What is Keratoconus?
The clear, dome-shaped surface of the eye is called the cornea. Keratoconus is a progressive disease and occurs when the cornea begins to thin and bulge outward into a cone shape.
Keratoconus can cause multiple vision problems, such as blurred vision and sensitivity to light. It is usually initially found in teenagers and can slowly progress for years if left undiagnosed.
Vision problems from the early stages of keratoconus can be corrected with glasses, but later stages may require rigid gas permeable contact lenses. If the disease progresses, advanced stages may require cornea transplants.
What Causes Keratoconus?
Our eyes have different enzymes within them that keep them healthy and normal, but sometimes these enzymes can become imbalanced. Research has shown that imbalances may lead to weakening of the corneal tissue, which leads to keratoconus. Having an enzyme imbalance can cause oxidative damage from different compounds, often called free radicals, which causes the cornea to bulge forward.
Oxidative damage to the cornea is usually a result of genetics and inherited physicalities, keratoconus can be considered hereditary. However, it can also be associated with chronic eye rubbing and irritation, incorrect or poorly fitted contact lenses, and overexposure to harmful UV rays.
How Do I Know If I Have Keratoconus?
Symptoms of keratoconus include sensitivity to light and glare, blurred or distorted vision, sudden worsening vision, or the need for frequent changes in prescriptions. Astigmatism and nearsightedness are the most often recognized vision issues caused by keratoconus.
If you suspect you are experiencing symptoms of keratoconus, visit your optometrist for a comprehensive eye exam. During the exam, if your optometrist suspects you may be suffering from keratoconus, they will likely perform a topographic exam on your eyes.
Topography measures the curvature of your eye and creates a “map”, often coloured to show peaks and irregularities in the cornea. Keratoconus causes very distinctive changes on the maps, which allows your optometrist to make a correct diagnosis.
Risks and Complications
If keratoconus advances to a severe stage, the cornea may swell and scar. The inside lining of the cornea may begin to break down, allowing fluid to enter the cornea. If the cornea scars, your vision will deteriorate significantly and surgery may be the only corrective option.
How Can Keratoconus Be Managed?
If caught early, mild keratoconus can be treated with eyeglasses or soft contact lenses. Glasses and contacts do not correct the underlying cause of keratoconus, but help with distorted vision.
If you have mild keratoconus, traditional, soft contact lenses may be enough to manage your condition. Contact lenses for keratoconus are often made to order based on your specific measurements and corneal topography. They are larger than traditional contact lenses but can be more effective in managing keratoconus than glasses.
How Can Keratoconus Be Treated?
More advanced stages of keratoconus can be treated with rigid contact lenses, as they smooth the irregularities of the cornea and provide clearer vision. Additionally, in some cases, your optometrist may suggest using both a soft and rigid contact lens on the same eye to better correct blurred or distorted vision.
Several different types of contact lenses exist to assist in correcting vision hindered by keratoconus. You can seek out custom hybrid lenses, which combine rigid and soft lenses in one lens, as well as scleral lenses, which are large and rest on the whites of the eyes (the “sclera”). However, if the symptoms get progressively worse and the disease becomes more advanced, surgery may be the only corrective treatment.
There are two types of corneal crosslinking; epithelium-off and epithelium-on. Epithelium-off corneal crosslinking is a surgical procedure in which the outer layer of the cornea is removed to allow entry of a type of B vitamin called riboflavin, to help strengthen the tissue and stop bulging.
Epithelium-on corneal crosslinking is less invasive, as the cornea is left intact. This type poses less risk of infection and shorter recovery time.
Intacs are clear corneal inserts that are surgically implanted within the cornea to reshape the surface of the eye and correct vision. Intacs are often used when contact lenses or glasses no longer assist in correcting distorted vision. The surgery is very short, and intacs are removable and interchangeable.
Advanced stages of keratoconus may result in very thin or scarred corneas, which cannot be treated with glasses or lenses. At this point, the eyes may require a corneal transplant. Corneal transplants are usually simple surgeries and prognosis’ are generally positive, however, you may still require glasses or contacts for clear vision.
If you have keratoconus, we’re here to help. We carry a variety of specialty contact lenses, including options for patients with keratoconus. For more information about options for keratoconus, contact us to book an appointment.