Cigarette smoking and retinal ganglion cell layer and photoreceptor outer segment thickness: The Beijing Eye Study

To examine an association of cigarette smoking on retinal layer thickness.

The population-based Beijing Eye Study 2011 included 3468 individuals aged 50+ years. All participants underwent optical coherence tomography (OCT) of the macula. Using a multiple-surface OCT segmentation algorithm, the retina was segmented into nine layers. Information about cigarette smoking was assessed in an interview with a standardised questionnaire. The exclusion criterion was the presence of any retinal or optic nerve disease.

The study included 2173 participants (mean age: 61.7±8.4 years; mean axial length: 23.1±0.8 mm) with 660 (30.4%) participants with a smoking history and 1513 (69.6%) non-smokers. Mean duration of the smoking period was 8.7±14.9 years, and mean smoking quantity was 9.5±18.2 pack-years. In multivariable analysis, higher prevalence of smoking was associated with thinner whole retina (p=0.024; B=-1.64; 95% CIs -3.07 to -0.22), thinner ganglion cell layer (GCL) (p=.044; B=-0.39; 95% CI -0.78 to -0.01) and thinner photoreceptor outer segment layer (POS) (p=0.024; B=-0.38; 95% CI -0.72 to -0.05) with adjustments of age, gender, axial length, education level and hypertension. Similar results were obtained if the retinal thickness measurements were obtained in the various macular subfields. A longer period of smoking was related to thinner whole retina (p=0.009; B=-0.06; 95% CI -0.10 to -0.01), thinner retinal nerve fibre layer (RNFL) (p=0.011; B=-0.01; 95% CI -0.02 to -0.002), thinner GCL (p=0.006; B=-0.02; 95% CI -0.03 to -0.01) and thinner POS (p=0.025; B=-0.01; 95% CI -0.02 to -0.001) with adjustments of age, gender, axial length, education level and hypertension. Higher smoking pack-years were significantly associated with thinner GCL (p=0.022; B=-0.01; 95% CI -0.02 to -0.002).

Smoking was related to thinner GCL and POS in this population-based investigation, pointing towards and agreeing with an association between smoking and optic nerve damage or age-related macular degeneration.