Understanding your prescription ?

 

What you need to know

To start, below you can find a few abbreviations used by your ophthalmologist :

  • OD: Right eye
  • OS: Left eye
  • OU: Right and left eye
  • ADD: Addition
  • SPH: Sphere
  • CYL: Cylinder
  • DV: Distance vision
  • NV: Near vision
  • VA: Visual acuity
  • IV: Intermediate vision

What does an ophthalmologist's prescription look like?

The values of the correction you need, are expressed in quarters of diopters.

Distance vision

The values not in between brackets, preceded by a + refer to hyperopia, those preceded by a - refer to myopia.

The values in between brackets refer to an astigmatism, and the value that follows is expressed in degrees and corresponds to the axis of the astigmatism.

Near vision

This is presbyopia, with the correction to apply (here +1,50 for both eyes).

Notes:

The term "ADD" signifies "addition" for presbyopics, This is your reading addition and relates to the amount of additional correction needed to focus at close distances. This value is always positive.

It often occurs that each eye needs an individual correction.

Examples of prescriptions for the main defect of the eye

In ophthalmology, hyperopia, myopia, astigmatism and presbyopia are the main defects of the eyes that can be corrected with glasses or lenses.

Hyperopia ( what is this? )

Example of a prescription for a hypermetropic:

On the prescription OD: +2,50 OS: +3,00

It often occurs that each eye needs an individual correction.

Myopia ( what is it? )

Exemple of a prescription for a myopic:

On the prescription OD: -3,75 OS: -3,25

Astigmatism ( what is it? )

Astigmatism can accompany hyperopia and myopia.

Examples of prescriptions for a hypermetropic, astigmatic person:

On the prescription OD: +2,50 (+1,25) 90° OS: +3,00 (+0,75) 85°
or
OD: (90°+1,25) +2,50 OS: (85°+0,75) +3,00

The values between brackets indicate the value of the astigmatism. The last value, in degrees, indicates the axis of the astigmatism. It is indicated with a + or a - symbol between brackets. The description below can also be written as follows:

On the prescription OD: +3,75 (-1,25) 180° OS: +3,75 (-0,75) 175°
or
OD: (180° -1,25) +3,75 OS: (175° -0,75) +3,75

Exemples of prescriptions for a myopic and astigmatic person:

On the prescription OD: -4,50 (+2,00) 35° OS: -3,75 (+1,25) 65°
or
OD: (35° +2,00) -4,50 OS: (65° +1,25°) -3,75
Can also be written like this: OD: -2,50 ( -2,00) 125° OS: -2,50 (-1,25) 155°
or
OD: (125° -2,00) -4,50 OS: (155° -1,25) -2,50

Presbyopia ( what is this? )

The crystalline lens is unable to provide the power to adapt to a clear near vision. We have to assist the lens by adding a magnifying power for near vision, applied to the bottom part of multifocal lenses to correct presbyopia. The number appearing in this section of the prescription is always a "plus" power, even if it is not preceded by a plus sign. It is calculated as the difference between the power needed for the eye to have a clear far sight and the value needed to have a clear near vision. Generally, it will range from 0.50 to 3.00.

Example of a prescription for a presbiopic and myopic person:

On the prescription OD: -4,00 ADD: 2,00 OS: -3,50 ADD: 2,00

Example of a prescription for a hyperopic and presbiopic person:

On the prescription OD: +2,50 (+0,75) 15° ADD: 1,75 OS: +2,25 (+0,50) 75° ADD: 1,75

How to measure the pupillary distance?

It is important to inform us about your exact pupillary distance. If you neglect this, the lenses will not be perfectly adapted to your eyers. If you do not know your pupillary distance, do not hesitate asking your ophthalmologist. The pupillary distance can also be measured when you place your order. To do this, add the product of your choice to the shopping cart and use our measurement tool after having filled out your corrections.

If in doubt, do not hesitate to contact us.

Questions?
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