Purpose: To analyze the relationship between swelling of the arcuate nerve fiber layer (SANFL) and long-term decrease of retinal nerve fiber layer thickness after internal limiting membrane peeling for idiopathic epiretinal membrane, and to investigate if SANFL is related to a mechanical surgical damage.
Methods: Prospective, interventional consecutive case series of 46 eyes that underwent combined epiretinal membrane/internal limiting membrane peeling for idiopathic epiretinal membrane. Infrared, blue autofluorescence, color fundus imaging and measurement of retinal nerve fiber layer thickness in six peripapillary sectors by spectral-domain optical coherence tomography were performed preoperatively and at 2 weeks, 1, 3, 6, and 12 months after surgery. The presence of SANFL was checked postoperatively on infrared and blue autofluorescence fundus imaging, and the extent of each SANFL was measured on infrared fundus images.
Results: Areas of SANFL were identified in 39 eyes (84.8%) at 2-week follow-up. Retinal nerve fiber layer thickness significantly decreased in the temporal sectors at 1, 6, and 12 months (P < 0.0001). The linear extent of SANFL was significantly correlated with the percentage of reduction in retinal nerve fiber layer thickness in the temporal (R = 0.45; P < 0.0001) and infero-temporal (R = 0.23; P = 0.0008) sectors at 12 months of follow-up. Correspondence between sites of surgical grasping and the points of origin of SANFL was demonstrated on blue autofluorescence fundus images superimposed on intraoperative surgical frames.
Conclusion: Early postoperative SANFL is correlated with late focal retinal nerve fiber layer thinning in the temporal sectors. Intraoperative surgical grasping seems to be a leading factor for the onset of SANFL.