Ametropias and presbyopia

Abstract

The optical system of a normal eye, with the basic characteristics and relationships of its components is defined for the distinction between emmetropia and axial or refractive ametropias (myopia and hyperopias). The techniques for the study of the optical state of the eyes (refractometry) are synthesized and other of their results (astigmatisms, anisometropias) are commented. It is also analysed the capability of the ocular focal power change (accommodation) and its progressive deterioration with the time (presbyopia). Symptoms and signs caused by the presbyopia and by the ametropias (reduction of visual acuity, ocular pains and irritations, headache, aversion to visual tasks, hordeola, strabismus, amblyopia, etc.), respective treatments and prognosis of the evolution are also considered.