Your Rx is what an ophthalmologist (an MD) or optometrist (a doctor of optometry) provides to correct your vision with a pair of eyeglasses with corrective lenses.

 


SPY

CYL

AXIS

PRISM

ADD

PD

OD-RIGHT

-5.50

-0.50

165


+2.00

31.5

OS-LEFT

-4.50

-1.00

25


+2.00

31.5

 

(you need an Rx written specifically for eyeglasses; an RX for contact lenses will not work for eyeglasses!)

 

An Rx will have horizontal rows or vertical columns. The top row or first column will always be for the right eye, abbreviated as od. The second row or column will always be for the left eye, abbreviated as OS. Each row of an RX has three main sections: sphere (SPH), cylinder (CYL), and axis. The SPH section corrects nearsighted or farsighted vision. The CYL and axis sections correct astigmatism.

 

There may also be a fourth section on the Rx, NV-add (for near vision-reading addition), which could be used to order a pair of bifocal or progressive glasses with a close-up vision section in the bottom part of the lens. The SPH, CYL, and NV-add numbers will always have a plus or minus sign.

 

SPHERE (SPH): 

Specifies the strength of lens required to correct your focus - a plus sphere to correct long-sightedness (hyperopic - difficulty focusing on close objects) and a minus to correct short-sightedness (myopia - difficulty focusing on distant objects.)


CYLINDER (CYL): 

Is the measure for astigmatism. There is always a plus (+) or minus (-) sign present. There may not be a value of cylinder in your prescription.

Axis (AXE):

Will only appear if there is a value for cylinder (CYL), as it relates to the cylindrical lens and denotes a reference point that indicates the direction of the power of the cylindrical lens. It will be a number between 1 and 180.

Addition (ADD): 

Is short for Reading Addition (Sometimes referred to as SEG POWER as well)- It is additional plus power in the lower portion of a multifocal lens (progressive or bifocal) that is required for near vision.


PUPILLARY DISTANCE (PD): 

Is a measurement used to accurately centre the lenses in the frame that you have selected? PD is the distance from the centre of the pupil (black circle) in one eye to the centre of the pupil in the other eye. The PD is an essential measurement, and may be written with the Pupillary Distance listed for each eye respectively, for example, RE: 31,5 LE: 31,5, or as one measurement PD: 63. Either way, you may choose from our dropdown list your PD according to your prescription.


VISUAL ACUITY (VA):

Not relevant for making the glasses! Visual acuity describes the acuteness or “sharpness” of vision; that is the ability to perceive small details. Example: you need an acuity of 0.5 in order to get a drivers license, which means you should be able to read signs from 20 meters away.


PRISM (PRS):

In case you have values in this field you need to contact us before you order. Specifies any vision displacement, like double vision.


BASE (BAS): 

In case you have values in this field you need to contact us before you order. Specifies in what direction the prism is to be set.