and safety assessments were performed at specific time intervals.

Volunteer participants were screened for study eligibility during a Screening Visit and enrolled after signing the study-specific informed consent form. Subjects meeting all inclusion/exclusion criteria were scheduled for 3 treatment visits, which were at least 2 days, but no more than 7 days apart. At each treatment visit, baseline measurements were taken, then either the study drug or placebo was administered to both eyes. Afterwards, efficacy and safety assessments were performed at 20, 35, 50, 65, 80, 120, and 180 minutes. Participants' treatment assignments for each treatment visit were equally randomized using 1 of 2 sequences - ABB or BAA, where A was the study drug and B was the placebo.

Inclusion Criteria:

• Ability to provide written consent and return for all study visits
• Photopic pupil diameter <= 3.5 mm in each eye

Exclusion Criteria:

• Allergy to phenylephrine hydrochloride, tropicamide, or benzalkonium chloride
• History of benign prostatic hyperplasia
• Use of a benzodiazepine, monoamine oxidase inhibitor, tricyclic antidepressant, anticonvulsant, or cholinergic drug
• History of closed-angle glaucoma
• Anatomically narrow anterior chamber angles
• Ocular surgery or laser treatment of any kind
• History of chronic or acute uveitis
• History of traumatic iritis or hyphema
• History of traumatic mydriasis or angle recession
• History of heterochromia
• Irregularly-shaped pupil secondary to ocular trauma or congenital defect.
• History of neurogenic pupil disorder
• History of anterior chamber intraocular lens (IOL) or iris-fixated IOL
• History of iris surgery, iris atrophy, or iris-cornea apposition/touch
• Unwilling or unable to discontinue use of contact lenses at treatment visits.
• Current active eye disease for which topical or systemic ophthalmic medication is necessary, except for dry eye disease managed using artificial tears.
• Presence of a severe/serious ocular condition, or any other unstable medical condition that, in the Investigator's opinion, may preclude study treatment and/or follow-up
• Pregnancy or lactation

Adverse event data was collected over each participant's study participation period, which was a maximum of 14 days.

There were no differences in the presentation of study treatment administered and all study personnel conducting ophthalmic assessments after study treatment administration were masked to treatment assignment.