To determine the effectiveness of correcting astigmatism by laser refractive surgery by a vectorial astigmatism outcome analysis that uses 3 fundamental vectors. Let i be a unit vector pointing east, j be a unit vector pointing north, and k be a unit vector pointing up. Many physical quantities are best described as vectors. The corneal keratometric sia for the toric iol calculator was also derived by applying the alpins method of vector analysis to data from surgical cases performed prior to this study. Appendix a fundamentals of vector analysis abstract the purpose of this appendix is to present a consistent but brief introduction to vector calculus.
The intended putt the path from the ball to the hole corresponds to alpins target induced astigmatism vector tia, which is the astigmatic change by magnitude and axis the surgeon. Vector analysis of 1year astigmatic outcomes from a. Mg programmed astigmatic and drafted the initial manuscript. The alpins method employs the vector analytic approach to astigmatism analysis, involving an ophthalmic surgical analysis system, called assort alpins statistical system for ophthalmic refractive surgery techniques, designed to help plan and analyze the results of refractive, corneal, and cataract surgical procedures. Dec 10, 2019 alpins method of vector analysis is recommended to detect the effectiveness of any type of astigmatic treatment.
The alpins method of astigmatism analysis has many parallels to the game of golf. Vector analysis investigation of toric intraocular lens with no deviation from the intended axis atsushi kawahara,1,2 yoshinori takayanagi1 1takayanagi clinic, kushiro, 2sapporo kato eye clinic, sapporo, hokkaido, japan aim. Full text vector analysis of astigmatism in keratoconic. Vector analysis investigation of toric intraocular lens with. In fact, vector analysis could be used to determine the astigmatic effect of the healing process itself by comparison of data at various stages in the postoperative period.
Vector and tensor analysis is a new work, first published by dover publications, inc. Vector analysis of the effects of fslasik and toric icl. The study involved 44 eyes from 44 patients who had a preoperative refractive cylinder. The book has well written, well organized, and would be an excellent addition to anyones bookshelf. His software program assort is widely used for the planning of refractive surgery and provides many derived indices. Jrs standard for reporting astigmatism outcomes of refractive. Astigmatism analysis by the alpins method sciencedirect. Noel alpins is a widely respected contributor to many international meetings, having written comprehensively on the use of astigmatism vector analysis.
Pdf slack incorporated practical astigmatism planning. Astigmatism analysis by the alpins method noel alpins, fraco, frcophth, facs abstract purpose. To our knowledge, this is the first report of vector analysis of the at torbi 709m iol. Vectors in euclidean space the coordinate system shown in figure 1. Vector analysis of manifest and corneal astigmatism in keratoconic eyes with previous icrs and cxl reveals more accuracy and predictability of manifest refraction in calculating sia. Pdf on jul 1, 2014, noel alpins and others published vector analysis with the femtosecond laser find, read and cite all the research you need on researchgate. The aim of the current study was to analyze the astigmatic changes after cataract surgery with the implantation of the acrysof toric iol alcon laboratories, inc. Standardized analyses of correction of astigmatism by. R1, wherer1 andr2 are the position vectors of pointsp1 andp2,respectively. A reanalysis of astigmatism correction british journal. The addition of two vectors a and 3 follows the parallelogram law of geometry or the triangular headtotail rule, as shown in figure a. Standardization for reporting medical outcomes facilitates clinical study comparisons and has a fundamental role on research reproducibility. Pdf vector analysis of astigmatism changes by flattening. To determine linear regression models between alpins descriptive indices and thibos astigmatic power vectors apv, assessing the validity and strength of such correlations.
It should be emphasized that this appendix cannot be seen as a textbook on vector algebra and analysis. The alpins method uses vector mathematics to determine a goal for astigmatism correction and analyze factors involved if. Standardized analyses of correction of astigmatismeydelman et al of such data. Irregular astigmatism is quantified by a vector calculation called topographic disparity. Vector analysis of the effects of fslasik and toric icl for. Calculation of 3 fundamental vectorsthe tia, sia, and difference vectorconstitutes the basis of the alpins vector analysis method. Vector analysis, rotational stability, and visual outcome.
