![]() However, in some prescriptions, near vision correction (the sum of far vision correction and addition) may be directly stated, reason why this value could appear with a positive or negative sign before the number.īase: BU (base up), BD (base down), BI (base in, toward the wearer’s nose) or BO (base out) It usually goes from +0.50 diopters to +3.50 diopters, being always a positive value. The value represents the refractive power to be added to far vision correction, with the aim of providing a clear near vision as well. Addition defines the spheric power that will correct presbyopia. With this data, the optician’s shop will be able to provide several solutions: progressive, bifocal, or near monofocal glasses. It is the necessary information in case a near vision correction is needed. Astigmatism, just like myopia and hyperopia, is expressed using multiples of 0.25 diopters.Ībbreviations and designations: ADD or Addition ![]() In case we only suffer from astigmatism, the sphere box would be the one left empty or with a 0 value. If no value appears, this box is left empty or filled with a zero, which means there is no astigmatism. Values are also expressed in diopters and may have a positive or negative sign before the number. ![]() They indicate the power and positioning direction of toric lens, which corrects this type of refractive error. This element may appear right after the spheric value. The sphere is what is known as diopters and it defines the power of the lens needed to correct visual errors that we have, such as myopia (in which the sign before the number will be negative ) or hyperopia, (always with a positive sign before the number ), always using multiples of 0.25 diopters (+0.25, -3.75…).Ĭylinder: CYL, Cylinder. Let’s see them.Ībbreviations and designations: Esf, Sph, Sphere The prescription format can substantially vary, but terms and abbreviations will be in almost all cases the same. We include below an eyeglass prescription sample from Institut Català de Retina: The aim of optical correction is to improve quality of vision and therefore, quality of life. This data will be enough in the optician’s shop to have your glasses or contact lenses made, although in the second case some values will have to be adjusted. With the aim of making it easier to understand this kind of prescription, we include hereinafter a prescription sample with a description of the most frequent concepts and abbreviations that may prove useful to everybody in order to understand eyeglass prescriptions.Īn eyeglass prescription is intended to define the p erfect visual correction needed to enjoy the best visual acuity both in distance vision and near vision. However, for most eyeglasses wearers, this kind of prescription may be unintelligible, whether for its terminology or for the long list of abbreviations it includes. When having our vision examined by an optometrist, we leave the consultation with a prescription known as vision correction or eyeglass prescription, in which we see several data and abbreviations indicating, among other things, our refractive state.
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