Let’s say you just had an eye examination and got eye glass Prescription . Now you must be wondering What is it?
In this post i will try to explain eye glass prescription in most simple way .Generally you will see this type of prescription
The first thing you should understand in your eye glass prescription is OD and OS . Here ( OD ) means Right eye and(OS) means Left eye.
SPH (or Sphere)indicates the eyeglass prescription power, or how strong your lenses need to be to correct your vision. If the number appearing under this heading has a minus sign (–), you are nearsighted (MYOPIA ) ; if it has a plus sign (+), you are farsighted (HYPERMETROPIA)
CYL (or Cylinder)indicates astigmatism, a condition where the cornea is irregularly shaped which causes blurred or distorted vision.The number in the cylinder column with a minus sign (for correction of nearsighted astigmatism) or a plus sign (for farsighted astigmatism). Cylinder power always follows the sphere power in an eyeglass prescription.
AXIS describes the degree and direction of your astigmatism. It is defined with a number from 1 to 180. If an eyeglass prescription includes cylinder power, it also must include an axis value, which follows the cyl power and is written after “x” when written freehand.
ADD is added magnifying power in the lower part of a multi-focal lens. It’s used to correct presbyopia which is the inability to focus on close objects. If you need a bifocal or progressive lens, there will be an ADD.The number appearing in this section of the prescription is always a “plus” .Generally, it will range from +0.75 to +3.00 D and will be the same power for both eyes
Your prescription, including both eyes, will generally look something like this
Here The first number in the series identifies your degree of nearsightedness or farsightedness. A plus sign (+) indicates you are farsighted, a minus sign (-) indicates you are nearsighted. This number is called your spherical correction. Here Refractive power is -2.00 in Right eye and -2.75 in left eye .The second number in your prescription identifies what degree of astigmatism you have i.e. how well or poorly your eye focuses light onto the retina. The number can be written either with a (+ sign) or a (- sign). This number is called your cylindrical correction. Here cylindrical power is 1.00 in right eye and -0.75 in left eye.The third number indicates the direction of your astigmatism. Here axis is 100 in right eye and 90 in left eye. . Your prescription might also contain the abbreviations NV (near vision) which means your prescription is for Reading only.
Considering above example
If any one ask you the power you should say i have -2.00 spherical power with -1.00 cylindrical at 100 axis for right eye and -2.75 spherical power with -0.75 cylindrical at 90 axis in left eye and my near add is +2.25