The exact causes of keratoconus are not known.
The exact causes of keratoconus are not known. It is believed that a combination of genetic and environmental factors can increase the risk of keratoconus. Risk factors for keratoconus include
- Having a family history of keratoconus. 1 in 10 people with the condition has a parent or blood relative with keratoconus.
- Frequent rubbing of the eyes, probably due to constant irritation of the eyes due to exposure to dust, toxic fumes, or allergies.
- Having certain conditions such as Ehlers-Danlos syndrome, hay fever, asthma, retinitis pigmentosa, and Down syndrome.
What are the symptoms of keratoconus?
Symptoms of keratoconus usually change and progressively worsen as the disease progresses. They include:
- Blurred and/or distorted vision
- Double images
- Sudden worsening vision and reduced vision
- Increased sensitivity to bright light
- Glares
- Decreased vision at night and dim light
- Requiring changes in eyeglass prescriptions frequently
How is keratoconus treated?
Treatment for keratoconus depends on the severity and progression of the condition. There are usually two ways to treat keratoconus: one is slowing or stopping the progression of the disease and the other is the improvement of vision. The eye surgeon (ophthalmologist) would be able to suggest an appropriate treatment plan after evaluating the condition. Treatment options include:
- Lenses:
- Eyeglasses or soft contact lenses: In the early stages of keratoconus, soft contact lenses and eyeglasses can be used to correct vision and see clearly. However, the condition continues to progress, and the shape of the cornea continues to change; hence, most people need to change their prescription for eyeglasses or contacts frequently.
- Rigid contact lenses: Hard/rigid, gas permeable contact lenses may be used in more advanced keratoconus. They may feel uncomfortable initially, but most people adjust to wearing them. They provide excellent vision and can be customized to fit the patient’s corneas.
- Piggyback lenses: A hard contact lens is placed on top of a soft one (piggybacking). This may be advised for patients who don’t adjust to hard/rigid lenses.
- Hybrid lenses: Contact lenses with a rigid center and that is softer on the outside are used for increased comfort.
- Scleral lenses: They are usually used for patients with very irregular changes in the corneal shape in advanced keratoconus. The lens is placed on the sclera (the white part of the eyes) instead of directly on the cornea. They are usually fitted by the ophthalmologist.
- Therapies:
- Corneal collagen cross-linking: This is a newer treatment procedure in which the cornea is administered with riboflavin eye drops and treated with ultraviolet light. This causes cross-linking of the collagen of the cornea, causing the cornea to stiffen, stabilizing the cornea. The procedure can slow or stop further changes in the shape of the cornea and worsening of keratoconus and reduce the risk of progressive vision loss. The procedure may be combined with the use of lenses or eyeglasses. This procedure can also prevent the need for surgery.
- Surgery: Surgery may be required if there is corneal scarring, extreme thinning of your cornea, and poor vision, and when other treatments wouldn’t be beneficial. Surgery for keratoconus is keratoplasty (corneal transplant). Keratoplasty is usually very successful in correcting keratoconus, but there is a small risk of complications, such as graft rejection, poor vision, infection, and astigmatism. There are two types of keratoplasty:
- Penetrating keratoplasty: This is a full cornea transplant, involving removal of a full-thickness portion of the central cornea and replacement with donor corneal tissue.
- Deep anterior lamellar keratoplasty (DALK): The inner lining of the cornea, called endothelium is preserved, over which the donor corneal tissue is transplanted. There is a lesser risk of rejection in this than penetrating keratoplasty.