Ophthalmology
Keratoconus
Keratoconus is a progressive disorder that affects the cornea—the outermost layer of the eye. The middle of the cornea gradually thins and bulges outward, forming a rounded cone shape. These structural changes result in vision problems. Left untreated, it can cause progressive vision loss. In most cases, both eyes are affected.
Overview
Keratoconus affects about one in every 2,000 Americans. It can occur in one or both eyes and is more prevalent among teenagers and adults in their 20s, but it can affect individuals as young as nine years old.
Mass. Eye and Ear was one of the first U.S. hospitals to offer corneal cross-linking for the treatment of keratoconus in 2016. Today, it’s still one of just a few hospitals in New England that performs the procedure.
6Common Symptoms
- Distorted vision, where objects appear wavy or bent incorrectly (from astigmatism)
- Blurred vision, where objects appear out of focus or hazy (from nearsightedness)
- Swelling
- Development of scar tissue that impairs vision
- Glare and light sensitivity
- Frequent changes in eyeglass prescription
Potential Causes and Risk Factors
Tiny fibers of collagen protein help the cornea to stay flat against the eye. If these fibers weaken, the cornea cannot hold its shape and begins to bulge and become more cone-shaped.
Potential risk factors include:
- Family history of the condition
- Overexposure to ultraviolet light from the sun
- Excessive eye rubbing
- Chronic eye irritation
Diagnosis
Keratoconus is diagnosed with an eye exam and tests that may include:
Keratometry: A circle of light is focused on the cornea and measures the reflection to determine the basic shape of the cornea.
Eye refraction: A test that measures the strength of your vision and detects refractive errors.
Optical coherence tomography: A non-invasive imaging tool that was co-discovered at Mass. Eye and Ear. These images provide a detailed look at the cornea surface and measure its thickness.
Treatment
Early on, eye glasses or soft contact lenses may help provide vision correction. However, as the disease progresses, you will likely need some form of medical or surgical treatment to preserve your vision.
The U.S. Food and Drug Administration has approved Intacs for the treatment of mild-to-moderate keratoconus. This small, curved device is surgically inserted into the cornea to help reshape the cornea and improve vision. The surgery is generally performed as an in-office procedure. Healing time is gradual, often taking three months to obtain the best vision.
Complications with Intacs are rare, but may include under-correction, over-correction, induced astigmatism, infection, glare, halos, and extrusion of the insert. Minimal scarring may also occur in the area of the rings.
This minimally invasive, in-office procedure is the only treatment that can slow or stop the progression of keratoconus. During this FDA-approved procedure, riboflavin eye drops are placed in the eyes and activated by ultraviolet light.
In severe cases, your ophthalmologist may recommend a corneal transplant. This surgery is successful in more than 90 percent of those with advanced keratoconus. Several studies have also reported that 80 percent or more of these patients have 20/40 vision or better after the operation.
