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Irregular astigmatism

Because irregular astigmatism typically occurs in already compromised corneas, the trade-off between correcting corneal optics and preserving corneal integrity must be carefully balanced, Dr Stojanovic said. He treats HOAs first because they cannot be corrected with spectacles or soft contact lenses The causes of secondary forms of irregular astigmatism include corneal surgery, trauma, dystrophies, a Curr Opin Ophthalmol . 2000 Aug;11(4):260-6. doi: 10.1097/00055735-200008000-00007 irregular astigmatism that in which the curvature varies in different parts of the same meridian or in which refraction in successive meridians differs irregularly. lenticular astigmatism astigmatism due to defect of the crystalline lens

Astigmatism: What Is Astigmatism?

Irregular Astigmatism - ESCR

  1. Irregular astigmatism can result from conditions such as Keratoconus or other naturally occurring corneal degenerations. Corneal injuries can also cause irregular astigmatism. One of the most common causes of Irregular Astigmatism is refractive surgery. If the treatment zone is not perfectly centered, Irregular Astigmatism can occur
  2. or component and the unsatisfactory vision is mostly due to the cataract. The best treatment path would be to remove the cataract, place the implant, and take the patient's vision to where it was 10 years ago. • Cataract and anterior basement membrane dystrophy
  3. Irregular astigmatism. This is a combination of higher-order aberrations such as coma, trefoil and quadrafoil, each of which can be quantified in terms of Zernike polynomials. This is a combination of higher-order aberrations such as coma, trefoil and quadrafoil, each of which can be quantified in terms of Zernike polynomials

Micro-irregular astigmatism can be defined as irregular astigmatism with undefined patterns or irregularly irregular astigmatism. This happens when multiple irregularities come together, which can.. Irregular astigmatism will look like an asymmetric bowtie pattern on a corneal topography or Pentacam. One side of of the bowtie is flatter and the other side is steeper. Irregular astigmatism cannot be fully corrected with glasses, and sometimes not with soft contact lenses Irregular astigmatism is not as common as regular astigmatism. The surface of cornea in irregular astigmatism is not smooth, but rough with ups and downs like ridges and valley. As a result the light is not focused at one point on retina as it passes through the lens. A mild case of irregular astigmatism may cause slight blurring and distortion. Irregular astigmatism is normally the result of injury or keratoconus and occurs when the cornea is pulled into a distorted shape, due to scarring or the progression of a cone in keratoconus. The resulting shape cannot be catered for by spectacle lenses or regular soft contact lenses that mould themselves around the shape

What the Editors have accomplished is the compilation of a highly useful text that uses the unifying theme of irregular astigmatism to span a wide range of topics including wavefront optics, corneal imaging, tissue biomechanics, refractive surgery, keratoconus, lamellar and penetrating keratoplasty, vector mathematics, corneal cross-linking, and much more However, irregular astigmatism usually causes some type of distortion in your vision and neither spectacles, nor medically necessary contact lenses, correct the vision. The exact cause of irregular astigmatism without the presence of eye disease or injury is not known

Contact Lens Spectrum Irregular Astigmatism Part 3 Corneal Imaging An Introduction Pathologic Causes Of Irregular Astigmatism Astigmatism Correction Topo Guided Ablation Irregular Astigmatism How To Find Type Of Astigmatism Through Prescription Regular And Irregular Astigmatism Doctor Damien Gatinel Figure 4 From Proposed Classification For Topographic A Rational Approach To Irregular Astigmatism There are three types of regular astigmatism: Oblique — This occurs when the principal meridians are not at 90 degrees or 180 degrees. Typically, the principal... With-the-rule — The principal meridian is at 90 degrees or close to that number. The vertical meridian is also at its... Against-the-rule. Irregular astigmatism, which is less common than regular astigmatism, is often associated with prior ocular surgeries, such as radial keratotomy (RK) trauma to the eye, or eye conditions such as keratoconus. Similar to regular astigmatism, irregular astigmatism can cause vision to appear blurry or distorted

