Evaluation of a new IOLMaster algorithm to measure axial length

PURPOSE: To evaluate the ability of the new IOLMaster with Advanced Technology version 5 software (Carl Zeiss Meditec, AG) to measure axial length (AL) in patients having preoperative cataract extraction evaluation. SETTING: Private practice, Arizona, USA. METHODS: This single-center study comprised 54 eyes (33 patients) scheduled for cataract extraction. Visual acuity, manifest refraction, and Lens Opacities Classification System III (LOCS III) scores were recorded. Twenty AL measurements per eye were acquired using an IOLMaster with Advanced Technology version 5 software. The AL measurements were analyzed and classified into 4 methods: standard, standard manipulated, composite-5, and composite-20. RESULTS: Axial length measurements were successfully obtained in 55.6%, 94.4%, 92.6%, and 96.3% of eyes with the standard, standard manipulated, composite-5, and composite-20 methods, respectively. Axial length measurement availability (ability of the software to provide an AL measurement) was not statistically significantly affected by nuclear color, nuclear opalescence, or cortical changes with any method. However, posterior subcapsular changes statistically significantly affected the standard and composite methods (P <.05) and marginally affected the standard manipulated method in measuring the AL (P = .0868). Axial length availability was significantly reduced in eyes with posterior subcapsular cataract of LOCS III grade 5.0 or higher. CONCLUSIONS: The 2 composite methods performed as well as the more time consuming, complicated standard manipulated method in measuring AL. More than 90% of eyes could be measured by the composite methods. Dense posterior subcapsular cataracts significantly reduced the ability of the composite and standard manipulated methods to Successfully measure AL.