What is Keratoconus?
Keratoconus literally means the cone-shaped cornea
(American Academy of Ophthalmology, 2011)
Keratoconus Definition – An eye disorder characterized by an irregular corneal surface (cone-shaped) resulting in blurred and distorted images. Keratoconus is a condition of the eye, which causes the cornea to thin out, resulting in a protrusion of the cornea. Due to the protrusion, the front of the eye appears cone-shaped, causing the light passing through to be distorted.
Signs and symptoms of keratoconus may change as the disease progresses.
The symptoms a keratoconus patient may have included:
- Blurred or distorted vision
- Increased sensitivity to bright light and glare
- Problems with night vision
- Many changes in eyeglass prescriptions
- Light Streaking
Keratoconus is not associated with physical symptoms such as inflammation and redness; therefore, this condition may go undetected for a long period of time. Most individuals who develop keratoconus will have an occurrence in both eyes. Individuals with undiagnosed keratoconus typically notice their vision deteriorating in one eye and gradually to the next eye. They may complain of halos, glares, and ghosting of images.
What Are My Treatment Options?
Glasses or Soft Contacts – In the early stages, glasses or soft contacts can deliver immediate but temporary vision correction. Unfortunately, due to the progressive nature of the condition, there will be a point where glasses and contacts will no longer work.
Rigid gas-permeable (RGP) contact lenses – As the condition worsens, RGPs and other specialty contacts are the next options.
In the later stages, iron will begin to deposit around the protrusion of the cornea, causing the tissue to further thin and develop a secondary condition known as Vogt’s Striaes. Vogt’s creates a white line deep in the stroma of the eye, which becomes visible around the cornea and base of the protrusion. Another secondary condition, found in rare cases of keratoconus, is Acute Hydrops; a condition where water floods the thinned areas of the cornea, which causes corneal scarring.
If you are experiencing keratoconus, our San Antonio keratoconus eye doctors at Parkhurst NuVision will guide you in the best direction for your treatment options! See the information below regarding corneal transplants.
What is a corneal transplant?
A corneal transplant, also known as a corneal graft, or as penetrating keratoplasty, involves the removal of the central portion (called a button) of the diseased cornea and replacing it with a matched donor button of the cornea. Corneal grafts are performed on patients with damaged or scarred corneas that prevent acceptable vision. This may be due to corneal scarring from disease or trauma. In this photo of a recent transplant, the stitches can be seen clearly on the right side.
A common indication for keratoplasty is keratoconus. The eye-care practitioner must decide when to recommend keratoplasty for the keratoconic patient. This is often not a simple, straightforward decision. Keratoplasty for keratoconus is highly successful; however, there is a long recovery period and a risk of severe ocular complications.
Very careful contact lens fittings are necessary before recommending a corneal transplant. One study found that 69% of keratoconus patients, most referred for transplant, could be successfully fit with contact lenses if special lens designs were used. Thus, prior to transplant, every effort should be made to optimally fit the patient with contact lenses, especially if there is not significant corneal scarring affecting vision. However, a few patients become intolerant to contact lenses and require a transplant earlier than otherwise would be necessary. If the patient has a large area of thinning, a very debentured cone or significant blood vessel growth into the usually clear cornea, called revascularization, a transplant may be performed earlier than otherwise indicated by the visual performance, as these factors may require a larger than normal transplant button size and/or increase the chance of rejection if allowed to advance too far.
Patients Need a Corneal Transplant When:
- Vision is not good enough to perform daily activities.
- There is pain or recurring infections in the damaged cornea
Healing After Corneal Transplant
The healing process following transplant is long, often taking a year or longer. The time from surgery to the removal of the stitches is commonly 6 to 17 months. The patient may be on steroids for months. Initially following surgery the donor button is swollen and even following healing the button is usually thicker than the corneal bed in which it rests.