Lower baseline retrobulbar blood flow velocities predict structural progression in obese patients with open-angle glaucoma.

Abstract

Purpose: To examine the retrobulbar blood flow parameters and structural progression in open-angle glaucoma (OAG) patients with different Body Mass Indices (BMIs) over a 5-year period.

Methods: 112 OAG patients (38 normal weight, BMI <25, NW; 40 overweight, BMI 25-30, OW; 34 obese, BMI >30, OB) were assessed for retrobulbar blood flow in the ophthalmic (OA) and central retinal (CRA) arteries as measured by color Doppler flowmetry and for intraocular pressure using Goldmann applanation tonometry at baseline and every 6 months for a 5-year period. 76 patients (30 NW, 25 OW, 21 OB) were assessed at 5-year follow-up. Structural progression was monitored with optical coherence tomography and Heidelberg retinal tomography and was defined as two consecutive visits with Retina Nerve Fiber Layer thickness decrease ≥8% and/or horizontal or vertical cup/disk ratio increase ≥0.2 compared to baseline. Mixed-model ANCOVA was used to test for significant change from baseline to 5-year follow-up. Time to structural progression was analyzed using Cox proportional hazards models. Interactions were tested to determine if the effects of the factors on progression time differed by BMI category.

Results: From baseline over a 5-year period, OA End Diastolic Velocity (EDV) decreased with changes of -2.40 (-3.63, -1.34; p<0.0001) in NW, -1.87 (-3.30, -0.67; p=0.0013) in OW, and -2.55 (-4.36, -1.05; p=0.0003) in OB patients. Lower baseline OA EDV was associated with shorter time to structural progression in OB (p=0.0097) but neither in NW nor OW patients, leading to a significant difference between groups (p=0.0289).

Conclusions: Lower baseline OA EDV was predictive of glaucomatous structural progression in OB after 5 years, but neither in NW nor in OW patients. These data suggest that retrobulbar blood flow velocities may play a different role in the structural progression of the disease according to BMI.