Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ASTIGMATISM”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 451 records · Page 25Linked to original sources
PubMed1990

Long-term results of corneal wedge resections for the correction of high astigmatism.

We retrospectively evaluated 41 corneal wedge resections, performed for the correction of high astigmatism in 40 patients who were spectacle and contact lens intolerant. Keratometric astigmatism decreased from an average of 11.7 diopters (range 5 to 22.5 D) preoperatively to 3.5 diopters (range 0 to 10 D) postoperatively, representing a mean reduction of 8.2 D (range 0 to 16.5), or 70%. The length of follow-up averaged 11 months. Twenty-five, 15 and 9 cases had a follow-up of at least 3, 5 and 10 years, respectively. In 16 cases the keratometry readings remained stable over the years. However, in 1 case of Fuchs' endothelial dystrophy (follow-up 13 years) and 5 cases of keratoconus (follow-up 3, 4, 12, 13 and 14 years) the astigmatism gradually increased during the various follow-up periods. In 3 other cases the astigmatism gradually decreased over the years. Corneal wedge resection is an effective technique for managing high corneal astigmatism. The results remain stable over the years except in some patients with keratoconus.

Adolescent↗
PubMed1998

[A prospective clinical study of correction of myopic astigmatism by combined treatment with PRK and T-incision and photoastigmatic refractive keratectomy. The results after one year].

BACKGROUND: In contrast to the correction of simple myopia there is no widely accepted technique for the correction of myopic astigmatism. Currently two techniques are available: the photoastigmatic refractive keratectomy (PARK) and the combination of arcuate keratotomies with standard PRK (PRK-T). METHODS: In two groups, 67 patients underwent a correction of myopic astigmatism in a total of 87 eyes (19 by PRK-T and 68 by PARK), and were followed for 1 year. The spherical equivalent was -6.7 D in both groups and the refractive astigmatism ranged from -1.0 to -6.5 D. The PARK procedure was performed by means of an elliptic ablation (Kertom I, Schwind) with a 5.8 x 8.1 mm zone. The PRK-T technique consisted of two arcuate keratotomies with a free optical zone of 7 mm and a standard myopic PRK at least 6 weeks later. RESULTS: The 1 year follow-up was completed in 57 out of 87 eyes included in the study. At 1 year post-operation, 83% of the PRK-T group and 80% of the PARK group had an uncorrected visual acuity of 20/40 or better. The refractive astigmatism was reduced by 76% in the PRK-T group and by 67% in the PARK group. The spherical equivalent was -0.59 +/- 1.1 D at 1 year after PRK-T and -0.28 +/- 1.04 D after PARK. In three eyes of the PARK group (6.7%) a visual loss of more than one Snellen line occurred. Two of these eyes had a preoperative myopia of more than -6 diopters. CONCLUSION: Both techniques have the potential to reduce myopic astigmatism, however, the success rate is not as high compared to spherical PRK. Also, the complication rate of 2.5% in corrections to -6 D is significantly higher than that with spherical myopic PRK.

Adult↗
PubMed2005

Vector analysis of high early postoperative astigmatism after congenital cataract surgery.

BACKGROUND: Corneal astigmatism is a well-documented finding after cataract surgery. Postoperative astigmatism is of greater importance in children than in adults, because of its adverse effect on vision development and the risk of amblyopia. The purpose of this study was to evaluate refractive outcomes in eyes- which had high early postoperative astigmatism after congenital cataract surgery. METHODS: We retrospectively reviewed the charts of 74 children (112 eyes), who underwent congenital cataract extraction with intraocular lens implantation, using limbal incision, scleral tunnel, or clear corneal incision. Thirty-two eyes of 28 children, aged 2 months to 11 years, had astigmatism of 3.0 diopters (D) or more when assessed 1 week after surgery. Changes in cylinder vector, spherical equivalent (SEQ) and defocus equivalent (DEQ) between 1 week and 5 months postoperatively were calculated for each group. RESULTS: Mean SEQ and DEQ were 0.7+/-3.5 D and 5.1+/-2.8 D, respectively, at 1 week postoperatively- and -0.2+/-3.4 D and 3.1+/-2.3 D, respectively, at 5 months postoperatively in the three groups. DEQ levels showed a significant reduction during the 5-month follow-up period (P<0.001). The mean astigmatism vector was 2.9+/-3.3 D x 93 degrees in all the three groups 1 week postoperatively- and 0.2+/-1.1 D x 153 degrees at 5 months after surgery. A significant change during 5-month follow-up in cylinder vector (P<0.02) and SEQ (P=0.01) was found after operations using scleral tunnel technique. CONCLUSION: Children- who underwent congenital cataract surgery by different surgical techniques showed a significant spontaneous reduction in DEQ values. A significant change in cylinder vector and SEQ was found after operations using scleral tunnel technique.

