Spontaneous Closure of a Macular Hole in Macular Telangiectasia Type 2

Abstract

Purpose:

Spontaneous closure of a macular hole in macular telangiectasia type 2 (MacTel) with vision improvement is described.

Methods:

A case report is presented.

Results:

A 71-year-old man presented with a 1-week history of distorted vision in his left eye. Left visual acuity (LVA) was 20/80. Optical coherence tomography showed an almost full-thickness left macular hole with an intact internal limiting membrane drape. Small inner retinal cavitations were present at the right macula; multimodal imaging confirmed MacTel. Managed conservatively, at 5 months the patient’s LVA had improved to 20/60, the defect was no longer full thickness, and the external limiting membrane had reconstituted. At the right macula, the inner cavitations grew and outer cavitations developed, but the external limiting membrane remained intact. At 32 months, right VA was 20/20 and LVA was 20/40.

Conclusions:

This case of MacTel with spontaneous closure of a macular hole was associated with an overlying internal limiting membrane drape.

Introduction

Macular telangiectasia type 2 (MacTel) is a bilateral retinal disease of unknown etiology that typically presents in the fifth to seventh decade. ^1,2 MacTel is diagnosed based on clinical features and characteristic changes on multimodal imaging. ² There are only 2 previous reports of MacTel presenting with an almost full-thickness macular hole with an overlying intact and continuous internal limiting membrane (ILM) that closed spontaneously. ^3,4 Paunescu et al ⁵ coined the term “ILM drape” to describe an intact ILM overlying cavitations in MacTel. We present a case of MacTel with documented spontaneous closure of a macular hole with an associated ILM drape that resulted in improvement in visual acuity (VA).

Methods

Clinical examination and multimodal imaging including spectral-domain optical coherence tomography (OCT) imaging (Zeiss Cirrus 5000; Carl Zeiss Meditec), confocal blue reflectance and autofluorescence imaging (Spectralis HRA + OCT; Heidelberg Engineering), and fluorescein angiography (Zeiss Visucam 524) were performed.

Case

A 71-year-old man presented with a 1-week history of distorted vision in the left eye. His unaided right VA (RVA) was 20/25 and left VA (LVA) was 20/80, with no improvement with pinhole (PHNI). One year previously his LVA was 20/30. The patient had a background of type 2 diabetes (on oral hypoglycemics), hypertension, and gout. A superficial crystal was seen clinically at the right macula. OCT of the right macula demonstrated small inner retinal hyporeflective spaces (cavitations) consistent with MacTel (Figure 1A). An almost full-thickness defect was present at the left macula except for an ILM drape (Figure 2A). ⁵ Vitreomacular separation had occurred at the right macula but not at the left. Fluorescein angiography showed leakage temporal to and involving the fovea.

Figure 1.

Spectral-domain optical coherence tomography of the right macula from superior to inferior at (A) presentation and (B) 8 months.

Figure 2.

Spectral-domain optical coherence tomography (OCT) of the left eye (A) from superior to inferior demonstrating a near full-thickness macular hole with overlying internal limiting membrane drape at initial presentation, (B) 2 months, and (C) 5 months. OCT raster images at 2 and 5 months are at finer intervals (0.075 mm) compared with OCT at baseline (0.25 mm).

The patient was treated conservatively in light of the reduced surgical success rate of macular hole closure in MacTel compared with idiopathic macular holes. ^1,6 At 2 months’ follow-up, LVA had fallen to 20/100 (PHNI) (Figure 2B). At 5 months, LVA had improved to 20/60 (PHNI) and the defect was no longer full thickness. Inner and outer retinal cavitations were now separated by a reconstituted external limiting membrane (ELM) (Figure 2C). RVA remained 20/25 with a slight increase in the size of the cavitations on OCT. At 8 months, LVA was 20/40 (PHNI) and the cavitations were unchanged. In the right eye, a posterior vitreous detachment had occurred. Inner and outer cavitations had developed at the right macula, separated by an intact ELM (Figure 1B). RVA remained at 20/25 (PHNI) despite discontinuity of the ellipsoid zone. Fundus autofluorescence demonstrated partial loss of central attenuation bilaterally (Figure 3). At 11 months, LVA was 20/50 (pinhole 20/32), improving to 20/16 with refraction but dependent on fixation.