Management of irregular astigmatism - PubMe

  1. Cylinder measures what degree of astigmatism you have, or how flat or irregular the shape of your cornea is. The more your eye looks like an American football (instead of a basketball), the more astigmatism you have. Axis is measured in degrees, and refers to where on the cornea the astigmatism is located. Axis numbers go from 0 to 180
  2. Fourier Analysis of Corneal Irregular Astigmatism After Small Incision Lenticule Extraction and Comparison to Femtosecond Laser-Assisted Laser In Situ Keratomileusis. Sideroudi H, Sekundo W, Kozobolis V, Messerschmidt-Roth A, Lazaridis A Cornea 2019 Dec;38(12):1536-1542. doi: 10.1097/ICO.0000000000002029
  3. Purpose: To evaluate the safety, efficacy, and on-eye performance of new-generation hybrid contact lenses (HCLs) in visual rehabilitation of eyes with irregular astigmatism and rigid gas-permeable (RGP) contact lens intolerance or failure. Methods: The charts of patients who had been fit with new-generation HCLs were retrospectively reviewed

Irregular astigmatism definition of irregular

Irregular Astigmatism - Warren Eye Care Cente

Irregular astigmatism is when the two different curves are notperpendicular to each other(blue and red lines, Figure 2). Due to this irregularity, contact lenses need to be personalized to match these curves. The terms irregular and regular astigmatism are used to describe the curvature of the eye, not necessarily the health of the eye Astigmatism is also regular or irregular. Most cases are regular, which means that the front of the eye is oval in shape. Irregular astigmatism, on the other hand, may result from a corneal distortion, degeneration or from surgery. Scleral lenses for Irregular Astigmatism Axis of the principal meridian Regular astigmatism - principal meridians are perpendicular. (The steepest and flattest meridians of the eye are called... With-the-rule astigmatism - the vertical meridian is steepest (a rugby ball or American football lying on its side). Against-the-rule astigmatism. Ch. 21 Irregular astigmatism: LaserSight Ellipsoid model and topography-driven aspheric treatment / D.D. Liu et al Ch. 22 Treatment of irregular astigmatism: developing an ideal corneal surface with the iVIS suite / A. Stojanović, M.R. Jankov I Irregular Astigmatism: Diagnosis and Treatment. Ming Wang, ed., Thorofare, NJ: Slack Inc.; 2007. $174.95. I have to confess, my first thought before cracking the binding on this one was that it was probably not going to take the place of my summer poolside paperback. I even asked myself if this is a topic that deserves its own dedicated textbook

Irregular Astigmatism Irregular change of refractive power in different meridia Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website Purpose: To treat irregular astigmatism by applying separate appropriate treatments in each of the two distinct hemidivisions of the cornea. Setting: Cheltenham Eye Centre, Melbourne, Australia. Methods: Two general surgical strategies are presented. The first applies the principles of optimization separately to each corneal hemidivision to achieve the maximum reduction in astigmatism when. In this manner, what causes irregular astigmatism? Most astigmatism is regular corneal astigmatism, which gives the front surface of the eye an oval shape.Irregular astigmatism can result from an eye injury that has caused scarring on the cornea, from certain types of eye surgery or from keratoconus, a disease that causes a gradual thinning of the cornea Irregular Astigmatism book. Read reviews from world's largest community for readers. Since the advent of keratorefractive surgery and its rising populari.. Irregular Astigmatism: Diagnosis and Treatment is intended to help prevent and reduce the iatrogenic creation of irregular astigmatism, as well as provide effective treatment when postoperative complications do arise.Treatment technologies addressed [callisto.ro

Cylinder measures what degree of astigmatism you have, or how flat or irregular the shape of your cornea is. The more your eye looks like an American football (instead of a basketball), the more astigmatism you have. Axis is measured in degrees, and refers to where on the cornea the astigmatism is located. Axis numbers go from 0 to 180 Regular astigmatism vs irregular astigmatism, corneal curvature - A State of Sight #57 Play. Astigmatismo regular e irregular

