Cornea and Keratoconus

Cornea:

It is a vessel-free and transparent structure located in the front of the eye, responsible for focusing light and protecting the eye from external factors. This tissue is the most powerful focusing refractive medium of the eye. Cornea’s refractive feature allows the light coming from the external environment to focus on the retina. It has a glassy transparent and smooth texture. Although it is veinless, the nerve distribution is 300-400 times denser than the skin. Corneal nutrition is provided by oxygen in the tears and intraocular fluid. The nerve fibers stimulate the blink reflex and thus keeps the cornea constantly moist with tear, thus preserving the integrity of its surface.

Corneal transparency may be impaired after congenital, genetic or subsequent trauma, infection or surgery. If the transparency of the cornea deteriorates, the visual quality decreases. Any damage on the cornea may reduce vision as well as cause severe pain, stinging, burning and sensitivity to light. Early and correct treatment is essential as damage to the cornea will permanently affect vision. Degenerative diseases of the cornea such as dry eye, herpetic keratitis, corneal infections and keratoconus are more common conditions.

Keratoconus Treatment:

The transparent front layer of our eye is called cornea. Corneal layer is the most important optical element that determines the degree of refraction of the eye, allowing us to see the objects clearly. The cornea normally has a certain convexity. In keratoconus patients, the amount of outward swelling of the cornea gradually increases, in other words the cornea hangs forward. As a congenital feature, increased corneal convexity causes astigmatism in keratoconus patients. In this group of patients, astigmatism affects visual quality and decreases life quality severely because eye convexity is not symmetrical in the upper and lower quadrant of the corneal surface and cannot be corrected with contact lenses or glasses.

Increased sensitivity to light, double vision, glare, burning, stinging, redness, seeing rings around the lights, especially the appearance of ghost images while driving, can be listed as patient complaints.

Because keratoconus is a progressive disease, these complaints tend to increase gradually. In elderly patients, a permanent white stain occurs in the center of the cornea and keratoplasty (Corneal Transplant) becomes inevitable in this period. Irregular astigmatism affects life negatively in patients who experience the early stages of the disorder with mild adversities. It is not possible to correct this type of astigmatism with glasses. Therefore, keratoconus patients are not satisfied with the prescription glasses they are prescribed many times or may repeatedly attempt to wear contact lenses to no avail.

Application of EXCIMER LASER surgical procedures such as PRK, LASEK or LASIK to keratoconus patients would be a medical malpractice. Already weakened corneal layer would be further weakened by these surgical procedures and the disease progression would accelerate even more. This causes the vision to decline rapidly.

What are the Treatment Methods of Keratoconus?

Crosslink
Intacs (Corneal Ring) Method

Crosslink

Intacs (Corneal Ring) Method

Crosslink

CROSSLINK (CCL- CORNEAL CROSS LINKING)

Crosslink treatment strengthens the bonds between the collagen fibers in the cornea. Therefore, this treatment helps strengthen the structure of the cornea almost like a vitamin for the eye. By using Ultraviolet A and Riboflavin in drop form, the bonds between the collagen fibers in the cornea are augmented and the cornea becomes stronger. Ultraviolet A and liquid riboflavin are used for this purpose. Riboflavin is instilled into the cornea for a long period and then UV-A is applied to the cornea in order to form cross-links. Visual increase can only be due to the strengthening of the corneal structure and the decrease of the abnormal cornea steepness.

Can crosslinking treatment be used in combination with Intacs or corneal transplantation?

Yes, it can be applied in combination. Crosslinking treatment can be applied before or after Intacs treatment or after cornea transplantation. This treatment should not be considered as a separate surgical procedure, because there is no surgical intervention made to the eye, it is applied by sending ultraviolet radiation to the eye without even making contact.

Is Crosslink treatment reliable?

Adequate corneal thickness is one of the necessary criterias for this treatment. Riboflavin, which is instilled into the eye before the procedure, also infuses into the eye in order to prevent any damage to the eye.

Intacs (Corneal Ring) Method

INTACS

What is Intacs?

INTACS, also known as, corneal rings; is one of the treatment methods developed for keratoconus patients. 2 pieces of transparent semicircles are inserted into the cornea. Since these tiny rings are inserted into the eye by intralase tunneling through the laser method, they are completed in a very short time and there are no complications during the procedure. These rings are not noticeable from the outside and, most importantly, do not feel like contact lenses. The rings, which can be easily removed at any time, do not leave any permanent marks that affect the vision since they are not placed in the visual center. Rings of different thickness levels are placed according to the degree of the keratoconus disease. The purpose of placing the ring in the cornea is to return the central portion of the cornea to the normal anatomical position. With this treatment, the amount of vision without glasses will increase in keratoconus patients. The visual impairment of the patient is expected to decrease.

How is Intacs Applied?

INTACS is applied in 2 stages

Tunneling with intralase (LASER) (15 sec.)
Insertion of rings (max 5 min.)
In the postoperative period, no restriction from daily life is required. Recovery period is accompanied by the use of eyedrops for a few weeks.

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