We appreciate the insightful comments of Dr Oh concerning our article, in which we describe the correlation between the recovery of foveal microstructure and visual function after macular hole (MH) closure. We reported that the presence of photoreceptor inner/outer segment (IS/OS) junction was correlated with good visual recovery after MH surgery. Using spectral-domain optical coherence tomography (OCT), we found that the restoration of external limiting membrane (ELM) is closely associated with that of the IS/OS junction.
Dr Oh provided additional points of view concerning our observations. He pointed out that change in foveal contour such as thickening or widening of the foveal center, which was observed on the serial OCT images in our Figure 3, may be the result of the regeneration or rearrangement of retinal layers. In reply to this comment, we re-examined the postoperative OCT images in our study and investigated the relationship between central foveal thickness (CFT) and length of IS/OS junction or ELM defect. There was a significant negative relationship between postoperative CFT and postoperative IS/OS junction defect ( r = −0.37, P = .0173; r = −0.40, P = .0099; r = −0.53, P = .0006; at 1, 3, and 6 months, respectively). The correlation between postoperative CFT and ELM defect was significant only at 1 month ( r = −0.38, P = .0138). These data suggest that IS/OS junction or ELM restoration is accompanied by foveal thickening. The reason for the absence of correlation between CFT and ELM defect at 3 and 6 months may be because ELM defect was 0 μm in most eyes at these times. There was no significant correlation between postoperative CFT and visual acuity ( P > .05 for all), which was consistent with the previous report. The visual outcome may not be dependent on CFT, but rather on the IS/OS junction or ELM restoration.
In traumatic MH, we reported a bridge formation of the tissue, which mimicked foveal detachment, in the process of spontaneous MH closure. In our study, we observed foveal detachment in 28% of eyes at 1 month, 12% at 3 months, and 7% at 6 months. There was no significant difference of IS/OS junction or ELM defect between eyes with and without foveal detachment at each observation point ( P > .05 for all).
We agree with Dr Oh’s comment that changes in foveal contour also were influenced by the factor that the serial images may not have been obtained exactly in the same location. Bottoni and associates analyzed changes of the outer retina after MH repair using Spectralis OCT (Heidelberg Engineering, Heidelberg, Germany) with the AutoRescan function, which automatically guides the OCT instrument to scan the same location. However, there may be a slight variation of the position in their serial images, as also pointed by the authors. We also agree with the comment that “3 or 6 months seems too short of a time for the outer foveolar defect to be healed completely.” It has been reported that outer foveolar defect was observed in one third of the eyes at 12 months. In our study, we found incomplete restoration of IS/OS junction in 70% at 6 months. Thus, further studies to evaluate the recovery of foveal microstructure for a longer period are needed.