A Rational Approach to Irregular Astigmatis

  1. Define irregular astigmatism. irregular astigmatism synonyms, irregular astigmatism pronunciation, irregular astigmatism translation, English dictionary definition of irregular astigmatism. astigmatism top: normal eye with light focusing on the retina bottom: astigmatic eye with light focusing in different places on or in front of the retina
  2. Types of Irregular Astigmatism. There are two types of irregular astigmatism: Macro-irregular astigmatism: It can be defined as irregular astigmatism with defined patterns or regularly irregular astigmatism. The primary cause of this type of astigmatism is the formation of the steep or flat area that is at least 2 mm in diameter. Micro.
  3. The fluid beneath rigid lenses, irrespective of design, will correct anterior corneal asymmetry and irregularity, whether in the form of regular corneal astigmatism or those that cause higher order aberrations and irregular astigmatism. Unlike soft toric lenses the correction does not, as a rule, depend on the orientation of the contact lens so.
  4. Irregular astigmatism in the cornea is when the curvature of the eye's surface is not perfectly round and is in fact curved unevenly. For example, it could be steeper towards the bottom of the eye and less so towards the top. It could even involve multiple configurations where the eye is curved in multiple directions
  5. Irregular astigmatism can also encompass irregularities in the surface shape of the cornea, and can result from a variety of causes, including degenerative processes (keratoconus and pellucid marginal degeneration), surgical (corneal transplants or refractive surgery), infectious (bacterial or viral ulcerative keratitis) or trauma

Many patients after PK may still need hard or gas-permeable contact lenses due to residual irregular astigmatism. Any type of refractive procedure is considered a contraindication in keratoconic patients due to the unpredictability of the outcome and risk of leading to increased and unstable irregular astigmatism Irregular Cornea: Astigmatism usually is caused by an irregularly shaped cornea. Instead of the cornea having a symmetrically round shape (like a baseball), it is shaped more like a football, with one meridian being significantly more curved than the meridian perpendicular to it

Astigmatism is termed regular when the principal meridians are at 90° to each other; otherwise, it is termed irregular. When astigmatism is present, the optical system is incapable of generating a clear image. [1 Corneal irregular astigmatism, such as asymmetry and higher order irregularity components, was the largest in eyes with oblique astigmatism, followed by those with ATR, WTR, and minimum. Irregular astigmatism definition at Dictionary.com, a free online dictionary with pronunciation, synonyms and translation. Look it up now

Pathologic Causes of Irregular Astigmatis

  1. ICD Code H52.21 is a non-billable code. To code a diagnosis of this type, you must use one of the four child codes of H52.21 that describes the diagnosis 'irregular astigmatism' in more detail
  2. H52.21 should not be used for reimbursement purposes as there are multiple codes below it that contain a greater level of detail. The 2021 edition of ICD-10-CM H52.21 became effective on October 1, 2020. This is the American ICD-10-CM version of H52.21 - other international versions of ICD-10 H52.21 may differ
  3. some of the most effective ways to plan preoperatively, manage regular and irregular astigmatism during cataract surgery, as well as managing postoperative complications. Recent findings Recent developments in technology have provided increased courses of action for astigmatism management during cataract surgery. Additional options of toric IOLs with presbyopic platforms, light adjustable.
  4. I rregular astigmatism occurs when the principle meridians are not 90 degrees apart and different parts of the same meridian have different degrees of curvature (Figure 1).Irregular astigmatism causes a reduction in the best-corrected spectacle acuity, a scissors reflex on retinoscopy and, most notably to patients, monocular diplopia, blurred vision and glare/halos
  5. irregular astigmatism is often used to describe patients with irregular corneal surfaces (Figure 1-B). Importantly, all eyes have at least a small amount of irregular astigmatism (American Academy Ophthalmolo gy, 2005) when the entire corn eal surface is assessed, but this is not relevant from a clinical point of view. Significant irregular.

Irregular astigmatism. Irregular astigmatism occurs when the two principal meridians are not placed at a right angle, but instead are opposite to one another. Irregular astigmatism is the largest reason for the cause of disease, injury, or inflammation of the cornea. Astigmatism by the rule is one where the vertical meridian refracts rays. Not Valid for Submission. 367.22 is a legacy non-billable code used to specify a medical diagnosis of irregular astigmatism. This code was replaced on September 30, 2015 by its ICD-10 equivalent Regular Astigmatism Irregular cornea or lens bend of the eye causes regular astigmatism, which is one of the types of astigmatism. In this condition, the principal meridians are consistently separated by 90 degrees from one another. For this situation, there will be a back to back variety in the refractive force, starting with one meridian then.

The term irregular astigmatism is often applied to a distorted corneal topography, whereby two major meridians may not even be easily identified; in simple terms, it can be defined as an unrefractable eye. As a consequence, visual function can be severely affected. Conventional treatments are often insufficient and/or unsatisfactory. Spectacles may lead to intolerable aniseikonia, and. Irregular Astigmatism: Diagnosis and Treatment is intended to help prevent and reduce the iatrogenic creation of irregular astigmatism, as well as provide effective treatment when postoperative complications do arise. Complications discussed include: • Decentered treatment • Small optical zone • Central island • Oblate cornea.

