Even heavy smokers who have since quit may still experience lasting damage. Photo: Reza Mehrad on Unsplash.

Smoking is known to worsen the outcomes and be a modifiable risk factor for numerous ocular diseases, including glaucoma. A new study found that among glaucoma patients, heavy smokers especially were more likely to have visual field loss in affected eyes. They concluded that smoking levels may act as a significant predictor of disease progression.

The retrospective cohort study involved 511 eyes of 354 patients with primary open-angle glaucoma (POAG) who had at least three years of follow-up and five visual field tests. The median baseline age was 64.8 years, and 35% of the cohort was of African ethnicity. Approximately 60% of patients reported a history of alcohol consumption, 42% reported a history of smoking and 11% were heavy smokers at baseline.

They found that higher smoking intensity was associated with faster visual field loss by -0.05µm/year per 10 pack-years, while alcohol consumption showed no association. Other factors associated with faster rates of visual field worsening over time included history of smoking, lower BMI and older age.

“A total of 38.5% of eyes progressed among patients with ≥20 pack-years smoking, while 26% of eyes progressed among never smokers,” the researchers noted in their study. They reported that in heavy smokers, median visual field mean deviation worsened to -14.5dB from -3.7dB at baseline, while in glaucoma patients who never smoked, the final visual field mean deviation was -10dB from a baseline of -3.2dB.

The researchers pointed out that even heavy smokers who have since quit the habit may still run into consequences of lasting damage from the high level of chemical inhalation and nicotine absorption. “The effect of smoking intensity with ≥20 pack-years on vascular and neural tissue may be extended in smokers and attribute to faster glaucoma progression later in life,” they explained.

The data from this study highlights yet another reason to prevent people from smoking: to slow the progression of glaucomatous disease and improve visual outcomes. It also cautions that close monitoring is necessary for patients who smoke or used to smoke more than 20 packs a year.

Mahmoudinezhad G, Nishida T, Weinreb RN, et al. Impact of smoking on visual field progression in a long-term clinical follow-up. Ophthalmology. June 16, 2022. [Epub ahead of print].