Switching to Vapes Raises Eye Disease Risk, Major Study Finds
Switching from cigarettes to vapes is widely understood as a harm reduction strategy.
A major new study suggests that when it comes to eye health, that switch still carries a measurable risk — one that complete abstinence from nicotine avoids entirely.
What the Study Found
The research was conducted by Sangwook Cheon and Yihyun Kim at Korea University College of Medicine in Seoul, and published on June 13 in the American Journal of Ophthalmology — one of the field's leading peer-reviewed journals.
Researchers drew on data from South Korea's national public health insurance system, starting with 179,273 adults who had smoked traditional cigarettes between 2011 and 2012 and reported quitting by 2018 or 2019.
To ensure a fair comparison, the team matched participants by age, gender, medical history, existing conditions and lifestyle — producing a balanced cohort of 32,316 people divided into two groups: those who had quit all nicotine and tobacco, and those who had switched to non-combustible alternatives including e-cigarettes and vapes.
Researchers then followed participants for an average of 4.6 years, tracking whether they developed any of five major eye conditions: cataracts, glaucoma, age-related macular degeneration, diabetic retinopathy, or refractive and accommodation disorders.
The result was consistent and statistically significant.
Those who had switched to vapes or other smokeless nicotine products had a 7% higher risk of developing a major vision-impairing eye disease compared with people who had quit nicotine entirely, according to Medscape's clinical summary of the findings.
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Which Eye Conditions Were Most Affected
The 7% overall increase was not distributed evenly across all five conditions.
Diabetic retinopathy — damage to the blood vessels of the retina caused by high blood sugar — showed the strongest association with switching to smokeless nicotine.
Refractive and accommodation disorders — conditions affecting how well the eye focuses, including disorders that impair near or far vision — were also significantly elevated in the switching group.
The association with cataracts, glaucoma and macular degeneration was present but more modest across the full cohort.
In raw numbers, the study recorded 6,328 new cases of eye disease during the follow-up period. The incidence rate was 41.1 cases per 1,000 person-years among complete quitters, compared with 44 cases per 1,000 person-years among those using nicotine alternatives — a gap that remained consistent across the 4.6-year observation window.
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Why Vapes May Still Harm the Eyes
The mechanism behind the finding is not fully confirmed, but researchers point to nicotine itself as the likely driver.
Nicotine causes blood vessels to constrict — reducing circulation to the delicate vascular structures of the eye, including the retina and optic nerve. This vascular effect is present whether nicotine is inhaled as combustible smoke or absorbed through vapour.
Combustible cigarettes also carry tar and carbon monoxide, which are known to cause additional systemic damage. E-cigarettes eliminate those compounds, which is why they are widely promoted as a less harmful alternative.
But the Korean data suggests that for eye disease specifically, eliminating tar and carbon monoxide while maintaining nicotine intake does not eliminate the elevated risk. The nicotine-driven vascular effect may be sufficient on its own to maintain measurably higher rates of certain eye diseases.
The University of Colorado Anschutz Medical Campus has noted separately that vape cartridges often contain significantly higher nicotine concentrations than standard cigarettes — with one cartridge estimated to deliver the equivalent of up to 20 cigarettes worth of nicotine. That concentration difference may partially explain why the risk persists or in some cases exceeds expectations for smokers who switch.
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What the Researchers Said — and What the Study Cannot Confirm
The researchers framed the findings as a direct argument for incorporating eye health into smoking cessation counselling.
"These findings support smoking-cessation counseling for switchers and risk awareness within routine ophthalmic care," the study team concluded.
The recommendation is aimed at eye care practitioners who see patients who vape or use smokeless tobacco alternatives and may not currently be screening them for elevated disease risk.
There are meaningful limitations the researchers acknowledged.
Smoking and product use were self-reported, meaning some participants may have understated their use, overstated their cessation, or used multiple products simultaneously — a pattern the data could not fully capture.
The study also did not account for how long it had been since each person had quit smoking, which could affect how much residual damage from prior combustible use was influencing the results.
The cohort was overwhelmingly male — a reflection of historical smoking demographics in South Korea — which the researchers said may limit how directly the findings apply to women.
Despite these limitations, the study is notable for its scale. At 32,316 matched participants followed over 4.6 years, it is among the largest analyses of this specific comparison ever conducted, and the finding was consistent across the observation period rather than driven by a specific subgroup.
What It Means in Practice
Quitting nicotine entirely remains the option most protective of eye health according to this data.
For people who have switched from cigarettes to vapes as a step toward quitting entirely, the study does not suggest the switch causes no benefit — combustible cigarette smoke carries harms beyond what the study measured. But it does challenge the assumption that switching to vapes is broadly equivalent to quitting when it comes to long-term vision.
Eye care providers are increasingly being called on to ask patients about vaping history alongside smoking history, given that the vascular mechanisms linking nicotine to eye disease do not appear to be eliminated by switching products.
The researchers' recommendation is direct: people who have switched from cigarettes to vapes should be made aware of the continuing elevated risk, and eye health monitoring should be part of routine care for anyone currently using any nicotine product.
