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Keratoconus develops when the cornea, your eye's transparent, dome-shaped front surface, thins and gradually bulges outward into a cone shape.
A cone-shaped cornea creates impaired vision and may induce light and glare sensitivity. Keratoconus often affects both eyes, albeit one eye is frequently affected more than the other. It typically affects people between the ages of 10 and 25. The disease may proceed slowly for ten years or more.
You may be able to fix vision difficulties with glasses or soft contact lenses in the early stages of keratoconus. Later on, you may be required to use rigid, gas permeable contact lenses or other types of lenses, such as scleral lenses. If your illness worsens to an advanced level, a cornea transplant may be required.
A novel procedure known as corneal collagen cross-linking may help to halt or stop the progression of keratoconus, potentially avoiding the need for a cornea transplant in the future.
WHAT ARE THE SYMPTOMS OF KERATOCONUS?
Keratoconus symptoms include the following:
- Vision in one or both eyes deteriorates gradually, usually in late adolescence.
- Even with glasses on, the person may have double vision while gazing with just one eye.
- Bright lights appear to have halo effects surrounding them.
Keratoconus patients will find that their vision gradually becomes distorted. The transformation can come to an end at any time or it can last for years. Keratoconus eventually affects both eyes in the majority of people.
WHAT ARE THE COMPLICATIONS OF KERATOCONUS?
In some cases, your cornea may enlarge quickly, resulting in decreased vision and corneal scarring. This is caused by a disorder in which your cornea's inner lining breaks down, allowing fluid to enter the cornea (hydrops). The swelling normally goes away on its own, but a scar may form that impairs your vision.
Advanced keratoconus can also cause scarring of the cornea, especially where the cone is most visible. Scarring of the cornea worsens vision difficulties and may necessitate cornea transplant surgery.
HOW IS KERATOCONUS DIAGNOSED?
Your eye doctor (ophthalmologist or optometrist) will analyze your medical and family history and perform an eye exam to diagnose keratoconus. Other tests may be performed to obtain more data about the shape of your cornea. The following tests are used to diagnose keratoconus:
- Eye refraction: Your eye doctor will use sophisticated equipment to measure your eyes to check for visual impairments during this test. He or she may ask you to look through a phoropter (a device with wheels of different lenses) to help determine which combination provides you the finest vision. A hand-held equipment (retinoscope) may be used by some doctors to evaluate your eyes.
- Slit-lamp examination: In this test, your doctor shines a vertical beam of light on the surface of your eye and examines it using a low-powered microscope. He or she examines your cornea for shape and checks for other potential abnormalities in your eye.
- Keratometry: Your eye doctor will shine a circle of light on your cornea and measure the reflection to establish the basic shape of your cornea in this test.
- Computerized corneal mapping: Corneal tomography and corneal topography are special photographic procedures that record images to produce a comprehensive shape map of your cornea. Corneal tomography can also be used to determine the thickness of your cornea. Corneal tomography can frequently detect early indications of keratoconus before slit-lamp inspection.
WHAT ARE THE TREATMENTS FOR FOR KERATOCONUS?
Treatment for keratoconus is determined by the severity of your condition and how quickly it progresses. In general, there are two approaches to treating keratoconus: delaying disease progression and improving eyesight.
If your keratoconus is worsening, corneal collagen cross-linking may be recommended to slow or stop it. This is a novel technique that may eliminate the need for a cornea transplant in the future. This treatment, however, does not reverse keratoconus or enhance vision.
The severity of your keratoconus determines how well you can see. Eyeglasses or contact lenses can be used to treat mild to moderate keratoconus. This will most likely be a long-term treatment, especially if your cornea stabilizes over time or due to cross-linking.
With severe disease, the cornea of some persons with keratoconus becomes damaged, making contact lens usage difficult. Corneal transplant surgery may be required in certain cases.
Lenses
- Soft contact lenses or glasses: Early keratoconus eyesight can be corrected with glasses or soft contact lenses. However, when the shape of their corneas changes, people commonly need to modify their prescription for eyeglasses or contacts.
- Hard contact lense: Hard (stiff, gas permeable) contact lenses are frequently used to treat advanced keratoconus. Although hard lenses can be painful at first, many people acclimate to them and they can provide great vision. This lens may be customized to fit your corneas.
- Piggyback lenses: If rigid lenses bother you, your doctor may advise you to "piggyback" a hard contact lens on top of a soft one.
- Hybrid lenses: For added comfort, these contact lenses contain a firm center with a softer ring around the exterior. People who have difficulty using hard contact lenses may prefer hybrid lenses.
- Scleral lenses: In advanced keratoconus, these lenses are excellent for very irregular shape changes in your cornea. Scleral lenses, as opposed to typical contact lenses, sit on the white component of the eye (sclera) and vault over the cornea without touching it.
If you wear rigid or scleral contact lenses, have them fitted by an eye specialist who has experience treating keratoconus. You'll also need to have regular inspections to see if the fit is still satisfactory. An improperly fitted lens might cause corneal injury.
Therapies
Cross-linking of corneal collagen The cornea is drenched with riboflavin eyedrops and treated with UV light during this process. This causes corneal cross-linking, which stiffens the cornea and prevents additional shape changes. By stabilizing the cornea early in the disease, corneal collagen cross-linking may assist to lessen the likelihood of progressive vision loss.
Surgery
If you have corneal scarring, excessive thinning of your cornea, poor vision even with the strongest prescription lenses, or an inability to wear any form of contact lenses, you may require surgery. Surgical choices depend on the location of the bulging cone and the severity of your problem.
- Penetrating keratoplasty: If you have corneal scarring or significant thinning, you will almost certainly require a cornea transplant (keratoplasty). A full-cornea transplant is performed with penetrating keratoplasty. A full-thickness section of your central cornea is removed and replaced with donor tissue during this treatment.
- Deep anterior lamellar keratoplasty (DALK): The DALK technique saves the cornea's inner lining (endothelium). This helps to avoid rejection of the vital inner lining, which can occur with a full-thickness transplant.
Cornea transplantation for keratoconus is normally highly successful, however problems including eye graft rejection, impaired vision, infection, and astigmatism are possible. Astigmatism is frequently treated by reintroducing hard contact lenses, which are usually more comfortable following a cornea transplant.