Astigmatism↗
PubMed1983

Goldmann applanation tonometry in patients with regular corneal astigmatism.

By averaging vertical and horizontal applanation readings from the Goldmann tonometer, we developed a simple technique that accurately measures intraocular pressure in patients with regular corneal astigmatism. This procedure eliminates the need for keratometry and oblique alignment of the applanator. When the applanator is oriented normally, with the mires displaced horizontally, intraocular pressure is underestimated for with-the-rule corneal astigmatism and overestimated for against-the-rule corneal astigmatism. The error is approximately 1 mm Hg for every 4 diopters of astigmatism. For oblique axis corneal astigmatism, the error is smaller and approaches zero when the axis is either 45 or 135 degrees.

Analysis of Variance↗
PubMed2004

Quantitative evaluation of regular and irregular corneal astigmatism in patients having overnight orthokeratology.

PURPOSE: To quantitatively assess changes in regular and irregular corneal astigmatism in patients having overnight orthokeratology. SETTING: Matsumoto Eye Clinic, Ibaraki, Japan. METHODS: A prospective study was conducted of 64 eyes of 39 patients having overnight orthokeratology for myopia. Inclusion criteria were an uncorrected visual acuity (UCVA) of 20/20 or better after treatment and a minimum follow-up of 3 months. Using Fourier series harmonic analysis, videokeratography data were decomposed into spherical component, regular astigmatism, asymmetry (tilt or decentration), and higher-order irregularity. RESULTS: Orthokeratology significantly reduced the manifest refraction from -2.60 diopters (D) +/- 1.13 (SD) to -0.17 +/- 0.31 D (P<.0001, paired t test) and improved the UCVA from 0.82 +/- 0.30 to -0.11 +/- 0.06 logMAR (P<.0001). Regular astigmatism increased significantly from 0.53 +/- 0.23 D preoperatively to 0.63 +/- 0.40 D postoperatively (P =.0206). The asymmetry component increased significantly from 0.35 +/- 0.22 D to 0.64 +/- 0.40 D (P<.0001). Higher-order irregularity did not change significantly: 0.14 +/- 0.11 D before treatment and 0.17 +/- 0.20 D after treatment (P =.2166). The amount of myopic correction correlated significantly with the increase in the asymmetry component (Pearson correlation coefficient, R = 0.40, P =.0009) but not with the increase in regular astigmatism (R = 0.24, P =.055). CONCLUSIONS: Irregular corneal astigmatism significantly increased, even in clinically successful orthokeratology cases. The effect of the changes on visual function should be studied further.

Adolescent↗
PubMed2004

Linear-long incisions with a small optical zone for the correction of astigmatism in older patients.

PURPOSE: To evaluate the efficacy of astigmatic keratotomy (AK) by paired linear (transverse)-long incisions within a small optical zone in older patients with 3.00 diopters (D) or more of astigmatism who are intolerant of contact lenses, spectacles, or both. DESIGN: Prospective, noncomparative case series. PARTICIPANTS: Twenty-one eyes (20 patients; age range, 58-87 years) treated at clinics of the Taipei Veterans General Hospital were included in this study. METHODS: Paired linear incisions (90 degrees in length) with a central optical zone (OZ) of 4.5 mm were made to correct high astigmatism in older patients. The incisions were 80% of the corneal thickness and parallel to the axis of the steepest cylinder. MAIN OUTCOME MEASURES: Refraction, keratometry, corneal topography, and visual acuity with and without correction were measured as the outcome indicators. RESULTS: The mean course of the stabilization of corneal curvature was 1.8 months. Significant improvement from a preoperative corneal astigmatism of 4.52+/-1.39 D to a postoperative value of 1.82+/-0.88 D (P<0.0001) was shown. Marked axis deviations of more than 30 degrees were observed in 5 cases and corneal perforation was observed in 1 case. When the corneal curvature stabilized, uncorrected visual acuity was improved by 2 lines or more in 15 eyes (71.4%). Spherical equivalents and best-corrected visual acuity did not change significantly. Postoperative glare was absent in all patients. CONCLUSIONS: We conclude that AK by linear-long incisions extending from a small OZ is effective and safe for correcting astigmatism.

