Comparison Between Pentacam and NIDEK AL-Scan Optical Biometer in Analysis of Anterior Segment Parameters

Abstract

SUMMARY A ccurate measurement of anterior segment parameters is essential for preoperative assessment, surgical planning, and follow up in cataract and refractive surgery. (79) The pentacam is considered one of the most comprehensive instruments for investigating the anterior segment of the eye. The pentacam images the anterior segment of the eye by a rotating scheimpflug camera. (19) The pentacam allows fast, non-contact examination of the anterior segment of the eye while the patient is setting in front of the camera. This provides good patient comfort without application of local anaesthetics and causing corneal erosions. (20) Recently, Optical biometry replaces the Ultrasound (US) biometry in the refractive surgery community due to its ability to obtain non-contact measurements regardless of the experience of the examiner. (59) In 1999, Optical biometry with partial coherence interferometry (PCI) (the IOL Master optical biometer; Carl Zeiss) was introduced into clinical practice. (59) In 2012, a new optical biometry device (The AL-Scan optical biometer; Nidek) has been introduced into clinical practice that can operate in a fully automated mode that measures all biometric parameters without realignment, It uses partial coherence interferometry (PCI) technique and Scheimpflug imaging to measures six ocular parameters in about 10 seconds : axial length(AL) , corneal keratometry (K) over 2.4 mm and 3.3 mm diameter, anterior chamber depth (ACD), central corneal thickness (CCT), white to white (WTW), and pupil diameter (PD). (58)