Smoking Intensity Impacts Choroidal Microvasculature Dropout Area in Glaucoma

This article was originally published by HCPLive.

Smoking intensity is associated with larger choroidal microvasculature dropout in patients with glaucoma, particularly those with moderate to severe disease, according to a retrospective, cross-sectional study.¹

The investigative team, led by Sasan Moghimi, MD, of the Department of Ophthalmology at the Shiley Eye Institute, University of California at San Diego, suggested these data indicate the potential role of smoking in the pathogenesis of glaucoma.

“In the current study, smoking intensity was associated with microvasculature dropout area, suggesting that having an intense history of tobacco consumption may affect the choroidal and deep optic nerve microvasculature,” investigators wrote.

Cigarette smoking is a known risk factor for the incidence and progression of various ophthalmic disorders, including age-related macular degeneration (AMD), cataract, and retinal vein occlusion (RVO). Its role, however, in glaucoma is less certain. Some literature has suggested that smoking has no association with glaucoma, while other studies have reported an increased risk of open-angle glaucoma progression.²

The disease is marked by the loss of retinal ganglion cells, resulting in the progression of functional loss and visual field deterioration.³ Choroidal microvasculature dropout, a localized parapapillary perfusion defect, is identified using optical coherence tomography angiography (OCTA). In this cross-sectional analysis, Moghimi and colleagues assessed the effects of smoking on choroidal microvasculature dropout in patients with primary open-angle glaucoma.¹

The analysis recorded the self-history of tobacco consumption. Smoking intensity was quantified using the pack-year index, defined as the consumption of 20 cigarettes daily for 1 year. Eyes were assessed as glaucomatous based on 2 or more consecutive, repeatable, abnormal visual field test results with evidence of glaucomatous optic neuropathy.

Multivariable linear mixed-effects models were used to determine the effect of smoking intensity on choroidal microvasculature dropout and angular circumference. Covariates included age, sex, race, self-reported diabetes, and visual field mean deviation (MD). Sensitivity analysis was performed by categorizing the glaucoma severity, as determined by visual field MD.

Patient smoking

Image credit: ehabeljean - stock.adobe.com

A total of 223 eyes of 163 patients with primary open-angle glaucoma who had completed imaging with OCTA were included for analysis. Of these patients, 55 (33.7%) patients had a history of tobacco consumption (21.8%, 0–10 pack-years; 21.8%, 10–20 pack-years; 56.4%, >20 pack-years). A higher proportion of moderate and advanced glaucoma was observed in eyes with a history of smoking, compared with those without a smoking history (P = .004).

Upon analysis, choroidal microvasculature dropout was observed in 37 (51.4%) eyes with a history of smoking and in 67 (44.4%) eyes with no history of smoking (P = .389). The analysis showed a larger microvasculature dropout area and wider angular circumference among smokers compared with non-smokers (P = .068 and P = .046, respectively).

Further, in a multivariable model adjusted for relevant variables, greater smoking intensity was significantly associated with a larger microvasculature dropout area (OR, 0.30; 95% CI, 0.01-0.60; each 0.01 mm² per 10 pack-years; P = .044).

Among eyes (n = 104) with moderate to severe glaucoma (visual field MD < −6), smoking intensity was associated with larger ​​microvasculature dropout area (OR, 0.47; 95% CI, 0.11-0.83; each 0.01 mm² per 10 pack-years; P = .011). However, among eyes (n = 102) with early glaucoma (MD ≥ –6), there was no observed association (OR, –0.08; 95% CI, –0.26 to 0.11; P = .401).

Based on these data, Moghimi and colleagues indicated the relationship between smoking intensity and microvasculature dropout is dependent on the severity of the disease. They noted the association may be due to the microvascular circulation being severely compromised in eyes with moderate to advanced glaucoma.

“A history of intense tobacco consumption may have led to further deterioration of microvessels, thereby contributing to more extensive glaucomatous damage,” investigators wrote. “Conversely, in eyes with mild glaucoma having healthier microvessels, smoking intensity may not induce substantial damage to the choroidal perfusion.”

References

1. Nishida T, Micheletti E, Latif K, Du KH, Weinreb RN, Moghimi S. Impact of smoking on choroidal microvasculature dropout in glaucoma: a cross-sectional study. BMJ Open Ophthalmol. 2023;8(1):e001421. doi:10.1136/bmjophth-2023-001421
2. Nishida T, Mahmoudinezhad G, Weinreb RN, et al. Smoking and progressive retinal nerve fibre layer thinning in glaucoma. Br J Ophthalmol. 2023;107(11):1658-1664. doi:10.1136/bjo-2022-321237
3. Weinreb RN, Leung CKS, Crowston JG, et al. Primary open-angle glaucoma. Nat Rev Dis Primers. 2016;2:16067. doi:10.1038/nrdp.2016.67