[article] in OVS : Optometry & Vision Science > vol. 96, 02 (Février 2019) . - p. 95-102 Titre : | Fixation stability with bessel beams | Type de document : | article de périodique | Auteurs : | Dipesh Bhattarai, Auteur ; Andrew J. Lambert, Auteur ; Marwan Suheimat, Auteur | Année de publication : | 2019 | Article en page(s) : | p. 95-102 | Langues : | Français (fre) | Descripteurs (mots clés) : | [Thésaurus HELB]:Paramédical:instrumentation [Thésaurus Mesh]Dépistage visuel [Thésaurus Mesh]Diagnostic par imagerie [Thésaurus Mesh]Optométrie [Thésaurus Mesh]Tests de vision
| Mots-clés : | fixation stable | Résumé : | SIGNIFICANCE Ophthalmic imaging instruments that require stable fixation can benefit by using Bessel beams in the form of monitor-based Bessel images.
PURPOSE The purpose of this study was to investigate fixation stability using laser Bessel and Gaussian beams and monitor-based images of these targets.
METHODS The right eyes of 16 participants were presented with seven fixation targets: monitor-based images of a bull's eye/cross hair, a Gaussian beam, a Bessel beam with four rings and a Bessel beam with three rings; laser Gaussian beam, laser Bessel beam with four rings, and laser Bessel beam with three rings. Participants fixated target centers for five runs, in which each run presented the seven targets for 20 seconds each. An Eye Tribe tracker sampled eye positions at 30 Hz. Standard deviations along horizontal (σx) and vertical meridians (σy) and areas of bivariate contour ellipses (BCEAs) of fixation positions were calculated, and statistical significances of target differences for these parameters were determined.
RESULTS Average σx, σy, and BCEAs ranged from 0.26 to 0.35°, 0.38 to 0.55°, and 0.78 to 1.31 degrees2, respectively. Target differences in σx (χ26 = 13.0, P = .04), (σy) (χ26 = 36.819, P < .001), and BCEA (χ26 = 34.406, P < .001) were statistically significant. There were significant post hoc differences between some of the target pairs for σy and BCEA, but not for σx. Monitor-based Bessel beam targets provided significantly smaller σy and BCEAs than the bull's eye/cross hair combination and the monitor- and laser-based Gaussian beam targets.
CONCLUSIONS Monitor-based images of Bessel beams provided better fixation targets than did a bull's eye/cross hair combination, monitor-based Gaussian images, and laser Gaussian beams, but no claim can be made that laser Bessel beams provide better fixation targets than do laser Gaussian beams. Monitor-based Bessel images should be useful for ophthalmic imaging instruments requiring stable fixation | Permalink : | https://bibliotheque.helb-prigogine.be/opac_css/index.php?lvl=notice_display&id= |
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