How To Read Your Eyeglass Prescription.

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Understanding eyeglass prescription is not that difficult if you know its basic terms. Let's understand them one by one:

(Right Eye) OD : '' Oculus Dexter''

It is written in the prescription of the right eye.

 (Left Eye) OS:  ''Oculus Sinister ''

It is written in the prescription of the left eye.

Sphere (SPH):

This number shows your nearsightedness (myopia) or farsightedness (hyperopia).If the number is negative (-), then you will face some difficulty in seeing things at a distance (myopia).If the number is positive (+), then you will have difficulty seeing close up objects (hyperopia).


Cylinder (CYL): 

This shows astigmatism. It can be either negative or positive. If you have this number, then you have astigmatism.

Axis: 

This is the angle of the cylinder, which ranges from 0 to 180 degrees. It shows in which direction the astigmatism occurs.

Add: 

This number is for your reading glasses or bifocals. It is usually positive and shows the difference between distance and near vision.

Five Points About Correcting Presbyopia with an Add

1. As a general guideline, the following rule of thumb for Add strength is often helpful: 

• At age 45, the typical Add that is needed is +1.50 diopters.

• At age 50, the typical Add that is needed is +2.00 diopters.

• At age 55, the typical Add that is needed is +2.50 diopters (the typical maximal strength 

Add).


Prism:

If you have double vision or alignment problems, then a prism may be valuable in this section.

PD (Pupillary Distance): 

This is the distance between the patient's pupils. This is important because it ensures that your lenses are in the correct center of your eyes.Yes. If PD is not correct, you may have discomfort or blurred vision while wearing glasses. Its measurement is usually in millimeters.Any part, then definitely If the patient has a prescription, then PD is also mentioned in it. 


Here’s an example prescription:

  • OD: -2.00 SPH, -0.75 CYL, 160 AXIS
  • OS: -1.75 SPH, -0.50 CYL, 175 AXIS
  • ADD: +2.25

This means:

  • For the right eye (OD), you have -2.00 diopters of nearsightedness, -0.75 diopters of astigmatism, and the astigmatism correction is oriented at 160 degrees.
  • For the left eye (OS), you have -1.75 diopters of nearsightedness, -0.50 diopters of astigmatism, and the astigmatism correction is oriented at 175 degrees.
  • The additional +2.25 diopters are added for reading or close-up work.


If you are confused about any part, then you must consult your eye doctor. Hope this information will help you.

                                     M Rameez Naqvi 






I'm Optometrist From JHU Delhi

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