How to Read my Prescription?

A Quick Read on Knowing all About your Prescription!

If you have vision concerns then your optometrist will prescribe you wear eyeglasses. He will hand you a eyeglasses prescription that is filled with numbers and abbreviations.

So, when you decide to buy glasses online it's important that you know what these abbreviations mean!

Here is what they mean:

OD: It stands for Oculus Dexter, pertaining to your right eye.

OS: It stands for Oculus Sinister, pertaining to your right eye.

OU: It stands for Oculus Uterque, pertaining to both the eyes.

Some eye doctors will use the modern abbreviations like RE and LE for right and left eye too!

Now that you know what these Latin Terms on your prescription mean let's delve into deeper to help you buy designer glasses online by making sure you enter the right prescription!

SPH: Sphere:

This is the degree of correction required in your lenses to correct far or nearsightedness. It is measured in DP (diopters). If the number preceding the abbreviation SPH is (+) then you have farsightedness, and if the number is (-) then you are short-sightedness. If there is nothing mentioned before SPH, then you are farsighted. Spherical stands for an equal meridian distance of the eye.

Axis:

Axis is measured in degrees from 1 to 180. 90 represents the vertical meridian of the eye and 180 represents the horizontal meridian of the eye. This is to determine the orientation axis of astigmatism. If your prescription includes the CYL power then it must also have AXS power, denoted by an ‘x’

ADD:

ADD is specifically for presbyopia or reading vision that is related to the aging of the eyeball. This is the power used on the bottom lens of a bifocal or multifocal. Since presbyopia is corrected by magnifying vision, it will always be written with a (+) sign and even if it is not mentioned it is taken into as (+) power only.

CYL: Cylinder

This term CYL is specifically used for people who have astigmatism. It indicated the amount of lens power you need to correct astigmatism. If there is nothing mentioned in the CYL column you either have no astigmatism or it is so less that it need not be mentioned. The correction of astigmatism is based on the meridian and the lens curvature.

Just like SPH, the (+) sign is for far-sighted astigmatism and (-) is for nearsighted astigmatism.

Prism:

This is measured in diopters and is measured to cover for any eye alignment concerns. It is written as p.d. Or a superscript triangle is drawn freehand. The amount of prism is indicated by fractional units like ½, and the direction of the prism is noted by reference to the base.

PD: Pupillary Distance

This stands for pupillary distance and measures the distance between the pupil of one eye to the other. In reference to frames or glasses, it is measured from the centre of the prescription lenses to the other, to ensure the prescription glasses correct your vision right and the size is right for you.

Cylindrical, Spherical and Add power are always written in diopters, prism will be written in decimals and axis are whole numbers between 1 to 180.

Now that you know all the terms that are mentioned on your eyeglass prescription, you have learnt the most important part to buy prescription sunglasses online or prescription glasses online at Optically!

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