What Is a Biometry Eye Test?

A biometry eye test is an examination to measure eye length and the power of the cornea, according to the National Center of Biotechnology Information. Data from a biometry test is used to calculate the correct power of intraocular lens implants, according to the London Eye Hospital.

The power of the lens and cornea and the length of the eye determine the refractive power of the human eye, according to NCBI. After cataract or refractive surgery, it is essential to implant an intraocular lens with the best refractive power into the individual’s eye. An accurate biometry eye test yields data that are used to determine the ideal power of the intraocular lens that gives the best refraction. Inaccuracies in this test leave the patient with a significant refractive error.

Biometry is a noninvasive procedure that takes a few minutes and is performed using either ultrasound technologies or optical coherence interferometry, according to the London Eye Hospital. In the case of ultrasound biometry, a local anesthetic eye drop is introduced into the eye before performing the test. To avoid mistakes in biometry, the doctor needs to ascertain that the machines are working optimally and use the correct formula when calculating the intraocular lens power, according to NCBI.