Efficacy of orbscan ii and pentacam topographers by a. Orbscan ii is a 3dimensional slitscanning topography system for analysis of the corneal anterior and posterior surfaces as well as pachymetry. Corneal changes after laser refractive surgery for myopia. Both orbscan ii and iolmaster agreed with echoscan in measuring acd. A complete orthoptic and ophthalmologic examination was performed. Orbscan orbscan manual factor data at orbscan manual measurement zone are also recorded maunal table 3. The mean horizontal corneal diameter measurements with the galilei, the eyesys and the orbscan ii were 12.
Holzman to evaluate the curvature and other dimensions of the cornea, which can tell him which procedure is right for you, as well as the degree of correction. Comparison and repeatability of keratometric and corneal. The images used to construct the anterior corneal surface,posterior corneal surface,anterior iris and anterior lens surfaces. Sep 17, 2018 orbscan orbscan manual factor data at orbscan manual measurement zone are also recorded maunal table 3. The mean postoperative pachymetry measured by us, orbscan 0. In the later version, namely the orbscan ii, the placido disc technique was incorporated to enable direct measurement of corneal curvature. Agreement between orbscan ii, vumax ubm and artemis2 very. Comparison of corneal thickness measurements using orbscan. Research article open access agreement between orbscan ii. Mar 31, 2016 the mean wtw distance measurements with the orbscan ii and itrace were 11.
Measurement of angle kappa with orbscan ii and galilei g4. The values of diff and anterior chamber depth acd were recorded. To validate the use of orbscan ii slitscanning topography for measuring posterior corneal curvature, by comparing corneal power calculations using. The orbscan ii topographer, combined slitscanning with a placido disk, has the capacity to directly acquire elevation and curvature data of both anterior and posterior corneal surfaces. It uses a slitscanning system to measure 18 000 data points and uses a placidobased system to make necessary adjustments to produce topography data. The difference of means between the orbscan ii and pentacam was 0. None of the equipment posted for sale on is owned by medwow, should you have any questions regarding a specific item, please direct them to the appropriate seller by making use of the available communication channels on the items page. Early diagnosis of keratoconus with orbscan ii anterior. Comparison of the orbscan ii topographer and the itrace aberrometer for the measurements of keratometry and corneal diameter in myopic patients. Data regarding the corneal pachymetry and anterior chamber depth. Central corneal thickness measurement with pentacam. Furthermore, the statistical model showed a marked significant difference in the orbscan ii assessment of keratectasia and change in acd p pentacam and orbscan ii before and after. Agreement between clinical history method, orbscan iiz, and. Unify triangulated and reflective data to obtain accurate surfaces in elevation, slope, and curvature.
This value was measured three times per eye and per device, and the average was retained. Holzman to evaluate the curvature and other dimensions of the cornea, which can tell him which procedure is. Orbscan ii by orbtek bausch and lomb sets a new standard for precision measurement of the anterior segment of the eye. Orbscan corneal topographer technology lasik flaum eye.
The pentacam oculus is one of a number of rotating scheimpflug imaging systems produced in germany. Corneal topography, computer assisted photokeratoscopy. Orbscan ii, ubm and artemis2 vhfus are summarized in table 2. Only a moderate level of agreement was found among these values. The new platform, which features multiple enhancements driven by more than 20 years of field use and research, is designed to serve as an indispensable screening tool to the increasing number of ophthalmic. The current version of these documents and the interpretation guide are on. Orbscan ii anterior system was used for early diagnosis of keratoconus. Comparison of corneal thickness measurements using orbscan ii.
Radius of the posterior sphere of reference the mean radius of the posterior bfs from the. Pairwise comparisons of the orbscan ii vs ubm and orbscan ii vs artemis 2 vhfus. Comparison of corneal thickness measurement with orbscan ii and ultrasonic pachymetry article pdf available in journal of refractive surgery thorofare, n. Central and peripheral corneal thickness measurement with. Evaluation of orbscan ii corneal topography in individuals. Statistical evaluation was performed using the paired t test, pearson correlation, and blandaltman analysis for comparison of measurement techniques. It uses calibrated video and a scanning slit beam to measure x, y, and z locations of several thousand points. This study aimed to determine the repeatability and reproducibility of orbscan for anterior and posterior best fit. There was a statistically significant difference between mean acd measured with the orbscan ii, ubm and artemis 2 vhfus, as determined by anova p0.
Radius of the posterior sphere of reference the mean radius of. Orbscan ii and itrace systems in 100 myopic patients. There was a statistically significant difference between mean acd measured with the orbscan ii, ubm and artemis2 vhfus, as determined by anova p0. Accuracy of orbscan ii slitscanning elevation topography.
Feb 25, 2008 the reason for higher measurements by orbscan ii pachymetry as compared to ultrasound is the difference in the manner the instruments operate. Nov 20, 20 to measure angle kappa distance with orbscan ii and galilei g4, and to evaluate possible variations in this value for different accommodation degrees. The orbscan ii mean power maps were obtained at the following paracentral zones. High reproducibility was also found for all orbscan measurements r 2 0.
