Macular vascular circulation and retinal oxygen saturation changes for idiopathic macular epiretinal membrane after vitrectomy

Abstract

Purpose: To investigate the postoperative changes in retinal-choroidal blood flow area and retinal vascular oxygen saturation among patients with idiopathic macular epiretinal membranes (iERMs).Methods: This study prospectively included 24 eyes of 24 consecutive patients who underwent vitrectomy for iERMs. The flow area of choriocapillary layer, retinal superficial capillary plexuses (SCPs) and retinal deep capillary plexuses (DCPs) were performed using optical coherence tomography angiography with angiovue prototype software, and retinal vascular oxygen saturation was measured using retinal oximeter with the built-in software. The flow area of choriocapillary layers and mean retinal vessel oxygen saturation before and after surgery were compared. Results: Three months after vitrectomy, the foveal flow area of choriocapillary layer increased clinically significantly from 1.5 AE 0.2 to 1.6 AE 0.2 mm 2 (p = 0.02). The retinal vascular changes of SCPs and DCPs were not statistically significant. The mean retinal arterial oxygen saturation was 89.9 AE 11.3% preoperatively and increased to 94.5 AE 9.7% postoperatively (p = 0.04). Foveal retinal thickness revealed a clinically significant decrease from 547.8 AE 88.2 lm to 403.0 AE 47.5 lm after surgery (p < 0.05). Postoperative best corrected visual acuity had no statistically significant correlation with foveal flow area of the choriocapillary layer and retinal vascular oxygen saturation.Conclusions: There was a decrease of retinal thickness, an improved flow area of choriocapillary layer in macular region, and an increase of retinal arterial vascular oxygen among iERMs patients after vitrectomy.

The Postoperative Course of Choroidal and Central Retinal Thickness in Epiretinal Membranes with Respect to Membrane Severity

“…It was observed that the CT and the blood flow area of choriocapillaris were reduced in patients with iERM. After vitrectomy, the blood flow area of choriocapillaris increased, while CT showed inconsistent results over previous studies [8-11].…”

“…The iERM applies traction on the retina that causes an increase of CT and affects retinal vessels. Retinal arteries become dilated and tortuous in the natural course of ERM formation and as a result may alter the hemodynamics of the affected area [5-8, 18-22]. The blood flow area of choriocapillaris was reduced in patients with iERM and increased after vitrectomy [8, 9].…”

“…Structural changes and the role of the choroid with regard to ERM severity stages or vitrectomy combined with cataract surgery versus vitrectomy without cataract surgery have not yet been explained sufficiently [8, 9]. With the help of new OCT modalities like enhanced depth imaging, swept-source OCT (SS-OCT) imaging and OCT angiography, a better pre- and postoperative visualization and evaluation of retinal structures and the choroid became possible [12].…”

The Role of OCT Angiography in the Assessment of Epiretinal Macular Membrane

“…In our investigation, both these plexi have a peculiar progression: from baseline to the first month, we can see a reduction in vessel and perfusion density and, postoperatively, a significant increase. Li et al [14] have explained the variations found as retinal blood flow improvement after vitrectomy, followed by retinal arteriolar saturation which increases due to the removal of vitreous body, which could reduce the retinal oxygen consumption and allow oxygen diffusion and transport from the anterior segment. ere was no parallel change in venous saturation which suggests that it was possibly caused by better oxygen use during tissue repairment during this period.…”

Correlation between Visual Acuity and Optical Coherence Tomography Angiography Parameters in Unilateral Idiopathic Epiretinal Membrane

“…We found that the flow area of the SCP and CCP in ERM eyes had a statistically significant decrease, while that of the DCP had a marginally significant decrease compared with normal fellow eyes. It is generally believed that ERM distributed in the macula can exert a mechanical force on the superficial retinal vessels, primarily affecting the SCP vessels, and may cause proportionate impairment in the DCP and CCP [21][22][23]. However, we demonstrated that the flow area of the CCP, which theoretically suffered the least tractional force by ERM, was significantly reduced, while the flow area of the DCP was less affected.…”