Laser vs ultrasound biometry—a study of intra- and interobserver variability

Abstract

Background Accurate biometry is of vital importance in achieving predictable postoperative refraction following cataract surgery. Aim To evaluate the accuracy and consistency in biometry, achieved by the new generation laser biometric system in comparison with the ultrasound biometric system. Methods The study was randomized and prospective. Biometry was performed in 68 eyes of 39 patients by three groups of biometrists (expert, intermediate user, novice). Expert and intermediate users are compared as group A, and expert and novice are compared in group B. Axial length, anterior chamber depth (ACD), and keratometry results are compared by t-test analysis. Results Axial length measurement variation between expert and non experts was 10 times less using laser than ultrasound (Po0.001). ACD measurement variation was also significantly less when using laser compared to ultraound (P ¼ 0.003). Need for some level of user training is indicated in ACD measurement since group A achieved more consistent readings than group B. Keratometry measurements on the laser system were unreliable due to high range of results. Biometric failure was seen in 12% of eyes undergoing laser and 1% undergoing ultrasound biometry. Conclusion Axial length determination by laser biometry is more accurate and consistent at all levels of biometrist expertise, compared to ultrasound biometry. ACD and keratometry measurements on the laser systems need some degree of user training in order to produce consistent results.

Anterior chamber width measurement by high-speed optical coherence tomography

“…These include ultrasound A scan and B scan, slit scanning, Scheimpflug photography, and laser interferometry. [22][23][24][25][26][27][28][29][30][31] This study shows that OCT also is able to make this measurement very precisely. The interimage and interrater SD were 0, which means that the variation is less than our pixel depth (8.8 μm in aqueous).…”

Agreement analysis of LENSTAR with other techniques of biometry

“…Kielhorn et al 31 showed that both experienced and inexperienced operators of the IOLMaster returned essentially similar measurements for IOL power. In constrast, Goel et al 32 reported that AL measurement variation between expert and non-expert operators for ultrasound biometry was 10 times higher compared with IOLMaster. In overcrowded ophthalmology clinics worldwide, we see clear advantages in adopting optical low-coherence reflectometry (OLCR) or partial coherence interferometry (PCI) devices in consultation sessions.…”

Beyond Cognitive Signals

“…Other examples exist in the field of eye [5] and head [6] biometry for health applications. Worth mentioning in the case of eye biometry is the laser system, which provides higher accuracy and consistency than the ultrasound system.…”