Criteria for Diagnosis of Pathologic Myopia
Myopia is commonly classified into three groups: mild (≤3.0 diopters, D), moderate) >3.0 D), and high (>6.0 D). The limits of these types vary with each investigator. Many researchers have designated values such as >4.0D, >6.0D, or >8.0D as high myopia . On the basis of this information, Duke-Elder had suggested that high myopia, which is primarily caused by retinal degeneration in the posterior pole, should be named pathologic myopia. The pathological form can be distinguished from simple myopia, which is defined as variations within normal limits of the optical system of the eye . However, it is sometimes difficult to define pathologic myopia as the eye with retinal degeneration in the posterior pole. Another definition states that high myopia accompanied by visual dysfunction is pathologic myopia and that this is distinguishable from simple myopia . Although theoretically acceptable, this definition is not suitable for clinical practice and mass screening because it must be confirmed by various examinations.