Safety and Efficacy of Nyxol (0.75% Phentolamine Ophthalmic Solution) in Subjects With Dim Light Vision Disturbances

The objectives of this study are: * To evaluate the efficacy of Nyxol to improve mesopic low contrast visual acuity (mLCVA) in subjects with Dim Light Vision Disturbances (DLD) * To evaluate efficacy of Nyxol to improve visual performance * To evaluate the safety of Nyxol

Placebo-controlled, double-masked, multiple-dose, Phase 3 study in approximately 160 randomized subjects with DLD (approximately 136 that are evaluable for efficacy), evaluating safety and efficacy of Nyxol in subjects with DLD following administration of Nyxol once daily (QD) at or near bedtime (at 8PM to 10PM) in both eyes (OU) for 14 days. Following the successful completion of screening, each subject will be stratified by iris color (light/dark irides) and will then be randomized to treatment (masked) 1:1, Nyxol or placebo (vehicle). Treatment (Nyxol or placebo) will be administered in both eyes (OU) by the subjects at or near bedtime each day. At the first visit subjects will be screened for study eligibility. Treatment visits will occur 2 times: Day 8 (+1 day)/Visit 2 and Day 15 (+1 day)/Visit 3. mLCVA evaluations shall be performed on each of these days. A follow-up visit (Visit 4) phone call will occur 1 to 3 days after Visit 3. At select sites OPD Scan measurements will be made using wavefront abhermettry.