Figure 3.

At 8 months, compared with green reflectance imaging (A and B), confocal blue reflectance imaging (C and D) demonstrates increased parafoveal reflectance; and fundus autofluorescence (E and F) shows partial loss of central hypoautofluorescence bilaterally.

At 24 months, right best-corrected VA (BCVA) was 20/16 and left BCVA was 20/32. The cavitations at the right macula had slightly enlarged but the ELM remained continuous, while at the left macula cavitations persisted but the continuity of the ellipsoid zone was largely restored (Figure 4). At final follow-up at 32 months, right BCVA was 20/20 and left BCVA was 20/40. Near vision was N6 in the right eye and N12 in the left eye, and mild distortion persisted in the left eye. The OCT appearance was unchanged bilaterally compared with the 24-month visit.

Figure 4.

Spectral-domain optical coherence tomography at 24 months of the (A) right eye and (B) left eye.

Conclusions

This is a case of MacTel with spontaneous closure of an almost full-thickness macular hole with an overlying ILM drape. To the best of our knowledge, only 2 such cases have been previously described, also in the absence of vitreomacular separation or posterior vitreous detachment. ^3,4

The pathophysiology of macular hole formation in MacTel is likely to be different from that of idiopathic full-thickness macular holes, in which tractional forces at the vitreomacular interface are usually present. ⁷ MacTel is associated with Müller cell degeneration with formation of cavitations and neurosensory atrophy. ^2,8 Müller cells are the predominant glial cells in the retina and occupy the full thickness of the retina, participating in the formation both of the ILM and ELM. ^9,10

It has been traditionally thought that closure of idiopathic macular holes is largely dependent on the release of vitreomacular traction either surgically or spontaneously. Morawski et al ¹¹ showed that spontaneous hole closure can occur in the absence of vitreomacular traction release. In their case series, “bridging” glial cells appeared to be the key to hole closure, which they termed the bridging phenomenon. In 2 previous reports of hole closure in MacTel, the ILM remained intact. ^3,4 The ILM is principally formed by the basement membranes of the Müller cells and astrocytes, ^9,10 and we speculate that the presence of a continuous ILM may facilitate hole closure by a bridging mechanism. In Figure 2A (middle) and Figure 2B (upper) of the present case there does appear to be a thin, faint hyperreflective line within the macular hole that may represent an extension of the ELM or bridging glial cells as Morawski and colleagues ¹¹ showed in their case series.

Nalcı et al ⁴ showed reconstitution of the ELM enabled hole closure, as in the present case. Interestingly, our patient developed inner and outer cavitations at the right macula, but the ELM remained intact. The ELM is produced by zonulae adherentes that largely join the inner segments of the photoreceptors to the supporting Müller cells. ⁹ MacTel is understood to be a Müller cell disease, ⁸ and the ELM is likely to play an important role in the prevention or resolution of almost full-thickness macular holes in this disease.

Shukla and Venkatesh ¹² described spontaneous closure of a full-thickness macular hole in MacTel; however, in their case the defect was truly full thickness with no overlying ILM drape. The configuration was similar to that of an idiopathic macular hole with separation of the posterior cortical vitreous from the macular hole edges, which also differs from our case.

Vitrectomy for full-thickness macular holes in MacTel is often associated with poor anatomic and visual outcomes, hence our conservative approach. ^1,6 Spontaneous hole closure in MacTel was observed in our case and may have been facilitated by the intact ILM drape, absence of vitreomacular traction, bridging of glial cells, and reconstitution of the ELM. In cases in which an ILM drape is associated with an otherwise full-thickness macular hole, a diagnosis of MacTel should be considered, because observation may be more appropriate than surgery in this context.