It is refractive defect of the eye in which collimated light produces image focus in front of the retina when accommodation is relaxed.
Those with myopia see near objects clearly but far away objects appear blur.
Classification:
Myopia has been classified in various manners.
By Cause:
•Axial myopia: an increase in the eye’s axial length.
•Refractive myopia: condition of the refractive elements of the eye.
Curvature myopia: excessive, or increased, curvature of one or more of the refractive surfaces of the eye, especially the cornea.
Index myopia: variation in the index of refraction of one or more of the ocular media.
By Clinical Entity:
•Simple myopia: optically too powerful for its axial length.
•Degenerative myopia/ malignant/ pathological/progressive myopia: characterized by marked fundus changes, such as posterior staphyloma, and associated with a high refractive error. (more…)