Humans are able to see the beauty of the world with the gift of eye sight. Having good eyesight or eye vision can go a long way. It helps a human to be productive and be independent. However, many may not be blessed to have normal eyes or good vision. Some may have eye vision issues from birth and some may be as result of a disease progression. There are many eye disorders that could lead to visual disturbances. In this DoctorOnCall’s article, we will be learning about one of the many eye disorders associated with visual disturbances known as keratoconus.
Keratoconus is a vision disorder characterised by the abnormally shaped cornea (the outer front part of the eye) that becomes thin and irregularly shaped. In this condition, the cornea bulges outward and resembles a cone shape. To better understand how keratoconus affects the cornea, it is best to know a bit more on the normal cornea. The normal cornea is a clear and dome-shaped window, located at the front of the eye. The cornea focuses the light into the eyes. Thus, when there are changes to the shape of the cornea, the light rays will be out of focus and result in vision issues.
It is estimated that 1 in 700 to 2000 people are affected by keratoconus. It often starts in people in their late teens to early 20’s. About 1 in 10 people with keratoconus have family members with the same condition. It is not known what causes keratoconus but it is associated with diseases such as atopy (allergic disorders), Down’s syndrome, Leber’s congenital amaurosis, retinitis pigmentosa and connective tissue disorder such as Ehlers-Danlos syndrome. Keratoconus is also associated with eye allergies and excessive eye rubbing, especially aggressive “knuckling” eye rubbing. More than dozens of genes have been associated with keratoconus. Most frequent associated genes play a role in eye development, formation of the cornea structure, molecules and protein forms in space between cells (extracellular matrix), immune system response and regulation of cell growth. Thus, when there is disruption to any of these processes and combined with environmental triggers such as excessive eye rubbing or tendency developing allergic disorders, it can lead to development of keratoconus.
In the early stage, keratoconus causes slight blurring and distorted vision. This will also increase light sensitivity and glare. Symptoms usually appear in late teens or early 20’s and progress for 10-20 years. After this period of time, the progress will slow down. Keratoconus typically affects both eyes but each eye can be affected differently. The less affected eyes may show a high amount of astigmatism or mild steepening. Cornea bulges and vision become more distorted as keratoconus progresses. In some cases, the cornea swells and causes sudden significant decrease in vision. Swelling may last for weeks or months. This swelling happens when the cornea cone-like shape protrudes and causes tiny cracks. The tiny crack will gradually be replaced by scar tissue as the crack heels. In cornea with scar tissue, it loses its smoothness and becomes less clear, making vision more distorted and blurrier. In later stages, a person with keratoconus may not be able to wear contact lenses as they become no longer properly fitted and become uncomfortable to wear one. Keratoconus usually takes years to go from early to late stage. However, keratoconus may get worse quickly for some people.
A person diagnosed with keratoconus is usually treated to provide functional visual acuity and to stop changes to the corneal shape if progressing. Treatment depends on the symptoms. In mild symptoms, vision may be corrected by eyeglasses and special hard contact lenses may be given to help maintain the vision in proper focus. Other ways of keratoconus are treated by using intact to help flatten the curvature of cornea, collagen cross-linking by using special UV light and eye drops to strengthen the cornea, or even corneal transplant in severe symptoms. In case of keratoconus associated with atopy, topical antihistamines or anti-inflammatory. Immunomodulatory treatment such as topical steroid or cyclosporine is given.
Patients or even you, may wonder if you can live a normal life with keratoconus. Yes, for most people with keratoconus can live a normal life as long as the eye problems are taken care of. With proper care and treatment, there is no reason why keratoconus would stop you from living your best life. However, bear in mind, it might cause some difficulty at times especially when left untreated properly. Progression of symptoms may actually cause certain activities such as studying, reading and driving at night become somewhat difficult. Fret not, many treatment options available now can help to improve these conditions and even stop the keratoconus from getting worse. The most important thing is for patients to get regular eye exams and follow treatments as instructed. Having discussion on the best treatment options for you can help you feel more confident and disciplined toward the treatment plan.