Abstract
Purpose :
To evaluate the structural changes in perifoveal capillary architecture using optical coherence tomography angiography (OCTA) in patients undergoing idiopathic epiretinal membrane (ERM) removal and to analyze the correlation between foveal vessel displacement, capillary integrity, foveal thickness and visual outcomes.
Methods :
We analyzed 72 eyes of 72 patients with idiopathic ERM. Ophthalmic evaluation included best-corrected visual acuity (BCVA) and swept-source OCTA before surgery and 1, 3, and 6 months post-surgery. En face OCTA images of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) were obtained for each eye. The length from the foveola to the vessel branching point (FBL) in SCP and fractal parameters, such as fractal dimension (FD) and lacunarity in DCP were measured and calculated using ImageJ and FracLac. Correlations between FBL, FD, lacunarity, foveal thickness and visual outcomes were assessed before and after ERM surgery.
Results :
The FBL in SCP, representing tangential traction of ERM, was significantly increased postoperatively. Most of the change took place after the first one week and reached a plateau at one month after surgery. The maximum difference of FBL was significantly correlated with preoperative central foveal thickness and BCVA (all P<0.01). In terms of fractal characteristics for perifoveal DCP, FD gradually increased during 6 months after surgery and lacunarity decreased steadily and reached a plateau at 3 months after surgery. These fractal parameters were significantly correlated with central foveal thickness at preoperative visit (all P<0.01). However, the correlations between fractal parameters and BCVA were not significant.
Conclusions :
This study shows that fractal characteristics, such as FD and lacunarity of perifoveal capillary networks undergo gradual improvement after ERM removal. OCTA may serve as a tool to quantify the changes of distortions in inner foveal layers due to tractional forces in patients undergoing ERM surgery.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.