A Nightly Drop Tested Against Glare, Halos, and Starbursts
A once-nightly eye drop that moderately shrinks the pupil helped about one in five adults with poor night vision read at least three more lines on a dim, low-contrast eye chart after two weeks of use. Only 3% of people using a placebo drop reached the same mark, according to phase 3 results published online Sept. 2 in the American Journal of Ophthalmology.
The multicenter trial, called LYNX-1, enrolled 145 adults who reported glare, halos, or starbursts in low light and whose pupils widened to at least 5 millimeters in dim conditions. The drop contains 0.75% phentolamine and is being developed by Opus Genetics, formerly Ocuphire Pharma, with commercial partner Viatris. It is not approved to treat night vision problems. The trial itself is not new: its results were first presented at medical meetings in 2023, and this is the full peer-reviewed report.
For people who have stopped driving after dark, the practical question is whether a prescription drop could one day make oncoming headlights easier to handle, and how soon. The evidence so far is encouraging but limited, and results from a final confirmatory trial have not been made public.
Inside the LYNX-1 Results
Participants were randomly assigned to phentolamine or placebo and used one drop in each eye every night for 14 days. The main goal, measured on day 8, was a gain of 15 or more letters, or three lines, on the dim-light chart. Thirteen percent of treated participants reached it, compared with 3% on placebo. By day 15, the treated share rose to 21%, while placebo stayed at 3%. Treated participants also reported less severe glare, halos, and starbursts.
A small analysis done after the trial, limited to the 25 participants who had LASIK, showed a stronger early response. In that group, 29% of treated participants reached the vision goal on day 8, compared with 9% on placebo, the company reported. The group was too small to support firm conclusions.
The drop works on the optics of the eye. Pupils widen at night, letting light pass through the outer edges of the cornea and lens, where small irregularities can scatter it into rings and streaks. Phentolamine blocks receptors on the muscle that dilates the iris, keeping the pupil somewhat smaller in dim light. In the trial, that moderate pupil shrinking lasted at least 20 hours.
The authors noted that the drug "does not engage the ciliary muscle," the focusing muscle inside the eye. That sets it apart from older pupil-shrinking drops, which act on that muscle and can raise concerns about retinal tears or detachment in people already at risk. Side effects in the trial were generally mild and short-lived.
The Evidence Check on a Promising but Modest Effect
MedicalDaily Evidence Check: LYNX-1 was a randomized, placebo-controlled phase 3 trial of 145 participants, published in a peer-reviewed journal. It found better dim-light eye chart scores and fewer reported visual disturbances over two weeks. It did not measure driving performance, crash risk, or long-term safety. The trial was sponsored by the drug's developer, and several authors have reported consulting ties to the company.
Medscape's coverage of the paper described the difference between groups as fairly modest, with wide variation in who responded, and noted that the study did not use standardized, validated vision questionnaires. Roughly four in five treated participants did not reach the main vision goal.
A second trial limited to people who had refractive surgery showed a narrower gap. LYNX-2 enrolled 199 people with reduced low-light, low-contrast vision after procedures such as LASIK. In that study, 17.3% of treated patients reached the vision goal at day 15, compared with 9.2% on placebo, Opus Genetics reported in topline results released in 2025. Patients were treated and followed for six weeks, and Viatris said it saw no tachyphylaxis, a fading of the effect with repeated use, over that period.
The FDA has granted the drug Fast Track designation for night driving impairment after refractive surgery, a status meant to speed development and review. Opus said a confirmatory trial, LYNX-3, would report topline results in the first half of 2026, but the company's August financial update did not include them.
Dr. Jay Pepose of the Pepose Vision Institute in Chesterfield, Missouri, the lead author of the LYNX-1 paper, who has served as chief medical advisor to Opus Genetics, has pointed to the safety stakes. Some patients with poor low-light vision after refractive surgery "are more likely to be involved in motor vehicle collisions," he said in a company announcement about the trial.
Steps for Night Drivers While the Drop Remains Unapproved
People most likely to notice glare and halos include those who have had LASIK, PRK, SMILE, or radial keratotomy; adults developing cataracts; and people with dry eye or an outdated glasses prescription. Many of those causes are treatable now, so a new or worsening night vision problem deserves an eye exam rather than a wait for new drugs.
Sudden changes are different. A new shower of floaters, flashes of light, a shadow or curtain over part of your vision, or halos with eye pain and nausea can signal an emergency and need same-day care.
For everyday driving, updating prescriptions, keeping windshields and headlights clean, choosing anti-reflective lens coatings, and avoiding unfamiliar routes after dark can help. Readers should not use pupil-shrinking drops prescribed for other conditions to treat night glare without an eye doctor's guidance.
Phentolamine 0.75% is already sold as Ryzumvi to reverse pupil dilation after eye exams, but that approval does not cover night vision. No price or insurance coverage has been set for night vision use, so out-of-pocket costs are unknown.
The next regulatory milestone involves a different use. The FDA set an Oct. 17 decision date for the same drop as a presbyopia treatment, according to Opus Genetics' annual corporate update. Approval for night vision problems would require confirmatory data and a separate FDA review.
The takeaway for drivers is measured. A nightly drop helped a meaningful minority of adults see better in dim light, but it is not a proven fix for night driving, and an eye exam remains the most useful first step for anyone struggling after dark.
Key Questions Answered
What did the new study find?
In the 145-person LYNX-1 trial, 21% of adults using 0.75% phentolamine eye drops gained at least three lines on a dim, low-contrast eye chart by day 15, compared with 3% on placebo.
Is this a new trial?
No. LYNX-1 results were first presented at medical meetings in 2023. What is new is the full, peer-reviewed publication in the American Journal of Ophthalmology.
Can I get these drops for night glare now?
No. The drop is not FDA-approved for night vision problems. The same ingredient is approved only to reverse pupil dilation after eye exams.
Who might benefit most?
The trial enrolled adults with glare, halos, or starbursts and large pupils in dim light. People who had LASIK showed a stronger early response in a small follow-up analysis, but that finding needs confirmation.
Does this prove the drop makes night driving safer?
No. The trial measured eye chart scores and reported symptoms over two weeks. It did not test real-world driving or crash risk.
What should I do about night glare today?
Get a comprehensive eye exam, update your prescription, and ask about cataracts or dry eye. Limit night driving if you feel unsafe, and seek same-day care for sudden vision changes.
When could it be approved for night vision?
No date has been set. Results from the confirmatory LYNX-3 trial and an FDA review would come first.
