EFFECT OF SMOKING ON MACULAR FUNCTION AND STRUCTURE IN ACTIVE SMOKERS VERSUS PASSIVE SMOKERS

Purpose: The aim is to study the effects of cigarette smoking on the structural and functional alterations of the macula in eyes of healthy young smokers. Methods: Cross-sectional clinical study included 100 active smokers (Group 1) and 100 age-and sex-matched healthy passive smokers (Group 2). All participants underwent a complete ophthalmologic assessment, axial length measurement, central corneal thickness measurement, spectral domain optical coherence tomography, and multifocal electroretinogram. Urine samples were collected to measure urinary levels of cotinine and creatinine with subsequent calculation of the cotinine creatinine ratio. Results: Central foveal thickness (255.62 +/- 17.23 and 264.75 +/- 17.35 mu m, respectively, with P = 0.0003) and subfoveal choroidal thickness (377.48 +/- 30.32 and 385.08 +/- 21.10 mu m, respectively, with P = 0.04) were significantly lower in active smokers than those of passive smokers. Retinal response density of ring 1 (31.08 +/- 2.29 and 33.46 +/- 3.83 nV/deg(2), respectively, with P < 0.001) and Ring 1 (R1) P1 amplitude (0.81 +/- 0.07 and 0.95 +/- 0.16 mV, respectively, with P < 0.001) were significantly lower, whereas R1 P1 latency (43.02 +/- 0.97 and 40.39 +/- 2.08 milliseconds, respectively, with P < 0.001) was significantly longer in active smokers than those of passive smokers. The mf-ERG ring ratios were significantly lower in the active smokers than those of passive smokers. Conclusion: In the absence of clinically apparent foveal toxicity, CFT, SFCT together with ring amplitude ratio could be used as good predictors of subclinical nicotine induced foveal changes.