We thank Drs dell’Omo and Mura for their comments regarding our article. In almost all of our cases, we performed 5 horizontal and 5 vertical raster scans at least 3 times using spectral-domain optical coherence tomography (OCT), and selected a representative image centered on the fovea.
In our results, 32 of the 50 metamorphopsic eyes (64%) after rhegmatogenous retinal detachment (RD) surgery exhibited normal-appearing OCT findings without any disruption of inner/outer segment (IS/OS), external limiting membrane (ELM), or abnormal macular contour. As Drs dell’Omo and Mura pointed out, outer retinal folds (ORFs) and IS/OS skip reflectivity abnormalities (RAs) might have been included in these 32 cases with normal-appearing OCT. ORFs tend to resolve spontaneously within 6 months or less following vitrectomy. However, we evaluated the patients at 6-12 months postoperatively. Thus, it is difficult to detect transient retinal morphologic abnormalities occurring in the 6-month period after surgery.
From the total of 32 cases with metamorphopsia and normal-appearing OCT, therefore, we extracted some cases whose OCT images were obtained within 6 months postoperatively. As a result, we were able to investigate OCT images within 1 month postoperatively in 5 of the 32 cases, and within 3 months postoperatively in 20 of the 32 cases. The results showed that 2 of the 32 cases had ORFs at the fovea at 3 months postoperatively. The ORFs resolved, but IS/OS skip RAs remained at 6 months postoperatively. Seven of the 32 cases had hyperreflective IS/OS line at the foveal region at 3 months postoperatively, of which the hyperreflective IS/OS line resolved at 6 months postoperatively in 5 cases and no change was observed in the other 2 cases. We are not sure whether the hyperreflective IS/OS line in these 7 cases had ORFs within 3 months postoperatively.
Nine of the 20 cases whose OCT images were obtained at 3 months postoperatively had neither ORFs nor IS/OS skip RAs. It could be considered that certain retinal morphologic abnormalities existed in these cases within 3 months following surgery. dell’Omo and associates found that the presence of ORFs was associated with metamorphopsia. In consideration of our results and those of the previous report, our findings suggested that transient retinal morphologic abnormalities such as ORFs and IS/OS skip RAs occurred within 6 months after operation and caused metamorphopsia in some of the cases with “normal-appearing OCT.”
However, some other cases demonstrated metamorphopsia that was unexplainable by a transient retinal morphologic change. One patient exhibited normal-appearing OCT findings and severe metamorphopsia even 10 days after surgery.
Future studies involving more evaluation points with shorter intervals may further facilitate our understanding about metamorphopsia after RD surgery.