ED Drugs and Glaucoma: New Study Reveals Risk
A large study published in the British Journal of Ophthalmology analyzed data from nearly 74,000 men over 40, half of whom had received prescriptions for tadalafil (the active ingredient in Cialis). Results showed that men taking the drug had a 22% higher likelihood of developing glaucoma over five years, with a 33% increased risk for the most common form of the disease.
While the absolute numbers remain modest (3.93% of tadalafil users developed glaucoma vs. 3.16% in the control group), this translates to thousands of additional cases across a huge user base. Glaucoma often leads to irreversible vision loss if caught too late.
Not the First Warning: A Look Back
This is not the first time ED drugs have been linked to eye problems. In 2022, researchers at the University of British Columbia reviewed data from over 200,000 men and found that regular users of PDE5 inhibitors (including sildenafil, tadalafil, and vardenafil) faced an 85% higher risk of serious eye conditions, including serous retinal detachment, retinal vein occlusion, and ischemic optic neuropathy (NAION).
NAION strikes suddenly—blood flow to the optic nerve drops, and vision in one eye can fade within hours. Reports of NAION after taking Viagra surfaced soon after the drug launched in 1998. Although Pfizer once pushed back, regulators still required label updates.
Potential Mechanisms: How Do the Drugs Affect the Eye?
PDE5 inhibitors relax smooth muscle by boosting nitric oxide signaling, which helps achieve an erection. However, the same family of enzymes exists in retinal cells. At high doses, sildenafil can interfere with PDE6—critical for converting light into nerve signals—causing blue-tinted vision or light sensitivity.
At chronic lower doses, the story shifts toward vascular effects. Reduced blood pressure or altered flow in tiny eye vessels might starve the optic nerve or retina over time.
Expert Recommendations: Risk and Prevention
Experts emphasize that the data do not prove causation, but the pattern repeats across studies. Here are key recommendations:
- Men with glaucoma risk factors (such as high blood pressure, sleep apnea, or crowded optic discs) should consult an eye specialist before use
- Long-term users should have regular eye pressure checks and optic nerve imaging
- Anyone with a history of NAION should strictly avoid these medications
- Avoid high-dose or non-prescription use without medical supervision
Urologists and ophthalmologists suggest that doctors ask about family eye history before writing a first prescription, and patients should proactively inform their eye doctor about ED medication use.
As research continues, regulators may revisit drug labeling. For men planning long-term use, regular eye exams are especially important. The Xiaoshu Health App can sync with Apple Health to track relevant metrics, helping you record medication use and eye exam results for more comprehensive health data for your doctor.