From the Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Department of Ophthalmology (WES, BJL, GG); and the Department of Ophthalmology (SK), the Institute of Vision Research, Yonsei University College of Medicine, Seoul, South Korea.
The authors have no financial or proprietary interest in the materials presented herein.
Address correspondence to William E. Smiddy, MD, 900 NW 17th Street, Miami, FL 33136.
Improvements in optical coherence tomography (OCT) have allowed for greater understanding of vitreomacular anatomy, particularly in the variety of conditions that seem to be mediated by vitreomacular traction. The increased speed and resolution of new, commercially available spectral domain OCT (SD-OCT) systems have further improved the visualization of these features. Myopic traction maculopathy1–4 seems to be in the family of vitreomacular traction disorders, but its mechanism of formation is not clear.
The purpose of this study is to present a case of myopic traction maculopathy that was serially imaged using time domain OCT (TD-OCT) and SD-OCT. The features and findings allow for formation of hypotheses regarding the pathogenesis and mechanism of visual loss.
The study design was an interventional case report. Images were obtained with TD-OCT (Stratus OCT; Carl Zeiss Meditec, Inc., Dublin, CA) and SD-OCT (Cirrus HD-OCT; Carl Zeiss Meditec, Inc.).
A 55-year-old woman was first examined by the investigators for worsening central metamorphopsia and visual loss in the right eye. Best-corrected visual acuity (BCVA) at presentation to the investigators was 20/30 in the right eye and 20/40 in the left eye, with -17.75 D in both eyes. Amsler grid testing showed worsening distortion in the right eye but was normal in the left eye. Ocular history was notable for a decrease in BCVA from 20/20 in both eyes and refraction increased from -12 D in both eyes over the previous 23 years. Fundus photography and fluorescein angiography 3 years previously depicted peripapillary atrophy with retinal pigment epithelium (RPE) mottling in the macula without apparent epiretinal membrane formation (Fig. 1). The patient had been treated elsewhere with thermal laser for extrafoveal choroidal neovascularization nasally in the right eye 3 months after that study. Her first OCT 1 year before examination disclosed an epiretinal membrane, distorted foveal contour and layers, and a deep retinal schisis-like appearance (Fig. 2). The Stratus OCT depicted a more prominent preretinal layer and some deep retinal edema in the right eye (Fig. 3).
Figure 1. (A) Color Fundus Photography of the Right Eye 5 Years Before Surgery Showed Peripapillary Atrophy with Atrophic RPE Changes and What Appears to be a Weiss Ring Indicating Posterior Vitreous Detachment Inferior to the Optic Disk (arrows). (B) Fluorescein Angiography Showed Window Defects Without Leakage (arrows). (C) the Color Photograph of the Left Eye Has Similar Atrophic Macular RPE Changes and Apparent Weiss Ring (arrows).
Figure 2. Stratus OCT of the Right Eye 3 Years Before Surgery Showed Preretinal Tissue (arrowheads) with Marked Distortion of Inner Retinal Structures and Cystic Schisis-Like Change (asterisks) in the Deep Layers of the Retina.
Figure 3. Stratus OCT 2 Months Preoperatively Shows a Similar Degree of Preretinal Tissue (arrowheads) and Deep Retinal Schisis-Like Change (asterisks), but also (A) a Possible FTMH in the Right Eye, and (B) a Mild, Preretinal Tissue Component (arrowheads) in the Left Eye.
The patient’s medical history was remarkable for a high rheumatoid antibody titer, chronic inactive hepatitis B, and Leiden factor coagulation deficiency.
One month later, her clinical situation had not changed. A possible full-thickness macular hole (FTMH) was suspected from the printed (raster) cuts of SD-OCT imaging, but it was not confirmed until other (cube) cuts were reviewed later (Fig. 4). Surgical intervention was not recommended at that time because BCVA was still 20/40.
Figure 4. (A) SD-OCT 1 Month Preoperatively Shows the Preretinal Layers More Prominently (arrowheads) with More Distinct Distortion of the Deep Retinal Layers (outer Nuclear Layer; Asterisks) and a Probable FTMH (arrow). (B) In the Left Eye, the Preretinal Layer and the Deep Retinal Layer Stretching Are More Distinct than Was Evident with the Stratus OCT.
An additional month later, the BCVA had decreased to 20/100 in the right eye and the central visual disturbance symptoms had worsened. An SD-OCT in the right eye showed more distinct preretinal tissues, distortion of the outer retinal areas, a small pocket of subretinal fluid, and an unequivocal definite FTMH (Fig. 5). A vitrectomy with membrane peeling and fluid–gas exchange was performed in the right eye.
Figure 5. SD-OCT 10 Days Preoperatively Shows Unequivocal FTMH.
