On August 19, 2026, Gizmodo reported on a study published that month in the British Journal of Ophthalmology linking long-term tadalafil use to an elevated risk of glaucoma — a finding that rippled through consumer health media for the following two weeks and reached mainstream men's outlets by August 31. Researchers in Taiwan drew on an anonymized real-world patient database, comparing 36,927 men over 40 taking tadalafil for lower urinary tract symptoms against 36,927 age-matched men not on PDE5 inhibitors, and tracked both groups over five years.

Why It Matters

Tadalafil is now one of the most widely dispensed drugs in the men's health economy, and the telehealth platforms built on it — Hims, Ro, BlueChew and a long tail of copycats — have spent five years normalizing daily-dose subscription models specifically because recurring pills beat one-off scripts on lifetime value. That business model is precisely the exposure profile this study examined. A daily-dose safety signal is a materially different commercial risk than an as-needed one. Nobody in the sector should overreact to a retrospective database study with a sub-1% absolute risk difference and no proven causal mechanism. But the ED telehealth category is already under regulatory pressure over data privacy and subscription billing, and it operates in an advertising environment where "FDA-approved generic, delivered discreetly" does a lot of heavy lifting. If ophthalmic screening guidance eventually attaches to chronic PDE5 use, the friction lands squarely on the asynchronous, no-office-visit model that makes these platforms cheap to run. Expect the smarter operators to get ahead of it with intake-form screening questions about family history of glaucoma — a low-cost hedge that also happens to look good in a future enforcement action.

The headline number: tadalafil use was associated with a roughly 22% higher relative risk of developing glaucoma over the five-year window, along with elevated rates of ocular hypertension and open-angle glaucoma, and a greater likelihood of starting glaucoma treatment. The authors' recommendation was measured — "Ophthalmic evaluation and follow-up may be considered, particularly in patients with risk factors for glaucoma."

The absolute numbers are far less dramatic than the headlines. Per Gizmodo's reporting of the data, 3.93% of men over 50 taking tadalafil developed glaucoma across the five years versus 3.16% of non-users — a 0.77 percentage-point absolute difference. Crucially, the cohort studied was taking a daily low dose for an enlarged prostate, not the higher intermittent doses typical of on-demand erectile dysfunction use. Stanford urology professor Craig Comiter told Healthline that "the absolute risk was less than 1% greater with daily tadalafil," and urologist S. Adam Ramin characterized the risk as "relatively small, but it's important to discuss this with patients." Cedars-Sinai ophthalmologist Bavand Youssefzadeh told Men's Health the study "shows an association between tadalafil and glaucoma, but it does not prove that tadalafil causes glaucoma," calling it "an important signal that deserves further study, not a definitive cause-and-effect finding."

Mechanistically, the leading hypotheses are unglamorous but plausible. PDE5 inhibitors relax smooth muscle and dilate blood vessels; Ohio State clinical professor of optometry Aaron Zimmerman noted to Men's Health that in the eye this can increase intraocular fluid and pressure, and separately that impaired autoregulation of blood supply to the optic nerve in older adults could compound the effect.

Sources

Update — 2026-09-06

{Initial entry — story first created.}

Update — 2026-09-22

A second, much larger BJO study widens the signal from one drug to the whole class. On September 11, 2026, the British Journal of Ophthalmology published online a UK nested case–control study that moves this story off tadalafil specifically and onto erectile dysfunction medication generally — and it dwarfs the August cohort study covered above. Medscape reported the finding on September 21.

The study. Led by Ruolan Fan at University College London's Institute of Health Informatics, with co-authors from Moorfields Eye Hospital, City St George's, King's College London and the University of Birmingham, the team used nationally representative UK primary care records from Clinical Practice Research Datalink Gold and Aurum. They matched 218,056 men diagnosed with primary open-angle glaucoma 4:1 by age and practice against 876,872 controls with no glaucoma diagnosis or treatment. Mean age was 69 in cases, 68 in controls. ED medications had been prescribed to 20% of cases versus 17% of controls. Adjusted for age, ethnicity and deprivation, ED medication use was associated with significantly higher POAG risk: OR 1.29 (95% CI 1.25–1.32) in CPRD Gold and OR 1.17 (95% CI 1.15–1.18) in CPRD Aurum. Older age and Black or Asian ethnicity were consistently associated with increased risk.