Wed like to understand how you use our websites in order to improve them. Measure surface elevation directly by triangulation of backscattered slitbeam. The placido disk and 40 slits are sequentially projected on the cornea, then the anterior and posterior edges of the slits are captured and analyzed, and. Galilei, eyesys and orbscan ii measurements were compared with one another. To establish the accuracy of orbscan ii orbtek inc. Results indicated that values of diff and acd were increased in 4 eyes of 2 patients with keratoconus trend. Acd measurement differences with the 3 studied devices proved to be statistically significant. Unlike current topography systems which scan the surface of the eye at standard points, the orbscan ii acquires over 9000 data points in 1. The state of the art orbscan ii is one of the most technologically. Keratoconus with congenital cataract, high myopia and high. These results indicate the orbscan device achieves a high degree of agreement and correlation with pachymetry.
The aim was to compare the anterior chamber depth acd measurements taken with orbscan ii, ultrasound biomicroscopy ubm and the artemis2 vhf veryhighfrequency ultrasound scanner in normal subjects. In another study of orbscans ability to measure corneal thickness, researchers in. Central corneal thickness measurement by ultrasound versus. Bausch and lomb orbscan iiz corneal analysis system. Data were analyzed using the paired sample t test, blandaltman plots, and linear regression. At that time, orbscan was the only commercially available machine that could measure surface elevation of the cornea. In addition, the data from the right and left eyes were compared for each device. Doclive free unlimited document files search and download. This optical mapping or corneal topography system mapping system is a diagnostic tool that shows the overall architecture of the cornea including surface power, thickness, front and back shape. One orbscan operator performed acd measurements in all eyes first. Knowing the shape and position of both corneal surfaces allows the computation of the thickness of the entire cornea.
The orbscan ii had wide limits of agreement when compared with both the galilei 11 to 47. The middle dotted line corresponds to orgscan average bias. Pairwise comparisons of the orbscan ii vs ubm and orbscan ii. To validate the use of orbscan ii slitscanning topography for measuring posterior corneal curvature, by comparing corneal power calculations using this value with the standard keratometric method. The same patterns were obtained with the orbscan ii system for the same subject also displaying greater astigmatism of the posterior surface. For each device, the intraclass correlation coefficient for cct was. Furthermore, the statistical model showed a marked significant difference in the orbscan ii assessment of keratectasia and change in acd p orbscan ii device, the forward protrusion of the posterior corneal surface appears to coincide with a paradoxical reduction in depth of the anterior chamber. The orbscan ii also provides anterior segment data in the form of topographic surfaces. The second generation orbscan ii is a hybrid system that uses both projective slit scanning and reflective placido methods. The state of the art orbscan ii is one of the most technologically advanced corneal topography systems. Comparison of the orbscan ii topographer and the itrace. Measure surface slope directly using specular reflection, supplemented with triangulated elevation.
The wide variety of maps can make orbscan bewildering. Pdf evaluation of machine learning classifiers in keratoconus. Utilizing a scanning slit measurement system, the instrument provides the clinician with important diagnostic information about the cornea, iris, and lens. Orbscan ii measured significantly lower cct compared with pentacam 20. Orbscan corneal topographer technology lasik flaum. Oct 23, 2008 orbscan ii by orbtek bausch and lomb sets a new standard for precision measurement of the anterior segment of the eye. Central corneal thickness measurements using orbscan ii. Bausch and lomb orbscan ii topographer vsi vision systems inc. There was a statistically significant difference between mean acd measured with the orbscan ii, ubm and artemis2 vhfus, as determined by anova p 0. Refractions and orbscan ii mapping were obtained in a standard fashion preoperatively and at varying times postoperatively, when the eyes were deemed stable from lasik surgery. The mean keratometry values with the orbscan ii and itrace were 43. Central corneal thickness was measured in 203 eyes after myopic lasik. Comparison of corneal thickness measurement with orbscan ii.
Pdf repeatability and reproducibility of orbscan ii. Cornea is the most powerful refractive element of the eye contributing 43d70% of refractive power of eye. P orbscan ii is a threedimensional slitscan topography system for analysis of the corneal surfaces and anterior chamber. Since the shape of corneal surface determines its refractive power, even a minor modification of its surface can lead to significant alteration of image formed on retina.
Orbscan ii, noncontact specular microscopy, and ultrasonic pachymetry in eyes after laser in situ keratomileusis. To compare central corneal thickness measurements of three pachymetry devices in eyes after laser in situ keratomileusis lasik. The aim was to compare the anterior chamber depth acd measurements taken with orbscan. Comparison of anterior chamber depth in healthy myopic. Bausch and lomb orbscan 2 topographer model information.
Subjects having any type of ocular pathologic features or surgery or a family history of keratoconus were not included in this study. The mean wtw distance measurements with the orbscan ii and itrace were 11. The mean differences, sds, loa and pairwise comparisons using pvalues for acd measurements using the orbscan ii, ubm and artemis2 vhfus are summarized in table 2. Comparative evaluation of refractive surgery candidates with.
In this prospective study, one eye from each of 60 normal subjects was randomly selected. Pdf repeatability and reproducibility of orbscan ii researchgate. Pairwise comparisons of the orbscan ii vs ubm and orbscan ii vs artemis2 vhfus. Validation of orbscan ii posterior corneal curvature. The original version of orbscan slitscanning topography system was launched in 1995. Pdf comparison of the orbscan ii topographer and the. Three subjects dropped out of the study because they were apprehensive about the ubm examination. A topography unit is a machine that takes a specialized photo of the cornea, the front transparent window of the eye.
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