[Application and results of biometry of the eye in implantation of intraocular lenses].

Before extracapsular cataract surgery with implantation of a Binkhorst four-loop lens, keratometric readings were taken and anterior chamber depth was measured with a pachometer in 52 patients. The axial eye length was determined with A-scan echography using the Kretz technique 7200 MA unit with a 8 MHz probe and the immersion technique. The biometric control after surgery showed no change in the spherical equivalent of keratometric values. The mean anterior chamber depth was 3.19 mm (+/- 0.3 mm). No systematic correlation between anterior chamber depth before and after surgery was found. The dependence of the change in anterior chamber depth (DVK) on the cataract thickness (L) is described by the linear regression DVK = 2.22 mm - 0.47 L with a correlation coefficient as low as 0.68. The remaining refractive error after lens implantation, established by subjective testing, was compared with the calculated values. The calculated lenses were found to be more minus than the corrections required by the patients. We conclude that the calculated lens powers had been overestimated and were therefore myopizing in relation with the established length. If postoperative emmetropia had been aimed at on the basis of biometric data and conventional calculations, however, weaker lens powers would have been chosen with postoperative hypermetropia resulting.