Topographers

Topography and tomography are not the same thing

Placido-based topographers map the front surface of the cornea from reflected rings. They are fast, well proven and sufficient for contact-lens fitting and routine refractive screening. Slit-scanning and Scheimpflug tomographers additionally map the posterior surface and full-corneal thickness, which is what makes them useful for detecting early keratoconus and for post-refractive assessment.

Which you need follows from the work. A practice screening refractive candidates and watching for ectasia wants posterior elevation data. A practice fitting lenses and checking astigmatism does not have to pay for it.

What to check before buying

• Calibration status against the manufacturer's reference, with a recent report.
• Software version, the analysis modules licensed, and whether updates are still available.
• Whether the treatment-plan export to your refractive laser is licensed and version-compatible.
• Condition of the cone or scanning optics and the alignment mechanism.
• Whether the workstation, monitor and table are included.
• Every unit MP MedPharma sells, new or certified refurbished, comes with documented service history and warranty coverage.