The Safety and Efficacy of Phentolamine Mesylate Ophthalmic Solution in Subjects With Severe Night Vision Disturbances

Randomized, double-masked, multiple dose Phase 2 parallel evaluation of the safety and efficacy of phentolamine mesylate (PM) ophthalmic solution in 60 subjects with severe night vision complaints, evaluating ocular and systemic safety and efficacy following administration of phentolamine mesylate (.05% or 1%) in both eyes for 15 days. Subjects were randomized into three groups with a 1:1:1 randomization. The groups received either (1) phentolamine mesylate ophthalmic solution 0.5%, (2) phentolamine mesylate ophthalmic solution 1.0%, or (3) placebo, once daily (QD) for 15 days. The treatment period was 15 days, plus 6 additional days over the next 14 days. After 15 days, all subjects were given the opportunity to receive an additional 6 doses of 1.0% phentolamine mesylate to be taken once daily as needed over the next two weeks. There was a post-dosing follow-up evaluation 7 days after the last dose. Study participants completed a night vision questionnaire at pre-treatment and after 15 and 29 days. Efficacy evaluations included contrast sensitivity (mesopic, with and without glare), mesopic distance high contrast visual acuity (HCVA) and mesopic distance low contrast visual acuity (LCVA). Safety evaluations included photopic distance HCVA, a complete ophthalmic examination and measurement of heart rate and blood pressure.