Association of Retinal Nerve Fiber Layer (RNFL) Thickness with Smoking Using Optical Coherence Tomography (OCT) in Pakistani Population

Abstract

Background: Smoking has multisystem effects on human body due to hypoxia and systemic inflammation, which it produces. This contributory effect is observed in ocular tissues as well. The aim of the study was to evaluate retinal nerve fiber layer (RNFL) thickness in healthy individuals with a history of smoking, using optical coherence tomography (OCT). Methods: Patients healthy eyes n=300 were examined. Two groups were made; Group A with history of smoking (n=50) and Group B with no history of smoking (n=250). Subjects with a history of diabetes, hypertension, raised intra ocular pressure (IOP >21 mmHg), any neurological disease or family history of glaucoma were excluded from the study. Independent t-test was used to assess the thickness variation with smoking status. ANOVA was used to analyze the differences in both groups. p value <0.05 was taken as significant. Results: The mean retinal nerve fiber layer (RNFL) thickness was found to be 96.44 ± 9.32 μm in Group A eyes. It was found to be significantly increased (p=0.02) in Group B 99.54 ± 9.32 μm. The mean RNFL thickness 93.52 ± 8.60 μm in smokers with history of more than 10 years was found decreased compared to the thickness 98.66 ± 3.96 μm in those with history of smoking less than 10 years. Conclusion: Retinal nerve fiber layer (RNFL) was found to be decreased in subjects with positive history of smoking. This difference signifies that smoking is associated with ocular pathologies. Future protocols may be included in screening for RNFL thickness in smokers for early detection and prevention of optical diseases. Keywords: Smoking; Retina; Retinal Nerve Fiber Layer (RNFL); Retinal Damage; Optical Coherence Tomography (OCT).