Standardization for reporting medical outcomes facilitates clinical study comparisons and has a fundamental role on reproducibility [1, 2]. In refractive surgery (RS), the first set of standards for outcomes reporting was originally proposed by Waring in 1992  and later implemented as a set of six standard figures summarizing the accuracy, efficacy, safety, and stability of a surgical procedure [4,5,6,7,8,9,10]. It is now required to include these graphs for RS manuscripts submitted to the Journal of Refractive Surgery (JRS) , the Journal of Cataract and Refractive Surgery (JCRS)  and Cornea . Other journals, such as Ophthalmology, also recommend the use of these standard graphs in their author guidelines . Due to these specifications, the reporting of outcomes of particular surgical techniques, studies, case reports or case series are standardized, and results are easily comparable between and within RS studies .
The set of six figures was recently expanded to nine graphs in order to include additional information regarding astigmatism outcomes , and a similar set of standards was recently added to cover lens-based refractive surgery . While these newer figures cover the main outcome measures for refractive surgery, in studies where astigmatism correction is a contributing feature, supplementary vectorial astigmatism analyses should be conducted [1, 2]. For astigmatism vector analyses, JRS , and JCRS  recommend using the Alpins Method [10, 12,13,14,15] reported as single-angle polar plots [1, 11]. The Alpins vector analysis method consists of a set of four graphs, and each answers specific questions related to astigmatism correction . These four graphs allow a more detailed understanding of astigmatism outcomes pre- to post-surgery, and can better identify precision in surgical results [10, 12,13,14,15]. The Alpins Method lends itself to any ocular procedure where astigmatism outcomes need to be thoroughly assessed , such as PRK, LASIK, LASEK, SMILE, incisional keratotomy, collagen cross-linking, intracorneal ring segments, as well as lens-based procedures such as Phakic IOL, cataract surgery and refractive lens exchange with multifocal IOL and/or Toric IOL, as well as the various modified surgical techniques or procedures to treat various RS complications that exist today [16,17,18,19,20,21,22,23,24,25].
The six and nine standard graph formats described above can be created by downloading free macro-enabled Microsoft Excel spreadsheets [1, 2], as well as with paid web-based and desktop software specially designed for refractive surgery outcomes analysis. In contrast, an automated specialized freeware for the production of the four standard vector analysis graphs remains unavailable, thus limiting their widespread use. In this context, we present AstigMATIC, a free standalone executable application that produces the four standardized astigmatism vector graphs as per the latest standards of refractive surgery journals. AstigMATIC should help clinicians and researchers rapidly understand clinical outcomes using the Alpins Method and will provide them with vector graphs that respect current journals standards for research publications and presentations.
Reporting and visualizing vectorial astigmatism outcomes
A growing number of journals and authors agree that reports including vectorial astigmatism should adhere to the vectorial astigmatism nomenclature first described by Alpins [10, 12,13,14,15]. The Alpins Method has been used for the last 25 years and has become a widely-accepted approach in the field with several hundred peer-reviewed publications utilizing it [10, 12,13,14,15]. The Alpins Method graphs include the following:
Target-induced astigmatism (TIA) vector: this graph shows the range of astigmatism (magnitude and axis) that the surgery intended to induce.
Surgically-induced astigmatism (SIA) vector: this graph shows the range of achieved astigmatism cylinder and axis treatment and is used to compare the achieved (SIA) astigmatism treatment to the intended (TIA) treatment.
Difference vector (DV): this graph shows remaining astigmatism and provides a summary of the astigmatic error considering both magnitude and axis. The DV is often used as an absolute measure of success and is preferably null.
Correction index (CI): this graph shows the under/overcorrection of the astigmatism treatment. The CI can also be used as a measure of success and is calculated as SIA divided by TIA. With an optimal surgical outcome it is equal to 1, and is greater and smaller than 1 if an overcorrection and undercorrection occurs, respectively.
Based on these well-established metrics [10, 12,13,14,15], AstigMATIC provides the automated production of these four recommended single-angle polar graphs. Advantages of using single-angle polar plots vs double-angle plots is that they are easily transferable to a clinical situation with corneal topography, treatment parameters, or the eye itself. Single-angle plots are also efficient and require half the space of double-angle plots . Journals will usually accept quality studies that employ either single-angle or double-angle representation, but given the above advantages, JRS and JCRS recommend the use of single-angle graphs. It is important to note that data points near 0° and 180° are not visually grouped and are on opposite sides on a single-angle polar plot. Ophthalmologists are familiar with single-angle polar plots and recognize that points near 0° are similar to points near 180° . To help visualize and group points within the same area, we added, as previously proposed elsewhere , a shaded region to highlight the areas of common orientation. The blue regions, spreading from 0 to 30 degrees and from 150 to 180 degrees, highlight against-the-rule astigmatism, the red region, spreading from 60 to 120 degrees, highlights within-the-rule astigmatism, while unshaded white regions, spreading from 30 to 60 degrees and from 120 to 150 degrees, highlight oblique astigmatism.
Of note, there are a limited number of papers that use the American National Standards Institute (ANSI) nomenclature , but the use of this nomenclature is incorrect and its use should be avoided . AstigMATIC uses the Alpins’ nomenclature as it remains the most widely used terminology and the only one that should be used in the field [10, 12,13,14,15].