Observational study finds tadalafil use associated with increased glaucoma risk in men — Evidence Review

A large observational study found that long-term use of tadalafil for urinary symptoms was associated with a higher risk of glaucoma and elevated eye pressure in men. Most previous research has not established a clear causal link, but some related studies suggest possible eye risks, particularly with long-term or daily use 2 3 6.

• Several earlier reviews and clinical studies have found mostly transient and reversible visual side effects from PDE5 inhibitors, with little evidence of serious, long-term ocular complications; however, epidemiological and case-based evidence has raised concerns about potential associations with glaucoma and increased intraocular pressure, especially for certain patient groups 1 3 6.
• Some cross-sectional and epidemiologic studies report a greater prevalence of glaucoma among long-term users of sildenafil or related drugs, supporting the need for further investigation and monitoring in high-risk populations 2 3 6.
• Randomized trials of daily tadalafil or sildenafil use for up to six months have not demonstrated significant retinal or visual toxicity, but large-scale, longer-term real-world analyses like the current study provide important context for assessing potential risks in broader patient populations 8.

Study Overview and Key Findings

Glaucoma is a leading cause of irreversible blindness worldwide, and understanding possible risk factors remains crucial, especially as the population ages and the use of medications such as tadalafil becomes more common. The current study addresses a timely clinical question: does long-term, daily use of tadalafil for urinary symptoms contribute to an increased risk of glaucoma or elevated intraocular pressure? Previous evidence has been inconsistent, particularly regarding the chronic use of PDE5 inhibitors in populations beyond those taking them for erectile dysfunction.

Property	Value
Study Year	2026
Organization	Taichung Veterans General Hospital, Taiwan
Journal Name	British Journal of Ophthalmology
Authors	Yun Hsia, Chien-Yun Tsai, Sheng-Chun Hung, Jun-Peng Chen, Ssu-Yu Pan, Hui-Ju Lin, I-Jong Wang, Chien-Hsiang Weng, Mi-Hyun Nam, Chien-Chih Chou
Population	Men aged 40 or older with urinary symptoms
Sample Size	n=73,854
Methods	Observational Study
Outcome	Risk of glaucoma, ocular hypertension, glaucoma treatment initiation
Results	Tadalafil users were 22% more likely to develop glaucoma.

Literature Review: Related Studies

To place these findings in context, we searched the Consensus paper database, which includes over 200 million research papers. The following targeted queries were used to identify relevant studies:

1. tadalafil glaucoma risk association
2. erectile dysfunction medications vision effects
3. long-term effects tadalafil eye health

Below is a summary table grouping the related studies by major research topics:

Topic	Key Findings
Does long-term use of PDE5 inhibitors increase glaucoma risk?	• Some epidemiologic and cross-sectional studies report higher prevalence of self-reported glaucoma among long-term users of sildenafil or other PDE inhibitors 2 3 6. • Most systematic reviews and clinical trials do not find a conclusive causal link between PDE5 inhibitor use and vision-threatening ocular complications, though case reports suggest rare events 1 7.
What types of vision changes are associated with PDE5 inhibitors?	• PDE5 inhibitors frequently cause mild, transient visual symptoms such as color vision changes, blurred vision, or increased light sensitivity, which are generally reversible 1 4 5. • Serious ocular events—such as nonarteritic ischemic optic neuropathy, retinal vein occlusion, and acute angle closure glaucoma—have been rarely reported, but no consistent pattern of long-term toxicity is established 1 5 7.
How does daily or long-term use affect eye health in clinical trials?	• Randomized controlled trials of daily tadalafil or sildenafil for up to six months found no significant changes in retinal function, intraocular pressure, or visual acuity compared to placebo 8. • Most long-term toxicology studies in animals and systematic investigations in humans do not indicate permanent damage to ocular structures at therapeutic doses when taken as prescribed 5 8.
Should certain patient groups take special precautions?	• Patients with pre-existing glaucoma, ocular hypertension, or high risk for glaucoma may require baseline vision screening and regular follow-up if prescribed PDE5 inhibitors, especially for chronic or high-dose use 3 6. • Physicians are generally advised to counsel all patients to discontinue PDE5 inhibitors and seek prompt evaluation if sudden vision loss occurs, even though a definitive causal link is unproven 7.

Does long-term use of PDE5 inhibitors increase glaucoma risk?

The new study's finding of a 22% increased risk of glaucoma among tadalafil users is supported by some epidemiologic evidence, although previous systematic reviews and clinical trials have not confirmed a definitive causal relationship. Notably, cross-sectional and database studies in the U.S. have reported higher prevalence of self-reported glaucoma among long-term PDE5 inhibitor users, suggesting that chronic exposure could be relevant in real-world settings 2 3 6.

