What is Keratoconus?
Keratoconus happens as a result of progressive corneal thinning into a bulging cone shape instead of the normal dome shape. The distorted corneal shape hinders clear vision meaning that the patient suffers from blurry vision and light sensitivity. Usually, this condition occurs in both eyes. The age of onset ranges between 10 and 25, it is easily corrected by eye glasses or soft contact lenses if diagnosed at an early stage. The condition progresses slowly (over the course of 10 years or more). If left untreated reaching late stages a rigid gas permeable contact lens may be prescribed. In the more advanced stages the patient will need to be scheduled for a corneal transplant.
What are the symptoms of Keratoconus?
Keeping in mind that symptoms vary according to the stage of the condition, a patient with Keratoconus will have
a bulging eye which will distort his vision and may cause sensitivity or problems with corrective eyewear.
Patients reportedly suffer from blurred or distorted vision, for example the patient might see the moon as multiple moons and so on. In addition, the patient may experience sudden worsening of vision due to scarring of the cornea.
Since patients see repeated versions of things, they might see duplicated light making them sensitive to bright light and glare.
- Problems with corrective eyewear:
As the condition progresses, the patient suffers from increased nearsightedness or astigmatism where the eyes is unable to focus effectively, that’s why the patient may need to change his corrective eye wear frequently like eyeglasses or contacts because they are not as effective in improving vision because they do not fit properly anymore.
What are the risk factors of Keratoconus?
The cause of keratoconus is yet to be discovered, but there are some factors that increase the risk of developing keratoconus for example:
- A genetic factor meaning that a person with a relative suffering from keratoconus is more likely to have the same condition himself.
- Mechanical factor like rubbing the eyes in a vigorous manner.
- Secondary to other diseases such as Down syndrome, hay fever and asthma.
What are the complications of Keratoconus?
Patients may suffer from what is known as corneal burst which involves the breakdown of the inner lining of the cornea, allowing fluid to enter the cornea and causing sudden worsening of vision and in some cases scarring of the cornea which may require corneal transplant surgery.
How is Keratoconus diagnosed?
The process of diagnosis involves reviewing patient’s history and performing tests to asses the vision and the shape of the cornea. These tests include:
The doctor measures the reflection of a circular light focused on the patient’s cornea in order to determine the shape of the cornea.
- The slit lamp examination:
The ophthalmologist asks the patients to look into a device (a microscope) where a light beam is directed to the eye to allow the doctor to see the eye structures better and determine any pathology like signs of infection or any abnormality in the shape of the cornea and the iris. This process is done one more time after applying eyedrops to inspect the back of the eye.
- Eye refraction test:
The eye doctor uses eye devices and charts to assess the patient’s vision. The doctor might use different combinations of lenses to recognize the right combination for the patient.
- Computerized corneal mapping:
Computerized corneal mapping is a non-invasive way to map the curvature of the corneal surface. During this exam, the doctor applies eyedrops to better examine the patient’s eye and asks the patient to rest his head on the chin support for 5 minutes to record images of the cornea. This test also measures the corneal thickness.
What are the treatments of Keratoconus?
Treatment of keratoconus differs from one patient to another according to the severity and progression of the disease. Patients with mild-to-moderate Keratoconus can be treated with eyeglasses or contact lenses. However, if the cornea is scarred or the patients face difficulty in wearing contacts, the doctor will decide if a surgery is required.
- Eye glasses or soft contact lenses
The doctor might prescribe eye glasses or soft contact lenses. However, patients might need to change their prescription frequently because the cornea changes its shape continuously.
- Hard contact lenses:
These lenses allow for a better vision for progressive cases, and they can be made to fit different corneas. However, they might be uncomfortable to wear.
- Hybrid lenses:
This type of contact lenses differs in that it is hard in the middle but softer in the round edge. This increases comfort.
- Piggyback lenses:
If patients find it too uncomfortable to wear the hard lenses, the doctor might prescribe a piggyback lens which is a hard contact lens on top of a soft one.
- Scleral lenses:
Scleral lenses are used in advanced cases where the shape of the cornea is highly deformed. They rest on the sclera (the white part of the eyeball) instead of the cornea itself. It covers the cornea without directly contacting it. Patients are advised to visit the doctor regularly to make sure these lenses fit perfectly.
There are some advanced cases of keratoconus where a surgery might be needed, for example corneal scarring or extreme thinning of the cornea or poor vision. The type of surgery depends on the location of the bulging part of cornea and the severity of the condition./p>
- Corneal inserts:
The ophthalmologist places intracorneal ring segments (tiny, clear plastic inserts in the shape of half circles) into the cornea to eliminate or decrease the protrusion and improve vision. There are many advantages to this surgery as it can restore a relatively normal corneal shape. It slows the progression of the disease as well as decreasing the chances of requiring a corneal transplantation. Also, it increases tolerance for contact lenses. This surgery is reversible in the sense that the intracorneal ring segments can be removed. On the other hand, corneal inserts surgery holds risks like injury or infection of the eye.
- Cornea transplant:
– Patients with extreme corneal thinning or scarring will need corneal transplants. There are different types of corneal transplantation.
– Lamellar keratoplasty is the removal of only a part of the cornea and replacing it with a brand new donor part of cornea.
– Penetrating keratoplasty (PK) involves the full thickness of the cornea.
– The deep anterior lamellar keratoplasty (DALK) is an alternative to PK. It decreases the risk of graft rejection because the Descemet’s membrane and the endothelium are left intact in the patient’s eye. However, it may affect visual acuity.
If you are experiencing any change in your vision like blurry or duplicated vision or sensitivity to light, visit an ophthalmologist immediately to identify the problem and treat it as early as possible.