Short-term effect of weight loss after bariatric surgery on IOP, RNFL thickness, and the optic nerve head blood flow measured by OCTA

Abstract

Purpose: To study the influence of weight reduction after bariatric surgery on the intraocular pressure (IOP), retinal nerve fiber layer (RNFL) thickness, and blood flow of optic nerve head by optical coherence tomography angiography (OCTA). Methods: This prospective observational cohort study included 60 obese patients. Body mass index (BMI), IOP, RNFL, and ganglion cell complex (GCC) thickness, rim area, and radial peripapillary capillary (RPC) vessel density were assessed before and 3 months after bariatric surgery. Results: The BMI and the IOP showed significant postoperative reduction to 40.45 ± 4.3 kg/m2 and 14.83 ± 2.5 mmHg while the preoperative results were 51.13 ± 4.83 kg/m2 and 16.95 ± 4.2 mm ( p < 0.0001), respectively. No statistically significant change was detected in the RNFL, GCC thickness, rim area, or the RPC vessel density ( p > 0.05). No statistically significant correlation was detected between the BMI changes and changes in the IOP, RNFL thickness, rim area, GCC thickness, or RPC vessel density. Conclusion: No significant effect of bariatric surgery on the RNFL thickness and the optic nerve head blood flow measured by OCTA despite a significant IOP reduction 3 months post-surgical. OCTA can be a useful tool to assess the short-term influence of significant weight reduction on the retinal microcirculation. Summary: Despite a significant BMI and IOP reduction following bariatric surgery in obese patients, the vascular flow of the ONH, measured by OCTA, and the RNFL thickness were not significantly affected. The former might be attributed to the complex autoregulatory mechanisms related to the ONH and its microcirculation.