Dr. Orwa Nasser MD MPH - Keratoconus

Keratoconus

Keratoconus is a condition in which the cornea loses its normal shape and begins to bulge out into a cone-shaped shape (conus). Over time, the cornea begins to thin, irregular astigmatism (angles, astigmatism or siliconization) develops and eyeglass prescription changes occur. If left untreated, this condition can lead to vision loss and blindness.

What causes keratoconus?
The exact cause and mechanism of keratoconus are largely unknown. Keratoconus can run in families and can occur more often in people with certain health conditions. People with keratoconus who tend to rub their eyes frequently can make the condition worse. Keratoconus usually appears in the teens or twenties, but it can also start in childhood.

What are the symptoms of keratoconus?
Continued thinning of the keratoconus leads to continuous and successive changes in the prescription of eyeglasses and to irregular astigmatism (angles, astigmatism or astigmatism). These changes lead to a gradual decrease in vision, double vision, halos and light rays, distorted vision and myopia. These changes often lead to the inability to fit eyeglasses or contact lenses. Sometimes, if the cornea becomes too thin, a sudden swelling of the cornea develops due to the accumulation of water in it and sudden loss of vision.

How is keratoconus diagnosed?
Keratoconus can be diagnosed by an eye examination and imaging of the cornea. The imaging examination of keratoconus is called topography. In this examination, the curvature of the eye surface is measured and a colored “map” of the cornea is formed. Keratoconus causes clear and prominent changes in these maps, which can be easily detected. There is another examination called tomography, which is one of the latest technologies that can detect keratoconus earlier, even before changes in the corneal topography occur.

Our eye center has a very advanced device for diagnosing keratoconus called Pentacam. This device performs a cross-sectional imaging of the cornea and produces different maps to diagnose keratoconus. The device also knows how to determine the degree of keratoconus and can track the smallest changes.
 

How is keratoconus treated?
The treatment of keratoconus focuses on two main goals: 

1. Stabilizing the Cornea and Preventing Progression:
This goal is achieved through a modern and advanced procedure known as Corneal Crosslinking (CXL). The purpose of this treatment is to strengthen and stabilize the cornea, preventing further thinning and curvature, and to slow or stop the progression of keratoconus.

Corneal crosslinking is recommended for almost all patients diagnosed with keratoconus, depending on the corneal thickness, age, and stage of the condition. It is highly advisable to perform the procedure as early as possible. It’s important to note that crosslinking does not correct vision, it serves to stabilize the disease and preserve the patient’s existing vision. At our Eye Center, the procedure is performed using the world’s most advanced crosslinking device, the AVEDRO system. This device ensures the safest, fastest, and most effective treatment, with a short recovery time and a high success rate.

The procedure is simple, safe, and performed under local anesthesia using numbing eye drops. During the treatment, Vitamin B2 (Riboflavin) drops are applied to the cornea, which is then exposed to ultraviolet (UV) light for a few minutes. The procedure is performed on an outpatient basis, requiring no hospital stay.

2. Improving Vision
Improving vision in patients with keratoconus depends on several factors, including the corneal condition, thickness, curvature, and the severity of the disease. In the early stages, vision can often be corrected with regular eyeglasses or soft contact lenses. In more advanced cases, visual improvement can be achieved with:

     - Rigid gas-permeable lenses
     - Scleral or semi-scleral lenses
     - Soft-K lenses
     - Hybrid lenses

For patients who cannot tolerate contact lenses, intra-ocular lens implantation (IOL) may be an effective solution.In severe cases, when contact lenses cannot be worn or when corneal scarring is present, corneal transplantation is the recommended treatment.

Corneal transplantation for patients with keratoconus?
Corneal transplantation is recommended in cases where vision cannot be corrected with glasses or contact lenses, or in cases where the cornea is very steep and thin, or in cases where scars appear on the cornea. There is a significant improvement in vision after a corneal transplant, although it may take more than a year for vision to stabilize. After the transplant, new glasses or contact lenses can be fitted if necessary. Some patients still need special contact lenses after a corneal transplant to get the best vision.
 

What types of corneal transplants are suitable for patients with keratoconus?
There are two main types of corneal transplants for patients with keratoconus. Based on the condition of your cornea, Dr. Orwa Nasser will advise you on the best type for you:
- DALK (Deep Anterior Lamellar Keratoplasty): In this procedure, only the outer layers of the cornea are removed and replaced with a cornea from a human donor, while preserving the healthy and effective inner layers. Many studies show less rejection of the corneal transplant in this type of procedure compared to the PKP procedure.
- PKP (Penetrating Keratoplasty): The entire cornea is transplanted with a human donor cornea.