Case of Spontaneous Closure and Recurrence of Macular Hole in Vitrectomized Eye

Introduction

Vitreous traction in the anteroposterior and tangential directions together with degeneration of the inner retinal layers at the central fovea, are believed to be important factors that can cause the formation and expansion of a full-thickness macular hole (FTMH).^1–3 However, a macular hole (MH) can develop in eyes with a complete posterior vitreous detachment (PVD)^4,5 and even after vitrectomy during which a PVD has been created.^6–9 It has also been reported that a spontaneous closure and recurrence of an MH can occur in a previously vitrectomized eye.^10–15 The associations of an epiretinal membrane (ERM) or an epiretinal proliferation (EP) with the development and closure of FTMH and lamellar macular hole (LMH) have been intensively studied by several researchers.^16,17

We report our findings in a patient who underwent a successful vitrectomy for a vitreous hemorrhage (VH) associated with a retinal tear. A FTMH developed during the postoperative period but closed spontaneously. However, optical coherence tomography (OCT) 4 months later revealed a LMH that developed into a FTMH and a second vitrectomy had to be performed to close the MH.

Case Presentation

A 64-year-old woman was examined at a local clinic because of reduced vision in her right eye of three days duration. Her best-corrected visual acuity (BCVA) in the right eye was hand motion at 30 cm and she had no history of trauma. Her intraocular pressure (IOP) was 12 mmHg and the axial length was 23.52 mm in the right eye. Ophthalmoscopy revealed a dense vitreous hemorrhage (VH), and she underwent successful pars plana vitrectomy (PPV) combined with cataract surgery the following day. A retinal tear that caused the hemorrhage was detected during vitrectomy and was treated with photocoagulation and gas tamponade. The decimal BCVA in the right eye had improved to 1.2 one week later.

Eight months later, a MH developed in the vitrectomized right eye (Figure 1A). OCT showed cyst-like changes in the retina and a thin hyperreflective membrane on the retinal surface. The patient complained of distorted vision even though her decimal BCVA was 1.2. PPV was planned, but was canceled 2 weeks later due to the spontaneous closure of the MH.

Figure 1 Serial optical coherence tomographic (OCT) images showing the development of a full thickness macular hole (FTMH) in a vitrectomized eye. Optical coherence tomographic (OCT) image of the retina with an epiretinal membrane that developed 8 months after a vitreous surgery (A). Two weeks later, the MH spontaneously closed. The OCT image was obtained 4 months later (B). A lamellar macular hole (LMH) with epiretinal proliferations developed 11 months later (C and D). Note that the image in D was obtained from raster images (6 mm in length) and it shows the epiretinal proliferation. A recurrence of the MH was found 13 months after the spontaneous closure of the MH (E), which was closed by a second vitrectomy (F). The OCT images were obtained on the following dates. (A). 201X. 1. 30, (B). 201X. 5. 28, (C and D). 201X+1. 1. 22, (E). 201X+1. 3. 18, (F). 201X+1. 6. 20.

Four months later, OCT showed a slight elevation of the ellipsoid zone and the interdigitation zone at the fovea but the patient reported that the distorted vision of her right eye was not present (Figure 1B). Eleven months after the spontaneous closure of the MH, a LMH with EP was detected in the vitrectomized right eye (Figure 1C and D). Nevertheless, her decimal BCVA was still 1.2. Two months later, the BCVA had decreased to 0.7 (Figure 1E), and OCT revealed a recurrence of the FTMH with cyst-like changes in the retina.

A second PPV combined with the insertion of the peeled internal limiting membrane (ILM) flap into the MH was performed. The yellowish tissue was not large and was able to be inserted into the MH without trimming. The retina was then tamponaded with 20% SF6 gas. The MH was closed, and the decimal BCVA was restored to 1.2 (Figure 1F). No recurrence was found at the last visit 5 months after the second vitrectomy.

