The human eye is a biological piece of functional art, capable of producing colorful moving three-dimensional images with high precision. At the same time, one can marvel at the aesthetic beauty of the human eye and its shape.
The Shape of a Healthy Eye
In a healthy and perfectly shaped eye, light passes through the cornea and crystalline lens, and is accurately focused onto the retina, located at the back of the gel-filled eyeball. This process enables an image to be passed onto the optic nerve and then the visual cortex of the brain. Accurate focus and convergence depend on the proper shape of each part of the eye. However, eyeballs can be either shortened (hyperopia) or elongated (myopia).
Unhealthy Eye Shapes That Impact Vision
The Myopic Eye
In an elongated myopic eyeball, the distance between the lens and retina is too long, leading the image to come into focus before reaching the retina. As a result, the photosensitive cells of the retina pick up a blurry image.
The Hyperopic Eye
In hyperopia or farsightedness, the opposite is the case. The eyeball is too short, as is the distance that light travels from lens to retina. Therefore, the image comes into focus behind the retina, causing distant objects to appear clear, whereas close ones do not come into proper focus.
While the crystalline lens is flexible and auto-adjusts its shape for proper focus, the cornea is static. A healthy cornea maintains its smooth dome shape. However, if the cornea is weak, the structure of the cornea cannot hold this round shape, causing the cornea to bulge outward and downward like a cone. Perfect curvature of the cornea ensures the correct bending of incoming light onto the lens, whereas inadequate curvature results in a refractive error.
An uneven or irregularly shaped cornea also distorts the image that forms at the retina. Common corneal irregularities include astigmatism and keratoconus.
Scleral Lenses for a Smooth Eye Shape
Scleral lenses are large contact lenses that rest on the sclera — the white part of the eye. The lenses span over the cornea, making them ideal for a deformed cornea as they even out the irregularity to create a perfectly shaped eye.
Contact Dr. Selena Chan at The Scleral Lens and Keratoconus Center at Pacific Rims Optometry to learn more about how your eye shape affects your vision. We'll be happy to discuss the different correction methods available that offer you sharp, comfortable and clear vision all day, every day.
We receive clients from San Francisco, Oakland, Berkeley, San Mateo, and throughout California.