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Corneal topography, also known as photokeratoscopy, is a medical imaging technique used for mapping the cornea’s anterior surface. This diagnostic tool creates a map of your cornea’s surface curvature. The data collected can then be viewed in different formats including axial, sagittal and elevations view.
Why corneal topography?
The human’s cornea is responsible for more than 70% of the eyes’ focusing power? Corneal topography helps detect irregular eye conditions such as Keratoconus, Pellucid marginal degeneration (PMD), and dry eye disease. Many of those are conditions that are commonly under-diagnosed. The approach outlines and marks a well-detailed visual description of the ultimate power and the shape of the cornea examined.
Useful information analyzed through corneal topography helps your optometrist monitor, diagnose, and treat dry eye conditions and other corneal disease. The collected data is then analyzed and used by optometrists and ophthalmologists for planning eye surgery and fitting contact lenses as well. Corneal topography is also used with other tests to determine the ideal ablation pattern to be used when correcting vision.
Role of corneal topography in contact lens fitting
Corneal topography is widely used by optometrists to describe and determine the shape of the cornea. This approach is recognized as an ideal diagnostic tool for monitoring and treating the cornea for various ocular conditions. However, the topographic parameters are also used in contact lens fitting providing reliable, repeatable, and accurate details. Topographical data for different parts of the cornea help your optometrist build custom-made contact lenses with varying curvatures to match your unique corneal shape.
Corneal imaging tools help in evaluation of eye conditions such as:
• Corneal deformities
• Astigmatism (regular or irregular such as Keratoconus)
• Corneal abrasions
• Other Corneal diseases
How corneal topography works
Corneal topography is a great tool that’s used with a repeatable approach to monitor for changes over time. Progression of certain corneal conditions is examined closely with serial topography over time which provides comparative analysis for best treatment plans and management. This approach is used in conjunction with other tests to help optometrists formulate better informed and more accurate decisions for their patients.
Basic test administration procedures:
• Patient sits facing a series of symmetrically arranged rings (illuminated patterns) where a set of data points are generated.
• The series of concentrated rings focus on the patient’s cornea, and later reflected back to the digital camera located at the bowl’s center
• The ultimate topography is thereby determined by the shape taken by the indicated sequence
• A computer is used to determine the height and position of the points across your cornea. The computer is linked to the corneal topography equipment to digitize the data points and produce a pattern of your corneal shape.
• A topographical map is then drawn using graphical formats.
Routine comprehensive eye examinations are important for accurate ocular disease detection. Most people should be seen for a comprehensive routine eye examination every one to two years. However, some patients need to be seen more frequently. Speak to your eye care professional on how often you should be seen for your routine eye exam. To book your comprehensive eye exam or dry eye assessment today with one of our optometrists, please contact our Queen St location in the Beaches.