Vision Correction Basics: Translating Your Eyeglass Lens Prescription

For anyone who wears glasses, the prescription can look like Egyptian hieroglyphs. Have you ever wondered what things like SPH, Axix, and Prism actually mean? Here’s a resource to help you understand what you are seeing on that little slip of paper or online prescription.

Translating Your Vision Prescription

The first thing you will notice when you look at your prescription are the initials OS and OD. These are Latin abbreviations. OD (oculus dextrus) means right eye and OS (oculus sinister) means left eye. If you see the abbreviation OU (oculus uterque) it means both eyes. Beneath these abbreviations, you will see a number, which refers to the amount of vision correction you need. The further away from zero, the number is, the stronger your prescription lenses will be. The number will have + sign if you are farsighted and a – sign if you are near sighted.

Some Common Abbreviations

SPH (Sphere): This refers to the presence if short (near) and long (far) sight that is present. Minus lenses are used to correct near sightedness and plus lenses are used to correct long-sightedness.

CYL (Cylinder): This refers to the presence (if any) of astigmatism. This condition arises when the eyeball is not completely spherical causing an inability to focus on either near or distant object.

PRISM: If the eyes need aligning so they can both look straight, this is the correction that is needed. A prism lens is used to bend the path of light without changing its focus.

AXIS: This is the angle at which the lens is set in the frame of the glasses. It is a measurement of 0-180 degrees which denotes the orientation of the cylinder.

ADD: This refers to the amount of correction to be added to your script.

Laser Surgery for Correcting Vision

For some people who prefer not to wear glasses or contact lenses, corrective laser surgery may be an option. For many people with relatively simple prescription lenses, laser eye surgery can correct their vision so completely that they will no longer need to wear glasses at all. Laser eye surgery works by reshaping the cornea and changing the focal point of the eye. The most common type of laser surgery is called Lasik.

Aftercare is very important, almost as important as the surgical procedure itself. The eyes will heal within 24 hours. You should not rub them during this time as it will affect the healing process. Your eye doctor will schedule you a series of follow-up exams. Your eyes may feel blurry or tear following the procedure for the first few days following laser eye surgery but this will gradually lessen. If you are interested in having your vision corrected with laser surgery, check out this table of average laser eye surgery prices.

Now you know how to translate your eyeglass prescription, you may have some questions for your ophthalmologist. Don’t forget to ask him or her next time you make an appointment.