Keratoconus

Keratoconus is an ocular disease that usually occurs at the beginning of puberty and tends to progress until the third decade of life. As a result of this disease, the normal shape of the cornea, which is round spherical, changes into a cone and and cause a significant decrease in vision. Keratoconus is a progressive disease occurs in one or both eyes, but usually both eyes are affected.

 What is keratoconus?

Keratoconus is a disorder of the eye which results in progressive thinning of the cornea and ultimately causes the cornea to weaken and bulge outward. This corneal abnormality is often in the lower half of the cornea and initially leads to astigmatism (it should be noted, however, that all cases of astigmatism are not due to keratoconus). In mild cases or in the early stages of keratoconus, eyeglasses can be used to correct astigmatism. So far, there has not been a certain treatment for slowing down the progression of keratoconus in the world. All treatments such as eyeglasses, contact lenses, intrastromal corneal ring segment have helped to correct only a part of the patient's vision.

 Young adults are susceptible to the accumulation of free oxygen radicals in their eyes. Under normal conditions, these free radicals are decomposed by the superoxide dismutase enzyme and do not harm the eyes. Some patients can not produce these protective enzymes. Eventually, the accumulation of these free radicals will damage the cornea tissue and reduce the strength of the cornea.

Signs of Keratoconus

Clinical symptoms of keratoconus are different depending on the severity of the disease. Since progression of keratoconus is gradual, it may be difficult to diagnose the disease initially. However, in some cases, the cornea can quickly progress. As the cornea becomes more irregular in shape, it causes progressive nearsightedness and irregular astigmatism to develop, creating additional problems with distorted and blurred vision. Glare and light sensitivity also may occur. Most keratoconus patients experience changes in their eyeglass prescription every time they visit their ophthalmologists in the clinic.

This surgery, introduced in the past few years, is the only way to arrest the development of the progression of Keratoconus.

It takes about an hour and takes place in the doctor's office or in the operating room. During the surgery, after removing corneal epithelium, a light sensetive eye drop, Riboflavin, a type of B vitamin, is dropped into the cornea, which then is activated by UV light (365 NM). It has been shown that this simple operation increases the transverse ligaments in the cornea collagen tissue, which ultimately increases its strength. This technique was first introduced by German ophthalmologists.

Who are good candidates for corneal cross-linking?

- Patients who have recently been diagnosed with keratoconus.

- Young and middle-aged people whose disease is progressive.

-  People with irregular corneas whose contact lenses do not fit properly on the center of their eyes.

 - Patient who has been diagnosed with keratoconus and has documented evidence of the disease progression

- The thickness of the cornea should be at least 400 microns.

- It is emphasized that the patient shouldn't be pregnant or breastfeeding.

This procedure is performed under local anesthesia using an ophthalmic anesthetic eye drop. The patient lays on the bed in the operating room and under sterile conditions. By inserting a special device, the eyelids are kept open. After removing the cornea cell surface (epithelium), a special eye drop is dropped every 3 minutes for 30 minutes and then for the next thirty minutes, UltraViolet radiation is emitted to the cornea, while every 5 minutes a drop is dropped in the eye. In newer methods, the intensity of UV radiation is increased and the radiation time is reduced to 5 to 10 minutes. At the end of surgery, a fresh bandage contact lens is applied until corneal epithelial healing takes place and the patient can come down from the bed with the eye open. Antibiotic drops, anti-inflammatory, artificial tears and analgesics are prescribed and the patient is discharged. This increases the cross-links between corneal collagen fibers and, as a result, increases the strength of the cornea.

Patient recovery rate

The studies have shown that corneal cross-linking can slow down or stop the progression of Keratoconus. It is even observed that this operation in some cases reverse the changes caused by keratoconus. The combination of collagen cross-linking and implanting INTACS lenses ( intracorneal rings) has a synergistic effect on keratoconus and its effect is far greater than INTACS implantstion done separately. It is usually necessary to wear contact lenses after cross-linking, but it seems that the process of corneal tissue destruction is inhibited by this surgery. The studies conducted in Europe shown corneal cross-linking is generally an effective and safe procedure, and in a few years that it has been done in the world, it has not needed to be repeated. Of course, longer and deeper studies are needed to investigate the need for secondary surgery.

