Regular eye examinations are essential to maintaining healthy eyes and sharp vision. Your optometrist conducts an eye test to check your vision. If you need to correct your eyesight, an eyeglass prescription will be written for you. It can be confusing. This guide will help you understand the various abbreviations or numbers in your eyeglass prescription.
Right Eye and left Eye
The abbreviations "OD", "OS", and "OS", used by optometrists, are for your left and right eyes.
- It's short for oculus dexter, the Latin phrase for "right eye". The Latin phrase "right eye" is oculus Dexter.
- Your left eye is OS. The Latin word for left eye is oculus Sinister.
- OU means both eyes. You may find a column in your prescription labeled "OU", which is the Latin abbreviation of "both eyes".
OD and OS are no longer used by some doctors or clinics. Instead, they now use RE and LE. Your right eye's information (OD orRE) is always listed before your left eye's information (OS orLE). This is due to the fact that, when you are facing your eye specialist, they will see first your left-eye and then second your right-eye.
Sphere
The sphere columns is abbreviated by SPH. It indicates how much lens power should be prescribed to correct nearsightedness and farsightedness.
- The presence of a minus symbol (-) in front of the number signifies nearsightedness.
- The plus sign (+), also known as farsightedness, is a symbol for a person who sees better at a distance but needs near-correction.
Lens power (D) is measured in Diopters. The more you move from zero in either direction, the stronger the prescription.
Cylinder
The number on the cylinder indicates your astigmatism level, if there is any. Astigmatism occurs when your front eyeball is more rugby ball-shaped than a regular round sphere.
If the number is minus (for correction of farsightedness astigmatism), it may be accompanied by a minus (for nearsightedness astigmatism). This column will be empty if you do not have astigmatism, or if the amount is too small to need correction.
Axis
If the eyeglass prescription also includes the cylinder value, then it must also include the axis, which tells you exactly where the corneal astigmatism is. The axis has a range of numbers from 1 through 180. Imagine a scale of protractor held right up in front your eye. This is the way meridians are determined.
- The vertical meridian is the number 90.
- The horizontal meridian is the number 180.
Include
The bottom of the multifocal lens can be magnified to correct presbyopia, the natural distance-sightedness that occurs with age. This magnifying power is simply to make reading easier. It is important to note that the number in this column will always be a power plus, even if it does not have a + sign. It usually falls between +0.75 D and +3.00 D.
A polyhedral object with multiple sides that refracts light
The prism is used when you have double-vision, meaning that you can see two versions of the same object. As it's not common, the box is left blank. When the box is filled in, it's usually written as a fraction (for example: 1 1/2). Prism direction is indicated by four abbreviations:
- Base up
- BD: base down
- Base In (towards nose)
- Base out (towards the ear)
The abbreviations indicate to the eyeglass maker where the prism should be placed on the eyeglasses for double vision correction.
You can get more information about your prescription
It is possible to find more information in your glasses prescription. For example, your optometrist might recommend certain lens coatings or make special remarks. It's best to bring your prescription when buying new glasses so that the optometrist can help you find the perfect pair.
Bottom Line
Your eyeglass prescription will tell the manufacturer of your glasses what kind and strength of lenses you require. The prescription will also tell them how much nearsightedness or farsightedness you have in each eye.
To protect your eye health, you should visit an optometrist at least once a year or annually.
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