has already been described in histopathological papers [31, 32].

Eckardt et al. demonstrated with SD-OCT that macular hole closure appears within 24 h of surgery in 54.5% of 13  the cases and in 48 h in 75.7%. Such fast closure of the macular hole after vitrectomy with ILM peeling may support the theory that ILM peeling is a type of refreshment of the edges of the macular hole, and allows for a similar situation to that observed in spontaneous macular hole closure, which is additionally supported by the gas bubble that provides a surface for cell migration so that the macular hole can close. According to Eckardt et al., if the macular hole does not close during the first 3 days, it will not close later on and will require repeated surgery [33].

The healing process does not end with macular hole closure. In the postoperative period, restoration of two hyperreflective lines, which are believed to be the ELM and the IS/OS junction, is observed [27, 34, 35]. Lee et al. presented three cases of restoration of the photoreceptor layer after macular hole surgery [34]. Chang et al. observed that 6 out of 7 eyes with macular hole closure had a decrease in the IS/OS defect size after the hole was closed. Visual acuity showed a trend towards improvement, but the improvement was not correlated with the change in the size of the IS/OS boundary defect [33]. Sano described 28 cases of healing of the IS/OS line. The visual outcomes were significantly better in eyes with a continuous IS/OS line than in those with a disrupted IS/ OS line [35].

Summary for the Clinician

■Elevation of the photoreceptor layer combined with asymmetric posterior hyaloid traction on the fovea can be considered an early step in macular hole formation.

■After successful surgery, various defects of the retinal layers in the fovea can be noted. Some of them may be influenced by surgical procedures.

■Visual acuity improves up to 12 months after surgery, as does the appearance of the fovea in SOCT.

13.9  Surgical Considerations

Vitrectomy as a method of treatment for macular holes was introduced in 1990–1991 by Kelly and Wendel [36]. During the 1990s, different adjuvants were used to improve the results of surgery. By the end of the 1990s

and the beginning of the 21st century, the increasing role of ILM peeling combined with vitrectomy and gas injection was observed. Various dyes are being used to improve the quality of ILM peeling. This kind of treatment is nowadays considered a standard procedure for the treatment of macular holes.

As this chapter is designed to present the diagnostics of macular hole with SOCT, surgical methods will not be widely presented or discussed. However, we recently presented a new method of treating large macular holes [37]with the use of an inverted ILM flap to cover the macular hole and to improve the closure rate of large macular holes. Postoperative SOCT examination after the use of the inverted ILM flap technique gave us the opportunity to demonstrate macular hole closure in those eyes. As can be seen, the ILM serves as a scaffold for tissue migration or proliferation with the aim of closing the macular hole. Without the use of SOCT, it would not be possible to observe this process. This mechanism may explain how full-thickness retinal defects close. Without a histopathological examination of the eyes after macular hole closure with the inverted ILM flap technique, one cannot be sure whether this process is due to glial proliferation or movement of the retinal cells [37]. Histopathological studies of the eyes operated on with vitrectomy but without ILM peeling show that glial proliferation (Muller cells) may be responsible for the healing process [31, 32]. A regeneration process of the photoreceptor cells, initiated by Muller glial proliferation, was recently described in zebrafish, and the same mechanism may take place in the above described situation. (Figs. 13.9, 13.10) [38].

Summary for the Clinician

■Vitrectomy with ILM peeling and gas injection is the method of choice in the treatment of macular holes.

■Spectral OCT demonstrates the mechanism of macular hole closure.

13.10  Lamellar Macular Hole and Macular

Pseudohole

The 1970’s, Gass described pseudomacular hole formation, as being caused by spontaneous contraction of an epiretinal membrane surronding but not covering the foveal area, and which may produce a biomicroscopic appearance simulating a full-thickness macular hole [39, 40]. Usually,

Fig. 13.9  The images show an extremely large macular hole with a minimum diameter of 1,268 × 1,958 µm, which was operated on using the inverted internal limiting membrane (ILM) flap technique and air injection [37]. (a) Fundus view. (b) Fluorescein

angiography (Topcon Company, Tokyo, Japan). (c) Spectral domain OCT (Copernicus; Optopol, Zawiercie, Poland) demonstrates preoperative view of a macular hole. RPE retinal pigment epithelium, ERM epiretinal membrane

Fig. 13.10  (a) Spectral OCT picture demonstrates closure of the macular hole presented in Fig. 13.9 with the inverted ILM flap only. (b) However, the next picture, 1 month later, demonstrates that the

these patients have no or very few complaints and visual acuity is normal or almost normal.

Haouchine et al. confirmed this observation with OCT [41]. Differential diagnosis of macular pseudoholes

ILM flap serves as a scaffold for tissue migration or proliferation along the ILM to close the macular hole. (c) Further closure is visible after 3 months (Copernicus HR; Optopol, Zawiercie, Poland) [37]

(Fig. 13.11a) from lamellar macular holes (Fig. 13.11b) may be difficult, but it is possible on the basis of OCT, which shows the lack of dehiscence of the inner foveal retina from the outer foveal retina in the pseudoholes.