title: WHAT IS THE FUNDAMENTAL NATURE OF PATHOLOGIC MYOPIA?
abstract: OBJECTIVE
  Despite being a major cause of visual impairment worldwide, pathologic myopia has not been clearly and consistently defined. This lack of a standardized definition has made comparisons among epidemiological studies difficult. Therefore, the purpose of this review was to summarize the definitions of pathologic myopia.
  
  
  METHODS
  A literature search was conducted of Pubmed to identify reports presenting definitions of pathologic myopia.
  
  
  RESULTS
  Although cut-off values for refractive error and increased axial length have been used in some studies, a definition based solely on such values is considered to just show a 'high degree of myopia'. Similarly, the presence of myopic fundus lesions in addition to a high degree of myopia has been used to define pathologic myopia; however, such lesions often develop with age and they are not characteristic of pathologic myopia.
  
  
  CONCLUSIONS
  So, what is pathologic myopia? This review covers the various proposed definitions for pathologic myopia, and describes its major features such as posterior staphyloma, variation in axial length, and the presence of myopic maculopathy. Some unanswered questions that serve as signposts to areas of interest for future research have also been discussed.
authors.affiliation: Department of Ophthalmology and Visual Science, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Ohno-Matsui
mesh_terms: D006801:Humans; D047728:Myopia, Degenerative / Q000175:diagnosis* / Q000503:physiopathology; D009900:Optic Nerve / Q000473:pathology*; D012029:Refraction, Ocular; D012160:Retina / Q000473:pathology*