Keratoconus is a progressive eye disease in which the normally smooth cornea thins and begins to bulge into a cone-like shape. The cornea is the clear, central part of the surface of the eye. In patients with keratoconus, the cone-shaped cornea refracts light incorrectly and causes distorted vision. The cause of keratoconus is unclear at present. Researchers have determined that there are certain biochemical and cell biology abnormalities that lead to thinning of the cornea. Genetic abnormalities have been implicated but no definitive proof exists at present. Eye rubbing has also been blamed for causing keratoconus or making keratoconus worsen.
Keratoconus symptoms can include
- Distorted and blurred vision
- Myopia (nearsightedness)
- Double vision
- Headaches due to eye strain
- Light sensitivity
Your doctor will measure the curvature of your cornea and examine the cornea with a microscope to determine whether these symptoms are a result of keratoconus.
In the early stages of keratoconus, glasses or soft contact lenses may help to correct the nearsightedness and astigmatism associated with the disease. As the condition progresses and the cornea becomes increasingly thin, more advanced treatment is required.
- Rigid Gas-Permeable Contact Lenses – If eyeglasses or regular soft contact lenses cannot control keratoconus, rigid gas-permeable (RGP) contact lenses are usually the preferred treatment. The rigid lens covers the cornea, replacing the cornea's irregular shape with a smooth, uniform refracting surface, improving vision. Rigid keratoconus contact lenses can be less comfortable to wear than soft lenses. Further, fitting contact lenses on a cornea with keratoconus can be challenging and time-consuming. If you are using RGP contact lenses, you will need to visit your doctor frequently to fine-tune the fit and prescription of the lenses, especially if your keratoconus continues to progress.
- INTACS – INTACS are plastic rings inserted into the mid-layer of the cornea to flatten it, changing the shape and location of the cone. INTACS may be needed when the distorted vision from keratoconus can no longer be corrected with contact lenses or eyeglasses. The implants are removable and exchangeable. If the keratoconus continues to progress, however, INTACS can only delay the need for a corneal transplant, not prevent it.
- Collagen Cross-Linking – Collagen keratoconus cross-linking is a relatively new method of treatment that is currently not FDA approved (therefore it is an investigational treatment). It works by strengthening the corneal tissue to stop it from bulging. In this procedure, eye drops containing riboflavin (vitamin B2) are applied to the cornea and then activated by ultraviolet light. This strengthens the collagen fibers within the cornea.
- Corneal Transplant Surgery – Surgery is needed for patients with advanced keratoconus, where other therapies no longer provide clear vision. This usually occurs in 15-20% of cases. In corneal transplant surgery, most of the cornea is removed and then replaced with a new donor cornea. The procedure has a success rate of over 97%.
Age-related macular degeneration (AMD) is a degenerative eye disease that causes damage to the macula, the central portion of the retina. As such, it impairs central vision. Patients often report difficulty with various daily activities, such as reading and driving. AMD is more common in the elderly.
There are two categories of macular degeneration. Aging and thinning of the macula cause the more common “dry” form. It tends to progress slowly. In contrast, the "wet" form carries a greater risk for significant vision loss. It is the direct result of the growth of abnormal vessels behind the retina. These vessels tend to leak fluid and blood that damages the macula.
SYMPTOMS CAN INCLUDE
- Blurred vision
- Distortion of straight lines
- Vision becomes blurry or distorted
- Words seem to crowd together, declined reading ability
- Eyeglasses do not help
Treatment depends upon the severity of the disease. Your ophthalmologist will discuss with you the various options: ultraviolet protection, dietary supplements, intravitreal injections.