Alpins method of vector analysis is recommended to detect the effectiveness of any type of astigmatic treatment. An introduction to tensors for students of physics and. The baileycarney method was chosen as it demonstrates the empirics ofvector analysis and can be read ily understood by those unfamiliar with the technique. Standardized analyses of correction of astigmatism by laser. The alpins methodology utilizes three principal vectors and the various ratios between them to provide an aggregate analysis for astigmatic change with parallel. Alpins vector analysis was used to evaluate astigmatic changes. Thank you for the opportunity to reply to the letter from alpins concerning our recent article in the bjo. An analysis of the astigmatic changes induced by accelerated. Thibos method which is perfect in descriptive analysis of astigmatism and alpins method which focuses on analyzing changes in. For this reason, here we introduce the notion of a. Three fundamental vectors are used in the analysis. His software program assort is widely used for the planning of refractive surgery and provides many derived indices transformations from the vector analysis of both refractive and topographic.
B unit vectors are nondenominate, have a magnitude of unity, and are used only to specify a direction. This case series prospectively assessed 62 eyes of 31 consecutive cataract patients with preoperative corneal astigmatism between 0. In summary, although both methods assess corneal or refractive astigmatism. A reanalysis of astigmatism correction british journal of. The dot product can be formed for any pair and the resulting scalar multiplied into the third vector. Pdf vector analysis, rotational stability, and visual. Like an unfamiliar software program that soon transforms into an indispensable tool, the alpins method for these clinicians becomes second. Pdf a new method of analyzing vectors for changes in. To understand the effect of astigmatism surgery by analyzing astigmatic changes according to their component parts. The alpins method, developed by australian ophthalmologist noel alpins, is a system to plan and analyze the results of refractive surgical. Vector analysis, a textbook for the use of students of mathematics and physics, founded upon the lectures of j. Mg and aw had the idea of creating the presented automated tool for astigmatism vector analysis using the alpins method. Some physical and geometric quantities, called scalars, can be fully defined by specifying their magnitude in suitable units of measure.
Vector analysis is an essential component of this refinement process. This is the second volume of a twovolume work on vectors and tensors. The alpins method of astigmatism analysis used in refractive, corneal and cataract surgery is programmed into the assort software. These four graphs allow a more detailed understanding of astigmatism outcomes pre to postsurgery, and can better identify precision in surgical results 10. Vector analysis, a textbook for the use of students of. The aim of this research was to evaluate vector analysis after implantation of toric intraocular lenses iols without deviation from the intended axis. Vector analysis of astigmatism changes by flattening. Vector analysis generalises these results onto curves, surfaces and volumes in rn example 0. This method is readily understood by using a golfing analogy because a golf putt resembles a vector which creates corneal steepening or flattening, possessing both. The sia is the overall effect of the incisions and the insertion of the toric iol. His software program assort is widely used for the planning of refractive surgery and provides many derived indices transformations.
Astigmatism analysis by the alpins methods planning. Pdf astigmatism analysis by the alpins method researchgate. B is defined as the product of the magnitudes of a and b and the sine of the angle between them. Refractive astigmatic changes were evaluated 1 week and 3 months postoperatively by vector analysis using the alpins method assort software, assort pty. Vector analysis of astigmatism correction after toric. The alpins vector analysis method consists of a set of four graphs, and each answers specific questions related to astigmatism correction. On occasions when we have taught a one semester course, we covered material. For example, the rate of movement through space can be described as speed. Vector analysis investigation of toric intraocular lens. May 07, 2015 recently, the journal of refractive surgery and ophthalmology have adopted the alpins method as part of standard refractive analysis.
This method is readily understood by using a golfing analogy because a golf putt resembles a vector which creates corneal steepening or flattening, possessing both magnitude and direction. Focus of the principal meridian with accommodation relaxed. In morlet et al s attempt to detail the use and limitations of vectors. Vector analysis, rotational stability, and visual outcome after implantation of a new aspheric toric iol article pdf available in journal of refractive surgery thorofare, n.
