Abstract
Purpose :
Since phacoemulsification became a refractive surgery, accuracy of power calculation of intraocular lens (IOL) is essential. The aim of this study is to compare two non contact biometers, IOLMaster700® (Carl Zeiss, Germany) recently commercialized was compared to Lenstar® (Haag-Streit, Switzerland).
Methods :
This prospective study included patients referred to our center for cataract surgery in June 2015. They benefited measurement with IOLMaster700® and Lenstar®. We compared and analyzed the correlations between the different biometric eye parameters (axial length -AL-, mean keratometry, central corneal thickness, anterior chamber depth -ACD- from epithelium, crystalline lens thickness and the white to white distance). The IOL power calculated with the SRK/T and Haigis formulas was analyzed. We compared data by a paired t-test and correlations were evaluated by the Pearson correlation coefficient.
Results :
129 eyes of 129 patients were included (50.8% female). The failure rate was 0.7% for both devices.
Concerning the biometric data, there is a statistically significant difference in measurements of white to white distance (11.97mm±0.07 with IOLMaster700 vs. 12.06mm±0.07 for Lenstar, p<0.001) as well as the ACD (3.06±0.07 mm with IOLMaster700 vs. 0.07 ± 3.07mm for Lenstar, p<0.001). Others measures (AL and keratometry) wasn’t statistically different between the two devices.
With SRK/T formula, IOL power isn't different (20.94D±0.51 for IOLMaster700 vs. 20.92D±0.50 for Lenstar, p=0.51). With Haigis formula, IOL power was statistically different between the two devices (21.04D±0.52 with IOLMaster700 vs. 20.84D±0.52 for Lenstar, p<0.01). In 31.25% of cases, calculated IOL was different between the two biometers, with the formula SRKT and 52.34% with the Haigis formula. There wasn’t a significant difference in refractive errors between the two machines regardless of formula.
The correlations between the two devices for all data are high. Highest Pearson coefficient is for axial length (r=1, p<0.01), Lowest is for the white to white distance (r=0.81, p<0.01).
Conclusions :
The measurements with both devices have a very good correlation. The implant calculation between the two devices differ in 31 to 52% of cases by the formula selected, which can be disadvantageous in case of multifocality. A study on postoperative refractive results would determine the custom constants to reduce the postoperative refractive error.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.