Public Education

The eye is an optical system that transforms light rays into electrical signals so the brain can perceive and recognize an image. To achieve this, the cornea and the lens refract (bend) the light rays entering the eye to focus it on the retina.

The cornea has an ellipsoid shape, allowing it to bend the light rays.

In Keratoconus (KC), there is a progressive change in the shape and characteristics of the cornea, making it thinner and more bulging, rendering it like a cone. This change in shape affects the normal role of the cornea;hence, the bending of the light rays is not perfect,leading to visual distortion. The patient complains of defective far and near vision, even with his glasses. Another complaint is seeing circles around the light sources (haloes). As the KC advances, the bulging and thinning become more prominent, making the visual symptoms worse.

The exact cause of KC is not known, yet a genetic factor can play a role. One of the major factors that contribute to the development and progression of KC is eye rubbing. Therefore, children's education about avoiding eye rubbing is crucial. KC can develop at any age, but when it starts at a younger age, medical attention is vital due to rapid progression.

The physician starts to suspect the presence of KC when the patient is not satisfied with the vision through his glasses despite all of the trials. Also, significant changes in the prescription of the glasses can raise suspicions about KC.

To reach a diagnosis for this disease, the physician usesdifferent tools to reach a definite diagnosis:
 

• Slit lamp: it s a microscope with an intense light source used to examine the patient’s eyes. It is a touchless, harmless tool. It doesn’t provide a definite diagnosis of KC but can help detect some changes in the corneal shape specific to KC.
   

• Corneal topography/tomography: an advanced investigation tool using built-in rotating cameras and discs that capture detailed pictures of the shape and the thickness of both surfaces of the cornea, hence detecting any abnormal minor change. This tool is the gold standard for diagnosing KC. It is harmless and needs no special preparation for the patient. It takes around 10 minutes to obtain a reliable picture of the cornea of both eyes.
   

• Corvis /ORA: After taking a picture of the cornea with the corneal tomography device, these investigation tools are used to assess the corneal biomechanics, which is the behavior of the cornea after being exposed to a quick touchless air puff. It provides more information concerning the strength of the cornea, and together with the corneal tomography, it helps the physician decide the adequate treatment modality and also during follow-up to evaluate whether the disease is progressing.

The aim of treating KC is that the patient obtains normal vision without distortion, even if with glasses, and to stop the progression of the disease.

In minor cases, if the patient is NOT young and can reach good vision with glasses, only regular follow-upis needed using corneal tomography. On the other hand, if the patient is young, good vision cannot be restored, or the case is advanced, other treatment modalities are available.

1. Contact lenses:
   Rigid hard CL or hybrid lenses are a type of lenses made of a special material. These lenses overcome the abnormal shape of the cornea; therefore, they can help restore good, normal vision not achieved by the glasses. The downside of these lenses is that they are a temporary treatment, as it doesn’t stop the progression of KC. Also, fitting the CL for some patients can be challenging and requires multiple visits until the patient feels comfortable.
    

2. Corneal collagen cross-linking (CXL)
   This treatment modality is effective in stopping the progression of KC. The cornea has collagen fibers,giving it strength. In KC, the cornea is weak, so this technique aims to strengthen the bonds between the collagen fibers, hence stopping or slowing the progression of KC. This is achieved by instillingRiboflavin (vitamin B2) into the patient’s eye. Underultraviolet rays, the riboflavin is activated and absorbed by the cornea, rendering it stronger. It is a simple procedure that requires the removal of the outer thin layer of the cornea called the Epithelium before the instillation of the riboflavin. The patient is left with a soft contact lens that is removed after three days when the removed epithelium is reformed. Antibiotics and steroid eye drops are used for a few weeks after this procedure. Some patients experience improvement of vision after CXL while others don’t, which is normal as this procedure aims to stop/slow the progression of KC rather than improve vision.
    

3. Intracorneal ring segments (ICR) implantation
   The idea of this surgical procedure is to introduceplastic rings in the front part of the cornea to enhance the mechanical effect and change the shape of the bulging cornea, trying to restore its normal shape or at least minimize the bulge. As a result, patients usually experience visual improvement and can , after this procedure, accept the glasses that were ineffectivebefore the insertion of the ring. To insert the ring, a small opening is made in the cornea either manually or by using a Femtolaser, and then the ring is inserted. It is a quick, simple procedure with minimal discomfort during the operation, and the patient resumes his daily activities right after.
    

4. Corneal Inlays
   A new treatment has been developed to reshape the cornea by implanting a donor corneal tissue within the cornea using the Femtolaser in a similar manner to ICR implantation to achieve the same goal. This technology is known as CAIRS.
    

5. Customized laser vision correction
   Laser vision correction is widely used and known to be used for patients with healthy cornea who are wearing glasses and willing to get rid of them. In KC, the laser machine is used for a different purpose: re-shaping the abnormal irregular bulging cornea. It has the same purpose as inserting the corneal ring segments but usesthe laser to achieve this goal instead of the mechanical effect done by the rings. In this technique, the picture of the cornea obtained by the corneal topography is uploaded to the laser machine. The laser starts to regulate the irregular surface of the cornea. Visual improvement and correction can be an extra benefit of this technique in re-shaping the abnormal cornea.
    

6. Phakic Intra-Ocular Lenses(IOLs)
   One of the options to provide KC patients with good vision not obtained with glasses is to implant a lens behind the iris ( the colored rounded structure in the eye ) and in front of the normal human lens. It is a simple surgical procedure requiring the creation of an opening in the cornea through which the IOL is inserted inside the eye and placed in the right position. The suitability of this option depends on each case upon evaluating the state of the corneal bulge and the vision.
    

7. Corneal transplantation
   If the above-mentioned treatment modalities are ineffective and the case is advanced, this major surgery is the last resort. It is done by replacing the cornea with a new, healthy one from a donor. It requires local anesthesia, and after the new cornea is placed, it is stabilized using sutures that will be removed after several weeks. It might take up to 1 year to obtain final results from this procedure.

As shown above, the treatment modalities for KC are widely varied, and the suitable treatment is specific to each case; that is why sometimes the patient can obtain different opinions regarding the treatment of his case from highly experienced physicians who are experts in the field of KC. There are different protocols for treating KC; none is known to be the only right or best treatment. Some physicians might choose to do two procedures, like inserting a ring combined with CXL, while others choose one option of them. In this case,the patient is advised to choose the treatment modality that best suits him.

KC is not an infectious disease that specific precautions or vaccinations can prevent, but raising awareness of the disease can help early detection and stop or at least slow down the progression of the disease.

• Parents who are re-diagnosed with KC should be aware of doing a routine check-up for their children as genetic factor plays a role in developing this disease.
   

• Patients who are wearing glasses, especiallychildren, should get regular follow for their vision at least once per year, as a significant change in the prescription of glasses raises suspicions of KC.
   

• Avoiding eye rubbing should be taught to children in school age as it is one the main factors in the development and progression of Kc. Also, children suffering from eye allergies should receive attention to treat the allergy so they don’t rub their eyes vigorously.