Vector analysis of astigmatic changes after cataract. The notion of the position vector to a point, p i, r i, and distance between. It was not our intention to give a complete overview of the history of cylinder vector analysis, which would have to take into account very early publications. Astigmatism and the analysis of its surgical correction. An introduction to vectors, vector operators and vector. A golf putt is a vector, possessing magnitude length and axis direction. A vector is a mathematical object that has both a scalar part i.
A method of astigmatism analysis by alpins may be used to determine both how much surgical change of the cornea is needed and after surgery to determine how close treatment was to the goal. Calculation of three fundamental vectors tia, sia, and difference vector constitutes the basis of the alpins vector analysis method. It considers both magnitude and orientation of astigmatism. We have, therefore, included reference table formats in appendix 2 for presentation of these data. A total planning and outcomes analysis software using the alpins method which includes graphical as well as numerical analyses for presentations and publications. In the german language, we find, for example, an article by graff. The alpins method forms the basis for astigmatism analysis methodology published by the american national standards institute and is the standard adopted by the journal of refractive surgery for analysing and reporting astigmatism results. Vector analysis of astigmatism according to the methods of alpins. Astigmatic uses a simple graphical user interface gui and allows the.
Astigmatic can be used to automatically produce the standard graphs for reporting outcomes for astigmatism correction, based on the alpins method, that are recommended by refractive surgery and ophthalmology journals 10, 12,14,15. A nonzero vector is a directed line segment drawn from a point p called its initial point to a point q called its terminal point, with p and q being distinct points. Vector analysis, which had its beginnings in the middle of the 19th century, has in recent years become an essential part of the mathematical background required of engineers, phy sicists, mathematicians and other scientists. However, the alpins method 14 vector analysis including the astigmatism orientation showed that astigmatism changed significantly, by 0.
Recently, the journal of refractive surgery and ophthalmology have adopted the alpins method as part of standard refractive analysis. Unlike other approaches to astigmatism analysis, citation needed the indices of the alpins method can be subjected to conventional forms of statistical analysis, generating averages, mean magnitudes and summated vector means, standard deviations, etc. The alpins vector analysis method consists of a set of four graphs, and each answers specific questions related to astigmatism correction 1. If a is not a null vector then ajaj is a unit vector having the same direction as a. Aw designed the simulated datafiles and performed astigmatic validation. The alpins method is a vectorial analysis that allows determination of the effectiveness of a specific astigmatic treatment. Vector analysis using mathematica overview we have already seen how to use mathematica for several different types of vector operations.
In preparing this two volume work our intention is to present to engineering and science students a modern introduction to vectors and tensors. However, this quantity is more completely described as velocity. For clarity and reference, we have set out in table 1 the original alpins method. Vector analysis of astigmatism in keratoconic eyes after. We know that the dot and cross products of two vectors can be found easily as shown in the following examples. For algebra on vectors and tensors, an index must show up twice and only twice. Patient outcomes following implantation with a trifocal. Sep 21, 2018 standardization for reporting medical outcomes facilitates clinical study comparisons and has a fundamental role on research reproducibility. Vector analysis of astigmatism changes by flattening, steepening, and torque noel a. Volume 1 is concerned with the algebra of vectors and tensors, while this volume is concerned with the geometrical. However a function on a circle is as valid as on a straight line. In addition to his many writings and lectures, he continues to investigate the vector analytic approach to astigmatism analysis that he pioneered the alpins method. Crowe distinguished scholar in residence liberal studies program and department of mathematics university of louisville autumn term, 2002 introduction permit me to begin by telling you a little about the history of the book1 on which this talk2 is based. New method of quantifying corneal topographic astigmatism that corresponds with manifest refractive cylinder.
In a recent perspective by morlet et al 1 there are a number of omissions and fundamental errors of content that lead to erroneous conclusions. Vector analysis of astigmatism changes by flattening, steepening, and torque article pdf available. Alpins and thibos vectorial astigmatism analyses scielo. The recommendations promoted by morlet et al introduce greater complexity to an already complicated.
423 22 1168 764 1096 282 1005 619 1477 789 1095 619 280 1217 401 438 1364 538 727 622 28 880 647 1118 1175 934 197 529 298 336 625 1564 192 1522 293 918 1030 1090 350 303 569 1105 1416 807 567 1154 1336