Single Dose Study of Phentolamine Mesylate Eye Drops in Patients With Severe Night Vision Disturbances

Double-masked, placebo-controlled, single-dose Phase 2 study in 24 patients experiencing severe night vision difficulties to evaluate ocular and systemic safety and efficacy following administration of one drop of phentolamine mesylate 1.0% QD in each eye for 1 day.

Inclusion criteria

• Male or female patients ≥ 18 years of age
• Currently experiencing severe night vision difficulty as reported subjectively
• At least two patches below the normal range at any two frequencies in Contrast Sensitivity done under mesopic conditions with glare
• Improvement in low contrast visual acuity (LCVA) in dim light during illumination of contralateral eye
• Good general health
• Written informed consent to participate in this trial
• Ability to comply with all protocol mandated procedures and to attend all scheduled office visits

Exclusion criteria

• Patients with untreated cataracts grades 1-4
• Patients who wear contact lenses
• Less than 5 weeks post-refractive surgery (LASIK or PRK)
• Less than 5 weeks post intraocular lens insertion
• Low blood pressure (systolic <120 mm Hg or diastolic <80 mm Hg)
• A history of heart rate abnormalities
• Administration of any investigational drug within 30 days of study initiation
• Use of any eye drops with a pharmacologic effect on the pupil within 7 days of Visit 1
• Use of any systemic alpha adrenergic antagonists (Appendix 1)
• Known local or systemic hypersensitivity to adrenergic antagonists
• For women of childbearing potential: currently pregnant or lactating, or unwilling to use birth control during the study