Does Tadalafil (Cialis) Raise Your Glaucoma Risk?

Possibly, but only by a small amount, and the evidence is split. In one large 2026 study of men taking tadalafil for urinary symptoms, 3.93% developed glaucoma over 5 years compared with 3.16% of similar men not taking it, about 8 extra cases per 1,000 men. A second large study of men taking drugs in the same class for erectile dysfunction found slightly less glaucoma, not more. Both studies were built from health records, so neither proves the drug causes or prevents anything.

Tadalafil is the drug sold as Cialis. It belongs to a class called PDE5 inhibitors, along with sildenafil (Viagra). Besides erectile dysfunction, tadalafil is taken as a 5 mg pill every day for lower urinary tract symptoms: a weak stream, urgency and night-time trips to the bathroom that come with an enlarged prostate. Glaucoma is damage to the optic nerve, the cable that carries vision from the eye to the brain, and high pressure inside the eye is its main risk factor.

What the Data Show

The study that raised the concern is a multinational health-record study of 36,927 men on tadalafil and 36,927 matched men on no PDE5 inhibitor. All were 40 or older, all had urinary symptoms, and none had glaucoma at the start. Over up to 5 years, glaucoma was about 22% more common in the tadalafil group. In absolute terms, that is 3.93% against 3.16%, a gap of 0.77 percentage points. Put another way, about 1 in 130 men would need to take tadalafil for 5 years for one extra case to appear.

That study found the same direction for three related outcomes. Ocular hypertension, meaning raised eye pressure before any nerve damage, was about 32% more common. Primary open-angle glaucoma, the common slow and painless type, was about 33% more common. Starting glaucoma treatment was also about 33% more common. The pattern held in men over 50 and when the earliest months of use were set aside.

A second large health-record study looked at men 40 and older with erectile dysfunction and compared long-term users of any PDE5 inhibitor with non-users. Here, open-angle glaucoma was less common among users: 3.88% against 4.28% at 3 years, about 16% lower after adjustment. The authors called this a possible protective link that needs confirming in prospective studies.

So two studies of tens of thousands of men each landed on opposite sides. They studied different men (urinary symptoms versus erectile dysfunction), and the second pooled all drugs in the class rather than tadalafil alone.

Does Cialis Affect Eye Pressure?

Daily tadalafil did not change eye pressure in the one long-term randomized trial. In that trial of 244 men given daily tadalafil 5 mg, daily sildenafil 50 mg or a placebo for 6 months, there were no significant differences between groups in eye pressure, visual function or retinal tests.

Short-term effects are less clear. In a placebo-controlled study of 9 healthy volunteers, a single 100 mg dose of sildenafil raised eye pressure by 26%, from 13.1 to 16.5 mm Hg, at 60 minutes, and pressure returned to normal within 2 hours.

A 2026 review of PDE5 inhibitors and glaucoma concluded that most studies show no clinically meaningful or lasting effect on eye pressure, and that the rises seen in a few studies were small and brief.

Why Could Cialis Affect the Eye?

PDE5 inhibitors work by boosting nitric oxide signaling, which relaxes the muscle in blood vessel walls and widens them. That is how they help erections and relax the prostate and bladder outlet. The eye has the same enzyme. The 2026 review reports that these drugs increase blood flow in the eye, most of all in the choroid, the layer of blood vessels behind the retina.

One proposed route to higher eye pressure is extra blood flow to the ciliary body, the small structure that produces the fluid inside the eye. A 2019 review put forward that idea and noted that most eye-pressure studies were small, often lacked a control group and mostly enrolled healthy volunteers with no glaucoma risk.

The blood-flow effect cuts both ways. Poor blood supply to the optic nerve is thought to play a part in glaucoma, which is why some researchers suspect these drugs could protect the nerve instead of harming it. That would fit the second health-record study, but it has not been tested in a trial.

Can You Take Cialis If You Have Glaucoma?

No study has tested long-term daily tadalafil in people who already have glaucoma. The closest evidence is a double-blind crossover trial in 15 people with open-angle glaucoma. A single 100 mg dose of sildenafil, the maximum dose, produced no significant change in eye pressure compared with placebo.

The 2026 review found no lasting eye-pressure effect in the studies it covered, including those in people with established open-angle glaucoma. The 2019 review recommended a vision screening exam before starting a PDE5 inhibitor and careful follow-up afterward, especially with tadalafil, with daily use and in people with glaucoma risk factors.

Angle-closure glaucoma is a different disease. It happens when the drainage angle at the front of the eye is narrow and suddenly blocks, causing a painful red eye, blurred vision, halos around lights and sometimes nausea. That is an emergency. In the large tadalafil study, angle-closure glaucoma was not significantly linked to the drug.

What Other Eye Side Effects Does Cialis Cause?