Discussion

There have been several reports of a MH that developed in vitrectomized eyes, however only a limited number of cases had a recurrence of a MH after a spontaneous closure (Figure 1).^10–15 The mechanism causing the MH formation after vitrectomy has not been definitively determined. Earlier studies have suggested two possible mechanisms: the formation of an epiretinal membrane (ERM) which exerts tangential traction on the foveal retina and causes the development of a MH. This type of MH is referred to as the tangential tractional type of MH⁶ and is related to the development of a MH after vitrectomy.^7,8 The other type of MH develops in eyes with cystoid macular edema and is referred to as the cystoid degeneration type of MH.⁶ It is believed that the rupture or dehiscence of the roof of the cysts leads to the FTMH. There are also patients with repeated recurrences and spontaneous closures of a MH which one author suggested was caused by retinal inflammation.¹²

In our case, the first MH occurred 8 months after vitrectomy. Because an ERM was observed in the OCT images, we suggest that this MH is a tangential traction type of MH. Surgery was planned to release the traction but it was canceled due to a spontaneous closure of the MH. A spontaneous closure can be caused by a shift in the tractional forces caused by an ERM and the presence of bridging retinal tissues in the MH.^9,10 An ERM was observed in our patient, and the spontaneous closure may have occurred because the MH opening was small and the direction of traction by the ERM had changed.

If the ILM peeling had been performed during the primary surgery, it may have led to another situation. Further analyses are needed to determine if ILM peeling is necessary during vitrectomy for eyes with a rhegmatogenous VH.

A LMH was detected immediately before the second vitrectomy for the MH and ERM. EPs were also observed in the retina around the MH in the OCT images. The cellular origin of the EPs was not determined, but Pang et al postulated that it is primarily caused by the proliferation of Müller cells in the inner retina.¹⁸ In addition, the connections between the foveolar Müller cells and EP were thought to stabilize the foveal structure by preventing the elevation of the inner layers of the foveal walls which could cause an enlargement of the degenerative cavitation.¹⁹

There are also reports that EPs can act on MH closure and reopening.^20–25 Thus, Watanabe et al suggested that EPs exert a force while attempting to seal the hole, and the more widespread ERMs have sufficient force to create a reopening.²¹ It has been suggested that the main cellular components of EPs were glial and vitreal cells, such as fibroblasts and hyalocytes. However, a histological study showed that many of the cells of EPs were positive for glial fibrillary acidic protein, and the number of cells expressing α-smooth muscle actin was low.²² These findings suggested that EPs have less tractional force than ERMs. The suggestion that the mechanism that created the first MH also caused the second MH cannot be eliminated. On the other hand, it may be possible that the first MH was only partially closed as noted when the OCT images of the MH was examined more carefully. In our patient, the configuration of the macula appeared to be normal and micro and small MHs were not observed in the raster images taken serially at each visit (Supplemental Figure 1). The second MH developed 13 months later, and it is possible that cellular migration and phagocytosis occurred around the macula during this period. This may then exert tension on the retina through another mechanism, and due to the presence of EPs and cyst-like changes, we suggest that the development of the second MH was associated with a degenerative mechanism.

Although it has not been determined conclusively whether EPs should be completely removed or inserted into the MH during vitrectomy, we inserted the yellowish tissue and ILM flap into the MH during the surgery according to the findings of earlier cases.^25–27 Further analyses of this procedure should lead to a better understanding of the pathology of MHs.

This study had several limitations. This was a single case, and the assumed mechanism for the development and spontaneous closure of the MH cannot be expanded to other cases. No histopathological examinations were performed on the surgically excised specimens. Nevertheless, we believe that these findings will contribute to a better understanding of the pathogenesis of MH opening and closing.

In conclusion, the findings made in our case illustrate the different OCT findings including macular configuration in eyes with a MH. Careful observations during its development is necessary to determine the possibility that repeated MH development is due to different mechanisms. Further analysis of microstructural changes is required to determine the exact pathogenesis of MHs.