Abstract
Purpose:
To examine the relationship between changes in retinal and macular morphology and retrobulbar blood flow in diabetic and non-diabetic patients with open angle glaucoma (OAG) after three years.
Methods:
68 patients (15 diabetic, 53 non-diabetic) with OAG were assessed for retinal nerve fiber layer (RNFL) thickness and macular morphology using optical coherence tomography (OCT) and retrobulbar blood flow in the ophthalmic artery (OA), central retinal artery (CRA) and nasal (NPCA) and temporal (TPCA) posterior ciliary arteries using color Doppler imaging (CDI) at baseline and three years follow up. Pearson correlations were calculated to evaluate the associations between measurements at baseline and between the changes in measurements between baseline and 3 years.
Results:
In OAG patients with diabetes, change in OA resistive index (RI) was strongly and negatively correlated with change in average RNFL thickness (r=-0.93, p=0.02), inner superior macular thickness (r=-0.85, p=0.03), outer inferior macular thickness (r=-0.97, p=0.03), inner nasal macular thickness (r=-0.85, p=0.03), outer temporal macular thickness (r=-0.95, p<0.01) and macular volume (r=-0.90, p=0.01) and change in NPCA RI was strongly and negatively correlated with change in temporal RNFL thickness (r=-0.90, p=0.04), inner nasal macular thickness (r=-0.84, p=0.03), inner temporal macular thickness (r=-0.84, p=0.03) and macular volume (r=-0.83, p=0.04) with statistical significance over three years. In OAG patients without diabetes, these correlations were weak and did not reach statistical significance (r=-0.32 to 0.02, p>0.05). There was a statistically significant difference in strength of correlations between groups for each relationship (p<0.01). In diabetic patients, change in CRA EDV was correlated with change in superior and inferior RNFL thickness (r=-0.89, p=0.05; r=-0.72, p=0.19). Other correlations between CRA and NPCA PSV and EDV were weak (r=-0.57 to 0.33) in both diabetics and non-diabetics and only statistically significant in non-diabetics (diabetics p>0.05, non-diabetics p<0.01).
Conclusions:
Changes in vascular resistance were strongly correlated with deterioration of the RNFL and macula in OAG patients with diabetes. This suggests that diabetics may have a stronger vascular component to their glaucomatous progression than non-diabetics.
Keywords: 498 diabetes •
585 macula/fovea •
436 blood supply