Ophthalmic Surgery, Lasers and Imaging Retina

Case Report 

Dome-Shaped Macula: A Compensatory Mechanism in Myopic Anisometropia?

Pearse A. Keane, MRCOphth, MSc; Arijit Mitra, DO, MRCSEd; Imran J. Khan, MRCOphth; Fahd Quhill, FRCOphth; Samer M. Elsherbiny, FRCOphth

Abstract

The purpose of this article was to describe a patient with dome-shaped macula in the setting of mild myopic anisometropia and to speculate regarding the role of this feature as a compensatory mechanism in ocular development. The clinical records of a 49-year-old woman with this condition were reviewed. Spectral-domain optical coherence tomographic images revealed evidence of a dome-shaped macula. B-scan ultrasonography measured axial lengths of 23.8 mm in the right eye and 22.8 mm in the left eye. Spherical equivalents were −1.375 and +0.375 in the right and left eyes, respectively. Examination of the left eye was unremarkable. Dome-shaped macula has previously only been described in patients with high myopia. These findings support the hypothesis that myopic anisometropia, rather than absolute refractive status, is central to the development of dome-shaped macula and that this feature represents a protective mechanism aimed at reducing the effects of anisometropia.

Abstract

The purpose of this article was to describe a patient with dome-shaped macula in the setting of mild myopic anisometropia and to speculate regarding the role of this feature as a compensatory mechanism in ocular development. The clinical records of a 49-year-old woman with this condition were reviewed. Spectral-domain optical coherence tomographic images revealed evidence of a dome-shaped macula. B-scan ultrasonography measured axial lengths of 23.8 mm in the right eye and 22.8 mm in the left eye. Spherical equivalents were −1.375 and +0.375 in the right and left eyes, respectively. Examination of the left eye was unremarkable. Dome-shaped macula has previously only been described in patients with high myopia. These findings support the hypothesis that myopic anisometropia, rather than absolute refractive status, is central to the development of dome-shaped macula and that this feature represents a protective mechanism aimed at reducing the effects of anisometropia.

From the NIHR Biomedical Research Centre for Ophthalmology (PAK), Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, Islington, Greater London; Birmingham and Midland Eye Centre (PAK, AM, IJK, FQ, SME), Birmingham, West Midlands; and Royal Hallamshire Hospital (FQ), Sheffield, United Kingdom.

Supported in part by the Department of Health’s NIHR Biomedical Research Centre for Ophthalmology at Moorfields Eye Hospital and UCL Institute of Ophthalmology.

The authors have no financial or proprietary interest in the materials presented herein.

The views expressed are those of the authors and not necessarily those of the Department of Health.

Address correspondence to Pearse A. Keane, NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, Cayton St., Islington, Greater London EC1V 9, United Kingdom. E-mail: pearse.keane@moorfields.nhs.uk

Received: June 19, 2011
Accepted: March 20, 2012
Posted Online: May 31, 2012

Introduction

“Dome-shaped macula,” a structural state where the macula possesses a central mound-like contour, has recently been identified in patients with high myopia using optical coherence tomography (OCT).1 In this article, we describe a patient with dome-shaped macula in the setting of mild myopic anisometropia and speculate regarding the role of this feature as a compensatory mechanism in ocular development.

Case Report

A 49-year-old woman presented to the Birmingham Midland Eye Centre for examination. Visual acuities were 20/40 in the right eye and 20/20 in the left eye. Ocular imaging, obtained 6 years previously, revealed evidence of atrophic retinal pigment epithelium changes with associated late phase leakage on fluorescein angiography in the right eye, mimicking the appearance of chronic central serous chorioretinopathy (Fig. 1). Spectral-domain OCT was performed, revealing a dome-shaped macula (Fig. 2). B-scan ultrasonography measured axial lengths of 23.8 mm in the right eye (23.4 mm to the anterior aspect of the elevation) and 22.8 mm in the left eye, and revealed no evidence of choroidal hemangioma (Fig. 2). Spherical equivalents were −1.375 and +0.375 in the right and left eyes, respectively. Examination of the left eye was unremarkable. The patient reported no recent change in her vision and observation of her condition was recommended.

(A) Early and (B) late fluorescein angiographic frames demonstrating an appearance similar to that of chronic central serous chorioretinopathy. (C) Indocyanine green angiography revealing no evidence of choroidal neovascularization or circumscribed choroidal hemangioma.

Figure 1. (A) Early and (B) late fluorescein angiographic frames demonstrating an appearance similar to that of chronic central serous chorioretinopathy. (C) Indocyanine green angiography revealing no evidence of choroidal neovascularization or circumscribed choroidal hemangioma.

Spectral-domain optical coherence tomography (OCT) images (3D OCT-1000, Topcon, Tokyo, Japan) illustrating the presence of a “dome-shaped macula” in the (A and C) right eye and a normal foveal contour in the (B and D) left eye. B-scan ultrasonography measured axial lengths of 23.8 mm in the (E) right eye (23.4 mm to the anterior aspect of the elevation [F]) and 22.8 mm in the (G) left eye.

