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

Resumen

Myopia is a highly frequent ocular disorder worldwide and patholog-ic myopia is the 4th most common cause of irreversible blindness in de-veloped countries. Pathologic myopia is especially common in East Asiancountries. Ocular alterations associated with pathologic myopia, especiallythose involving the macular area—defined as myopic maculopathy—arethe leading causes of vision loss in patients with pathologic myopia.High myopia is defined as the presence of a highly negative refractiveerror (> -6 to -8 diopters) in the context of eye elongation (26-26.5 mm).350Although the terms high myopia and pathologic myopia are often usedinterchangeably, they do not refer to the same eye disease. The two keyfactors driving the development of pathologic myopia are: 1) elongation ofthe axial length and 2) posterior staphyloma.The presence of posterior staphyloma, which is the most common find-ing in patients with pathologic myopia, is the key differentiating factor be-tween high and pathologic myopia. The occurrence of staphyloma will, inmost cases, eventually lead to other conditions such as atrophic, traction, orneovascular maculopathy. Posterior staphyloma is for instance, responsiblefor the differences between a myopic macular hole (MH)—with and with-out retinal detachment—and idiopathic MH. Posterior staphyloma typicallyinduces retinal layer splitting, leading to foveoschisis in myopic MH, an im-portant differentiating factor between myopic and emmetropic MH.Myopic maculopathy is a highly complex disease and current classi-fication systems do not fully account for the numerous changes that occurin the macula of these patients. Therefore, a more comprehensive classifi-cation system is needed, for several important reasons. First, to more pre-cisely define the disease stage to improve follow-up by enabling cliniciansto more accurately monitor changes over time, which is essential giventhe progressive nature of this condition. Second, unification of the current-ly-available classification systems would establish standardized classifica-tion criteria that could be used to compare the findings from internationalmulticentric studies. Finally, a more comprehensive classification systemcould help to improve our understanding of the genetic origins of this dis-ease, which is clearly relevant given the interchangeable—but erroneous—use of the terms high and pathologic myopia in genetic research.