In very rare cases, the macular hole may close spontaneously without any surgery (Fig. 11.3). In these eyes, closure of macular hole begins at the inner layers of the retina. Our observations of these cases allow us to suggest that if the edges of macular hole are not completely smooth, spontaneous healing may occur [7].

After surgery, the macular hole closes during the first day in about 55% of cases and in 65–75% within 48 hours [8, 9]. This has been presented with a specially prepared OCT device, which allows OCT scans to be performed whilst the patient remains in a prone position [8]. Kikushima demonstrated that SS-OCT allows retina scans as early as 20 min after surgery in a gas-filled eye [9]. Because we perform the inverted ILM flap technique with an air tamponade in idiopathic macular hole cases, we can obtain good quality scans with the SS-OCT device after a few days. This is possible because air disappears quickly in the first days after surgery. We can observe U-type and V-type or irregular closure at the one-week follow-up visit. The best functional results are achieved with U-type closure [10]. Macular hole closure always begins in the inner retina layers (Fig. 11.4).

Interestingly, we may see at the one-week visit that macular hole is closed with ILM only (Fig. 11.4d). This may happen in 15–30% of cases (Nawrocki, unpublished data). We would like to suggest that those holes would not close or would stay flat open if a traditional approach was performed. Flat open macular hole appearance is defined as edges of the hole being flat on the pigment epithelium while bare pigment epithelium is visible in the center of the fovea (Fig. 11.4e). In the past this was considered as macular hole closure, but in our opinion such cases should rather be considered as surgical failures because visual acuity shows no improvement in follow-up.

In 2008, using spectral domain OCT, our group described different retina structure pathologies after macular hole surgery [10]. The following retinal abnormalities were observed: photoreceptor defect defined as linear lack of photoreceptors in the subfoveal area with normal retinal reflectivity; cysts in outer retinal layers; nerve fiber layer defect; elevation of all retinal layers in fovea; and retinal pigment epithelial defects. The study was performed after vitrectomy with ILM peeling and gas for idiopathic FTMH. Even at that time, we suggested some regeneration process occurred in the foveal architecture.

Due to the high resolution of SS-OCT, we can sometimes visualize the ILM flap covering the macular hole at the first post-operative follow-up (Fig. 11.5). After employing the inverted ILM flap technique, it is interesting that in many cases, such as U-type closure (Fig. 11.4a), we do not see any sign of the inverted ILM flap itself on the surface of the retina, whereas in V-type closure or irregular closure cases, we see some presence of ILM (Fig. 11.4b, c).

In some cases, during the first control after surgery the macular hole is closed with ILM flap only. We refer to these cases as “flap closure.” During the next weeks or months of follow-up, we may observe almost complete regeneration of retinal tissue under the flap of ILM, and we suggest that this also confirms that ILM, as a base membrane, serves as a scaffold for retinal tissue to proliferate or migrate in the foveal area (Fig. 11.6).

During follow-up the ILM flap may become less visible but in some cases, after complete closure of macular hole, the ILM flap may change its position or even float above the surface of the retina. Interestingly, in macular holes initially closed with ILM only, we observe reappearance of retinal layers during the follow-up period and even the reformation of photoreceptor layers, even if the flap itself has become somewhat detached from the retinal surface (Fig. 11.7).

After surgery, or in rare cases with spontaneous resolution, macular hole closure always begins in the inner layers of the retina. During follow-up we observe healing of the inner and outer layers of the retina and photoreceptor layers. The process of regeneration lasts many months. We should usually reserve our judgment until 1 year after surgery, and in many cases complete reformation of the retina layers is not observed until even later. It is interesting to observe regeneration of retina tissue during follow-up. It was once thought that nervous tissue does not regenerate. We now know better, and looking at multiple examples after macular hole surgery we clearly see that as retina layers reappear the retina architecture normalizes and this correlates with improvement in visual acuity. These changes are clearly visualized with SS-OCT (Fig. 11.8).

With the new device we were also able to present that, contrary to the regeneration of foveal architecture, we see new defects in the nerve fiber layers as shown in Fig. 11.8c, d. These defects are known as dissociated nerve fiber layer (DONFL) [11]. DONFL is defined as indentation of inner retinal layer or formation of small dimples visible in the retinal nerve fiber layer, and can appear even 6–12 months after surgery. The most recent modification of the inverted ILM flap technique, called “the temporal inverted ILM flap technique,” allows us to reduce the number and area of nerve fiber layer defects [2]. With this technique we observe DONFL only on the temporal side of the fovea where ILM had been peeled. We do not see them between the fovea and the optic nerve where ILM was not peeled.