Enhanced Penetration for Axial Length Measurement of Eyes with Dense Cataracts Using Swept Source Optical Coherence Tomography: A Consecutive Observational Study

Introduction: The aim of this study was to find cases in which the axial eye length could not be measured with partial coherence interferometry (PCI) technology and to assess if it could be measured using swept source optical coherence tomography (ss-OCT) technology. Methods: All patients were measured at their pre-assessment visit 1 week prior to cataract surgery using conventional optical biometry (PCI technology, IOLMaster 500, Carl Zeiss Meditec AG, Jena, Germany). Patients in whom one or both eyes could not be measured using PCI technology were invited to participate in the study and to be measured with the ss-OCT (IOL Master 700, Carl Zeiss Meditec AG, Jena, Germany) device. Results: Altogether, 1226 eyes of 613 patients were measured consecutively, and 78 eyes were not measured successfully with PCI technology. Among those with unsuccessfully measured eyes, 23 patients were willing to participate in the study, and two of those were also unsuccessfully measured with the ss-OCT device (8.7%, 2/23). However, 91.3% (21/23) of the eyes that were unsuccessfully scanned with PCI technology were measurable with the ss-OCT device. The estimated overall rate of unsuccessful scans with the ss-OCT device was 0.5% (6/1226) (p(chi 2) < 0.01). Conclusion: ss-OCT technology significantly improves the rate of attainable axial eye length measurements, especially in eyes with posterior subcapsular cataracts, but also in eyes with dense nuclear cataracts, except for white cataracts.