An investigative study on the impact of smoking on visual evoked response of healthy volunteers

Abstract

Background: Cigarette smoking not only has numerous deleterious effects on respiratory and cardiovascular systems of the body but also poses a threat to damage the visual system and may lead to poor eyesight. Visual evoked potentials (VEPs) reflect electrical phenomena occurring during the visual processing so are widely used both in research and in clinical practice to elucidate the function of the visual system. Aim of Study: To explore the effect of smoking on the VEP response of healthy volunteers. Materials and Methods: VEP recordings were taken using an Evoked Potential Recorder (RMS EMG. EP MARK II) where the stimulus configuration consisted of transient pattern-reversal method, in which a black-and-white checkerboard was generated (full field) on a VEP monitor. Results: The mean age of thirty smokers was 46.70 ± 17.33 years compared to 47.25 ± 15.62 years in 60 controls (range 19–76 years). Predominant P100 latency delays in 60% of cases, of which 55.56% had markedly prolonged latencies. Both latency delay and amplitude reduction were seen in remaining 40% of cases, i.e., 12 of 30 smokers. Marked prolongation of latency with marked amplitude reduction was observed in 9 (75%) of these 12 cases and all belonging to the most chronic smokers. Conclusion: To the best of our knowledge, ours is one of the first studies to comment on implications of smoking on VEP. As VEP abnormalities obtained in cases of smokers having extreme chronicity were severe, substantial, and explicit, we propose that VEP could be a useful neurophysiologic tool to demonstrate the visual deficits due to smoking.