Astigmatism Types - Regular and Irregula

Astigmatism is common and can be classified as regular or irregular astigmatism. Learn the difference between these in this episode of A State of Sight with. Irregular astigmatism, right eye. H52.211 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes. The 2021 edition of ICD-10-CM H52.211 became effective on October 1, 2020. This is the American ICD-10-CM version of H52.211 - other international versions of ICD-10 H52.211 may differ The cause of astigmatism is unknown. It is most often present from birth. Astigmatism often occurs together with nearsightedness or farsightedness. If astigmatism gets worse, it may be a sign of keratoconus. Astigmatism is very common. It sometimes occurs after certain types of eye surgery, such as cataract surgery

Irregular astigmatism. Principal meridians that aren't perpendicular are considered irregular. Injuries or scarring also may produce irregular astigmatism in the cornea. Other causes include keratoconus, a long-term thinning of the cornea, and some forms of eye surgery. Corneal and lenticular astigmatism Astigmatism is one of the most common refractive errors found in eyes today. Dr. Teske from The Eye Doctors of New Tampa explains what it is and how it's tre.. METHODS: Retrospective analysis of 41 TE-PTK procedures in cases of irregular astigmatism after refractive surgery or with corneal irregularities. The TE-PTK ablations were performed according to preoperative epithelial thickness maps obtained using an Artemis very high-frequency digital ultrasound arc-scanner (ArcScan, Inc., Morrison, CO)

How Do I Correct Regular and Irregular Astigmatism

Astigmatism is classified in different ways and diagnosing the type of astigmatism is the most important point that should be taken into consideration before trying to correct it. 12 Totally, it is classified into two main groups that are known as regular and irregular. 13 In the regular astigmatism, there is 90-degree difference between the. Astigmatism is a common condition in which the surface of the eye, or cornea, is not curved in the normal way, resulting in blurred vision. The abnormal. New Blockchain Computer science Movies. Movies. Computer science. Blockchain. New. Search the database for a subject of technological news, tutorials or article

If you have irregular astigmatism, it's more likely to be the result of damage caused to the cornea by some form of eye injury; this form is where the curve of the cornea isn't even. It can't always be corrected using glasses, but, can sometimes be corrected with contact lenses неправильный астигматиз

521759089 - EP 3517111 A3 20191211 - COMPOSITIONS AND METHODS FOR TREATING PRESBYOPIA, MILD HYPEROPIA, AND IRREGULAR ASTIGMATISM - The present invention is directed to compositions and methods for treating ocular conditions, including presbyopia, mild hyperopia, irregular astigmatism, hyperopic accommodative esotropia, and glaucoma. The compositions can also be used to potentiate or enhance. Irregular astigmatism is quantified by a vector calculation called topographic disparity. Focus of the principal meridian. With accommodation relaxed: Simple astigmatism Simple hyperopic astigmatism - first focal line is on the retina, while the second is located behind the retina

Causes Of Irregular Astigmatism: How Can It Be Corrected

in treatments of irregular astigmatism have so far been of variable quality at best1-10 and the reasons for lesser suc-cess can probably be grouped into 3 main categories: (1) Use of preoperative measurements that do not include the relevant details of irregular astigmatism; (2) use of abla-tion-planning software that fits the desired postoperativ Irregular astigmatism in a corneal topographic map of the left eye of a patient with significant epithelial basement membrane dystrophy. The patient experienced glare and a general decline in quality of vision. Simulated K shows the flattest meridian at 39 degrees and the steeper meridian at 129 degrees N = nasal; T = temporal The irregular astigmatism must be corrected nonsurgically to allow them to function. Scleral lenses address irregular astigmatism, dry eye disease, visual function, and pain associated with this condition. Elevated lesions of the conjunctiva such as pingueculae and pterygia 3 often present challenges in fitting the patient desiring refractive. Irregular astigmatism remains a significant challenge in the daily practice of the corneal/refractive surgeon. In the book, Irregular Astigmatism: Diagnosis and Treatment, Editor Ming Wang has compiled a comprehensive offering regarding the current state of our knowledge in this challenging area.The book is comprehensive and well written, deserving the attention of all active clinicians

irregular astigmatism and toric IOL naoye As posted before, after cataract surgery in April, my right eye went from -8.5 to -1.0 with 20/40 vision (great, considering ERM and corneal HSV scar) There are two different types of astigmatism: regular and irregular. Regular astigmatism is the type most often referred to. This is an irregular shape of the eye, or football shaped eye, that is often genetic. Irregular astigmatism, on the other hand, is usually caused by damage to the eye and often requires surgery or contacts to improve If irregular astigmatism is present, this may be seen as an irregularly distorted reflection of the mires (Figure 2D). Placido disc evaluation can also be used to guide suture removal following penetrating keratoplasty. Selectively removing sutures can reduce post-operative astigmatism (Figure 2C). Figure 2