• Cross-sectional analyses indicate that long-term sildenafil or theophylline use is associated with higher odds of self-reported glaucoma, even after adjusting for confounders 2.
• Reviews highlight the lack of conclusive evidence from case reports and clinical trials, but recognize rare instances of serious ocular events in PDE5 inhibitor users 1 7.
• The mechanistic basis for increased risk remains unclear, but observational data like that from the current study add weight to the argument for careful monitoring, especially in men using tadalafil daily for non-erectile dysfunction indications 3 6.
• The new findings build on concerns raised by epidemiologic data but contrast with the largely reassuring results from shorter-term randomized trials 8.

What types of vision changes are associated with PDE5 inhibitors?

Across multiple studies, the most commonly reported visual side effects of PDE5 inhibitors are mild and transient, such as color vision disturbances, light sensitivity, and blurred vision. Serious adverse events are rare and inconsistently linked to drug use, but isolated reports of glaucoma, optic neuropathy, and retinal vascular events have prompted ongoing scrutiny 1 4 5 7.

• Mild visual symptoms occur in 3–11% of users and are generally reversible upon discontinuation of the medication 1 4.
• Case reports have described serious events like nonarteritic ischemic optic neuropathy and central retinal vein occlusion, but data are insufficient to establish a strong causal relationship 1 5 7.
• Reviews note that visual side effects tend to be dose-related and are more likely with higher-than-recommended doses or recreational use 4 5.
• The new observational study focuses specifically on glaucoma and ocular hypertension, areas where previous evidence has been inconsistent and less robust 2 3 6.

How does daily or long-term use affect eye health in clinical trials?

Randomized controlled trials and long-term toxicology studies have not demonstrated significant adverse effects of daily tadalafil or sildenafil use on retinal function or intraocular pressure over periods up to six months. These findings suggest that short- to mid-term daily use at therapeutic doses is unlikely to cause overt eye toxicity in the general population 5 8.

• A six-month randomized trial found no significant differences in retinal function, IOP, or visual acuity among subjects taking daily tadalafil, sildenafil, or placebo 8.
• Systematic investigations in humans and animals have not identified long-term structural or functional eye damage at standard doses 5 8.
• The discrepancy between clinical trial findings and some real-world epidemiologic data may be due to differences in patient selection, duration of follow-up, or underlying risk factors 2 3 8.
• The current study's longer follow-up and large sample size provide additional data on risks associated with extended use, though causality remains unproven 3 6.

Should certain patient groups take special precautions?

There is consensus across reviews and guidelines that individuals with existing risk factors for glaucoma—such as a family history, ocular hypertension, or high myopia—should be monitored closely if prescribed PDE5 inhibitors for chronic use. While the overall risk appears low for most users, vigilance is warranted given the potential for rare but serious adverse events 3 6 7.

• Vision screening exams and regular follow-up are recommended for high-risk patients prior to and during long-term PDE5 inhibitor therapy 3 6.
• Physicians are advised to educate all patients about the signs of acute vision loss and to discontinue medication promptly if such symptoms arise 7.
• The new study reinforces these recommendations by documenting higher risk among chronic tadalafil users, especially those with pre-existing glaucoma risk factors 3 6.
• These precautions are especially relevant for populations using PDE5 inhibitors daily and for indications other than erectile dysfunction, such as lower urinary tract symptoms.

Future Research Questions

The current evidence highlights several gaps in our understanding of the ocular safety profile of PDE5 inhibitors, particularly with regard to long-term use in diverse patient populations. Further research is needed to clarify causality, underlying mechanisms, and optimal monitoring strategies.

Research Question	Relevance
Does long-term daily use of tadalafil directly cause glaucoma in at-risk populations?	Establishing causality is essential for clinical decision-making. Observational studies suggest an association, but prospective studies are needed to determine if the drug itself increases risk, especially in those with other glaucoma risk factors 2 3 6.
What are the mechanisms by which PDE5 inhibitors affect intraocular pressure and optic nerve health?	Understanding biological mechanisms could clarify why some patients experience increased eye pressure or optic nerve damage, and may guide safer prescribing and monitoring practices 3 6.
Are the ocular risks of tadalafil different from other PDE5 inhibitors such as sildenafil?	Comparative studies could reveal whether certain drugs in this class carry higher or lower risks, informing personalized medication choices and risk stratification 1 2 4.
What is the long-term risk of glaucoma in diverse ethnic and age groups using PDE5 inhibitors?	Most existing studies focus on predominantly White, older male populations; broader, more diverse cohorts are needed to determine generalizability and identify vulnerable subgroups 2 3.
Can pre-treatment optic nerve screening and regular eye monitoring reduce the risk of vision loss in patients on chronic PDE5 inhibitor therapy?	Interventional studies could determine whether enhanced ophthalmic surveillance improves outcomes and helps prevent vision-threatening complications in high-risk groups 3 6.