Rapid Morphological Restoration of Normal Foveal Contour After Spontaneous Epiretinal Membrane Separation from Retina in Eye with Macular Pseudohole: A Case Report

Introduction

The epiretinal membrane (ERM) is characterized by epiretinal fibrocellular proliferation,¹ usually occurring in elderly patients, and is usually associated with posterior vitreous detachment (PVD).^2,3 In general, ERM slowly advances and can cause a disruption of the foveal structure,⁴ leading to visual dysfunction and metamorphopsia.⁵ To release traction, vitrectomy and ERM peeling are used and are effective in improving the visual dysfunction, metamorphopsia, and visual acuity.^6–8

A spontaneous separation of the ERM from the retina is a relatively rare occurrence.⁹ It has been reported that spontaneous separation may occur in eyes with secondary ERM, particularly in young patients.^10,11 Self-separation of an idiopathic ERM, however, is exceedingly rare in eyes with a macular pseudohole.^12,13

In this study, we present a case of idiopathic ERM that spontaneously separated from the retinal surface of the eye with a macular pseudohole, immediately following resolution of visual deterioration and morphological findings.

Case Description

This study was carried out at the Akita University Hospital. The procedures conformed to the principles of the Declaration of Helsinki, and an informed written consent was obtained for the treatment and publication of this case report and accompanying images, following an explanation of the procedures to be used and the possible complications.

A 66-year-old man who had metamorphopsia due to an ERM in the right eye was referred to our hospital for treatment (Figure 1). Our examination showed that he had an ERM with a macular pseudohole with a visual acuity of 20/20 in the right eye. The patient had not retinal breaks and history of any ocular and systemic disorders, indicating that the ERM was primary and not secondary to trauma or inflammatory diseases. Fundus photograph taken at the initial examination in our hospital, showing an ERM with a round hole, centered on the fovea giving the appearance of a macular pseudohole. Spectral domain optical coherence tomography (SD-OCT) image shows the presence of PVD, retinal folds with a contraction of the ERM in the macular region, and partial separation of the ERM from the sensory retina in the inferior area. Moreover, without vitreous traction, the ERM appeared to be more contracted compared to that in an OCT image taken at the referral hospital 3 months earlier.

Figure 1 Fundus photographs and spectral domain optical coherence tomographic (SD-OCT) images of a 66-year-old man with metamorphopsia caused by an epiretinal membrane (ERM). A macular pseudohole was also present. (A) An SD-OCT image showing an ERM which is seen as a hyperreflective layer (white arrows) on the retina. A macular pseudohole (asterisk) can also be seen in the SD-OCT image. These images were taken at the referral hospital 3 months before the initial examination in our hospital. (B) Fundus photograph taken at the initial examination in our hospital showing an ERM with a round hole centered on the fovea giving the appearance of a macular pseudohole. (C) SD-OCT image shows the macular pseudohole (asterisk) and retinal folds with a contraction of the ERM in the macular area and a partially separation of the ERM from the sensory retina in the inferior area at the initial examination (white arrows). (D) Fundus photograph taken 2 months later. The ERM and the macular pseudohole are absent and the fundus has an almost normal appearance. (E) SD-OCT image shows no ERM and almost normal appearance of the retina without remaining undulations 2 months after the initial visit (white arrows).

We intended to perform vitrectomy to remove the ERM, but within 2 months after the initial visit, the ERM spontaneously separated from the retina. Fundus photograph showed that the ERM and the macular pseudohole are absent and the fundus has an almost normal appearance, and without remaining undulations, SD-OCT image showed no ERM and almost normal retina appearance. His vision improved to 20/15 after the ERM separation.

Discussion

Several cases of spontaneous ERM separation in eyes with a macular pseudohole have been reported, and the time of separation was distinct and depended on the patient’s age.^14–18 However, the separation can occur as long as 5 years after the detection of the ERM. Our case showed a rapid progression of the ERM contraction resulting in spontaneous separation from the retina within a total of 5 months (3 months before and 2 months after the initial visit) after it was first detected. Our case also had a rapid recovery of the foveal structure and improvement of vision.

The pathophysiology of spontaneous ERM separation is multifactorial and several mechanisms are being considered.¹⁷ The first one is PVD with pulling of ERM by detaching vitreous. Spontaneous ERM separation is more common in eyes with PVD.⁹ Second, the immature ERM’s contracting forces become stronger than its adhesions to the retina, resulting in slow tangential traction on the ERM’s edges and gradual separation from the edges toward the center. The third one is acute tearing of ERM at its weakest central point and retraction of a part of the membrane toward the epicenter, including increased stress on the ERM like Valsalva.¹⁷ The exact cause of spontaneous ERM separation is not easy to detect in each case. However, the second and third mechanisms should be related with the spontaneous ERM separation in the current case since the case had PVD at the initial visit.

It has been reported that eyes with a macular pseudohole associated with an ERM have a relatively well-preserved foveal function.¹⁹ This is probably because this type of ERM does not cover the foveal area and has a limited impact on the function of the foveal area. Furthermore, the structural characteristic would be related to the faster restoration of the foveal structure in comparison to the normal idiopathic ERM, which is typically associated with a shift in the foveal morphology as seen by the reduction of foveal concavity.¹⁹

Conclusion

Therefore, we suggest that cases with an ERM-associated macular pseudohole should be closely monitored for the possibility of a spontaneous separation of the ERM from the retina.