Hypermetropia

Synonyms

Hyperopia; Farsightedness

Definition and Characteristics

The eye has insufficient refractive power for its axial length. The far point of the eye, conjugate to the sharp retinal image with accommodation relaxed, i.e., from which light rays focus on the retina, is placed behind the eye. Hypermetropia may be axial (axial length too short for the relatively low refractive power of the eye) or refractive (index – anomalous refractive indices of one or more media, curvature – increased radius of curvature in any refractive surface, or anterior chamber–decreased anterior chamber depth – hyperopia); physiological (each component of refraction lies within the normal distribution) or pathological (lies outside the limits of normal biological variation, typically with reduction of axial length by a space-occupying lesion); and, with regard to the action of accommodation, total hyperopia may be divided into latent (uncovered by cycloplegic refraction) and manifest (maximum positive lens...