Prescription:

What is an eyewear prescription?

It’s an order written by an optometrist or ophthalmologist that specifies the value of all parameters deemed necessary to construct and/or dispense corrective lenses appropriate for a patient.

The prescription would typically include the power to which each lens should be made in order to correct blurred vision due to refractive errors including myopia (near sightedness), hyperopia (far sightedness), astigmatism (abnormal curvature of the cornea) and presbyopia (loss of ability to focus for near vision).

A dispensing optician will take a prescription written by an optometrist or ophthalmologist and/or assemble the frames and lenses to then be dispensed and sold to the patient.

By law, Opticians are obliged to provide you with a prescription, once you’ve had a thorough eye test with their Optometrist.
They must give you a copy of your prescription without requiring you to make a purchase.

How do you read an eyeglass prescription?

A prescription contains the powers for the lenses of each eye (including a reading addition if necessary), information on the separation of the lenses and could include special requirements such as types of tinting, coatings and so on.

The lens correction for nearsightedness is indicated by a minus sign (-), while a plus sign (+) indicates farsightedness. Cylindrical lenses for astigmatism are designated by cyls., cx, or (x).

Let’s analyze the following prescription:
O.D. -3.00 D c/w -2.00 D cx 180
Add: +1.50
PD: 62

The “O.D.” indicates the prescription for the right eye. O.D. stands for the Latin phrase “oculus dexter” and indicates the right eye.

The “O.S.” stands for the Latin phrase “oculus sinister” and indicates the left eye.

The “-3.00 D” means that the patient has -3.00 diopters of nearsightedness.
The “c/w” means “combined with.”

The “-2.00 D cx 180″ means that the patient also has -2.00 diopters of astigmatism at axis 180 degrees.

The “Add: +1.50″ indicates the power of a bifocal addition.

The “PD: 62″ is a measurement of the distance between the pupils, a necessary measurement for ensuring a proper fit for the glasses.