Comparison of total keratometry measurement between a swept source optical coherence tomography biometer and scheimpflug imaging
First Author: A.Carreira PORTUGAL
Co Author(s): F. Moraes D. Lopes T. Loureiro G. Alves J. Cardoso N. Campos
To assess the agreement of total keratometry measurements obtained using a Swept Source Optical Coherence Tomography (SS-OCT) biometer and anterior segment tomography with Scheimpflug camera, and to compare the prediction accuracy of refractive astigmatism of these devices.
Ophthalmology Department of Garcia de Orta Hospital, Almada, Portugal
This prospective study enrolled patients with cataract undergoing phacoemulsification surgery. Anterior chamber depth (ACD) and steep K (K2) and flat K (K1), astigmatism and axis of total and anterior corneal surface were assessed by a SS-OCT biometer (Zeiss IOLMaster 700) preoperatively and one month after surgery and were compared to the measurements obtained with Pentacam HR. Postoperative refractive astigmatism was then compared to total and anterior corneal astigmatism measured by these devices. The resulting data were analyzed by IBM SPSS Statistics V.25.0.
This study included 78 eyes of 78 patients, with a mean age of 75,35±8,25 years. Preoperatively, all values were similar between the two devices, with the exception of total K1, that was higher in IOLMaster 700 (average 43,78±1,67 vs 43,37±1,85, p<0.001). Postoperatively, all values were similar between the two devices except K1 and total K1 values, that were higher in IOLMaster 700 (average 43,58±1,60 vs 43,37±1,64, p=0.001; 43,54±1,68 vs 43,18±1,80, p<0.001, respectively). ACD was higher in IOLMaster 700 (average 3,12±0,51 vs 2,61±0,87, p<0.001). Postoperative anterior corneal astigmatism value measured by IOLMaster 700 was the closest to final refractive astigmatism.
For the majority of anterior and total keratometry measurements, IOLMaster 700 can be used interchangeably with Pentacam HR. Although postoperative anterior corneal astigmatism measured by IOLMaster 700 was the closest value to final refractive astigmatism in our study, all measurements were similar. These findings suggest that the two devices might have an equivalent prediction accuracy of patient’s final refractive astigmatism.