Effect of smoking on retina nerve fiber layer and ganglion cell-inner plexiform layer complex

Purpose: The aim of this study is to show the effects of smoking on retina layers, especially retina nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer complex (GCIPL). Materials and methods: Participants smoking for more than 10 years at least 1 pack of cigarettes a day and a control group, both including participants between ages of 20 and 50 years with no other systemic or ocular diseases were studied. After normality tests, an independent sample t test was used to analyze the differences in age, sex, spherical equivalent (SE), intraocular pressure (IOP), axial length (AL), GCIPL and RNFL values between the groups. Results: There were 44 participants in each group. There were 32 (62.5%) men and 12(37.5%) women in smokers and 36 (77.88%) men and 8 (22.22%) women in control group. Mean ages were 39.85 +/- 8.41 and 38.66 +/- 10.47 years, mean spherical equivalent (SE) values were +/- 0.15 +/- 0.4 and 0 +/- 0.29 dioptries in smokers and control groups, respectively. The IOP, AXL, GCIPL and RNFL values were 17.58 +/- 3.41 mmHg, 23.69 +/- 0.56 mm, 84.3 +/- 5.83 mu m and 92.3 +/- 3.51 mu m in the smokers group and 18.5 +/- 2.91 mmHg, 23.45 +/- 0.72 mm, 86.11 +/- 8.02 mu m and 97.66 +/- 8.23 mu m in the control group. The inferior, superior, nasal and temporal values of RNFL quadrants were 123.18 +/- 26.14, 117.05 +/- 5.51, 64.95 +/- 8.67 and 63.5 +/- 6.88 mu m in the smokers group and 130.81 +/- 11.8, 123.55 +/- 11.03, 72.44 +/- 9.84 and 58.44 +/- 7.48 mu m in the control group. There were no significant difference of age, sex, SE, IOP, AXL and GCIPL values between the smokers and control groups (p>0.05). The mean RNFL was significantly thinner in the smokers group compared to controls (p = 0.03, independent t test). Inferior and superior quadrants of RNFL decreased in smokers group (p = 0.01 and p = 0.03, respectively) but temporal and nasal quadrants did not seem to be changed (p = 0.96 and p = 0.07, respectively). Discussion: Smoking may affect RNFL thickness but not GCIPL.