Why the framing differs. Notably, the authors are not primarily making a drug-safety argument. They use ED — a condition with well-established vascular associations — as a marker to test the long-proposed but thinly evidenced vascular mechanism in glaucoma pathogenesis. That is a different research question than "does tadalafil raise IOP," and it partly explains why the association survives at a population scale this large. It also means the confounding problem cuts both ways: if ED itself is a vascular-risk marker for glaucoma, the drug may be standing in for the underlying condition rather than causing anything.

One correction to the entry above. The August cohort study is titled "Risk of glaucoma among patients using tadalafil for lower urinary tract symptoms: a multinational cohort study" in BJO's Online First listing, published August 4, 2026, and drew its cohort from the TriNetX Analytics Network — broader than the "researchers in Taiwan" framing in the initial secondary-source coverage. The core numbers reported above are confirmed by subsequent coverage: 36,927 regular tadalafil users aged 40+ versus an equal matched comparison group, glaucoma in 3.93% versus 3.16% over five years, a 22% relative increase, roughly 77 additional cases per 10,000 men, with tadalafil users about one-third more likely to develop elevated eye pressure, POAG, or to begin glaucoma treatment — and no significant increase for low-tension or primary angle-closure glaucoma.

Stated limitations, restated. Both papers are observational. The tadalafil study relied on diagnosis codes without direct measurement of intraocular pressure, visual fields or optic nerve changes; could not establish individual doses or cumulative exposure; and carries an obvious detection-bias problem, since men on regular prescriptions have more clinical contact and therefore more chances for glaucoma to be caught. The biological story is coherent but non-directional: PDE5 is expressed in the retina, ocular blood vessels, the structures producing aqueous humour and the optic nerve, and the researchers note the drug could in principle promote fluid drainage rather than impede it. Their recommendation is explicitly not discontinuation — it is that regular users with existing glaucoma, elevated eye pressure, severe myopia or a family history discuss eye monitoring with their clinician.

Updated read for the sector. Two peer-reviewed papers in the same major ophthalmology journal in two months, pointing the same direction, is no longer a single signal to be discounted — it is the beginning of an evidence base. The practical exposure for Hims, Ro, BlueChew and the long tail is unchanged in kind but larger in scope: the September paper implicates the drug class, not one molecule, which means as-needed sildenafil prescribing is now inside the question too. The hedge flagged in the original entry — adding ophthalmic history to asynchronous intake forms — has gone from prudent to close to table stakes, and it lands in the same quarter the FDA is reconsidering testosterone labeling and indications. The evidence base under men's sexual health prescribing is being revised on several fronts simultaneously.

New Sources

Update — 2026-09-30

A counter-signal from the same database. A propensity-matched cohort study published September 25, 2026 in Eye (Nature Portfolio) also used the TriNetX global EHR network, this time to ask whether PDE5 inhibitors affect diabetic retinopathy in men aged 50+ with both ED and type 2 diabetes. It compared 1,823 PDE5I users with 1,823 matched non-users over up to seven years. PDE5I use was associated with a lower incidence of overall diabetic retinopathy (HR 0.83), but that result lost significance after correction for multiple comparisons (adjusted p = 0.0626). The association with proliferative diabetic retinopathy held (HR 0.35, adjusted p < 0.0009). No differences were seen for diabetic macular oedema, intravitreal injections or laser treatment, and rates of eye follow-up were similar between groups, which argues against surveillance bias. The authors call it an association that "warrants further evaluation in prospective studies."

Read: The ED-drug eye-safety picture is mixed rather than simply negative. A glaucoma signal with daily tadalafil and a possible protective signal against advanced diabetic retinopathy both come from observational records data. For telehealth ED platforms, the practical point is unchanged: men with diabetes are a large share of ED patients, and baseline eye history belongs in the intake questionnaire.

New Sources