How the Eye Works

The eye is an incredibly complex organ that "processes" millions of images every day. The analogy is often made between the eye and a camera. The cornea and lens of the eye act the same way as a camera lens does to focus light. They focus the light onto your retina which acts like the film in a camera. The retina receives light and converts it into electrical signals which are transmitted to your brain by the optic nerve. The brain "processes" these signals which you recognize as images.

Unfortunately, not all eyes work perfectly. Refractive errors can be corrected with glasses and contacts. Some forms of refractive errors can be corrected with refractive surgery.

Refractive Errors

Myopia (Nearsightedness)
In a myopic eye, the cornea is too steep and/or the distance to retina is too long. The result is the light rays from distant objects fall into focus too far in front of the retina, making them look blurry.

 

Click here to see an example

 

Hyperopia (Farsightedness)
In a hyperopic eye, the cornea is too flat and/or the distance to the retina is too short. The result is the light rays from distant objects fall into focus too far behind the retina, making them look blurry.

 

Click here to see an example

 

Astigmatism
In a astigmatic eye, the cornea is more oval shaped then round. The comparison between the back of a soup spoon and the back of a teaspoon is often used. The result is the light rays from distant objects focus at different points inside the eye, making them look blurry and/or distorted.

Click here to see an example

 

Presbyopia
In a presbyopic eye, the eye has lost (or is losing) the ability to focus on objects that are near. Typically, when you look at something close your eye uses muscles to change the shape of your lens. This process is called accommodation. As we get older, our lens gets harder and the muscles that focus it weaken. The result is an inability to change the shape of the lens when objects are near. Most people start to notice this in their mid to late forties and usually have trouble reading and/or using a computer.

Privacy Policy

10 Brentwood Drive, Suite A • Ithaca, New York 14850 • 607-257-5599