What Is Keratoconus?
What causes -inflammatory, progressive eye disorder affecting the anterior surface of the cornea. The cornea gradually thins, causing it to bulge into a cone-like irregular shape. Because the cornea is responsible for refracting most of the light that comes into the eye, any irregularity of the cornea can result in significant visual impairment, affecting the way they see the world.
It is this irregular distortion of the cornea that makes vision correction with glasses less than optimal. For this reason, other means of correcting vision are often necessary.
What causes Keratoconus?
Keratoconus most often appears in a person’s late teenage years; although it can been diagnosed in people in their forties and fifties.
The actual incidence of keratoconus is estimated to occur in 1 to 5 persons per 1,000 in the general population.
Keratoconus has no known geographical, gender, ethnic or social pattern…it occurs in all parts of the world.
The exact cause of keratoconus is not known; however, there are many theories on what may trigger this disease. It is important to note that no one theory provides a complete explanation, and it is likely that keratoconus is caused by a combination of things. It is believed that genetics, the environment, and the endocrine system all play a role in keratoconus…
- Genetics-One scientific theory is that keratoconus is genetic in origin. About 7% of patients have other family members with the disease. current research indicates that there is less than a one in ten chance that a blood relative of a keratoconic patient will have keratoconus.
- Environmental Factors-Keratoconus may also be associated with overexposure to ultraviolet rays from the sun, excessive eye rubbing, a history of poorly fit contact lenses and chronic eye irritation.
- Endocrine System-Another hypothesis is that the endocrine system (which dictates the release of hormones) may be involved, since keratoconus is often first diagnosed in adolescence
- Another view holds that keratoconus is a degenerative condition perhaps linked to the altered balance between enzymes and inhibitors within the cornea.
- Keratoconus may also be secondary to some disease processes.
(Information source-Menicon and KC.org)
What is Ectasia?
- Ectasia is defined as the expansion of body tissue, in this case the cornea which is the clear dome covering the colored part of the eye.
- The cornea’s primary responsibility is to focus light onto the retina to create clear, sharp vision.
- When the cornea thins, or becomes ectactic, it distorts the vision causing blur, multiple images, glare, haloes, dry eyes, light sensitivity and other undesirable visual phenomena.
What is Pellucid Marginal Degeneration?
PMD is a degenerative corneal condition, often confused with keratoconus.
- Pellucid corneas involve a larger distorted area than keratoconus. It is not unusual for 50% or more of the corneal surface to be involved. Because so much of the cornea can be affected, fitting this type of cornea can be quite challenging.
- It is typically characterized by the, thinning in the inferior and peripheral region of the cornea
- PMD typically presents bilaterally, although some cases affect only one eye.
- Typically presents in their 20’s.
- The cause of the disease remains unclear.