High myopia is considered to be present if the patient has an anteroposterior axis greater than 26mm, according to one definition.
Understanding High Myopia by Axial Length
Myopia, or nearsightedness, occurs when the eye is too long or the cornea is too curved, causing light to focus in front of the retina instead of directly on it. The anteroposterior axis refers to the length of the eyeball from the front (cornea) to the back (retina).
Based on the provided information, high myopia is specifically defined by this physical characteristic:
- High Myopia Definition: A patient is considered to have high myopia if their eyeball measures greater than 26mm in length from front to back.
This is one method of defining high myopia, distinguishing it from less severe forms of nearsightedness based on the physical structure of the eye rather than solely on the lens power needed to correct vision (measured in diopters).
Prevalence of This Type of Myopia
The reference notes that this specific type of high myopia, defined by an anteroposterior axis exceeding 26mm, currently affects 2% of the population. There is also an observation that the prevalence of this condition is increasing in developed countries, although the exact reasons for this trend are not yet fully determined.
Understanding this definition based on the eye's axial length provides a structural perspective on what constitutes high myopia in certain contexts.