At surgery, there appeared to be a preexisting posterior vitreous separation, verified by the absence of deviation of the silicone tipped extrusion needle at the retinal surface. A bent MVR blade was used to engage and peel a thin, but broad, confluent tissue layer that seemed thicker than internal limiting membrane (ILM) but more cohesive than posterior hyaloid. It was removed from the eye in two large pieces with intraocular forceps. A fluid–air exchange was performed, and a 20% mixture of SF6 gas was infused, although the FTMH could not be unequivocally visualized intraoperatively.
Postoperatively, the patient maintained face-down positioning for 1 week. One month postoperatively, BCVA was 20/40 and central visual symptoms had improved markedly. BCVA remained 20/30 in the left eye. Repeat SD-OCT imaging showed closure of the FTMH, and the retinal cell layers had a more normal pattern, although the deep retinal stretching change persisted in the temporal midperiphery, beyond where the preretinal layer had been removed (Fig. 6). BCVA improved to 20/25 in the right eye, at the 3-month postoperative examination, but decreased at postoperative month 6 to 20/200 in the right eye, consistent with progressive, moderate nuclear lens opacities (potential acuity meter testing yielded 20/40).
Figure 6. Postoperative SD-OCT Shows Marked Diminution of the Outer Retinal Schisis and Absence of the Preretinal Layer. The Foveal Contour Has Been Reestablished, but Some Schisis-Like Findings Persist (asterisks) Temporally Beyond the Zone Where the Preretinal Layer Was Removed.
The diagnostic entity of the patient in this report has been described in detail.1–5 First reported by Takano and Kishi,2 it is a slowly progressive, degenerative disorder whose manifestations vary with the degree of myopia, posterior staphyloma, and vitreous degeneration and may culminate in macular hole formation.4 Poor contrast of the retina against depigmented RPE may make its features (including the macular hole) difficult or impossible to recognize by clinical exam; OCT may be required to detect the hole, as it was in our case. Variously called myopic maculoschisis, foveal schisis, and vitreoschisis, it is generally considered within the family of macular traction syndromes, but it occurs only in high myopia. The more generic term of myopic traction maculopathy, as coined by Panozzo and Mercanti, more accurately describes this entity because it is not truly retinoschisis (symptoms are characterized by metamorphopsia rather than a true scotoma), and there is frequently visual and anatomic improvement after surgery—two findings that would not be expected with retinoschisis.1 Imaging studies, including the higher-resolution SD-OCT, support these concepts.
The etiology of myopic traction maculopathy is uncertain. It is our hypothesis that progressive staphyloma formation generates a posteriorly applied force that gives the appearance that there is primary (anterior or tangentially directed) preretinal traction. The unique, deep retinal schisis-like appearance, visualized best by SD-OCT imaging, may be a reflection of the tight adhesion of the photoreceptor outer segments to the RPE, resulting in a radial stretching of the outer retina, and is consistent with this hypothesis. Furthermore, subclinical retinal elevations or stretching of outer layers may represent a mechanism for stimulating RPE depigmentation and clumping—the characteristic finding (with or without staphyloma) in myopic degeneration. The more prominent preretinal layer may be a compressed, taut, residual posterior hyaloid layer that has become flattened as it is stretched across the expanding retinal surface. The vitreous anatomy is well known to be unusual in high myopia and includes abnormally extensive areas of retinal adhesion and vitreoschisis.
While preretinal layers give the appearance of mediating traction,5 the retinal arterioles have also been hypothesized to do so,6 but this may be by lending firmer structural characteristics that serve as a tether point for the traction induced elsewhere. Macular hole formation in general seems to be the result of somewhat chronic, lateral force exerted on a fragile ILM or weakened inner retina.7 Typically, this seems to be from a primary, pre-retinal source. Macular hole formation has been found to be more common in eyes with more extensive RPE atrophy than in eyes with choroidal neovascularization8 and is especially common (approximately 50%) in myopic traction maculopathy.9 These observations support the hypothesis that the vitreoretinal traction and outer retinal stretching are due to the posterior movement of the staphyloma and lead to macular hole formation once the retinal tensile strength is exceeded at, presumably, its thinnest, weakest point. The deep, extraretinal (as contrasted to preretinal) source of the traction at the fovea may also account for the generally lower macular hole surgery success rates in high myopia.
