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 eye examinations.

The simulation is limited for several reasons, here's just a few:

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 want to try it out, just go to the bottom of this page, and follow the instructions from left to right.

DISCLAIMER

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.

Your sight without glasses or contact lenses:

LEFT		RIGHT

Your sight with wrong glasses or contact lenses:

LEFT		RIGHT

Start here: Feed your prescription below, and then push the button.

	Sphere	Cylinder	Axis
Right eye (OD):
Left eye (OS):

Preference: Meters (6/6) Feet (20/20)

Continue here: If you have glasses or contact lenses with a different prescription, feed it below and push the button:

	Sphere	Cylinder	Axis
Right eye (OD):
Left eye (OS):
Copy from prescription / copy swapped

With these glasses or contact lenses, your sight is equivalent to someone with the following prescription:

	Sphere	Cylinder	Axis
Right eye (OD):	0	0	0
Left eye (OS):	0	0	0

Last modified on Thu Aug 3 17:24:24 2023. E-mail: