First Clinical Evidence Linking Smoking to Increased Postoperative Macular and Retinal Nerve Fiber Layer Thickness in Cataract Surgery Patients: A Prospective Cohort Study

Abstract

Background: Postoperative macular edema may limit visual recovery following cataract surgery. Although smoking is recognized as a risk factor for ocular inflammation, its impact on early postoperative macular morphology following cataract surgery has not been investigated. Methods: This prospective cohort study enrolled 88 elderly patients undergoing elective cataract surgery in a single university teaching hospital. The patients were divided into long-term smokers and lifelong non-smokers. Spectral-domain optical coherence tomography (OCT) was used to assess the central subfoveal thickness (CST), cube volume (CV), cube average thickness (CAT), retinal nerve fiber layer (RNFL), and cup-to-disk ratio (CDR) preoperatively and on the 1st, 7th, and 14th postoperative days (PODs). The phacoemulsification time and cumulative dissipated energy were recorded. Linear mixed-effects models were used to assess group-by-time interactions, and multivariable regression, adjusted for baseline covariates, was employed for analyses. Results: Eighty patients were included in the final analysis. Smokers had significantly thinner baseline CST than non-smokers. Both groups showed early postoperative CST increases, but only smokers exhibited sustained and significantly greater increases in CV and CAT on POD 14 (CV Δ +0.30 mm3 vs. +0.04 mm3; p = 0.026; CAT Δ +6.5 µm vs. +1.2 µm; p = 0.037). The RNFL and CDR changes did not differ significantly at earlier timepoints. However, smokers showed a notably greater RNFL thickening on POD 14 (Δ +4.2 µm; p = 0.001). Smoking status remained the strongest independent predictor of these changes (p < 0.001), while phacoemulsification parameters showed no significant interaction effects. Conclusions: Cigarette consumption independently predicts pronounced postoperative macular and RNFL thickening after uncomplicated elective cataract surgery. These transient structural changes could complicate early glaucoma assessment and should be considered when interpreting postoperative OCT findings in smokers.