People also refer to corneal topography as corneal mapping, photokeratoscopy, or computer-assisted videokeratoscopy. All these refer to the same concept of producing digital images of the cornea's surface. 

The mapping tool produces a three-dimensional, color-coded map of the cornea. Eye doctors will analyze the image to determine several aspects of corneal health.

Eye doctors use a device called a corneal topographer. The device projects light onto the surface of the cornea in rings. It then collects the reflection produced by the light on the eye's surface. These reflections create the color-coded map. If you want to know more about corneal topography and its importance, read on.

What Do Ophthalmologists Use Corneal Topography For?

When a cornea is healthy, its curvatures are even, and its surface is very smooth. These are important in helping the eye focus light on the back of the eye. The cornea accounts for about 70 percent of the eye's focusing power. 

Corneal topography will reveal any irregularities in the shape of the cornea. Irregularities in the corneal surface may indicate disease, injury, or other conditions. An eye doctor can use the procedure for any of the following reasons:

• Monitoring, treating, or diagnosing conditions affecting the cornea

• Evaluation of corneal deformities or injuries

• Planning surgery for refractive errors

• Treating and evaluating astigmatism

• To determine the type of intraocular lenses for cataract surgery

• To track eye health after surgery

• Detecting keratitis, which is very infectious

• Assessing aspects affected by glaucoma

• Examining parts of the cornea

Types of Corneal Topography

There are three main types of corneal topography that ophthalmologists can use.

Placido Disc Topography

Placido disc topography systems focus on the anterior cornea. They gather information about tear film quality, irregularities, curvature, and foreign bodies. The system relies heavily on the tears that reflect the light it produces. The systems can either be large or small cone designs. 

Eye doctors prefer the small cone because it collects more detail and data points. However, large cones are much easier to use, and collecting data is easier too.

Scanning Slit-lamp and Scheimpflug Topography

These corneal topography systems provide information for the posterior and anterior cornea. They detect and manage corneal swelling. They are useful when the eye doctor deals with contact lens wearers who are affected more by this condition.

What Are the Common Topography Maps From Corneal Topography?

Axial Display Map

The axial display map is the most conventional technique for viewing the topography image. It focuses mainly on corneal power. Despite being the most conventional, eye doctors consider it less accurate. This conception arises from the fact that it produces a smooth map by collecting data averages. It determines the base curvature of a soft contact lens. 

Tangential Display Map

It is more accurate than the axial map because it provides accurate measurements of corneal curvature and power. Because of this, it is vital in fitting contact lenses like ortho-k lenses. Ophthalmologists can also use it to measure the power of a contact lens when it is on the eye. This feature is necessary when fitting multifocal lenses with different powers and meridians.

For more on why corneal topography is important, visit Clarity Vision at our offices in Holly Springs, Smithfield, Apex, Williamston, Clayton, North Carolina, or Suffolk, Virginia. Call (919) 646-2900, (919) 737-7200, (919) 367-2832, (252) 792-2250, (919) 550-4801, or (757) 638-2015 to book an appointment today.