What Is Keratoconus?
Keratoconus pronounced like KEHR-uh-toh-KOH-nus, is a tricky eye condition. It turns your normal round cornea into a bulging cone shape. Your cornea is like the camera lens of your eye. It helps focus light so you can see clearly and protects your eye from dirt, germs, and harmful sunlight. With Keratoconus, the light entering your eyedoesn't behave as it should because of this cone-shaped cornea.
What Are the Symptoms of Keratoconus?
Keratoconus comes with a bunch of symptoms, including:
Your vision gets blurry and distorted.
You might see double when you close one eye.
At night, you might see halos around lights.
Bright lights may look streaky.
Your eyes might become light-sensitive, and you could get frequent headaches. If these things sound familiar, it's time for a checkup to exclude Keratoconus.
How Can Keratoconus Affect My Life?
Keratoconus can mess with your vision, making everyday tasks like working, reading, watching TV, or driving difficult. It can stress you out, lower your self-esteem, and even take the joy out of memorable moments. Plus, it can damage playing sports and influence your personality.
How Common Is Keratoconus?
Keratoconus is more common than you might think. In the past, it was supposed to affect 1 in 2,000 people. But today, it's more like 1 in 400. This increase in numbers is due to more capability to diagnose cases that were missed before, thanks to improved technology.
What Causes Keratoconus?
The experts don't entirely agree on what causes Keratoconus, but here's what we know. It happens when the collagen fibers in your eye weaken. Collagen is like the glue that holds your cornea's shape together. When it cuts, your cornea loses its roundness and bulges like a lopsided rubber ball. One reason for this weakening could be the presence of "free radicals" in your eyes. These are bad guys produced by your corneas every day. Usually, antioxidants in your eyes keep them in check, but people with Keratoconus might not have enough antioxidants, leading to the cornea losing strength and bulging. Rubbing your eyes too much can also weaken them. A genetic link might also exist since it runs in families.
Can LASIK or RK Surgery Cause Keratoconus?
For some people, yes. LASIK or RK eye surgeries can trigger Keratoconus. These surgeries involve change to normal corneal structure; in some instances, they can lead to Corneal Ectasia. Even though LASIK screenings are better today, some patients who had the surgery in the past could still develop Keratoconus.
Are There Different Types of Keratoconus?
Absolutely! Keratoconus can come in different forms. Depending on the symptoms you're experiencing, you might have one of these types:
Forme Fruste Keratoconus is a milder version and a warning sign that the full-blown condition might be on the way. It usually only causes a few issues.
Nipple Cone Keratoconus makes your cornea form a cone shape, leading to blurry and wobbly vision.
Oval Cone Keratoconus causes your cornea to bulge into an oval shape, mainly at the bottom outer part. It might look like it's sagging.
• Pellucid Keratoconus involves thinning of the periphery of the cornea.
Globus Cone Keratoconus is the most severe form, causing your cornea to thin and bulge into a round shape.
How Is Keratoconus Diagnosed?
Doctors have several ways to diagnose Keratoconus, including:
Eye refraction uses special tools to check for vision problems.
Keratometry, where they shine a light into your cornea to measure how it reflects light and fits its shape.
Slit-lamp exams, where they shine a vertical light beam into your eye and use a microscope to look at the surface. This helps them see the shape of your cornea and spot other issues.
Corneal mapping is a high-tech technique using fancy tools to map the shape of your cornea.
Pachymetry, which measures how thick your cornea is. The tests you need depend on what your doctor has available and how severe your Keratoconus is.
How Bad Is My Keratoconus?
Eye doctors can determine how severe your Keratoconus is by looking at how steep the cones are, how thin your corneas are, and their shape.
How Can I Treat My Keratoconus?
The treatment for Keratoconus depends on what type you have. Here are some options:
For milder cases, regular eyeglasses do the trick.
Soft contact lenses can help.
Custom-made soft lenses are another option.
There are hybrid lenses that combine small rigid gas permeable (RGP) lenses with a soft skirt.
Special RGP lenses designed just for Keratoconus are available.
Some patients use small RGP lenses with a soft contact lens underneath.
Then there are large RGP lenses, also known as "Scleral" lenses.
Corneal intra corneal rings which areinserted in the cornea and remodel the abnormal shape of the cornea.
Customized laser correction regulates the abnormal shape of the cornea using laser machine.
Phakic intra ocular lenses can be implanted to help the patient achieve good vision not obtained by glasses , but it s doesn’t treat the cornea itself.
What's the Best Way to Treat Keratoconus?
There's no one-size-fits-all answer because everyone's eyes are different.
Can I Stop My Keratoconus From Getting Worse?
Like with many conditions, detecting Keratoconus early is crucial. If your treatment progresses, Corneal Crosslinking can help stop it. It's been shown to be 98% effective.
Does Keratoconus Always Get Worse?
Keratoconus worsens as you age, but there's a way to slow it down. A procedure called CXL (corneal cross-linking) can put the brakes on progressive Keratoconus. If you have it, watching it by seeing a Keratoconus specialist regularly is a good idea. Also, it might not affect both eyes the same way. If one eye is worse, they might only do the procedure on that eye and keep an eye on the other.
Does Keratoconus Cause Eye Pain?
Not always, but it can lead to discomfort. Most common Keratoconus symptoms include distorted vision , corneal thinning, bulging, or rounding. Some patients might develop corneal scarring, which could mean needing a transplant. If your eyes hurt suddenly and you have Keratoconus, don't wait – see your specialist immediately.
Can Keratoconus Go Away by Itself?
Keratoconus is a long-term eye condition that doesn't go away independently. Even if you have a corneal graft, it won't cure Keratoconus. If yours isn't too severe, special contact lenses like Scleral lenses can help you see better. These lenses rest on the white part of your eye (the Sclera) and don't touch the cornea.
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.
Diagnosis of Keratoconus
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.
Treating Keratoconus
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.
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.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.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.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.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.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.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.
Choosing the Right Treatment
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.
Preventing KC
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.