Do you remember in old cartoons when a character would see a delicious plate of food and his eyes would comically bulge out like footballs?
That pointed cone shape of the eye in such scenes isn’t much different from the effects of keratoconus, a vision disorder in which the cornea (the front part of the eye) goes from being its normal rounded shape to thinner and more pointed.
According to the Mayo Clinic, Keratoconus (ker-uh-toe-KOH-nus) occurs when your cornea — the clear, dome-shaped front surface of your eye — thins and gradually bulges outward into a cone shape. A cone-shaped cornea causes blurred vision and may cause sensitivity to light and glare.
Cornea Shape And Vision
The different structures of our eyes need to have very specific shapes in order to reflect light onto the light-sensitive retina and enable us to see clearly. The reason many people need glasses at an early age is that their eyes are too long or too short. This makes the image reflected through the lens fall in front of the retina or behind it, making images blurry at different distances.
With keratoconus, because of the misshapen cornea, the image reflected through the lens of the eye becomes distorted at any distance, producing multiple images or warping them before they reach the retina.
Symptoms And Progression Of Keratoconus
In early stages, keratoconus results in slightly blurred and distorted vision, as well as sensitivity to light and glare. Typically these symptoms will appear in the late teens or 20s, and may progress for up to twenty years before slowing. As keratoconus worsens, it can produce double vision, multiple images, glare around lights, and poor night vision.
In rare cases, the thinned cornea may develop a tiny crack because of the strain of the cone-like shape. When a crack forms, the cornea will swell, significantly impacting vision for weeks or months as it heals, leaving a scar behind that also impacts vision.
Vision Correction For Keratoconus
While there are no medications that can prevent keratoconus from progressing, its effects on vision are correctable with glasses or contact lenses in the early stages. Because the eye’s shape is changing over time, these may not fully correct the problem in the later stages, but rigid gas permeable lenses can still produce significant improvements. Regular eye appointments are very important to make sure contact lenses fit properly and continue to correct vision. In particularly severe cases, a corneal transplant may become necessary.
Changes In Your Vision? Schedule an appointment.
If you’ve noticed any changes in your eyesight, whether or not you are within the typical age range for developing keratoconus, it’s time to schedule your next eye appointment. You might only need an updated prescription for your glasses or contact lenses, but the changes could also be due to keratoconus or another more serious condition.
Your optometrist looks forward to seeing you!
Top image by Flickr user Aaron Stidwell used under Creative Commons Attribution-Sharealike 4.0 license. Image cropped and modified from original.
The content on this blog is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of qualified health providers with questions you may have regarding medical conditions.