How to Read Your Eyeglass Prescription

In order to improve your eyesight, your eye care professional may prescribe glasses if you are suffering from specific eye conditions. You may have difficulty understanding your prescription for glasses if it contains numbers and abbreviated words that you cannot understand. Understanding these abbreviations is therefore the first step in reading your prescription.

What your prescription means

An explanation of the most common abbreviations found on eyeglass prescriptions is provided below.

OD, OS, OU

There are several abbreviations for eyeglass prescriptions, including OD, OS, and OU. Oculus Dexter is a Latin term that means right eye and left eye, respectively. Oculus Uterque is a Latin term that means both eyes. These are the traditional abbreviations when prescribing glasses. The right eye is represented by a Re, while the left eye is represented by a E. Although some eye care professionals prefer to utilize modernized prescriptions, some prefer to use traditional abbreviations.

SPH

Sphere is an abbreviation for Sphere, which describes the amount of lenses needed for good vision expressed in diopters. The term essentially means that the correction for your sight is spherical. Shortsighted individuals will have a (-) under the abbreviation. Longsighted individuals will have a (+) sign under the abbreviation. You are not concerned about distance problems if your prescription includes the word Plano, PI, or an infinity sign. However, you may have astigmatism. The majority of values will range from 0.00 to +/-20.00.

Axis

It is the lens meridian in which there is no cylinder power to correct astigmatism. The axis number indicates in which direction a cylindrical power should be placed in your glasses in order to correct your astigmatism. The number can range from 1 to 180, where 90 represents the vertical position and 180 represents the horizontal one. However, the numbers do not indicate the strength of your prescription; they indicate only the position of astigmatism. CYL values can indicate the presence of the Axis.

CYL

A cylinder is an abbreviation for cylindrical lens. If you do not suffer from astigmatism, you may not see anything indicated in this column because it represents how much lens power you need for astigmatism. In most cases, the value ranges from +/-0.25 to +/-4.00. It can be positive or negative.

ADD

This is the additional correction required for reading, and it is used in reading glasses, bifocal glasses, and varifocal glasses. It represents the additional power over the distance prescription. Due to the same additional power for both eyes, it only appears once in your prescription, usually ranging in value from +0.50 to +3.50.

Prism

Prisms are used to correct lazy eyes, as well as mild conditions, such as specific eye disorders and conditions in which the image in focus must change. Prism dioptres are measured in prism dioptres, which have directions such as up, down, in, and out. The values may be as high as ten.

PD

This measurement ensures that you are looking through the right spot in your glasses when you get them because it determines how far apart the centers of your pupils are. It is measured in millimeters. In the event your eye care professional does not provide this measurement, you can take it yourself. On average, women are 62mm in height, while men are 64mm in height. However, this number can vary from 58mm to 68mm.

Dist./Inter/Near

In distance, glasses are prescribed to correct short-sightedness or long-sightedness. Distance prescription is suitable for walking, running errands, driving, and all other activities. Inter stands for intermediate. Near prescription glasses correct near-sightedness and are suitable for workers who need to pay attention to detail at work. Near prescription glasses are recommended for those who have intermediate vision.

BVD

Back Vertex Distance is the distance between the lens of your glasses and the apex of your cornea. It is adjustable to adjust the power of the lens in relation to the eye. You will need the measurements when modifying your eyeglass prescriptions. When your prescription exceeds +/- 4.00D, it is essential.

Note: Please keep in mind that an eyeglass prescription should not be used for contact lenses since it does not apply to the lens power of contact lenses. Eyeglasses are positioned at a distance from the eyes, while contact lenses are worn directly over the eyes, so an eyeglass prescription should only be utilized when shopping for eyeglasses.

Ask your eye care professional if you are unsure about your prescription.