Computerized Corneal Topography

YOUR CORNEA DELIVERS 70 PERCENT of the refracting (light bending) power of the eye. This front portion of the eye is the primary factor in focusing light on the retina at the back of the eye. When the cornea is too steep, or too flat, or is in some irregular shape, the focus does not fall properly on the retina. The result is blurred vision. Through minor modifications to the shape of the cornea, it is possible to refract light properly on the retina for clear, improved vision.

The cornea is the most pliable tissue of the eye, which is why eye doctors are working diligently to develop newer more efficient methods of reshaping it in order to improve unaided vision.

As mentioned earlier, this reshaping of the corneal by means of corneal molding does not compromise the corneal integrity. On the other hand, refractive surgical reshaping of the cornea always creates permanent irreversible changes to the corneal tissue. Why? Because tissue is permanently removed during corneal refractive surgery (LASIK and PRK). Cutting of the cornea occurs with a microkeratome and burning (removal) of corneal tissue happens with the laser ablation.

The amazing aspect of ortho-k is its ability to reduce myopia and improve unaided natural vision by molding the cornea without surgery. A key factor in the reshaping procedure is a precise analysis of the cornea. Today’s method of choice for measuring the curvature and elevations of the cornea requires a computer to analyze thousands of pieces of data for corneal topography analysis.

Computerized Corneal Topography

In the past decade computerized corneal topography has been utilized to assist eye doctors in measuring the curvature and topography of the cornea. Since the cornea is the most moldable component of the eye, it must be measured accurately for best reshaping results. This measuring procedure is called corneal mapping or corneal topography. Using a computerized camera and a computer, the subtle topographic differences in the cornea are analyzed for the doctor prior to commencing the ortho-k program of corneal reshaping. Mapping is done with a highly sophisticated computerized instrument called a Corneal Topographer.

The elevations, shape, and power changes of the cornea are displayed with sophisticated colored maps along with a variety of other computerized displays. This latest method of measuring the cornea is true state-of-the-art for analyzing the initial topography of the cornea and subsequent changes as the corneal molding therapy progresses.

Topograhy images on the computer screen

Corneal Topography testing being performed

The mapping of your cornea by computer with a specially designed camera involves color coding that displays the shape and elevations of the cornea. With a clear view of the topography of your cornea, the doctor can study and view the precise shape of your cornea. Since no two corneas are exactly alike, this topographic information is vital when and applied to the proper design of the therapeutic contact lenses.

Corneal Topography must be performed prior to treatment to establish a starting point for the therapy that follows. Topography is used to rule out any unusual abnormalities in corneal shape that could compromise the treatment. Topography is also the best method currently available by which to monitor the changes created while undergoing corneal molding.

Since the cornea is unique to each person, the shape will vary from patient to patient. During the mapping, the computer camera analyzes thousands of points on the surface of your cornea and displays these points in color on a monitor.

The mapping is generally performed with each ortho-k appointment to determine the corneal changes and the need to change your accelerated ortho-k lenses. Corneal mapping also provides information to assist in the design and custom fitting of your therapeutic lenses.