the Distometer is designed to accurately measure the vertex distance between the apex of the cornea and the surface of the spectacle Rx lens - a change in vertex distance results in a change in the effective power of the lens, this becomes especially sensitive above ± 5 D - the instrument allows you to quickly and accurately calculate the new correction necessary in the spectacle lens, to obtain the same visual acuity as was achieved with the trial lens - patients have been demanding greater Rx accuracy of custom progressive addition lenses, many of which require a vertex distance for accurate prescription calculation; this is especially true for the higher power lenses required by Low Vision patients, for use of prisms for Orthoptic exercises or Vision Therapy

• Incorrect vertex distance will change effective power of a prescription
• Avoid costly remakes and troubleshooting time by measuring vertex accurately
• With each distometer, you will receive a conversion scale for easy calculations