Topcon OM-4

The Topcon OM-4 is a used ophthalmometer, more commonly known as a manual keratometer, used to measure the curvature of the anterior surface of the cornea. It has long been a trusted instrument in optometric and contact lens fitting practices for its precision optics and mechanical reliability. This pre-owned example has been tested for proper mire alignment and function and is ready to be put back into clinical use. Operating on classic doubling-image keratometry principles, the OM-4 allows the examiner to manually align mires reflected off the corneal surface to determine corneal curvature in both principal meridians. This data is essential for fitting rigid and soft contact lenses accurately, as well as for detecting and monitoring corneal astigmatism and conditions such as keratoconus. The manual nature of the device gives experienced practitioners fine control over measurement technique, which many clinicians still prefer over fully automated systems for certain diagnostic purposes. Because manual keratometers like the OM-4 require no software updates or digital calibration cycles, they remain popular as reliable backup or primary instruments in optometry offices, teaching institutions, and contact lens fitting rooms. This unit offers an affordable path for practices to add proven keratometry capability without the higher cost of newer automated systems.