“Everyone has two eyes but no one has the same view”.

When you look at the prescription of an ophthalmologist regarding the eyeglasses you can see the term OS&OD; Where OS denotes the left eye (oculus sinister) and OD denotes the right eye (oculus dextus).

regarding eyeglasses

More about this we can see some more related terms like,
  • Near, Distance.
  • Kryptoc, Progressive.
  • Tint, constant.
  • Executive, photochromatic, Bifocal .
  • Spherical, cylindrical, axis etc.

In general, the further away from zero the number on your prescription, the worse your eyesight and the more vision correction you need.
There will be a (+) sign or a (-)sign towards the OS&OD where the plus sign represents the farsighted vision or hyperopia and the minus sign represents the nearsighted vision or myopia.

Computer Eye Test

Here, Hyperopia is a condition were near objects are blurred and the distant objects appear to be clear .Whereas, the myopia is a condition were distant objects appear blurred and near objects appear clear.

As per the opthalmological prescription the opticians will use the covex lens to rectify the hyperopia and the concave lens for the myopia.
These both plus & minus number represents diopter the unit to measure the correction, or focusing power of the lens your eye requires.

Here, Diopter is briefed as D.

For example, if your prescription says -1.00 you have one diopter of nearsightedness & if it is +1.00 you have one diopter of farsightedness. Also, there are age-related changes in the lens inside the eye which make it more difficult to focus on small print or close up objects. This change is known as presbyopia. Here, the ophthalmologist prescribes a reading glass. This is mostly usual for the people who are above the age of forty.

Here, we can see some tips to choose the power eye glass as,
  • Have an up-to-date prescription.
  • Get Your pupillary distance measured.(Distance between the two eye pupils).
  • Select & Buy the right frames.
  • Consider your personal & professional needs.
  • Beware on Add-ons.(get the essential alone).
  • Check the return policy.
  • Consider paying extra to get the frames you want.
  • Consider buying more than one pair of eyeglasses.
  • Use a protective case and a microfiber cloth.

A common mistake people often make when buying eyeglasses is not spending enough time considering their choices of eyeglass lens materials, designs and coating.

Tips to Choose eyeglasses
In the early days of vision correction, all eyeglass lenses were made of glass. Although glass lenses offer exceptional optics, they are heavy and can break easily, potentially causing serious harm to the eye or even loss of an eye. For these reasons, glass lenses are no longer widely used for eyeglasses.

Instead of glass material some of other materials were used for various good reasons as,
Plastic lenses – Made of CR 39 Polymer which is very light in weight, low cost with excellent optical qualities.
Polycarbonate lenses – Originally developed for United states Air force as a bullet proof .Later, it becomes a preferred material for children’s eyewear, safety glasses and sports eyewear.
High index plastic lenses – This high index plastic lenses are finely thin and lighter eyeglasses than the CR 39 & Polycarbonate. These are in very high demand nowadays.

So, before choosing the power eyeglass it is necessary to consider the condition & nature of work the person does to avoid irrelevance.