A new non-contact optical device for ocular biometry

Neurosciences Research Institute, School of Life and Health Sciences, Aston University, Birmingham, UK.
British Journal of Ophthalmology (Impact Factor: 2.98). 05/2002; 86(4):458-62.
Source: PubMed


A new commercially available device (IOLMaster, Zeiss Instruments) provides high resolution non-contact measurements of axial length (using partial coherent interferometry), anterior chamber depth, and corneal radius (using image analysis). The study evaluates the validity and repeatability of these measurements and compares the findings with those obtained from instrumentation currently used in clinical practice.
Measurements were taken on 52 subjects (104 eyes) aged 18-40 years with a range of mean spherical refractive error from +7.0 D to -9.50 D. IOLMaster measurements of anterior chamber depth and axial length were compared with A-scan applanation ultrasonography (Storz Omega) and those for corneal radius with a Javal-Schiötz keratometer (Topcon) and an EyeSys corneal videokeratoscope.
Axial length: the difference between IOLMaster and ultrasound measures was insignificant (0.02 (SD 0.32) mm, p = 0.47) with no bias across the range sampled (22.40-27.99 mm). Anterior chamber depth: significantly shorter depths than ultrasound were found with the IOLMaster (-0.06 (0.25) mm, p <0.02) with no bias across the range sampled (2.85-4.40 mm). Corneal radius: IOLMaster measurements matched more closely those of the keratometer than those of the videokeratoscope (mean difference -0.03 v -0.06 mm respectively), but were more variable (95% confidence 0.13 v 0.07 mm). The repeatability of all the above IOLMaster biometric measures was found to be of a high order with no significant bias across the measurement ranges sampled.
The validity and repeatability of measurements provided by the IOLMaster will augment future studies in ocular biometry.

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Available from: Jacinto Santodomingo-Rubido, Jun 04, 2015
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    • "Therefore, evaluating the instruments that precisely measure anterior corneal curvature is clinically important. Currently, a number of instruments are available for assessing corneal status and measuring corneal curvature, including Scheimpflug topography, optical coherence tomography, optical lowcoherence reflectometry, partial coherence interferometry, and slit-scanning topography/pachymetry systems [1] [2] [3] [4] [5]. The Galilei Dual-Scheimpflug analyzer (Ziemer Group, Port, Switzerland) is a high-precision optical system for evaluating corneal topography; it is different from the Pentacam (Oculus), a Scheimpflug-based system that derives its surface keratometry readings from Scheimpflug images. "
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