Figure 2. Spectral-domain optical coherence tomography (OCT) images (3D OCT-1000, Topcon, Tokyo, Japan) illustrating the presence of a “dome-shaped macula” in the (A and C) right eye and a normal foveal contour in the (B and D) left eye. B-scan ultrasonography measured axial lengths of 23.8 mm in the (E) right eye (23.4 mm to the anterior aspect of the elevation [F]) and 22.8 mm in the (G) left eye.

Discussion

Dome-shaped macula, a hitherto unrecognized feature, has recently been identified using OCT in patients with high myopia.1 In their original study, Gaucher et al. isolated their cohort by reviewing OCT scans of patients with high myopia; consequently, their subjects had a mean refractive error of −8.25 diopters (D) (range: −2 to −15.0 D) and a mean axial length of 26.92 mm (range: 24.4 to 29.2 mm).1 Although the findings described in the current study lie outside these ranges, we believe that the unifying element is the presence of myopic anisometropia—a feature seen in the patients described by Gaucher et al. We hypothesize the myopic anisometropia is central to the development of dome-shaped macula, rather than the absolute refractive status, and that this feature represents a protective mechanism aimed at reducing the effects of anisometropia.

Normal ocular development is disturbed in patients with high myopia, leading to abnormal axial elongation of the eye and ultimately to degenerative changes of the ocular coat. Where this occurs unilaterally, or to differing degrees in each eye, anisometropic amblyopia may result. In animal models, it has been shown that the choroid can increase thickness by as much as 1 mm (> 17 D) in response to myopic defocus; this pushes the retina toward the image plane and compensates for much of the refractive error. Increased synthesis of matrix macromolecules in the sclera is also seen.2,3 Thus, it seems plausible that formation of a dome-shaped macula in humans occurs by similar mechanisms and provides an equivalent compensatory function.

To date, much of the work on OCT imaging in the developing eye has used older, “time-domain” OCT technology such as Stratus OCT (Carl Zeiss Meditec, Inc., Dublin, CA).4 Due to the slow speed of Stratus OCT, automatic alignment of A-scans using image processing techniques is required to compensate for motion artifacts. Thus, features such as dome-shaped macula may be easily missed. This is not a requirement of newer OCT systems based on spectral-domain OCT technology. Furthermore, use of “enhanced depth imaging” and long-wavelength OCT allows enhanced visualization of the choroid and sclera.5 Use of these novel, noninvasive technologies may allow high-resolution longitudinal tracking of ocular development in humans—the insights provided by such studies may facilitate development of new therapies for both anisometropic amblyopia and pathologic myopia.

References

  1. Gaucher D, Erginay A, Lecleire-Collet A, et al. Dome-shaped macula in eyes with myopic posterior staphyloma. Am J Ophthalmol. 2008;145:909–914. doi:10.1016/j.ajo.2008.01.012 [CrossRef]
  2. McBrien NA, Gentle A. Role of the sclera in the development and pathological complications of myopia. Prog Retin Eye Res. 2003;22:307–338. doi:10.1016/S1350-9462(02)00063-0 [CrossRef]
  3. Nickla DL, Wallman J. The multifunctional choroid. Prog Retin Eye Res. 2010;29:144–168. doi:10.1016/j.preteyeres.2009.12.002 [CrossRef]
  4. Pang Y, Goodfellow GW, Allison C, Block S, Frantz KA. A prospective study of macular thickness in amblyopic children with unilateral high myopia. Invest Ophthalmol Vis Sci. 2011;52:2444–2449. doi:10.1167/iovs.10-5550 [CrossRef]
  5. Imamura Y, Iida T, Maruko I, Zweifel SA, Spaide RF. Enhanced depth imaging optical coherence tomography of the sclera in dome-shaped macula. Am J Ophthalmol. 2011;151:297–302. doi:10.1016/j.ajo.2010.08.014 [CrossRef]
Authors

From the NIHR Biomedical Research Centre for Ophthalmology (PAK), Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, Islington, Greater London; Birmingham and Midland Eye Centre (PAK, AM, IJK, FQ, SME), Birmingham, West Midlands; and Royal Hallamshire Hospital (FQ), Sheffield, United Kingdom.

Supported in part by the Department of Health’s NIHR Biomedical Research Centre for Ophthalmology at Moorfields Eye Hospital and UCL Institute of Ophthalmology.

The authors have no financial or proprietary interest in the materials presented herein.

The views expressed are those of the authors and not necessarily those of the Department of Health.

Address correspondence to Pearse A. Keane, NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, Cayton St., Islington, Greater London EC1V 9, United Kingdom. E-mail: pearse.keane@moorfields.nhs.uk

10.3928/15428877-20120524-02

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