Keratoconus (KC) is a condition that causes vision distortion. It occurs when the normally round cornea becomes thin and cone-shaped. This abnormal change prevents the light from entering the eye, hindering the retina’s ability to focus and, thus, distorting the image.
In healthy individuals, light travels through the cornea past the lens to the retina, allowing the brain to create an image. The corneal surface is normally smooth, so light can pass through with ease. In the case of keratoconus, the cornea becomes cone-shaped and its surface irregular, so the passing light is projected as a distorted image.
Here we will further explain the causes, symptoms, and treatment of keratoconus.
We know keratoconus causes the cornea to become cone-shaped, but how exactly does this occur? The cornea is held in place by tiny fibers of the protein collagen. When these fibers weaken, the shape of the cornea can no longer be sustained and changes over time.
Keratoconus is caused by a decrease in protective antioxidants in the cornea. Antioxidants protect the fibers that hold the cornea in place, but if antioxidant levels are low, there is not enough protection available, hence the gradual weakening of collagen fibers.
It is quite common to see keratoconus run in families, so if your parents or grandparents have had the condition, it’s important for children to monitor their eye health regularly. Keratoconus can take place as early as the teenage years, and the shape of the cornea can change either rapidly or slowly.
Keratoconus: Signs and symptoms
The earliest sign of keratoconus is slightly blurry vision, frequent changes in eyeglass prescriptions, or vision that cannot be addressed with prescription glasses. Other symptoms may include sensitivity to light, difficulty driving at night, a halo around lights, eye strain, headaches, eye pain, and eye irritation or excessive eye rubbing.
In its early stage, keratoconus can be difficult to diagnose, as it can resemble other common eye problems. Proper diagnosis of keratoconus involves a trained eye professional.
Keratoconus and vision loss
The changes in the cornea associated with keratoconus severely impair the vision. In the worst cases, a corneal transplant is required to restore vision. Laser eye surgery is not recommended for those living with keratoconus because it can further weaken the cornea and lead to vision loss.
Keratoconus cannot be diagnosed based on symptoms alone, so you will require a proper eye examination. Your eye doctor will look for sudden changes of vision in one eye, double vision when looking through one eye, objects near and far appearing distorted, bright lights appearing to have halos, lights streaking, seeing triple ghost images, and being uncomfortable with driving at night.
Your doctor will also need to measure the shape of the cornea to confirm that a physical change has taken place.
The following are some of the medical tests that may be implemented:
- Retinoscopy: Involves focusing a light beam on the retina and observing for a reflection of light as the beam is tilted back and forth.
- Slit-lamp exam: Used in conjunction with a biomicroscope, this test gives a detailed look of the eye structures. A Fleischer ring (yellowing-brown-greenish pigmentation) can be seen in keratoconus.
- Keratoscope: A non-invasive technique looking at the surface of the cornea.
- Corneal topography: Projects an illuminated pattern onto the cornea to determine its topology (the relationship between objects that share the same surface or border).
Early treatment requires the use of prescription glasses or rigid contact lenses. There is a specific procedure known as PTK that helps smooth out the scar and improve contact lens wear.
Another treatment is known as collagen crosslinking, which is effective for preventing keratoconus progression. Implants called Intacs are placed beneath the surface of the cornea to help reduce the cone shape and improve vision.
The last resort is a cornea transplant, which replaces the patient’s cornea with a donor cornea that is stitched into place.
The type of treatment depends on the severity of keratoconus.
Certain exercises may help slow vision degeneration associated with the early stages of keratoconus. The following are such exercises:
- Palming: Helps relieve astigmatism by reducing eye strain. It can be done by placing your right and left palm over the right and left eyes respectively. By relaxing and breathing deeply for 10 minutes, eye strain will be reduced.
- Strengthening: By participating in racket and team sports, visual acuity can be strengthened. It will help by improving eye-tracking, visual memory, reaction time, depth perception, and peripheral vision skills.
- Focusing: By using the swaying exercise, which requires focusing on an object in the distance as a focal point, then swaying from side to side while keeping your eye on the object, you can improve your focusing ability.