Correlation of the cholesterol-to-high-density-lipoprotein Castelli risk index-1 with the choroidal and retinal nerve fiber layer thickness in patients with diabetes mellitus without retinopathy

Abstract

Purpose: To determine the choroidal thickness and retinal nerve layer (RNFL) thickness changes in patients with diabetes mellitus (DM) without retinopathy in relation to their glycated hemoglobin (HbAic) and Castelli risk index-i (CRI-1) levels. Method: This study examined the right eyes of 340 subjects. CRI-I was calculated as the total cholesterol divided by high-density lipoprotein cholesterol. Five groups of 68 eyes were defined as follows: Group 1, control group consisting of healthy subjects; Group 2, DM patients with HbAic from 7% to 9%; Group 3, DM patients with HbAic from 7% to 9% and CRI-1 greater than 4; Group 4, DM patients with HbAic greater than 9.1%; and, Group 5, DM patients with HbAic greater than 9.1% and with CRI-1 greater than 4. Optical coherence tomography (OCT) measurements were taken using enhanced depth imaging. Choroidal thickness (CT) and RNFL thickness were compared within groups. Results: CT was found to be lower in all DM groups compared with healthy subjects. In all nasal areas, CT was significantly thinner in group 5 than group 4. RNFL loss was only seen in the inferior temporal quadrant of all DM patients compared with the control group. There was no statistically significant difference between subgroups in RNFL measurements. Conclusion: CRI-1, which is a marker of combined dyslipidemia abnormalities, is in use to predict atherosclerotic changes in DM patients. This study determined the CRI-1 also correlates with the CT of diabetic eyes but not the RNFL, and it can be used as an additional criterion in ophthalmological follow-ups of diabetic patients.