Smoking is associated with a significantly increased risk of a wide range of vision-threatening diseases, according to a large-scale global database analysis of more than 12 million patients – one of the most comprehensive assessments of its kind to date.
Drawing on the TriNetX electronic health records network, researchers analyzed 12.1 million individuals, including more than 300,000 smokers. After propensity score matching for age, sex, hypertension, and diabetes, the study compared matched cohorts of 300,867 smokers and non-smokers over a 10-year period, quantifying the relative risk across major ophthalmic conditions.
The findings reveal a consistent and statistically significant increase in risk across all evaluated diseases. The strongest associations were observed for posterior subcapsular cataract, uveitis, and retinal vascular occlusions, including central retinal artery occlusion and central retinal vein occlusion. As detailed in the study findings, many of these conditions demonstrated more than a two-fold increase in smokers compared with non-smokers.
Cataract risk overall was nearly doubled, with 9.5% of smokers developing cataract over ten years compared to 5.4% of non-smokers. Posterior subcapsular cataract showed the highest susceptibility, followed by nuclear and cortical subtypes.
Glaucoma risk was also significantly elevated, with the greatest increase seen in primary angle-closure glaucoma. Meanwhile, age-related macular degeneration (AMD) incidence was nearly doubled, affecting both non-exudative and exudative forms.
Although the relative increase in diabetic retinopathy (DR) was more modest, smokers still demonstrated significantly higher rates across all stages of disease. Similarly, ischemic optic neuropathy and uveitis showed notable associations.
Mechanistically, the authors highlight the role of oxidative stress, chronic inflammation, and microvascular dysfunction induced by tobacco exposure. These processes contribute to retinal ischemia, mitochondrial damage, and impaired ocular tissue integrity – pathways implicated across many of the observed conditions.
Despite the well-established systemic risks of smoking, its ocular impact still remains relatively under-discussed in clinical practice. The study authors note that many clinicians do not routinely assess smoking status or provide cessation support, even though fear of vision loss is a powerful motivator for behavioral change.
While the retrospective design limits causal inference, the scale and consistency of the findings provide compelling real-world evidence. Incorporating smoking history into risk stratification – and using quantitative data such as these to support counselling – may represent an underutilized opportunity to reduce preventable vision loss.