Aged↗
PubMed2004

Corneal regular and irregular astigmatism assessed by Fourier analysis of videokeratography data in normal and pathologic eyes.

PURPOSE: To assess corneal regular and irregular astigmatism using Fourier series harmonic analysis of videokeratography data in normal subjects, as well as in subjects with pathologic and postsurgical conditions. STUDY DESIGN: Retrospective, case-control study. PARTICIPANTS: Two hundred normal eyes, 58 eyes with keratoconus, 24 eyes with suspect keratoconus, 100 eyes that underwent LASIK, 101 eyes that underwent photorefractive keratectomy (PRK), and 79 eyes that underwent penetrating keratoplasty (PK). METHODS: Videokeratography data were decomposed, using Fourier analysis, into spherical power, regular astigmatism, asymmetry, and higher order irregularity. RESULTS: The normal range of the Fourier indices was defined as the mean +/-2xstandard deviation in the normal eyes, which were 40.81-47.13 diopters (D) for spherical power, 0-1.04 D for regular astigmatism, 0.02-0.68 D for asymmetry, and 0.05-0.17 for higher order irregularity. The keratoconus and suspect keratoconus groups showed significantly greater values in all indices than did the normal group (P<0.001 or 0.0001, Mann-Whitney test with Bonferroni correction). Eyes that had undergone LASIK and PRK had significantly smaller spherical power and regular astigmatism (P<0.0001) and significantly larger asymmetry (P<0.0001) than the normal eyes. All indices were significantly greater in the PK group than in the normal group (P<0.0001). Among the eyes tested in this study, eyes with keratoconus had the largest asymmetry, whereas eyes that had undergone PK had the most irregular corneas. CONCLUSIONS: The normal range was defined for the corneal irregular astigmatism index (asymmetry and higher order irregularity) to support future studies in this field. Eyes with ocular pathologic and postsurgical conditions were evaluated using the normal range.

Adolescent↗
PubMed2004

Treatment of astigmatism-related amblyopia in 3- to 5-year-old children.

Best-corrected acuity was measured for vertical and horizontal gratings and for Lea Symbols recognition acuity in 3- to 5-year-old children with high astigmatism and in non-astigmatic children. There was significant amblyopia among astigmatic children at baseline. There was no evidence that eyeglass correction of astigmatism resulted in a reduction in amblyopia over a 4-month average treatment duration (although vision in astigmatic children was significantly improved immediately upon eyeglass correction, indicating that eyeglass correction did provide a visual benefit). Treatment outcome results are discussed in terms of both methodological issues and theoretical implications.

Amblyopia↗
PubMed1993

Postkeratoplasty astigmatism with single running suture or interrupted sutures.

In a prospective randomized clinical trial we compared astigmatism after penetrating keratoplasty with two different suture techniques between two groups of patients (38 patients). The first group (18 patients) had a 24-bite single running 10-0 nylon suture (single running suture) with postoperative suture adjustment to decrease astigmatism. The second group (20 patients) had a combination of a 16-bite running 10-0 nylon suture and eight interrupted 10-0 nylon sutures (combined running and interrupted sutures) with selective postoperative removal of interrupted sutures to decrease astigmatism. The single running suture resulted in a lower postoperative astigmatism than a combined running and interrupted suture technique (single running suture, 2.7 +/- 2.2 diopters; combined running and interrupted sutures, 3.9 +/- 2.5 diopters; P < .02). Average length of follow-up was similar in both groups (single running suture, 9.0 +/- 2.2 months and combined running and interrupted sutures, 8.4 +/- 2.2 months). Minimal length of follow-up was six months in both groups. No running sutures were broken. The adjustable single running suture technique provided greater control of astigmatism after penetrating keratoplasty than a technique using a combination of a 16-bite running suture and eight interrupted sutures.

Adult↗
PubMedDate not supplied

Detection and classification of mild irregular astigmatism in patients with good visual acuity.

Videokeratography has been available for a decade, and this test is essential for determining the presence and type of irregular corneal astigmatism. Three eyes diagnosed with myopic astigmatism and considered good candidates for refractive surgery with conventional examination were studied. Color-coded maps with videokeratography showed regular astigmatism in one eye and the existence of irregular astigmatism in two eyes. Videokeratography showed that one of these eyes had a keratoconus suspect pattern and the second showed a pattern consistent with pellucid marginal degeneration. Videokeratography can detect and classify irregular astigmatism in cases where routine examination shows no abnormal findings.