Irregular astigmatism Speciality Sigh

irregular astigmatism is not normal and is not correctable with traditional means such as glasses and contact lenses. Patients with irregular astigmatism often see distortions in the vision such as ghosting. irregular astigmatism can result from an eye injury that has caused scarring on the cornea, from certain types of eye surgery or from. H52.21 is a non-specific and non-billable diagnosis code code, consider using a code with a higher level of specificity for a diagnosis of irregular astigmatism. The code is not specific and is NOT valid for the year 2021 for the submission of HIPAA-covered transactions. Category or Header define the heading of a category of codes that may be further subdivided by the use of 4th, 5th, 6th or. Treatment of irregular astigmatism with a 213 nm solid-state, diode-pumped neodymium:YAG ablative laser Ian Anderson, MD, Donald R. Sanders, MD, PhD, Paul van Saarloos, PhD, William J. Ardrey IV, PhD Purpose: To present the outcome of photorefractive keratectomy (PRK) using a new neodymium:YAG (Nd:YAG) laser in patients with irregular astigmatism

Irregular Astigmatism: Diagnosis and Treatment : Optometry

Epithelial basement membrane dystrophy is a relatively common cause of irregular, asymmetric and unstable corneal astigmatism. In mild cases, it may minimally change the corneal topography and. Irregular astigmatism is a relatively rare form of astigmatism in which the principal meridians of the cornea are not 90 degrees apart from each other. In some cases, irregular astigmatism is caused by keratoconus or scarring of the cornea from an injury Astigmatism. Astigmatism usually is the result of irregularities in the radius of curvature of the cornea. Astigmatism is not a pathologic state, but rather a variation in anatomy; most people have some degree of astigmatism. Trauma to the cornea can cause alteration of structure, leading to irregular astigmatism

Irregular Astigmatism in Dallas, TX Insight Complete Eye

Astigmatism usually occurs when the front surface of your eye, the cornea, has an irregular curvature. Astigmatism is one of a group of eye conditions known as refractive errors and these errors cause a disturbance in the way that light rays are focused within your eye The two sets measured a significantly higher amount of corneal irregular astigmatism in dry eyes than in normal eyes. Researchers obtained topographical data from 44 subjects with dry eye and 20 normal control subjects. The team then compared spherical, regular astigmatism and irregular astigmatism (asymmetry and higher-order irregularity. Mixed astigmatism; Based on principle meridians Astigmatisms are of two types regular and irregular. Regular astigmatism: Principal meridians are perpendicular to each other. With the rule astigmatism:-Vertical meridian is steeper than horizontal meridian.-Minus is placed in horizontal meridian (-cylinder×180

Cornea TopographyCorneal Topography for the Cataract Surgeon

A simple concise presentation of Astigmatism with recent advances in treatment of this optical defect,. Irregular astigmatism: nonuniform steepening that cannot be corrected by cylindrical lens (BCVA of 20/50 or worse due to irregular astigmatism). Expected topography: steep and flat axes less or more than 90 degrees apart. With-the rule astigmatism: Steeper in the vertical meridian. Against-the-rule astigmatism: Steeper in the horizontal meridia Astigmatism is a common vision problem caused by an irregular cornea or an irregularly shaped part of your eye (its lens). This irregularity changes the way light passes through or is refracted by.