The common ones are brief and harmless. A review of the evidence on these drugs and vision reports that changes in color perception and light sensitivity occur in 3% to 11% of sildenafil users, and that they are transient and reversible. The same review found no conclusive evidence that PDE5 inhibitors cause vision-threatening problems.

The rare serious ones are disputed. In a study of 213,033 US men taking these drugs, regular users had about 85% higher odds of a combined outcome: serous retinal detachment (fluid lifting the retina), a blocked retinal blood vessel, or ischemic optic neuropathy (a stroke of the optic nerve). These events were rare, at 15.5 cases per 10,000 person-years.

A larger study of nearly 2 million men with erectile dysfunction and over 2 million with an enlarged prostate found no consistent link between these drugs and any of those three eye problems. Men with an enlarged prostate who took a PDE5 inhibitor had about 14% more retinal vessel blockages, but men on other prostate drugs or prostate surgery had a similar rise, which points to the prostate condition rather than the drug.

Is Cialis Worse Than Viagra for Your Eyes?

No study has compared glaucoma risk between the two. The 6-month randomized trial gave both drugs daily and found no eye-pressure change with either. Tadalafil lasts much longer in the body than sildenafil, and the 2019 review listed tadalafil and daily use among the reasons for closer eye follow-up. That is a precaution based on how long the drug lasts, not a measured difference.

Is Daily Tadalafil Worth It for Urinary Symptoms?

For many men, yes. A meta-analysis of 13 placebo-controlled trials with 3,973 men found that tadalafil 5 mg once daily improved urinary symptoms and erections over 12 weeks.

The size of that benefit is moderate. Across 7 placebo-controlled trials of PDE5 inhibitors with 3,214 men, the urinary symptom score improved by 2.8 points more than with placebo on a 35-point scale, while urine flow rate did not change.

Dr. Kumar’s Take

The best reading of this evidence is that any glaucoma risk from tadalafil is small, and it may not exist at all. Two large studies disagree, the one long-term trial found no change in eye pressure, and the absolute gap in the study that raised the alarm was under 1 percentage point over 5 years.

What makes me take it seriously anyway is the nature of glaucoma. Open-angle glaucoma causes no symptoms until vision is already lost, and that vision does not come back. A baseline eye exam is quick and painless, and it is useful for any man over 40 whether or not he takes tadalafil. For a man starting a daily pill he may take for years, it is an easy step that settles the question for his own eyes.

Practical Takeaways

Get a baseline eye exam with a pressure check if you are starting daily tadalafil and plan to stay on it.
Be extra careful with risk factors: known high eye pressure, a parent or sibling with glaucoma, high nearsightedness, or African ancestry.
Tell your eye doctor you take tadalafil. It is easy to leave off a medication list when a urologist prescribed it.
If you already have open-angle glaucoma, keep your scheduled eye visits and let your eye doctor know before you start.
Seek care the same day for sudden vision loss in one eye, or a painful red eye with blurred vision and halos.
Do not stop tadalafil on your own over this study. Talk it through with your doctor.

FAQs

Does Cialis cause glaucoma?

It has not been shown to. One large health-record study found slightly more glaucoma in men taking tadalafil for urinary symptoms, about 8 extra cases per 1,000 men over 5 years. Another large study found slightly less glaucoma in men taking drugs in the same class, and neither design can prove cause.

Does tadalafil raise eye pressure?

Not in the one long-term randomized trial. Men taking 5 mg of tadalafil every day for 6 months had no difference in eye pressure from men on placebo. One tiny study of a single sildenafil dose found a short rise that faded within 2 hours.

Can I take Cialis with open-angle glaucoma?

No trial has tested daily tadalafil in people with glaucoma. A single maximum dose of sildenafil did not raise eye pressure in people with open-angle glaucoma, and reviews advise an eye exam and regular follow-up rather than avoiding the drug. Your eye doctor should know you are taking it.

Why does Cialis make my vision look blue or bright?

These drugs also act on an enzyme in the retina that handles color and light signals. Brief changes in color vision and light sensitivity occur in 3% to 11% of sildenafil users and go away as the drug wears off. Sudden loss of vision is different and needs urgent care.

Is Viagra safer for glaucoma than Cialis?

No study has compared them on glaucoma. A 6-month trial of each taken daily found no eye-pressure change with either. Tadalafil lasts longer in the body, which is one reason reviews suggest closer eye follow-up with daily use.

Bottom Line

Tadalafil has been linked to a small rise in glaucoma risk in one large study, about 8 extra cases per 1,000 men over 5 years, while another large study found the opposite. The only long-term trial found no change in eye pressure. If you take Cialis daily, keep taking it if it helps, and get a baseline eye exam with a pressure check, especially if glaucoma runs in your family.

Does Tadalafil (Cialis) Raise Your Glaucoma Risk?