Adolescent↗
PubMed2003

Amblyopia in astigmatic preschool children.

Best-corrected acuity was measured for vertical and horizontal gratings and for recognition acuity optotypes (Lea Symbols) in a group of three- to five-year-old children with a high prevalence of astigmatism. Results showed meridional amblyopia (MA) among children with simple/compound myopic or mixed astigmatism, due to reduced acuity for horizontal gratings. Children with simple/compound hyperopic astigmatism showed no MA, but did show reduced acuity for both grating orientations. Reduced best-corrected recognition acuity was shown by both myopic/mixed and hyperopic astigmats. These results suggest that optical correction of astigmatism should be provided prior to age three to five years, to prevent development of amblyopia.

Amblyopia↗
PubMed1985

Pterygia as cause of post-cataract with-the-rule astigmatism.

Pterygia often induce with-the-rule astigmatism as they invade the cornea. Significant amounts of astigmatism occur long before a pterygium encroaches on the visual axis. We present an example in which a 3.3-mm pterygium resulted in 9 diopters (D) of with-the-rule astigmatism. Six weeks after the pterygium removal, the patient's cornea became spherical, but by three months the pterygium had recurred 2.2 mm onto the cornea and induced 4 D of with-the-rule astigmatism. Since the second removal and the application of beta irradiation, there has been no recurrence. The final correction was -1.00 + 1.00 X 127 degrees with a visual acuity of 20/20 +3. Characteristic keratoscopic photographs are shown and contrasted with surgically induced with-the-rule astigmatism.

Astigmatism↗
PubMed2000

Effects of pterygium on corneal spherical power and astigmatism.

OBJECTIVE: To evaluate prospectively the corneal refractive status before and after pterygium surgery and its relationship with preoperative pterygium size. DESIGN: Prospective, nonrandomized, comparative (self-controlled) trial. PARTICIPANTS: One hundred thirty-six eyes undergoing primary pterygium removal surgery. MAIN OUTCOME MEASURES: Corneal spherical power, astigmatism, surface regularity index (SRI), and surface asymmetry index (SAI) before and after surgery, and the preoperative pterygium size. RESULTS: Before surgery, pterygium size significantly correlated with spherical power (Pearson's correlation coefficient, r = -0.370, P < 0.001), astigmatism (r = 0.600, P < 0.001), SRI (r = 0.367, P < 0.001), and SAI (r = 0.387, P < 0.001). The surgery significantly increased spherical power of the cornea, whereas astigmatism, SRI, and SAI were significantly decreased by the surgery (P < 0.01, paired t test with Bonferroni's correction of P value for multiple comparison). Surgically induced changes in spherical power (r = 0.598, P < 0.001) and astigmatism (r = 0.653, P < 0.001) significantly correlated with the preoperative pterygium size. Precise prediction of the magnitude of refractive changes based on the preoperative pterygium size was difficult. CONCLUSIONS: The presence of pterygium and its removal significantly influence the corneal refraction including spherical power, astigmatism, asymmetry, and irregularity, with the larger pterygium exerting the greater influence.

Adult↗
PubMed2000

Treatment of myopia and myopic astigmatism by customized laser in situ keratomileusis based on corneal topography.

OBJECTIVE: To evaluate the predictability, efficacy, and safety of customized laser in situ keratomileusis (LASIK) based on corneal topography in myopia and myopic astigmatism. DESIGN: Prospective, noncomparative interventional case series. PARTICIPANTS: One hundred fourteen patients (eyes) with myopia of -1 to -6 diopters (D) and astigmatism of 0 to -4 D (low myopia group), and 89 patients (eyes) with myopia of -6.10 to -12.00 D and astigmatism of 0 to -4.00 D (high myopia group). INTERVENTION: LASIK was performed with the Hansatome Microkeratome and the Keracor 217 spot-scanning excimer laser (Bausch & Lomb Surgical Technolas, Munich, Germany). Individual ablation patterns were calculated on the basis of elevation data obtained with the Orbscan II corneal topography system (Bausch & Lomb Surgical, Irvine, CA). MAIN OUTCOME MEASURES: Manifest spectacle refraction, visual acuity, and change in visual acuity at 3 months after surgery. RESULTS: At 3 months, 51 patients in the low myopia group and 40 patients in the high myopia group were available. In the low (high) myopia group, 96.1% (75.0%) were within +/-0.50 D of emmetropia, and uncorrected visual acuity was 20/20 or better in 82.4% (62.5%), 20/25 or better in 98.0% (70.0%), and 20/40 or better in 100% (95.0%). A loss of two or more lines of spectacle-corrected visual acuity occurred in 3.9% of the low and 5. 0% of the high myopia group. In low myopia, spectacle-corrected visual acuity was 20/12.5 or better in 5.9% preoperatively and in 13.7% at 3 months and 20/15 or better in 37.3% and 47.1%, respectively. Differences were statistically significant. CONCLUSIONS: The customized LASIK based on corneal topography used in this study showed high predictability and efficacy in myopia and myopic astigmatism of -1.00 to -6.00 D, and could possibly improve spectacle-corrected visual acuity in myopia of -1.00 to -6.00 D. Predictability and efficacy were somewhat lower in myopia and myopic astigmatism of -6.10 to -12.00 D. In both groups, a small number of patients lost two or more lines of spectacle-corrected visual acuity.

