Ametropie

Ametropie, or ametropia, is a refractive error in which the eye cannot focus light from distant objects onto the retina without corrective optics. It occurs when the eye’s optical power does not match its axial length, or when the cornea or lens has an abnormal curvature, producing blurred vision at one or both distances.

Main forms are myopie (nearsightedness), hyperopie (farsightedness), and astigmatisme (irregular curvature). Myopia means distant objects appear blurred; hyperopia means near objects are blurred. Astigmatism causes distorted vision due to uneven curvature of the cornea or lens. Presbytie is age-related loss of accommodation, usually worsening near vision after about age 40. Mixed or compound forms occur.

Diagnosis is made during a comprehensive eye examination. Refraction tests determine the corrective prescription in diopters. Additional measurements of corneal curvature and axial length help classify the ametropia. Modern imaging may assess the retina and optic nerve. Untreated ametropia in children can lead to amblyopia or reduced binocularity.

Treatment aims to restore clear vision and may include spectacles, contact lenses, or refractive surgery. Glasses or contacts correct the focal point, while procedures such as LASIK, PRK, or SMILE reshape the cornea. For some, ortho-k or multifocal lenses address presbyopia. Regular eye exams monitor changes, particularly in children and during growth.

Ametropia is common worldwide. Prevalence varies by region and age, with myopia increasing in many populations. Risk factors include genetics, schooling, and indoor lifestyle. Corrected ametropia generally yields good visual function, and prognosis is favorable when detected early and managed with appropriate correction.