Myopic maculopathy: Current status and proposal for a new classification and grading system (ATN)

https://doi.org/10.1016/j.preteyeres.2018.10.005Get rights and content
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Highlights

  • Progression of high myopia and the appearance of the staphyloma are the most relevant factors leading to myopic maculopathy.

  • Myopic maculopathy is a complex disease that comprises atrophic, tractional and neovascular changes that lead to vision loss.

  • None of current systems allow us to classify every patient as they do not include all three main components of the disease.

  • We propose a new grading system (ATN classification) that includes atrophic (A), tractional (T) and neovascular (N) changes.

Abstract

Myopia is a highly frequent ocular disorder worldwide and pathologic myopia is the 4th most common cause of irreversible blindness in developed countries. Pathologic myopia is especially common in East Asian countries. Ocular alterations associated with pathologic myopia, especially those involving the macular area—defined as myopic maculopathy—are the leading causes of vision loss in patients with pathologic myopia.

High myopia is defined as the presence of a highly negative refractive error (>−6 to −8 diopters) in the context of eye elongation (26–26.5 mm). Although the terms high myopia and pathologic myopia are often used interchangeably, they do not refer to the same eye disease. The two key factors driving the development of pathologic myopia are: 1) elongation of the axial length and 2) posterior staphyloma.

The presence of posterior staphyloma, which is the most common finding in patients with pathologic myopia, is the key differentiating factor between high and pathologic myopia. The occurrence of staphyloma will, in most cases, eventually lead to other conditions such as atrophic, traction, or neovascular maculopathy. Posterior staphyloma is for instance, responsible for the differences between a myopic macular hole (MH)—with and without retinal detachment—and idiopathic MH. Posterior staphyloma typically induces retinal layer splitting, leading to foveoschisis in myopic MH, an important differentiating factor between myopic and emmetropic MH.

Myopic maculopathy is a highly complex disease and current classification systems do not fully account for the numerous changes that occur in the macula of these patients. Therefore, a more comprehensive classification system is needed, for several important reasons. First, to more precisely define the disease stage to improve follow-up by enabling clinicians to more accurately monitor changes over time, which is essential given the progressive nature of this condition. Second, unification of the currently-available classification systems would establish standardized classification criteria that could be used to compare the findings from international multicentric studies. Finally, a more comprehensive classification system could help to improve our understanding of the genetic origins of this disease, which is clearly relevant given the interchangeable—but erroneous—use of the terms high and pathologic myopia in genetic research.

Keywords

Pathologic myopia
Staphyloma
Myopic maculopathy
Myopic traction maculopathy
Myopic choroidal neovascularization
High myopia
Myopic maculopathy classification
ATN classification system

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1

Percentage of work contributed by each author in the production of the manuscript is as follows: Jorge Ruiz-Medrano 25%, Javier A Montero 15%, Ignacio Flores-Moreno 15%, Luis Arias 10%, Alfredo Gracía-Layana 10%, Jose M Ruiz-Moreno 25%.