What Is Corneal Topography?

Corneal topography is a computer-assisted videokeratography (CAVK) device. Topography is the process of examining an object’s surface and creating a graphic representation of it. Corneal topography is a non-invasive technique used to map the curvature of the cornea’s surface. Since the introduction of corneal topography technology, corneal mapping has become a key tool for professional eye care practitioners. This process helps eye care doctors understand a patient’s eye health and diagnose certain corneal diseases.

What Is the Cornea?

The cornea is the transparent dome-shaped covering on the front of the eye and covers the pupil, iris, and anterior chamber of the eye. The cornea plays a key role in a patient’s vision quality and optical health. Responsible for roughly 70 percent of the eye’s optical power, the cornea works with the lens and anterior chamber to refract light.

Computer-Assisted Videokeratography (CAVK)

Computer-assisted videokeratography (CAVK) devices create a three-dimensional map of the patient’s cornea and is a simple and completely painless technique for evaluating corneal health. During a CVAK procedure, the patient is seated in front of a bowl that contains an illuminated pattern on a Placido cone disk. This pattern is typically a layering of concentric rings.

The eye care professional focuses the pattern onto the cornea’s anterior surface. The pattern is then reflected into a digital camera that is located at the center of the Placido cone, which is named after 1880 Portuguese ophthalmologist, Antonio Placido. He discovered the basic concept of reflecting rings onto the cornea to reveal the cornea’s contour lines.

The shape taken by the device’s reflected pattern reveals the cornea’s topography. Within seconds, the CAVK computer analyzes the data. This data provides the eye care professional with a grid containing thousands of points in varying heights and positions across the cornea. With this information, topographical maps can be created for evaluation by the eye care professional. Topographical maps can be displayed through several graphical formats. A sagittal map, for example, is color-coded according to the steepness of the cornea’s curvature.

What Is the Keratron?

The Keratron is a standard of reference in corneal topography technology and offers exceptional precision and test repeatability. The Keratron is able to highlight the most subtle corneal details and uses a proprietary camera and software to digitally map the cornea with thousands of numbers. The doctor utilizes this mapped data and computer aided design software to evaluate and treat various corneal conditions.

Why Use a Keratron?

The Keratron features a patented Eye Position Control System (EPCS) to capture corneal images only at the correct intended focusing distance. The system automatically corrects misalignments to ensure accuracy. The Keratron displays the patient’s tear film and still images on a large, high-resolution monitor.

The device features a Placido cone with 28 rings. The Keratron’s cone allows up to 90 percent of the corneal surface to be analyzed. The device is utilized to analyze refractive surgery candidates, diagnose corneal disease, and design custom contact lenses.