Keratoconus

The exact cause of keratoconus is unknown, but various genetic, environmental and biochemical factors are thought to play a role in the development of the disease. Here are the possible causes and risk factors for keratoconus:

Genetic Factors

• Family History: Keratoconus may have a familial predisposition. People with a family history of keratoconus have a higher risk of developing the disease.
• Genetic Mutations: Some genetic mutations may contribute to the weakening of corneal tissue and the development of the disease.
• Environmental Factors
• Eye Rubbing: Frequent and vigorous eye rubbing can lead to corneal thinning and deformities. Eye rubbing is thought to accelerate the progression of keratoconus.
• Allergic Diseases: Eye diseases such as allergic conjunctivitis can cause itching, which can trigger eye rubbing.

Biochemical Factors

• Enzyme Imbalances: Enzyme imbalances in the cornea can lead to weakening of collagen fibers and thinning of the cornea. Increased free radical damage and decreased antioxidant defense mechanism have been observed in corneal tissues of patients with keratoconus.

Other Medical Conditions

• Connective Tissue Diseases: Connective tissue diseases such as Ehlers-Danlos syndrome and Marfan syndrome may increase the risk of keratoconus.
• Down Syndrome: Individuals with Down syndrome have a higher incidence of keratoconus.

Hormonal Changes

• Puberty and Pregnancy: Keratoconus usually begins during puberty and may be associated with changes in hormone levels. It has also been reported that the disease may progress during pregnancy.

Contact Lens Use

• Rigid Contact Lenses: The use of inappropriate hard contact lenses can trigger the development of keratoconus by causing microdamages on the corneal surface.

The interaction of multiple factors plays a role in the development of keratoconus. These factors may differ from patient to patient. The progression of the disease can be controlled with early diagnosis and appropriate treatment methods.

The disease, which starts in adolescence, begins to show symptoms in the 20s and can progress until the age of 40. After the age of 40, progression usually stops. The rate of progression varies from person to person. In some people the disease may be stabilized within a few years, while in others it progresses for years.

Earlier onset of keratoconus means that the disease can progress more rapidly. It is therefore important that patients, especially those diagnosed at a young age, are closely monitored with regular eye examinations. Early diagnosis and appropriate treatment can slow the progression of the disease and prevent serious vision loss.

 Blurred or distorted vision. They see rounded edges of some objects.

 Sensitivity to light and brightness (photophobia)

 Night vision difficulties

 Eye discomfort or irritation

 Shadows or double vision in the visual field (monocular diplopia)

 The need to change eyeglass or contact lens prescriptions frequently

The most important examination finding in keratoconus patients is the steepened cornea and corneal striations (Vogt Striae) seen under the slit lamp.

Eye measurements show high myopia and astigmatism, but vision does not improve with glasses. This is a typical finding.

Corneal Topography should be performed for definitive diagnosis. Topography shows typical findings. Topographic measurements showing both anterior and posterior steepening of the cornea are required.

Keratoconus treatment varies depending on the degree of progression of the disease and the patient's level of vision. Here are the main methods used in keratoconus treatment:

Early Stage Treatments

1. Glasses and Soft Contact Lenses:

o In the early stages, visual disturbances can be corrected with glasses or soft contact lenses.

2. Rigid Gas Permeable (RGP) Contact Lenses:

o RGP lenses can be used to correct the shape of the cornea. These lenses correct the irregular surface of the cornea and provide clearer vision.

Advanced Stage Treatments

3. Hybrid and Scleral Lenses:

o Hybrid lenses are lenses made of hard material in the center and soft material in the periphery.

o Scleral lenses provide a more comfortable fit by completely covering the cornea and sitting on the white part of the eye (sclera).

4. Corneal Cross-Linking (CCL):

o Ultraviolet (UV) light and riboflavin (vitamin B2) are used to strengthen the cornea and stop the progression of the disease. This procedure hardens the cornea by cross-linking collagen fibers in the corneal tissue.

5. Introcorneal Rings (ICRS):

o Small ring-shaped implants are placed into the cornea to help correct the shape of the cornea. This procedure can improve visual acuity and facilitate contact lens wear.

Advanced Keratoconus Treatments

6. Corneal Transplant (Keratoplasty):

o In advanced cases of keratoconus, a corneal transplant (penetrating keratoplasty or lamellar keratoplasty) may be required. This procedure involves replacing the damaged cornea with donor corneal tissue.

7. Refractive Surgery:

o Refractive surgical procedures such as LASIK or PRK are generally not recommended in patients with keratoconus, but may be appropriate in some cases. The risks and benefits of these procedures should be carefully evaluated.

Other Management Strategies

8. Avoid rubbing the eyes:

o Rubbing the eyes can contribute to the progression of keratoconus. Therefore, it is important for patients to avoid rubbing their eyes.

9. Regular Eye Checkups:

o Regular eye examinations are necessary to monitor the progression of keratoconus and adjust treatment plans as needed.

Early detection and appropriate treatment of keratoconus can help prevent vision loss and improve the patient's quality of life. Treatment options should be based on the individual needs of the patient and the degree of disease progression.

CORNEAL CROSS-LINKING (CCL) TREATMENT:

Corneal Cross-Linking (CCL) is a procedure used to treat keratoconus and other ectatic corneal diseases. CCL aims to stop the progression of the disease by strengthening the corneal tissue. This treatment method increases the firmness and stability of the cornea by creating new bonds between the collagen fibers of the cornea. Corneal Cross-Linking Procedure can be described as follows:

1. Preparation:

o The ocular surface is cleaned and sterilized.

o Topical anesthetic drops are applied to numb the eye.

2. Epithelium Removal:

o The epithelium, usually the outermost layer of the cornea, is removed during the CCL procedure.

3. Application of Riboflavin Drops:

o After the epithelium is removed, drops containing riboflavin (vitamin B2) are applied to the cornea. These drops are applied for about 30 minutes to saturate the cornea with riboflavin.

4. Ultraviolet (UV) Light Application:

o The riboflavin-impregnated cornea is exposed to ultraviolet A (UVA) light at a specific wavelength. This usually takes 30 minutes and the interaction between the riboflavin and UV light creates new bonds between the collagen fibers of the cornea.

After Treatment

• Recovery: Patients may experience discomfort, blurred vision and a foreign body sensation in the eye, usually for a few days. Eye drops and protective lenses can be used during this period.
• Follow-ups: Regular eye checks are performed after treatment. As the cornea heals, the patient's vision and the progression of keratoconus are monitored.

Efficacy: CCL is very effective in stopping the progression of keratoconus. Some patients may also experience improvement in vision quality.

Corneal Cross-Linking treatment is an effective method to stop the progression of keratoconus and is usually recommended in the early stages of the disease. This treatment method improves the patient's quality of life and can prevent progressive vision loss.