[Biometry--an exact method for the measurement of the axial length of the eye].

High-frequency ultrasound, using a 10 MHz sound probe and an immersion technique, enables the measurement of the axial length of the eye to within an accuracy of 0.1 mm. The total axial length of the anterior surface of the cornea to the vitreoretinal interface is measured by ultrasound. Many authors add a retinal thickness factor to the echographic data. Addition of this retinal factor lowers the accuracy of axial length measurements. Biometry of both eyes can detect unilateral high-grade myopia as the only reason for unilateral exophthalmos. Accurate measurements of anterior chamber depth, lens thickness and axial length are of great diagnostic importance in glaucoma and are useful in the therapeutic management of this condition. Accurate biometry and preoperative calculation of intraocular lens power are indispensable procedures in obtaining optimal post-operative results in patients subjected to intraocular lens implantation.