Through oxidative stress, microvascular injury, inflammation and dysregulation of intraocular pressure, cigarette smoking is a well-established risk factor for several vision-impairing diseases, including cataract, glaucoma, age-related macular degeneration, diabetic retinopathy and more. With the global rise in noncombustible nicotine or tobacco products (NNTPs), including electronic cigarettes and heated tobacco, an increasing proportion of former cigarette smokers discontinue use of combustible products yet continue nicotine exposure in hopes of lowering health risks. The ocular safety of this switching behavior remains uncertain, which is why researchers recently sought to determine if switching to NNTPs is safer for eye health compared to complete nicotine abstinence.1 Unfortunately, they found that switchers had a higher risk of major vision-impairing eye diseases, but noted that the ocular safety of switching to NNTPs after smoking cessation remains uncertain.
Nearly 180,000 adults from the Korean National Health Insurance Service who smoked cigarettes in 2011 and 2012 but quit between 2018 and 2019 were classified into two groups: quitters and switchers.
Among 32,316 propensity score-matched adults who were followed for 4.6 years, 6,328 major vision-impairing eye disease events occurred. The incidence was 41.1 and 44 per 1,000 person-years for quitters and switchers, respectively.
Switching to noncombustible products was associated with an increased risk of major vision-impairing eye diseases (hazard ratio: 1.07). The risk elevation was most pronounced for diabetic retinopathy (HR: 1.24) and refractive and accommodation disorders (HR: 1.07). Findings remained consistent across various sensitivity analyses.
“We hypothesized that, if NNTPs were truly harm-reducing for the eye, switching would not be associated with higher risk than complete abstinence; conversely, an increased risk among switchers would indicate that NNTP-based cessation strategies may not be visually risk-neutral,” the authors write.
The authors explain that the mechanism of effect likely reflects both microvascular (e.g., in the case of diabetic retinopathy) and functional (e.g., refractive and accommodative) pathways. The former aligns with nicotine-related endothelial and vasoregulatory alterations; the latter, although often correctable, has large impact due to high prevalence and direct effects on daily function.
“A plausible explanation for the association with refractive and accommodation disorders is that this broad outcome may capture changes in visual function related to accommodative dysfunction or ocular surface instability,” the authors write.
Prior studies have shown that smoking can transiently reduce tear breakup time and amplitude of accommodation, while electronic cigarette use has also been associated with poorer tear-film quality. “These findings suggest that the observed association may reflect effects on accommodative function or the ocular surface, in addition to the better-established vascular pathways relevant to DR,” the authors explain.
Also, because even modest relative increases in common conditions may translate to meaningful population burden, these findings support smoking-cessation counseling for switchers and risk awareness within routine ophthalmic care. “Given that real-world disability and health care demands may be missed by single, narrowly defined measures, the inclusion of refractive and accommodation disorders in the composite allowed a comprehensive population-level evaluation of major vision-impairing diseases,” the authors write in their paper.
REFERENCE
1. Cheon S, Kim Y, Seok Kang E, et al. Noncombustible nicotine or tobacco product use after smoking cessation and major vision-impairing diseases: A nationwide cohort study. Amer J Ophthalmol. June 12, 2026. [Epub ahead of print].
Ethnic differences in Type 3 MNV noted in study
Previous research has suggested that ethnic differences may influence the characteristics of macular neovascularization. A recent study published in Retina focused on characterizing potential population-specific presentation patterns and exploring the clinical implications in patients with Type 3 macular neovascularization.1 Its researchers examined the baseline clinical and demographic data of treatment-naïve patients of Caucasian and Asian descent diagnosed with type 3 MNV. Asian patients were approximately five years younger than Caucasian patients. In the Asian cohort, a substantial proportion of type 3 MNV cases occurred in individuals aged <70 years, whereas in Caucasians, all cases were observed in those aged ≥70 years.
This finding suggests that the key factors contributing to type 3 MNV development, including hypoxia, RPE cell migration and VEGF secretion, may emerge at a relatively younger age in Asian populations, researchers say. Although the exact cause remains unclear, differences in the ocular and genetic characteristics may be involved.
This retrospective, multicenter, comparative case series included treatment-naïve type 3 MNV patients from Switzerland, Italy and South Korea. A total of 301 eyes (181 European and 120 Korean) from 248 patients were included.
Asian patients were significantly younger at presentation (76.1 years vs. 81.1 years), with type 3 MNV lesions located closer to the foveal center (mean distance: 810.7µm vs. 1061.4 µm). Central ETDRS circle involvement was observed in Asians (17.5 vs. 4.4 percent). Subfoveal choroidal thickness was similar between groups (154.1µm vs. 153.3 µm). The prevalence of reticular pseudodrusen was higher in Caucasians than in Asians (89 vs. 74.2 percent).
Multivariable analysis demonstrated that age, mean foveal distance and reticular pseudodrusen had the strongest associations with ethnicity. In discriminant model analysis, age and foveal distance were significant discriminant features.
“We postulate that if choroidal thinning contributes to hypoxia responsible for type 3 MNV, a critical degree of choroidal thinning may be required to trigger the disease, regardless of ethnic background,” the researchers note. “These findings suggest that choroidal thinning may serve as a key driver in the pathogenesis of type 3 MNV. In particular, not all patients with type 3 MNV exhibit a thin choroid; in such cases, alternative pathogenic mechanisms may play a more prominent role in disease development.”
Given that reticular pseudodrusen typically occurs in elderly individuals, its lower prevalence in Asians may be partially attributed to their younger age. However, this finding also suggests that type 3 MNV in Asians could be involved in a process less closely associated with reticular pseudodrusen.
“These findings suggest that while type 3 MNV may share common pathophysiological mechanisms across ethnicities, the contributing factors may differ in certain respects,” they conclude. RS
REFERENCE
1. Forte P, Fontana V, Park SM, et al. Ethnic differences in the presentation patterns of type 3 macular neovascularization. June 9, 2026. [Epub ahead of print].
