What does my glasses prescription mean?!

Best Answer - Chosen by Voters

Hello,

The figures refer to the strength of spectacles that you need, for each eye. Minus 3, means that you need a lens of strength "minus three diopters" (also spelled Dioptres), to correct the vision in your left eye. The strength of a lens in diopters, is the reciprocal of, (1 over), the focal (or focussing) length of the lens in meters.

So if a lens has a focal (focussing) length of 2 meters, it is said to be of strength 0.5 diopters, (1 divided by 2). Negative lenses are divergent lenses (for Short Sight), and positive lenses are focussing lenses, (for Long Sight).

A lens with a strength of -3.5 diopters, is a short-sight correcting lens, and is also slightly stronger than a -3.00 diopter lens.

There is no direct connection between the chart, and the strength of the correcting lens needed.

The 20/20 thing, just to be complete, - means that you can read at 20 feet, a chart which a normal-vision person can just read at 20 feet. 20/60 means, you can read at 20 feet, a chart which a normal- vision person can read 60 feet away.

I hope this is of some help. If you need diagrams to help you understand, please let me know, this is difficult stuff : )

Best wishes,

Belliger
retired uk gp

The only way to really know is to read an eyechart without your glasses on.

The prescription doesn't have a direct conversion to the visual acuity measurement ( 20/20 ect )

You would most likely be somewhere between 20/200 and 20/400 without glasses on.

The visual acuity and the prescription are 2 different measurements that mean 2 different things.

Optician