More on Prescriptions

Following on from the last post, there were a few other things I thought I might add.

In case you weren't sure, the higher the numbers the stronger the prescription.                

Another thing. Your glasses prescription and contact lens prescription will differ slightly. This is due to the contact lens being physically closer to your eye, usually resulting in a slightly different prescription to your glasses. Also your contact lens prescription doesn’t always show your degree of astigmatism.               

The following is an example of a prescription:

(Click on the image to enlarge). This prescription is read:               

“Right eye, -2.75, -1.00 axis 180. Left eye, -2.50, -0.50 axis 180. Add +2.25”.               

This means that the person is shortsighted or myopic (indicated by the " –" sign in front of the sphere measurement), with a slight astigmatism at an axis of 180 degrees from the horizontal. There is a reading addition of +2.25 indicating presbyopia.             

The “Sphere equivalent” measurement is achieved by adding half of the cylinder to the sphere. So in the case above the sphere equivalent is:               

RE: (-)1.00 / 2 + (-)2.75 = (-)3.25 and LE: (-)0.50 / 2 + (-)2.50 = (-)2.75

Comments

[Ashlee]

I really started to hate wearing my glasses so my mom bought me some contacts from http://www.contact.com. I rarely wear my glasses now. Why are the contact lens prescriptions different from regular eyeglass ones? weird...