Feasibility, Reliability and Reproducability of Partial Coherence Interferometry for Axial Length Determination in High Myopic Eyes

Abstract

Abstract: : Purpose: Knowing the problems of ultrasound biometry in axial length measurement in high myopic eyes we examined whether partial coherence laser interferometry (PCLI) is able to give reliable results on this patient group. Methods: At least two axial length measurements with the Zeiss IOL Master with a signal–to–noise ratio (SNR) >2 were undertaken in consecutive patients with an axial length >26.5 mm being examined before cataract surgery. Axial length measurements and the SNR in the myopic eyes (n=54) and in 49 emmetropic eyes as a control group were analyzed. In 30 eyes the intended calculated refraction was compared with the objective postoperative refraction following intraocular lens (IOL) implantation. Results:Axial length measurements were feasible in 48/54 high myopic eyes and in 44/49 eyes with normal axial length. Reasons for failure were dense cataracts and vitreoretinal pathologies. To achieve two reliable axial length values (SNR>2) a mean number of 2.2 measurements were necessary for the myopic as well as for the emmetropic eyes. In both groups measurements were not significantly influenced by the preoperative visual acuity. In 25 out of 30 myopic eyes IOL calculation achieved a postoperative refraction within 1.0 dpt of the intended refraction. Conclusions: Partial coherence laser interferometry shows a good clinical practicability, reproducibility and plausibiliby in high myopic eyes with stable retinal situation and clear media.

Keywords: refractive error development • cataract • myopia