What is Keratoconus?

Keratoconus is a progressive eye disease where the person’s normally round cornea thins and then begins to bulge into a cone-like shape. Because the cornea shape is now a cone, this deflects light entering the eye on its way to the retina and distorts vision.

Keratoconus can affect one or both eyes and it usually begins during the teens or early 20s. We treat keratoconus at Central Valley Eye Medical Group.

What is it?

Keratoconus, often referred to as “KC,” starts as the cornea thins. That then changes the shape. A normal cornea is round. If a person has astigmatism, the cornea will be oval. But a normal cornea should lie relatively flat. As the cornea thins with keratoconus, it causes the shape to change, pushing forward in the center to create a cone. This new shape doesn’t allow light to accurately enter the eye and hit the retina in a clear point of focus. This distorts vision.

What causes keratoconus?

There is a genetic predisposition to acquiring KC. The disease often affects more than one person is the same family. An imbalance of enzymes within the cornea makes it more susceptible to oxidative damage from compounds called free radicals. As the cornea weakens, it bulges forward.

Beyond potential genetic influences, keratoconus is associated with overexposure to ultraviolet rays from the sun, excessive eye rubbing, a history of poorly fitted contact lenses, and chronic eye irritation.

How is keratoconus treated?

At Central Valley Eye Medical, we use different methods for treating keratoconus. In mild cases, accurate, new eyeglasses or soft contacts may be all that is necessary, but these won’t do the job for more advanced cases.

  • Gas permeable contact lenses— These are the primary treatment for keratoconus. Gas permeable contact lenses are custom prescribed and manufactured in these cases. These special GP lenses provide a smooth surface that can focus light in place of the cornea’s distorted surface.
  • Corneal collagen crosslinking— The cornea is made of layers that are crosslinked together by collagen fibers. In this procedure, we saturate the cornea with riboflavin eye drops (vitamin B2) and then expose it to ultraviolet light. This causes a chemical reaction that increases the collagen crosslinks and makes the cornea stronger.
  • Surgery— This is only necessary is the most severe and advanced cases. These procedures involve a partial or full corneal transplant.

Is it time for your regular eye exam? Call the team at Central Valley Eye Medical, (800) 244-9907, to schedule your appointment at our Stockton or Manteca offices.

Posted in: Eye Conditions


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Dear Friends,

We at Central Valley Eye hope you and your families are well. During these uncertain times, we are taking all necessary precautions to keep patients and staff healthy as COVID-19 infections continue to rise. We are following CDC and American Academy of Ophthalmology guidelines, including extra diligent cleaning, and disinfecting around the office. Our waiting rooms have been reconfigured to allow more distance between chairs, and we are turning away all non-urgent patients who are symptomatic with cough or fever.

In keeping with government and institutional guidelines, as well as to promote the practice of "staying at home," we are implementing new restrictions. Starting March 20th, we will be limiting our clinic only to patients with eye conditions that could permanently threaten vision if not addressed within two months. This means that many appointments will need to be rescheduled. Additionally, some of our office locations may be closed on certain days, as patient volumes are expected to decrease significantly. If you are unsure whether to come in for your visit, please call us.

The clinic is also establishing a telemedicine service to address eye problems that are less urgent, which can be managed over the phone by a physician.

The doctors at Central Valley Eye will not be performing any non-urgent surgeries until further notice. Our surgery coordinators will be contacting patients to reschedule the surgeries that need to be postponed.

If you have any questions, please do not hesitate to contact us at 209-952-3700.

Warmest regards,

Brandy Simpson
Practice Manager
Central Valley Eye Medical Group, Inc.