Astigmatism↗
PubMed2001

Correction of irregular astigmatism with excimer laser assisted by sodium hyaluronate.

PURPOSE: To demonstrate the usefulness of excimer laser surgery assisted by sodium hyaluronate for the correction of irregular astigmatism after previous corneal refractive surgery. DESIGN: Prospective noncomparative case series. PARTICIPANTS: Fifty eyes with surgically induced irregular astigmatism. All the patients had been subjected previously to one or more of the following: laser in situ keratomileusis (LASIK), incisional keratotomy, photorefractive keratotomy, phototherapeutic keratotomy, laser thermokeratoplasty, and corneal trauma. Irregular astigmatism developed thereafter. METHODS: Stability of the corneal topography pattern before surgical decision was observed for at least 6 months with the C-SCAN corneal topography with Ray Tracing (Technomed GmbH, Germany) and the Eye-Sys 2000 Corneal Analysis System (Eye Sys Co., Houston, TX). The lowest pachymetry value was 310 microm in the thinnest portion of the cornea. Ablation was performed with the Technolas 217 C-LASIK excimer laser (Bausch and Lomb Chiron Technolas GmbH, Dornach, Germany), in phototherapeutic keratectomy mode, assisted by a mask of 0.25% sodium hyaluronate. We performed our ablation either on the surface or under a flap, whether elevated or newly cut. MAIN OUTCOME MEASURES: Uncorrected and best-corrected visual acuity, manifest and cycloplegic refraction, superficial corneal surface quality, image distortion, and predicted corneal visual acuity. RESULTS: At 3 months of follow-up, the irregular corneal surface was significantly improved in all cases (n = 50). The superficial corneal surface quality improved from 70.5% +/- 9.16% to 75.6% +/- 10.38 (P < 0.0001). Six eyes lost 1 line of best-corrected visual acuity, three eyes lost 2 lines, and five eyes lost 3 or more lines. The real corneal ablation depth obtained was equal to 63% of that programmed because of the influence of masking substance. Mean uncorrected visual acuity improved from 20/80 +/- 20/125 to 20/63 +/- 20/100 (P = 0.01). Predicted corneal visual acuity improved from a mean of 20/32 +/- 20/80 to 20/25 +/- 20/63 (P = 0.004). Image distortion improved from a mean of 13.95 +/- 3.64 to 12.16 +/- 3.92 (P < 0.0001). We obtained a hyperopic shift in 56% and myopic shift in 40% of eyes. After 6 months of follow-up the irregular corneal surface continued to improve in all cases (n = 32). The superficial corneal surface quality improved from 69.38% +/- 9.48% to 73.13% +/- 8.87 (P = 0.002). Two eyes lost 2 lines of best-corrected visual acuity, and 3 eyes lost 1 line. Ray tracing was significantly improved in all cases at the end of follow-up regarding superficial corneal surface quality (P = 0.002) and the image distortion (P = 0.05). Improvement of predicted corneal visual acuity was not significant (P = 0.11). The procedure proved to be safe, with a safety index of 1.1. Differences between the surface and stromal treatments and between pattern and nonpattern irregular astigmatism were not statistically significant. CONCLUSION: It is possible to produce a more regular corneal surface and to improve best-corrected visual acuity in patients with irregular astigmatism using plano-scan excimer laser assisted by viscous masking solution of 0.25% sodium hyaluronate.

Astigmatism↗
PubMed2001

Corneal irregular astigmatism and contrast sensitivity after photorefractive keratectomy.

