TOPLINE

In patients who struggled to see clearly in dim light and were bothered by glare, halos, and starbursts, a once-nightly eye drop — 0.75% phentolamine ophthalmic solution — significantly improved both measured vision and these symptoms. More than 20% of patients treated with the drop gained three or more lines on an eye chart by day 15 — compared with just 3% of those treated with placebo — and reported feeling notably less bothered by glare, halos, and starbursts.

METHODOLOGY

• Researchers evaluated the efficacy and safety of 0.75% phentolamine ophthalmic solution in 145 adult patients with self-reported night vision issues, a pupil that widened to at least 5 mm in dim light, and eye chart vision of 20/63 or worse in at least one eye under dim, low-contrast conditions, in a multicenter, placebo-controlled phase 3 trial.
• Patients were randomly assigned in a 1:1 ratio to receive either phentolamine ophthalmic solution or placebo, self-administered as one drop in each eye once nightly for 14 days.
• The mean age was 47.0 years in the phentolamine group and 45.4 years in the placebo group, and most patients in both groups were women; the largest subset (25 patients) had a history of keratorefractive surgery, with other underlying causes including cataract, blepharitis/dry eye, keratoconus, corneal scarring, and vitreous opacity.
• The primary efficacy endpoint was the percentage of patients who gained at least 15 letters (three lines) in the affected eye on an eye chart test of dim-light vision, measured at day 8 compared with baseline.
• Patients had three in-person visits — on days 1, 8, and 15 — followed by a phone call a few days later to check for any safety issues.

TAKEAWAY

• Significantly more patients in the phentolamine group than in the placebo group achieved the primary endpoint at day 8 (13% vs 3%; P < .05) and day 15 (21% vs 3%; P < .01).
• Patients treated with phentolamine also rated their overall night vision problems, on a scale of 1-7, as significantly less severe than those treated with placebo at both day 8 (4.3 vs 4.6; P < .01) and day 15 (3.3 vs 4.3; P < .0001). By day 15, they also reported significantly less trouble with glare, halos, and starbursts than those treated with placebo.
• Phentolamine caused a modest but significant reduction in pupil size under dim light: By day 8, pupils shrank by about 1.1 mm in the phentolamine group vs 0.1 mm in the placebo group (P < .0001), a difference that persisted through day 15.
• Side effects were generally mild and transient. Over the 14-day treatment period, 32% of patients on phentolamine vs 16% of those on placebo reported any side effect. The most common were discomfort at the drop site (13%); a metallic, bitter, or sour taste (11%); redness on the eye (9%); and redness of the skin at the drop site (9%).

IN PRACTICE

The authors wrote that phentolamine "does not engage the ciliary muscle. The effects of ciliary muscle contraction can potentially further increase the risk of vitreofoveal traction and retinal tears and detachment in subjects already at risk."

SOURCE

The study was led by Jay S. Pepose, of the Pepose Vision Institute in Chesterfield, Missouri. It was published online on September 2 in American Journal of Ophthalmology.

LIMITATIONS

The improvement in vision was fairly modest when comparing the phentolamine and placebo groups, highlighting heterogeneity in treatment response. The study also didn't use standardized, validated questionnaires — like the Quality of Vision Questionnaire or Vision and Night Driving Questionnaire. Although night driving is a major concern for this patient population, driving-specific complaints weren't tracked as their own outcome in the study.

DISCLOSURES

This study was supported by Opus Genetics. One author disclosed serving as the company's chief medical advisor; other authors disclosed serving as consultants to the company.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.