 

Other therapies

At the early stage of keratoconus, eyeglasses or soft contact lenses may help to correct regular nearsightedness and astigmatism. But with the progression of the disease and development of irregular astigmatism eyeglasses and regular soft contact lenses designs no longer provide adequate vision correction.

The use of hard contact lenses (RGPs) is essential at this stage. The presence of these lenses on the cornea causes the irregular surface of the patient's cornea to be covered by a flat surface, which corrects refraction.

The patients who can not tolerate hard contact lenses can use Hybrid Contact lenses (a combination of hard and soft contact lenses). An example of these lenses which are known as Clearkone hybrid contact lenses is easily accessible and can provide adequate vision to the patient, while it's much more comfortable to tolerate these lenses than hard contact lenses. The use of INTACS contact lenses and MyoRing corneal implantation is a major development in the treatment of keratoconus when the patient is unable to tolerate contact lenses.

Using these rings will not only improve vision without glasses, but also better lens tolerance and prevent the progression of the disease. Ophthalmologists of Noor Eye Hospital in Tehran-Iran have provided you with more information. Stay in touch with us through our website, email, social networks or direct contact.

In the first few days after surgery, blurred vision, tearing, burning and redness of the eye may occur. Redness, tearing and burning usually resolve after a few days, but blurred vision may take several weeks for your vision to stabilize completely. Usually, from 1-3 days after the surgery, you can do your daily activities such as studying, driving, and other daily activities.

 

- Does rubbing of the eyes leads to Keratoconus?

- Is there a possibility of keratoconus transmission from parents to children?

- Which Keratoconus patients require surgery?

- How are refractive errors treated in patients with Keratoconus?

- I'm a keratoconus patient. Can I undergo LASIK surgery?

- What are the characteristics of candidates for corneal crosslinking?

- What are the new treatments for keratoconus?

 

 

 

 

- Does rubbing of the eyes leads to Keratoconus?

Rubbing of the eyes, especially in people with severe seasonal allergies, can cause Keratoconus and, in acute cases, eyelid or eye ulcers.

- Is there a possibility of keratoconus transmission from parents to children?

 In fact, the risk of developing keratoconus for siblings of a patient with Keratoconus is greater than other people, but there is no inherited pattern for transmitting this disease.

Which Keratoconus patients require surgery?

Patients with advanced Keratoconus require rapid treatments, including surgery.

- How are refractive errors treated in patients with Keratoconus?

 In some patients with Keratoconus that have nearsigthedness and no astigmatism, you can correct the refractive error by inserting the intracorneal contact lenses inside the eye without removing the normal lenses.

 - I'm a keratoconus patient. Can I undergo LASIK surgery?

People with keratoconus can not undergo refractive surgeries such as LASIK, LASEK or PRK because these surgeries make the centeral part of the cornea thinner. Since keratoconus patients have a thinner cornea than normal, surgeries such as LASIK not only do not improve their vision, but also aggravate and even worsen their vision.

- What are the characteristics of candidates for corneal crosslinking?

- Patients who have recently been diagnosed with keratoconus.

- Young and middle-aged people whose disease is progressive.

- People with irregular corneas whose contact lenses do not fit properly on the center of their eyes.

 - Patient who has been diagnosed with keratoconus and has documented evidence of the disease progression

- The thickness of the cornea should be at least 400 microns.

- It is emphasized that the patient shouldn't be pregnant or breastfeeding.

- What are the new treatments for keratoconus?

Using prescription eyeglasses, contact lenses, Ultraviolet light, corneal collagen cross-linking, Keraflex, inserting intrastromal corneal ring segments, permanent implantable contact lenses and corneal transplantation.