Psychophysical evaluation of contrast sensitivity using Gabor patches in tobacco addiction.

This study, an extension of Fernandes et al. (2017), provided consistent contrast sensitivity function (CSF) measurements in a large sample. CSF was assessed for luminance stimuli in different 48 chronic smokers and 50 healthy nonsmokers. Stimuli for the CSF were Gabor patches with spatial frequencies of .2, 2.5, 5.0, 10.0, and 20.0 cycles per degree (cpd). The use of Gabor patches minimizes uncertainty in spatial position and detection of frequencies. The Gabor patches consisted of vertical gratings that were multiplied by a two-dimensional spatial Gaussian envelope. All of the groups were matched for gender and level of education. All of the participants were free from any neurological disorder, cardiovascular disease, and identifiable ocular disease, and they had normal or corrected-to-normal visual acuity. No abnormalities were detected on the fundoscopic examination or optical coherence tomographic examination. The smoker group had a lower CSF compared with healthy nonsmokers at all spatial frequencies. These results indicate that cigarette smoking or chronic exposure to its constituent compounds affects early-stage visual discrimination, suggesting the existence of deficits in early visual spatial processing in smokers.