Salzmann's Nodular Corneal Degeneration: The University ofAstigmatismAstigmatism : Antelope Mall Vision Center Optometry, Palmdale

H52.219 - Irregular astigmatism, unspecified eye answers are found in the ICD-10-CM powered by Unbound Medicine. Available for iPhone, iPad, Android, and Web Irregular astigmatism induced by lenticonus is a relatively symmetrical, spherical-like aberration because the protrusion of the anterior lens surface and under sclerosis are the center. In contrast, irregular astigmatism in typical keratoconus is an asymmetrical, coma-like aberration due to the displacement of the cone.. Purpose To quantitatively investigate the time course of changes in corneal irregular astigmatism and their relation to best spectacle-corrected visual acuity (BSCVA) in eyes with keratoconus. Methods Subjects were 47 patients (57 eyes) with keratoconus who had undergone videokeratography examinations at least twice, with an interval of 1 year or longer between each examination. By means of. This condition also causes irregular astigmatism and decreased vision. Keratoglobus is a rare eye disease that causes thinning of the cornea, particularly in the peripheral areas. Keratoglobus may be associated with connective tissue diseases (diseases affecting the skin, joints, and blood vessels) such as Ehlers-Danlos Syndrome Matthew Rauen, MD of West Des Moines, Iowa (Wolfe Eye Clinic) providescases of irregular astigmatism due to anterior corneal pathology. Thefinal case is trea..

Corneal Cases That No Clinician Should Miss | CollaborativeEYE

H52.21 is a non-billable ICD-10 code for Irregular astigmatism.It should not be used for HIPAA-covered transactions as a more specific code is available to choose from below. ↓ See below for any exclusions, inclusions or special notation This will show if your astigmatism is regular or irregular. Correction of regular astigmatism with IOL is more predictable than correction of irregular astigmatism with IOL. 3) Many years ago, before the toric IOL became available, eye surgeons including myself used a precise blade (a diamond blade) to make cuts on the sides of the cornea in a.

Irregular Astigmatism Example - Astigmatism Glaucoma

Although the percentages of regular and irregular astigmatism remain quite stable over the first 9 months, at the 12 month follow up visit an increase of the irregular astigmatism percentage is noted (from 61% at 9 months, to 72% at 12 months), together with an associated decrease of the combined regular patterns (from 35% at 9 months to 24% at. Among these complications, irregular astigmatism is perhaps the most difficult to treat.The first of its kind, Irregular Astigmatism: Diagnosis and Treatment synthesizes our knowledge and understanding of irregular astigmatism and addresses state-of-the-art technology in management and treatment. Dr Astigmatic keratotomy also proves useful when treating irregular astigmatism following corneal transplant surgery. While most congenital astigmatism appears as regular (ie, the steep and flat meridians of astigmatism lie 90° away from each other), after corneal transplantation, one quadrant may be especially steep or flat in relation to its. Topography-guided photorefractive keratectomy for irregular astigmatism after small incision lenticule extraction. J Refract Surg . 2014 ; 30 (6):429-432. 10.3928/1081597X-20140508-0 How Do Doctors Test Corneal And Irregular Astigmatism? The astigmatism testing is a pretty straight forward process as long as the problem is the lens. When the distortion is due to a misshaped lens that's known as lenticular astigmatism. As soon as an eye doctor determines that you have irregular corneal astigmatism the testing becomes more.

Regular and Irregular Astigmatism: What's the Difference

ICD-10-CM Code for Irregular astigmatism, bilateral H52.213 ICD-10 code H52.213 for Irregular astigmatism, bilateral is a medical classification as listed by WHO under the range - Diseases of the eye and adnexa What is Irregular Astigmatism or Keratoconus? The shape of the cornea is distorted, thus, the Irregular Astigmatism is unpredictable. Keratoconus is a type of irregular astigmatism in which the cornea is unstable because it has unusually thin areas. This causes it to bulge or distort, causing vision to blur Stigmatism (noun) State of having stigmata. Astigmatism (noun) A defect of a lens such that light rays coming from a point do not meet at a focal point so that the image is blurred. Astigmatism (noun) A disorder of the vision, usually due to a misshapen cornea, such that light does not focus correctly on the retina causing a blurred image PURPOSE: To evaluate the customized aspheric treatment zone (CATz) topography-guided ablation for the correction of irregular astigmatism induced by initial corneal refractive surgery or corneal injury. METHODS: CATz ablation was performed on 32 eyes of 28 patients. Each procedure was performed by photorefractive keratectomy (PRK) or LASIK. The aim of this study was to evaluate the efficacy, safety, and predictability of topography-guided treatments to enhance refractive status following other corneal surgical procedures. In a prospective case series study, 28 consecutive eyes of 26 patients with irregular astigmatism after radial keratotomy, corneal transplant, small hyperopic and myopic excimer laser optical zones, and corneal.