The Argos Advanced Optical Biometer (Movu; Figure 1) is a noninvasive, noncontact device designed to maximize the clinician's ease of use by streamlining biometric acquisition and minimizing discomfort for the patient. The Argos is not yet clinically available; however, according to the manufacturer, it outperformed competitor devices in clinical trials.1 The Argos consolidates the process of acquiring biometric parameters with a high success rate and accuracy, even in the densest of cataracts. It provides precise ocular biometry for accurate selection of IOLs using swept-source OCT.
With swept-source technology, a near-infrared swept laser is scanned across the patient's eye. As light is detected returning from boundary layers, an accurate reconstruction of the ocular physiology is created in the device's software. With the use of fast image reconstruction algorithms, real-time 2-D imaging of the eye is available during biometer alignment. Image acquisition for biometric and keratometric measurement takes the Argos less than 1 second, according to the company, with the device capturing six images in that span of time and generating three sets of results, calculating average and standard deviation values.
The Argos optical biometer is based on coherent optical interferometry and tomography with lateral scanning of a 1-µm swept-source beam. Keratometry (K) values are generated by illumination from a ring of 16 infrared LEDs. Using the reflected image from the LEDs in combination with the OCT signal, corneal curvature data are generated. Parameters measured include axial length (AL), central corneal thickness, anterior chamber depth, lens thickness, K values, pupil size, and toric axis.
The device is operated through a Windows-based graphical user interface. Tracking markers and a 2-D image window guide the user to achieve alignment. A joystick-mounted button is used to initiate data capture; after measurement, the technician can review the capture, assess the validity of the measurement by referring to the 2-D image, and perform fine tuning if necessary.
The sensitivity of the Argos is 10 times greater than that of other partial coherence interferometry devices, according to Movu; in Dense Cataract mode (Figure 2), it can increase sensitivity up to 100 times for AL detection, resulting in improved success rates.1
Biometry values are output in ready-to-print format, and unusual discrepancies between left and right eyes are flagged with alerts. IOL power calculations are made with the surgeon's choice of four IOL power formulas. Manufacturers' data for IOLs can be uploaded from the User Group for Laser Interference Biometry library. A desktop PC is required as a peripheral device. n
1. Argos. Movu website. http://movu-inc.com/product/. Accessed June 15, 2015.