There is a quote, ”I actually wear glasses because I need them to see .”

Yes,the eyeglasses are one of the secondary eye for those who are Visually weakened. Due, to age factor, natural health illness & many other environmental impact the human vision gets deteriorated.

To rectify this, power eye glasses are to be worn based on the prescription of opthalmologist.

 Usually, the prescription will be for the three major factors which affects the eye i.e,

i)Nearsightedness (or) Myopia

          Where the individuals have difficulty seeing far away objects. But, can see close up objects.

ii)Farsightedness (or) Presbyopia

          Where the closeup objects are blurry.


         A common imperfection in the eyes curvature.

Deciphering your eyeglass prescription can be cofusing, especially if you’re getting glasses for the first time.

Having a basic knowledge on numbers and letters on your prescription can help you make a smarter decision when it comes time to pick out your glasses.

Prescription Eyeglasses

Oculus Dexter(O.D) and Oculus sinister(O.S)

Here O.D denotes the right eyes and O.S denotes the left eyes respectively.

Sometimes, You can see O.U (Oculus uterque) which means “both eyes”.


If the numbers listed for sphere are negative, then you are nearsighted and if it is positive then you are farsighted.

So, we may understood whether we are farsighted or nearsighted through this.

Eyetest Prescription


This represents Astigmatism. Here, the plus and minus indicates the degree of correction needed for your astigmatism.


You may see either X or axis. Here the number between 0 and 180 presented, which  represents the orientation of astigmatism.

PRISM(p.d) and BASE:

Diplopia is a condition where the person feels double vision. So,the prism correction helps in this type of patients. The prism correction will also require a direction of the prism to be noted on the prescription, which is found under the “base” section. This will either say up, down or in, out depending the direction the light needs to be refracted.

Single vision Prescription

The eyeglass prescriptions are varied in types as,

i) Single vision

ii) Bifocal

iii) Trifocal and,

iv) Proressive.


This prescription can correct near or farsightedness & astigmatisms,through the entire lens.


This contain two corrective powers within the same lens and can correct both nearsightedness and farsightedness.


Trifocals contain three prescriptions within one lens where it corrects Distance, Near & Intermediate vision simultaneously.

Single vision, bifocal, trifocal, proressive


Progressive is  as similar to Trifocal. But, it does not have a visible line between prescriptions. So, this gives the wearer a seamless and uninterrupted view.

So, always make sure to ensure the right prescription type for buying your eyeglasses.


Shop Now at Zhagaram Eyewear Online in Chennai and Get 50% Exclusive Offer!!