Considering how often a glaucoma patient smokes or used to smoke may help determine whether more frequent monitoring is necessary. Photo: Reza Mehrad on Unsplash.

There are few health and ocular conditions not impacted by frequently smoking tobacco. In glaucoma, smoking is known to be a risk factor; however, until now, research on the association between smoking and disease progression had been lacking. Findings of the new longitudinal study revealed that higher smoking intensity is associated with faster rates of retinal nerve fiber layer (RNFL) thinning.

The patients included in the investigation had primary open-angle glaucoma, at least three years of follow-up and five visits with OCT scans. There were 466 eyes of 314 patients in the analysis, all with follow-ups between 6.4 and 6.7 years. Smoking intensity was calculated as packs per year as reported at the baseline OCT visit.

The researchers noted that 39% of the patients reported a history of smoking and that the average smoking intensity was 16.5 packs per year. The data showed that greater smoking intensity was significantly associated with faster RNFL thinning (-0.06µm/year per 10 packs/year increase) after adjusting for all other factors including alcohol consumption, BMI and race, none of which showed an association. They wrote in their paper, “Specifically, when smoking intensity is >eight packs/year, smoking intensity was associated with faster RNFL thinning in patients with glaucoma.”

The patients who had a slower rate of RNFL thinning over the study period smoked a mean of 15.1 packs per year, while those with a moderate to fast rate of thinning had a mean smoking intensity of 24.3 packs per year. In patients who smoked previously, 20.7% were classified with at least a moderate rate of RNFL thinning. Considering this finding, the researchers suggest it would be helpful if future studies focused on whether smoking cessation can reduce glaucoma.

Because patients who smoke may be at higher risk of faster and irreversible progression potentially leading to vision loss, the researchers concluded, “As with other risk factors for glaucoma, the smoking status of a patient can help guide both the frequency of monitoring and the glaucoma therapy.”

Nishida T, Mahmoudinezhad G, Weinreb RN, et al. Smoking and progressive retinal nerve fiber layer thinning in glaucoma. Br J Ophthalmol. September 13, 2022. [Epub ahead of print].