The number in the cylinder column can be negative (minus) or positive (plus). CYL always follows the SPH power on an eyeglass prescription. +3.00: represents 3 dioptres of long-sightedness CylinderĬylinder (CYL) indicates the amount of lens power needed to correct astigmatism. 6.25: represents 6 and ¼ dioptres of short-sightedness 2.00: represents 2 dioptres of short-sightedness A plus sign (+) means you are long-sighted and require convex lenses to correct your vision. A minus sign (-) means that you are short-sighted and require concave lenses to correct your vision. Sphere (SPH) indicates the amount of lens power prescribed to correct myopia (short-sightedness) or hypermetropia (long-sightedness). Instead of OD and OS, some ECPs use RE (right eye) and LE (left eye). OS: an abbreviation for oculus sinister, Latin phrase for left eye OD: an abbreviation for oculus dexter, Latin phrase for right eye OU: an abbreviation for oculus uterque, Latin phrase for both eyes Sphere power, cylinder power, and add power are written in decimal form in quarter dioptre increments (0.25D). The further away a number is from 0, the more correction or stronger prescription is needed to produce clear vision for distance and reading. Dioptresĭioptres (D) is the unit used to measure the degree or power of the corrective lens required for clear vision. This article will help you make sense of these numbers and letters and guide you on how to read your eyeglass prescription. Eyeglass prescriptions contain various numbers and letters that can be confusing at first. If your vision needs to be corrected, your eye care professional (ECP) will give you a prescription for eyeglasses or contact lenses and recommend the degree of the lens that you need to see clearly. Read more » VISUAL ACUITY (A.V.)Īlthough visual acuity is not required to make your lenses, it is very important for you, as it indicates the percentage of vision you will have with your glasses.Regular eye checks are an important part of keeping your eyes healthy and vision clear. If the pupillary distance does not appear on your prescription, and if you do not know it, offers the option to measure it virtually at the time you are trying on the frames or in the process of selecting the type of lenses for your glasses. You can find one or two values of pupil distance, noted as DP (Pupillary Distance) or DNP (Nasopupilar Distance) And the only way to do this is by knowing this value. The optical centers of the lenses must match the center of each pupil. This measurement is very important when making the lenses. LThe pupillary distance is the measure between the two pupils. The value of the prism will always be accompanied by the direction of the prism base (Upper, Lower, External or Internal Base) If you find this value in your prescription, please contact us. The prism, expressed in Prismatic Diopters, is the value used to correct a muscular imbalance and / or alteration of the binocular vision, in other words, a deviation of the eye. Sometimes in your eyeglass prescription you can see other values such as: If the Addition value is not included, your correction is for SINGLE VISION (VISIÓN SENCILLA) (see example 2). If an ADD value appears in your formula, it usually also shows the type of correction you need, either BIFOCAL or PROGRESSIVO. This information appears in bifocals and progressive lenses. This value is added to the distance correction so that the user has a good close up view. The addition, also known as ADD, is expressed in diopters and is the value used to correct presbyopia. Look at example 1 where the value of the astigmatism axis of the right eye is 160 °, and the axis of the left eye is 10 ° The axis indicates the direction of the cylinder and is expressed in degrees ranging from 0 ° to 180 °. If the cylinder box is empty, it means that you do not have astigmatism, and therefore, the value will be 0.00 All cylindrical value is accompanied by a value noted in the axis box. EAstigmatism may be associated with Myopia and / or Hyperopia. The most used notations are: Cylinder, Cilindro, Cyl or Cyl. Usually it appears with negative sign (-) although some professionals write it with positive sign (+). It is the power in diopters that indicates the amount of Astigmatism. If the word NEUTRAL appears in the sphere box, it means that the value of the sphere is 0.00. The value of the sphere is recorded in steps of 0.25 Diopters (+1.25, -2.50, +3.75). The notation appears as sphere, sph, or sph. Indicates the diopters that correct refractive errors such as nearsightedness (with negative (-) sign) or farsightedness (with the positive (+) sign).
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