+200,000 Operations Performed
Prof. Dr. Efekan Coşkunseven Keratoconus & Corneal Diseases
Experience and International Reference Approach in Keratoconus Treatment
Firsts in Turkey and the World
He is a globally recognized authority in keratoconus, whose treatment protocols have served as the foundation for training numerous physicians worldwide.
Visual Rehabilitation: Specialty Contact Lenses
Once disease progression has been halted with cross-linking — or in stable cases where progression has already stopped on its own — the primary goal becomes improving visual quality. The corneal irregularities caused by keratoconus (irregular astigmatism) prevent standard spectacles from providing clear vision.
This is where specialized contact lenses come in: by effectively masking these corneal irregularities, they allow light to focus at a single point, restoring clearer vision.
Rigid Gas Permeable (RGP) Lenses
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How They Work: As the name suggests, these lenses are rigid and maintain their shape. Rather than conforming to the irregular surface of the cornea, they rest stably on top of it. The space between the inner surface of the lens and the front surface of the cornea fills with the patient's own tear film. This fluid layer — known as the "tear lens" — fills in all the peaks and valleys of the corneal surface, creating a perfectly smooth new optical surface. Light refracting through this ideal surface reaches the retina with a sharpness that glasses cannot achieve.
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Challenges: Despite the high quality of vision they provide, their rigid structure makes them less comfortable than soft lenses, and an adaptation period is required. In cases of advanced cone protrusion in particular, keeping the lens stable and centered on the eye can be difficult.
Scleral Lenses
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How They Work and How They Are Designed: Scleral lenses represent one of the most advanced contact lens technologies available today, offering a breakthrough solution for patients with advanced disease or those who cannot tolerate RGP lenses. They have a significantly larger diameter than standard lenses and take their name from the fact that they rest on the sclera — the white of the eye.
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Corneal Clearance (Vaulting): The most critical feature of scleral lenses is that they make no contact whatsoever with the sensitive, irregular corneal tissue. They vault entirely over the cornea — much like a bridge — and settle on the less sensitive scleral surface of the eye.
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Application and Fluid Reservoir: Before insertion, the bowl of the lens is completely filled with preservative-free sterile saline. Once in place, the entire anterior surface of the cornea remains submerged in this sterile fluid reservoir. This layer of liquid neutralises even the most severe surface irregularities with remarkable precision.
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Advantages:
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Because there is no contact with the cornea, scleral lenses provide exceptional comfort — patients typically experience no sensation of irritation or foreign body.
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They keep the cornea continuously hydrated throughout the day, creating both a protective and therapeutic effect — making them particularly well suited for patients with dry eye disease.
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Even in the most advanced and irregular cases, they deliver remarkable gains in visual acuity.
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Hybrid Lenses
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How They Work: These lenses are designed to combine the advantages of two different lens technologies in a single lens. The central optical zone is made from a rigid gas-permeable (RGP) material, which delivers clear, sharp vision. Surrounding this rigid center is a skirt of soft lens material, which allows the lens to sit comfortably on the eye and significantly improves wearing comfort.
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Advantage: They aim to deliver the optical quality of a rigid lens combined with the comfort of a soft lens.