OBJECTIVE: To investigate the relation between contrast sensitivity and corneal irregular astigmatism in eyes after photorefractive keratectomy (PRK). DESIGN: Prospective observational case series. PARTICIPANTS AND CONTROLS: Seventy-nine eyes without corneal haze 6 months or more after PRK and 30 normal control eyes. METHODS: Videokeratography was taken with TMS-1 (Computed Anatomy Inc. New York, NY), and contrast sensitivity for day and night vision was measured using a Multivision Contrast Tester 8000 (Vistech Consultants, Inc., Dayton, OH). MAIN OUTCOME MEASURES: Regular and irregular astigmatism (asymmetry and higher order irregularity components) were computed using Fourier series harmonic analysis of the videokeratography data. Area under the log contrast sensitivity function (AULCSF) was calculated from the contrast sensitivity data taken at five spatial frequencies. RESULTS: After PRK, AULCSFs were significantly smaller for day vision (P = 0.007, unpaired t test) and night vision (P = 0.020) compared with normal controls. AULCSFs for day vision were significantly negatively correlated with asymmetry (Pearson's correlation coefficient, R = -0.23, P = 0.049) and higher order irregularity (R = -0.33, P = 0.004) components but not with the regular astigmatism component (P > 0.3). AULCSF for night vision correlated significantly with asymmetry (R = -0.31, P = 0.013) and higher order irregularity (R = -0.30, P = 0.016) components but not with the regular astigmatism component (P > 0.3). CONCLUSIONS: Corneal irregular astigmatism after PRK significantly influences contrast sensitivity.

Adult↗
PubMed1990

An adjustable single running suture technique to reduce postkeratoplasty astigmatism. A preliminary report.

The authors compared postkeratoplasty astigmatism over a 4-month period after surgery in a randomized, prospective study of two groups of patients (total N = 18) who received two different suture techniques. The test group N = 8) had a single running suture with postoperative suture adjustment; on the basis of computer-assisted topographic analysis, the suture was tightened in the flatter meridian and loosened in the steeper meridian in the first month after surgery. The control group (N = 10) had a standard double running suture procedure with no postoperative adjustment; the single running 10-0 nylon suture was removed 3 months after surgery. Four months after penetrating keratoplasty, mean (+/- standard deviation) astigmatism in the test group was 1.7 +/- 0.7 diopters (D), and all patients had less than 2.6 D of astigmatism. In the control group, mean astigmatism was significantly higher (5.4 +/- 2.4 D; range, 0.7-9.0 D; P less than 0.01). The results suggest that postkeratoplasty astigmatism can be reduced with the single running suture technique accompanied by postoperative suture adjustment.

Astigmatism↗
PubMed2000

Effect of a standard paired arcuate incision and augmentation sutures on postkeratoplasty astigmatism.

To analyze the efficacy of a standardized paired arcuate incision and augmentation suture technique in the treatment of various levels of post-penetrating keratoplasty (PKP) astigmatism. Lions Eye Institute, Royal Perth Hospital, Perth, Australia, and University of Dundee Department of Ophthalmology, Dundee, United Kingdom.A standardized paired arcuate incision and paired augmentation suture technique was used to treat 34 eyes with post-PKP astigmatism ranging from -3.50 to -20.00 diopters (D) at the spectacle plane. The technique consisted of paired arcuate incisions of 3 clock hours, 480 microm deep in the graft-host junction, and 2 pairs of augmentation 10-0 nylon sutures. The mean preoperative cylinder was -9.14 D +/- 4.38 (SD) and the mean postoperative cylinder, -3.59 +/- 1.92 D at the corneal plane after a mean follow-up of 50 +/- 43 weeks. This represents an empirical reduction in mean cylinder of 5. 55 D (60.7%). The Alpins correction index (surgically induced astigmatism [SIA] divided by target induced astigmatism) was calculated for each case, and the mean was 1.01 +/- 0.34, with a median of 0.91. Approximately 53.1% of cases achieved a correction index between 0.80 and 1.20, and the correction index correlated poorly with the initial magnitude of cylinder. A direct numerical relationship between SIA and the initial magnitude of cylinder was observed, although a standard surgical procedure was used in all cases.A simple standardized technique using paired arcuate incisions in the graft-host junction with paired augmentation sutures reduces the amount of cylinder in proportion to the magnitude of the preoperative cylinder and effectively reduces post-PKP astigmatism.

Astigmatism↗