What is corneal topography?
Corneal topography creates a map of front-surface curvature. Corneal tomography systems may add information about the front and back surfaces and thickness. A practitioner interprets the maps with refraction and eye examination; colours and numbers should not be read in isolation.
How does it support keratoconus assessment?
Maps help identify patterns of irregularity, document measurements for future comparison and indicate when further review or referral may be needed. Final diagnosis and medical treatment decisions belong to an ophthalmologist and depend on the full clinical picture.
When may corneal imaging be requested?
It may be useful when astigmatism or spectacle prescription changes quickly, vision remains distorted despite spectacles, an irregular cornea is suspected, a rigid or scleral lens is being fitted, or change needs to be compared after a previous procedure under the treating team's guidance.
What happens during the appointment?
Symptoms, current lenses and previous reports are reviewed. You look at a fixation target while several captures are taken, and a scan may be repeated to confirm quality. Results are discussed alongside refraction and ocular-surface findings, with referral or follow-up where appropriate.
Corneal maps and specialty lens design
A map describes irregularity but does not replace a diagnostic lens trial. Designing scleral lenses or other specialty contact lenses also requires clearance, edge, movement, vision and ocular-surface assessment.
Preparing for imaging
Bring previous maps or reports, spectacles and current contact lenses. Ask before the appointment whether you need a contact-lens break, because the instructions vary with lens type and the purpose of imaging.
Corneal topography questions
What is the difference between corneal topography and tomography?
Topography maps front-surface curvature. Tomography may add information about the back surface and corneal thickness. The practitioner chooses the relevant measurement and interprets it with the examination.
Does corneal topography hurt?
Most corneal mapping systems capture measurements without touching the eye, and imaging usually takes a short time. Steps can vary with the device and clinical situation.
Can a corneal map diagnose keratoconus by itself?
No. Maps are important but must be interpreted with history, refraction, corneal examination, thickness and previous measurements when available.
Should contact lenses be stopped before corneal imaging?
Contact lenses can temporarily alter corneal shape. The required break varies by lens type and the purpose of imaging, so contact the centre for individual instructions before the appointment.