In some cases, myopic traction maculopathy may be amenable to surgical intervention by removal of the prominent preretinal layers9–12; ILM peeling may be an important manuever.13,14 Although the anatomic and visual appearance of such patients commonly improves postoperatively, macular hole formation may still ensue, prompting some to recommend prophylactic internal gas tamponade. To our knowledge, this is the first report of SD-OCT imaging of myopic traction maculopathy. The potential diagnostic confusion between this and other preretinal traction entities has been clarified by improved OCT imaging capabilities. SD-OCT gives an especially clear rendering that offers findings that corroborate hypotheses regarding the pathogenesis and mechanisms of this and other entities. Ironically, though, the development of the macular hole was not initially apparent with SD-OCT due to the paucity of images reviewed in the clinic. These images were high-resolution B-scans spaced 250 μ apart, whereas the intervening spaces (where the hole was first apparent) were later visualized by reviewing the (lower-resolution) cube scans that are not currently provided in the standard printout. This emphasizes the importance of being able to view all of the scanning information available (including cube scan data), at least when trying to determine an early macular hole or other focal pathologies.
This report of SD-OCT imaging of this entity highlights its capabilities as well as the need for comprehensively analyzing all imaging information yielded. The findings in this case support the suggestion that the source of apparent vitreoretinal traction may be the posteriorly expanding staphyloma to the point of macular hole formation once the tensile strength of the retina is exceeded. The characteristic schisis-like appearance of the deep retina in this condition and the extensive RPE atrophy may also be evidence of this traction. Larger series are necessary to confirm this hypothesized mechanism. Removal of the preretinal elements allowed for improved vision by restoring retinal anatomy, thus allowing closure of the macular hole.
- Panozzo G, Mercanti A. Optical coherence tomography findings in myopic traction maculopathy. Arch Ophthalmol. 2004;122:1455–1460. doi:10.1001/archopht.122.10.1455 [CrossRef]
- Takano M, Kishi S. Foveal retinoschisis and retinal detachment in severely myopic eyes with posterior staphyloma. Am J Ophthalmol. 1999;128:472–476. doi:10.1016/S0002-9394(99)00186-5 [CrossRef]
- Sayanagi K, Ikuno Y, Tano Y. Tractional internal limiting membrane detachment in highly myopic eyes. Am J Ophthalmol. 2006;142:850–852. doi:10.1016/j.ajo.2006.05.031 [CrossRef]
- Ikuno Y, Tano Y. Early macular holes with retinoschisis in highly myopic eyes. Am J Ophthalmol. 2003; 136:741–744. doi:10.1016/S0002-9394(03)00319-2 [CrossRef]
- Gass JD. Muller cell cone, an overlooked part of the anatomy of the fovea centralis: hypotheses concerning its role in the pathogenesis of macular hole and foveomacular retinoschisis. Arch Ophthalmol. 1999;117:821–823.
- Ikuno Y, Gomi F, Tano Y. Potent retinal arteriolar traction as a possible cause of myopic foveoschisis. Am J Ophthalmol. 2005;139:462–467. doi:10.1016/j.ajo.2004.09.078 [CrossRef]
- Smiddy WE, Flynn HW Jr, . Pathogenesis of macular holes and therapeutic implications. Am J Ophthalmol. 2004;137:525–537. doi:10.1016/j.ajo.2003.12.011 [CrossRef]
- Shimada N, Ohno-Matsui K, Yoshida T, Futagami S, Tokoro T, Mochizuki M. Development of macular hole and macular retinoschisis in eyes with myopic choroidal neovascularization. Am J Ophthalmol. 2008; 145:155–161. doi:10.1016/j.ajo.2007.08.029 [CrossRef]
- Shimada N, Ohno-Matsui K, Baba T, et al. . Natural course of macular retinoschisis in highly myopic eyes without macular hole or retinal detachment. Am J Ophthalmol. 2006;142:497–500. doi:10.1016/j.ajo.2006.03.048 [CrossRef]
- Kobayashi H, Kishi S. Vitreous surgery for highly myopic eyes with foveal detachment and retinoschisis. Ophthalmology. 2003;110:1702–1707. doi:10.1016/S0161-6420(03)00714-0 [CrossRef]
- Kwok AK, Lai TY, Yip WW. Vitrectomy and gas tamponade without internal limiting membrane peeling for myopic foveoschisis. Br J Ophthalmol. 2005;89: 1180–1183. doi:10.1136/bjo.2005.069427 [CrossRef]
- Panozzo G, Mercnati A. Vitrectomy for myopic traction maculopathy. Arch Ophthalmol. 2007;122:1455–1460.
- Ikuno Y, Sayanagi K, Ohji M, et al. . Vitrectomy and internal limiting membrane peeling for myopic foveoschisis. Am J Ophthalmol. 2004;137:719–724.
- Kuhn F. Internal limiting membrane removal for macular detachment in highly myopic eyes. Am J Ophthalmol. 2003;135:547–549. doi:10.1016/S0002-9394(02)02057-3 [CrossRef]