Correlation of lamina cribrosa thickness and optic disc vascular density in diabetic retinopathy

To determine whether optic disc vascular density correlates with lamina cribrosa thickness and depth in diabetic retinopathy (DR).

A total of 85 participants, 30 controls (Group-1), 30 with nonproliferative DR (NPDR=Group-2) and 25 with proliferative DR (PDR=Group-3) were included in this prospective study. Detailed ophthalmologic examinations were performed, optic disc vascular density by optical coherence tomography angiography (OCTA), retinal nerve fiber thickness by OCT, lamina cribrosa thickness and depth by enhanced depth imaging OCT (EDI-OCT), prelaminar tissue thickness, and Bruch's membrane openings were measured and recorded. Groups were compared with ANOVA t-test and the relationship between the parameters was evaluated with Spearman's correlation analysis.

No statistically significant difference was found between the groups in terms of age and gender (p=0.741, p=0.922, respectively). In EDI-OCT, lamina cribrosa depth was significantly decreased in groups 2 and 3 (p<0.001). No statistically significant difference was observed between the groups in terms of lamina cribrosa thickness (p=0.115). Prelaminar tissue thickness was significantly thinner in Groups 2 and 3 (p<0.001). Bruch's membrane opening was significantly higher in Groups 2 and 3 (p=0.001). It was observed that the percentage of vascular density was significantly decreased in the inside disc, peripapillary, whole optic disc and inferior hemi in the groups with DR compared to healthy subjects (p<0.001), while the percentage of vascular density in the inside disc and whole optic disc images was correlated with proliferation. Retinal nerve fiber thickness and lamina cribrosa depth were significantly negatively correlated (r:-0.228 p=0.036).

There was no correlation between diabetic retinopathy and lamina cribrosa thickness. However, there was a correlation between lamina cribrosa depth, prelaminar tissue thickness and Bruch's membrane opening. By performing these correlated measurements in EDI-OCT in diabetic patients, information about whether optic disc vascularity is affected can be obtained.