Keratoconus is an eye disease that affects the structure of the cornea, resulting in loss of vision. Keratoconus occurs in approximately one in 2,000 individuals, typically beginning in puberty and progressing into the mid-30s. Early stages can be treated with glasses, but with progression of the disease into late childhood and early adulthood, corneal transplantation may be needed to restore sight. Corneal collagen cross-linking is a procedure designed to stop the progression of keratoconus or slow it down. Keratoconus is a leading cause of corneal transplantation in the United States. There is no known prevention for keratoconus.
Keratoconus is characterized by the thinning of the cornea and irregularities of the cornea’s surface. The cornea is the clear, outer layer at the front of your eye. The middle layer is the thickest part of the cornea, mostly made up of water and a protein called collagen. Collagen makes the cornea strong and flexible, and helps keep its regular, round shape. This healthy cornea focuses light so you can see clearly. With keratoconus, the cornea thins and bulges into an irregular cone shape, resulting in vision loss.
Keratoconus generally begins at puberty and progresses into the mid-30s. There is no way to predict how quickly the disease will progress, or if it will progress at all. Keratoconus typically affects both eyes, with one being more severely affected than the other.
Although keratoconus has been studied for decades, it remains poorly understood. The definitive cause of keratoconus is unknown, though it is believed that the predisposition to develop the disease is present at birth. A common finding in keratoconus is the loss of collagen in the cornea. This may be caused by some imbalance between production and destruction of the corneal tissue by the corneal cells.
The following may increase the risk of developing keratoconus:
Patients with a family history of keratoconus or with certain systemic disorders, such as Down syndrome, are at a higher risk of developing keratoconus.
Constant inflammation from allergies or irritants can contribute to the destruction of corneal tissue that may result in developing keratoconus.
Chronic eye rubbing is associated with developing keratoconus. It may also be a risk factor for disease progression.
Keratoconus is often discovered in the teenage years. Generally, young patients with advanced keratoconus are more likely to need some form of surgical intervention as the disease progresses.
Other symptoms of keratoconus include:
Glare and halos around lights, Difficulty seeing at night, Eye irritation or headaches associated with eye pain, Increased sensitivity to bright light, Sudden worsening or clouding of vision
Many keratoconus patients are unaware they have the disease. The earliest symptom is a slight blurring of vision or progressively poor vision that is not easily corrected.
In addition to a complete medical history and eye exam, your eye care professional may perform the following tests to diagnose keratoconus:
Treatment of keratoconus focuses on correction of vision and depends on the stage of the disease.
Current treatment for keratoconus includes glasses in the earliest stages to treat nearsightedness and astigmatism. As keratoconus progresses and worsens, glasses are no longer capable of providing clear vision, and patients need to wear a contact lens, usually rigid gas permeable (RGP) contact lens.
Progressive keratoconus can be treated by corneal collagen cross-linking (CXL). This one-time, in-office procedure involves the application of a vitamin B solution to the eye, which is then activated by ultraviolet light for about 30 minutes or less. The CXL causes new collagen bonds useful the evolution of the keratoconus.
While the treatment cannot make the cornea entirely normal again, it can keep vision from getting worse and, in some cases, may improve vision.
Cross-linking was approved as a treatment for keratoconus by the FDA in April 2016, after clinical trials showed that it stopped or produced a mild reversal in bulging of the cornea within three to 12 months after the procedure.
Stable Keratoconus or keratoconus treated by CXL can be implanted with ICRs (Intra Corneal Rings). VTRs are an advanced technology in the field of the corneal rings. They can re-shape and improve corneal deformation reducing astigmatism and increase patient visual acuity. The procedure of implantation takes about 15 minutes.
In a corneal transplant, a donor cornea replaces the patient’s damaged cornea. Corneal transplants is requested for patients with advanced keratoconus. After transplant surgery vision can remain blurry for about three to six months, and medication must be taken to avoid transplant rejection. In almost all cases, glasses or a contact lens are necessary to provide the clearest vision.