Associations between retinal thickness and background factors in eyes without retinal diseases

Retinal thickness measured using optical coherence tomography (OCT) is a major parameter to evaluate retinal diseases. However, it may be influenced by systemic factors. We retrospectively analyzed OCT images and blood sample data from 266 participants (49.1 ± 10.5 years) including 181 (68.0%) males who underwent medical checkups at Fujita Medical Innovation Center, Tokyo. Those with retinal pathological findings were excluded. Males had thicker retinas in the center and inner circles of Early Treatment Diabetic Retinopathy Study grid (P < 0.01 for all). Mean thicknesses of the superior areas were greater than those of the inferior areas in inner and outer circles (P < 0.01 for both). However, there were eyes with thicker inner inferior areas (72 eyes, 27.1%), which was observed more frequently in males (P = 0.018). Thicker retinas were associated with lower hemoglobin A1c levels in the center (P = 0.012), and inner temporal (P = 0.042) and inferior (P = 0.047) areas; lower creatinine levels in the inner temporal (P = 0.002), superior (P = 0.026), and inferior (P < 0.001) areas; and higher high-density lipoprotein cholesterol levels in the inner nasal (P = 0.029) and inferior (P = 0.029) areas after adjusting for age and sex. These results may be kept in mind in evaluating OCT data during clinical practice and future clinical trials, although further studies are warranted.