Myopia

Abstract

Myopia, also called near- or shortsightedness, refers to the refractive state of the eye whereby the images of distant objects are focused in front of the retina when the accommodation system is relaxed. Increased eye length, particularly vitreous chamber elongation, is the main correlate of human myopia. Uncorrected myopia prevents the individual from seeing distant objects clearly. Myopia can be corrected with concave (minus) lenses (using spectacles or contact lenses, or induced by refractive surgery). However, myopia is still a significant public health problem, not only because of its high prevalence, but also because it is a high-risk factor of vision-threatening conditions (e.g., retinal detachment and glaucoma) due to the changes produced in the posterior part of the eye caused by the increase in axial length. In addition, myopia may restrict the individual's vocational options. Myopia typically develops during the school years, progressing until adulthood. Various refractive surgery techniques are available currently to correct myopia. However, they are still expensive, there are risks associated to the surgery, and do not prevent the progression of myopia or its associated risks. The high economic impact of myopia is also due to the costs of eye exams, optical corrections, and medical management of complications. Despite extensive interest among scientists and clinicians, there are several fundamental unanswered questions underlying the development and progression of myopia.