Effect of smoking on retinal ganglion cell-inner plexiform layer complex in diabetes

Purpose: The aim of this study is to show the effect of smoking on retina layers measured by spectral domain optical coherence tomography (OCT) in diabetes, especially retinal ganglion cell complex and inner plexiform layer (GC-IPL) thickness.Materials and MethodsThe 92 smoking and 92 never-smoking subjects were divided into six groups­—healthy smokers group (HS), healthy nonsmokers group (HNS), diabetic smokers group (DS), diabetic nonsmokers group(DNS), diabetic retinopathy smokers(DRS) group, diabetic retinopathy nonsmokers group(DRNS), based on whether they were diagnosed as diabetes and the ET-DRS classification. After full ophthalmologic examination, retinal ganglion cell-inner plexiform layer complex(GC-IPL) thickness, and central macular thickness (CMT) were measured by OCT. Statistical analysis was performed to compare GC-IPL thickness and CMT values between groups. ResultsThere were no significant differences in GC-IPL thickness and CMT between the healthy smokers and healthy nonsmokers group. All quadrants of GC-IPL and mean GC-IPL were thinner in the diabetic smokers than diabetic nonsmokers group except that of inferotemporal GC-IPL thickness and CMT. Superonasal, superior GC-IPL and mean GC-IPL were thinner in the diabetic retinopathy smokers than diabetic retinopathy nonsmokers group. On the contrary, there were no statistically significant difference in other quadrants of GC-IPL and CMT. Multiple regression analysis demonstrated that advancing age and smoking behaviors are the most important determinants for mean GC-IPL. ConclusionSmoking may affect GC-IPL thickness in diabetes but not in the healthy people.