Simulating visual acuity
The purpose of this page is to give an idea of how blurry your vision is
when you don't use your glasses or contact lenses, or when you use a
prescription which doesn't match your eyes. This is illustrated by simulating
the blurry perception of a Snellen eye chart, which is commonly used to make
The simulation is limited for several reasons, here's just a few:
If you want to try it out, just go to the bottom of this page, and follow
the instructions from left to right.
- The magnitude of the optical aberration (how blurry the image gets)
depends on the width of the eye's pupil, which changes all the time.
- The brain and vision-related neurons make a lot correction work in
creating an illusion of a sharp image with clear edges.
- A positive spherical diopter in prescription can be cancelled by
the eye's own lens, but with a constant load on the ciliary muscle.
If you're in doubt with your own vision, go see an optometrist or
ophthalmologist. This page is at most for educational purposes, and
gives no guarantee whatsoever.
The author of this page has no eye-related professional education.
Last modified on Thu May 17 17:30:00 2012. E-mail: