Clinical effect of cross positioning method for correcting low and moderate astigmatism during small incision lenticule extraction / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To evaluate the clinical outcomes of using the cross-positioning method for correcting low and moderate astigmatism during small incision lenticule extraction(SMILE)surgery with Alpins vector analysis.METHODS: A total of 50 patients(81 eyes)with low and moderate astigmatism with the rule ≤1.50 D who underwent SMILE surgery at the laser myopia treatment center of Xi'an No.1 Hospital from May 2022 to November 2022 were included in the prospective randomized controlled study, and they were divided into two groups according to the random table, with 25 case(41 eyes)in cross-positioning group and 25 cases(40 eyes)in control group. In the cross-positioning group, the patients' head position was adjusted based on the cross intersection lines before the standard SMILE procedure, aligning the lateral canthi with the horizontal line and the midpoint of the eyebrows and the nose bridge with the vertical line. Postoperative visual acuity and refractive results at 3 mo were observed in both groups, and astigmatic changes were analyzed and evaluated using the Alpins vector analysis method.RESULTS: During the follow-up period, 6 cases(11 eyes)in the cross-positioning group were lost to follow-up, while in the control group, 8 cases(14 eyes)were lost to follow-up, with 19 cases(30 eyes)and 17 cases(26 eyes)finally included in the cross-positioning group and the control group, respectively. At 3 mo postoperatively, the uncorrected visual acuity(UCVA)of both groups' operated eyes was ≥1.0, and no serious complications occurred, with no significant differences in UCVA, best corrected visual acuity(BCVA), spherical power, and spherical equivalent between the cross-positioning group and the control group(all P>0.05). The cylindrical power in the cross-positioning group was 0.00(0.00, 0.00)D, which was lower than -0.13(-0.50, 0.00)D in the control group(P=0.01). The vector analysis results showed that the difference vector(DV)in the cross-positioning group was lower than that in the control group [0.00(0.00, 0.00)vs 0.13(0.00, 0.50), P=0.01], and the index of success(IOS)was better than that of the control group [0.00(0.00, 0.00)vs 0.18(0.00, 0.77), P<0.01]. At 3 mo postoperatively, 26(87%)and 15(58%)eyes in the cross-positioning group and control groups achieved an angle of error(AE)within ±5°, respectively.CONCLUSION: The cross positioning method was used to calibrate the patients' head position during SMILE surgery, which reduced the axial position error and improved the accuracy of SMILE in correcting low and moderate astigmatism.

Clinical analysis of functional optical zone after transepithelial photorefractive keratectomy in patients with different degrees of myopic astigmatism / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To evaluate the effect of preoperative degrees of myopic astigmatism and anterior corneal curvature on the functional optical zone(FOZ)after transepithelial photorefractive keratectomy(TransPRK).METHODS: Retrospective study was conducted on 78 patients(130 eyes)with myopia and myopic astigmatism who underwent TransPRK, and they were divided into control group(cylinder 0D), moderate astigmatism group(-0.50～-2.00D)and high astigmatism group(>-2.00～<-6.00D). The FOZ was measured and compared among the three groups 6mo after operation. The correlations between attempted correction, anterior corneal curvature, corneal aberrations, Q value, and the FOZ were analyzed.RESULTS: At 6mo after operation, the mean FOZ was 5.16±0.12mm in the control group, 5.29±0.23mm in the moderate astigmatism group, and 5.49±0.23mm in the high astigmatism group(P<0.001), and the FOZ of the high astigmatism group was significantly higher than moderate astigmatism and control group(P<0.05, P<0.001); Pearson correlation analysis showed that the changes in spherical equivalent, total corneal higher-order aberrations(HOAs), coma, and spherical aberration were all negatively correlated with FOZ(all P<0.05); and FOZ positively correlated with changes in the steep curvature(K2), mean curvature(Km), corneal astigmatism, and Q value(all P<0.01). Multiple linear regression analysis showed that there was still positive correlation between preoperative K2 and FOZ after adjusting for other risk factors(P<0.001).CONCLUSION: Patients with high astigmatism can obtain a larger FOZ and less induced coma after TransPRK. A larger FOZ can be achieved in eyes with steeper keratometry.

Changes of anterior and posterior corneal curvature and anterior chamber depth after SMILE / 国际眼科杂志(Guoji Yanke Zazhi)

·AIM:To observe the changes of anterior and posterior corneal curvature and anterior chamber depth after small incision lenticule extraction ( SMILE ) for low and high myopic astigmatism.·METHODS: Sixty-three cases ( 88 eyes ) undergone SMILE in our hospital were included. The patients were divided into two groups based on astigmatism degree:the Group A: -2. 00D to -4. 00D astigmatism, the Group B: - 0. 25D to - 1. 00D astigmatism. Patients were examined at 1wk, 1 and 3mo after operations. Visual acuity, intraocular pressure, refraction, corneal curvature and anterior chamber depth were recorded. The change of anterior and posterior corneal curvature and anterior chamber depth was compared. Spearman correlation analysis and independent t test were used for statistical analysis.·RESULTS: Surgery was done well in all patients without complications. No statistically significant difference was found between the two groups in posterior corneal curvature and anterior chamber depth preoperatively, postoperatively 7d,1 and 3mo (P>0. 05). One week postoperatively, the anterior corneal curvature was statistically significant from that of preoperative in both groups (P<0. 05), while there were no significant differences at 1 and 3mo after operation (P>0. 05).·CONCLUSION: No significant change of anterior and posterior corneal curvature and anterior chamber depth was found after SMILE for correcting low and high myopic astigmatism. One week after SMILE the anterior corneal curvature become stable.

Efficacy and safety observation after implantation of TICL in the treatment of high myopia with astigmatism / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To study the efficacy and safety of Toric implantable contact lens (TICL) implantation in the treatment of patients with high myopia and astigmatism.METHODS: Totally 90 patients (178 eyes) diagnosed as this disease were selected in our hospital during September 2012 to September 2016 by the method of random.The UCVA, BCVA, refraction, astigmatism coefficient, corneal endothelial cell, intraocular pressure, manifest refraction examination were accessed and compared before and after 3 and 9mo of surgery.RESULTS: After 3 and 9mo of the surgery, the UCVA and BCVA were much higher than those before treatment, which the difference was statistically significant (P0.05).The corneal endothelial cells at 3 and 9mo after operation were compared with those of before treatment, and we found that the differences were statistically significant (P0.05).CONCLUSION: TICL implantation in the treatment of patients with high myopia and myopic astigmatism has a more obvious clinical efficacy and safety and reliability.

Queratomileusis in situ asistida por láser de excímeros en la corrección del astigmatismo miópico / Excimer laser-assisted in situ keratomileusis for correction of myopic astigmatism

INTRODUCCIÓN: la queratomielusis es un procedimiento quirúrgico de valor en el tratamiento de las ametropías. OBJETIVO: determinar los resultados de la queratomileusis "in situ" asistida por láser de excímeros (LASIK) en la corrección del astigmatismo miópico. MÉTODOS: se realizó un estudio retrospectivo de 73 pacientes con astigmatismo miópico, operados con la técnica LASIK durante el año 2013 en el Hospital Militar "Dr. Carlos J. Finlay". Las variables fueron: edad, sexo, agudeza visual con corrección pre y postoperatorias, equivalente esférico, complicaciones trans-operatorias, postoperatorias inmediatas y tardías. Para el procesamiento de la información se utilizó programa SPSS. RESULTADOS: se mantuvo la agudeza visual previa corregida y no se detectaron complicaciones graves o irreversibles. Se observaron cambios significativos en las variables estudiadas con tendencia a la emetropía para un 92,3 %. CONCLUSIÓN: LASIK es una técnica segura y útil para la corrección del astigmatismo miópico, que permite mejorar la agudeza visual.

OBJETIVE: to determinate the results of Excímer laser assisted "in situ" keratomileusis (LASIK)in the correction of myopic astigmatism. METHODS: a descriptive, retrospective study of the results was performed after surgery LASIK in 73 patients with myopic astigmatism. The variables were: age, sex, pre and postoperative visual acuity without correction, spherical equivalent, intraoperative complications, postoperative immediate and late complications. Significant changes were observed in all the variables studied tending to emmetropia and 92.3 %. RESULTS: with the use of this surgical technique the corrected previous visual acuity remained and not serious or irreversible complications were detected. CONCLUSIONS: Lasik is a safe and useful technique for the correction of myopic astigmatism that improves visual acuity.

Rotational Stability after Toric Implantable Collamer Lens Implantation

PURPOSE: To evaluate rotational stability of Toric Implantable Collamer Lens (ICL) implantation to correct myopic astigmatism. METHODS: We estimated the degree of Toric ICL rotation together with change in visual acuity and astigmatism in 118 eyes of 66 patients who underwent Toric ICL implantation and had a long-term mean follow-up period of 37 months. RESULTS: After Toric ICL implantation, 107 (91%) out of 118 eyes showed uncorrected visual acuity of 0.8 or better. The mean postoperative astigmatism decreased to -0.64 +/- 0.61 D from a mean preoperative astigmatism of -2.96 +/- 1.13 D. The mean axis change of Toric ICL was 2.4 +/- 3.8 degrees during follow-up period. Two (1.7%) out of 118 eyes showed the axis change of more than 10 degrees. These two eyes had a decrease in visual acuity, rotational axis change of 18 degrees and 30 degrees, respectively, and increases in astigmatism of 1.50 D and 1.00 D, respectively. The remaining 116 eyes (98.3%) showed excellent rotational stability without visual acuity decreasing Toric ICL rotation during the follow-up period. CONCLUSIONS: Toric ICL implantation to correct high myopia with astigmatism rarely has axis rotation and maintains excellent rotational stability for long-term follow-up.

Visual quality observation after implantation of TICL for high myopia with astigmatism / 局解手术学杂志

Objective To assess the clinical outcomes about the visual qulitity of toric implantable contact lens ( TICL) implantation for high myopia with astigmatism. Methods Fifty-two eyes of 27 patients that underwent TICL implantation were examined. Uncorrected visual acuity( UCVA) ,best corrected visual acuity( BCVA) ,refraction,contrast sensitivity ( CS) with and without glare were evaluated before and after the treatment. Results Significant improvement in UCVA and BCVA were found at 1 month and 6 months after treatment (P0. 05), and the astigmatism at 1 month ( -0. 35 ± 0. 60)D and 6 months ( -0. 31 ± 0. 42)D after treatment were of no significant difference either (P>0. 05). The CS with and without glare were all significantly better than results before operation for 6. 0,12. 0 and 18. 0 cycles/degree (P0. 05). No significant difference were found preoperatively,1 month after treatment and 6 months after treatment in terms of CS with and without glare (P>0. 05). The satisfaction of this investigation was 100%. Conclusion The TICL performed well in correcting high myopia with astigmatism,and it is a good surgical option for the treatment.

Astigmatismo miópico posterior al LASIK en pacientes operados en el Centro Oftalmológico "Enrique Cabrera" de La Habana / Myopic astigmatism after LASIK in patients operated at "Enrique Cabrera" Ophthalmology Center from Havana

Se efectuó un estudio descriptivo, longitudinal y retrospectivo de los 264 pacientes operados de astigmatismo miópico mediante LASIK en el Centro Oftalmológico del Hospital General Docente "Enrique Cabrera" de La Habana, durante el 2009, con vistas a caracterizarles luego del tratamiento quirúrgico. En la casuística primaron el sexo femenino (61,7 %) y el grupo etario de 20-30 años (41,3 %), así como la agudeza visual preoperatoria de cuenta dedos a 0,2 (62,8 %) y la posoperatoria de 0,6 a 1,0 (98,1 %). Después de aplicada la terapéutica, la esfera disminuyó en 95,0 % de los integrantes de la serie a valores entre 0,00 y -1,00 dioptrías y el cilindro, en 98,7 %, con medidas inferiores a -1,50 dioptrías. Los valores queratométricos de 41,25 a 43,00 dioptrías estuvieron presentes en 72,1 % de los afectados y el equivalente esférico mostró un acercamiento sustancial a la emetropía en 82,3 % de las intervenciones, con un intervalo entre -1,00 y 0,00 dioptrías.

A descriptive, longitudinal and retrospective study was carried out in 264 patients operated on myopic astigmatism by means of LASIK at "Enrique Cabrera" General Teaching Hospital from Havana, during 2009, in order to characterize them after surgical treatment. Female sex (61.7%) and age group between 20 and 30 years (41.3%) prevailed in the case material, as well as preoperative and postoperative visual acuity of counting fingers of 0.2 (62.8%) and 0.6 to 1.0 (98.1%) respectively. After the treatment have been applied, in 95.0% of patients from the series the sphere decreased to values between 0.00 and -1.00 diopters, and the cylinder, in 98.7%, measuring less than -1.50 diopters. Keratometric values from 41.25 to 43.00 diopters were present in 72.1% of those affected and the spherical equivalent showed a substantial approach to emmetropia in 82.3% of the surgeries, with a range between -1,00 and 0,00 diopters.

Clinical Outcomes of Toric Implantable Collamer Lens implantation

PURPOSE: To assess the efficacy of the Toric Implantable Collamer Lens (Toric ICL) to treat moderate to high myopic astigmatism. METHODS: Toric ICL was implanted in 77 eyes of 40 patients with myopia (spherical equivalent [SE] between 3.5 and 18.5 diopters [D]) and astigmatism between 1 and 6 D. The patients were followed up for at least 3 months. Uncorrected visual acuity (UCVA), refraction, best spectacle-corrected visual acuity (BSCVA), adverse events, and postoperative complications were evaluated. RESULTS: At 3months postoperatively, the proportion of eyes with 1.0 or better UCVA (56 eyes out of 77 eyes, 72.7%) was significantly greater than the proportion of eyes with preoperative 1.0 or better BSCVA (38 eyes out of 77 eyes, 49.4%). The mean manifest refractive cylinder dropped from 2.78D (+/-1.05) at baseline to 0.35D (+/-0.34) postoperatively, an 87.4% decrease in astigmatism. Mean manifest refraction SE (MRSE) improved from -9.93D (+/-2.66) preoperatively to 0.15D (+/-0.33) postoperatively. A total of 96.1% of eyes were predicted accurately to within +/-0.75D of predicted MRSE. Mean improvement in BSCVA was 0.79lines; there were no eyes that lost two lines of BSCVA after 3 months postoperatively. CONCLUSIONS: The results support the efficacy and predictability of Toric ICL implantation to treat moderate to high myopic astigmatism.

Frecuencia de ametropías / Frequency of ametropias

Se realizó un estudio con una muestra aleatoria de 9 513 pacientes seleccionados (19 026 ojos) que presentaban ametropías y que asistieron a consulta de cirugía refractiva en el Instituto Cubano de Oftalmología "Ramón Pando Ferrer"; donde se encontró una mayor frecuencia de éstas en el sexo femenino con predominio en las edades entre los 21 y los 30 años. El astigmatismo miópico compuesto fue la ametropía más frecuente en la muestra, con diferencias de género a favor del sexo femenino; el astigmatismo hipermetrópico simple fue la única ametropía que no mostró diferencias entre los grupos de edades. Existió una correlación lineal positiva entre la edad y la intensidad de la hipermetropía y miopía en el grupo de pacientes entre los 18 y los 39 años. Hubo predominio de las miopías y las hipermetropías ligeras y moderadas. Entre las ametropías esféricas un 36, 8 % de ojos obtuvo un rango de severidad que excedía los criterios quirúrgicos. No se encontró relación entre la magnitud del cilindro y la edad de los casos estudiados. Los astigmatismos directo, oblicuo y oblicuo directo demostraron mayor frecuencia en la muestra, donde prevaleció el ojo derecho en el tipo directo e indirecto, mientras que en el ojo izquierdo predominaron el oblicuo directo y el oblicuo inverso. La anisometropía fue poco frecuente en la muestra y alcanzó solamente el 2,1 % del total de pacientes emétropes y predominó en el grupo de 31 a 35 a.

A descriptive study was conducted with a randomized sample of 9 513 patients selected (19 026 eyes) that presented ametropias and that received attention at the department of refractive surgery in "Ramón Pando Ferrer" Cuban Institute of Ophthalmlogy. Ametropias were more frequent among women aged 21-30. The compound myopic astigmatism was the commonest ametropia in the sample, with difference of gender in favor of females. The simple hypermetropic astigmatism was the only ametropia that did not show differences among the age groups. There was a positive lineal correlation between age and the intensity of hypermetropia and myopia in the group of patientes aged 18-39. It was observed a predominance of myopias and mild and moderate hypermetropias. In the spheric ametropias, 36.8 % of eyes had a severity range that exceeded the surgical criteria. No relation was found between the magnitude of the cylinder and the age of the studied cases. The direct, the oblique and the direct oblique astigmatisms showed a higher frequency in the sample, where the right eye prevailed in the direct and indirect type. The direct oblique and the inverse oblique predominated in the left eye. The ansimetropia was uncommon in the sample and reached only 2.1 % of the total of patients with ametropia. It moslty affected the group aged 31-35.

Evaluation of excimer laser photorefractive keratectomy for treatment of myopia and myopic astigmatism / 眼科新进展

Objective To evaluate the efficacy and accuracy of photorefractive keratectomy(PRK) for myopia and myopic astigmatism.Methods SVS APEX PLUS excimer laser with a wave length of 193nm(Summit Technology Inc.Waltham,Mass,USA) was applied.Three hundred and sixteen myopic eyes of 168 patients were treated with PRK from Suptember 1996 to October 1997,and 260 eyes(84%) of 150 patients were followed-up for more than three month,including male 68(116 eyes,40.1%) and female 82(144 eyes,59.9%).The preoperative spherical equivalent refractive errors ranged from -1.25D to -10.00D(mean -4.67D± 1.63D),and astigmatism ranged from 0 to -2.00D(mean -0.33D±0.45D). The patients were divided into two groups according to the refraction:group A(from -1.25D to -5.90D) and group B(from -6.00D to -10.00D).The number of eyes in the two groups were 220 and 40,respectively.Results In group A,After 10 days,68.9% had the uncorrected visual acuity(UCVA) equal to or one line better or lower than the preoperative best corrected visual acuity(BCVA).After 1 ,3,6 and 12 months,90%,96%,95% and 94% had the UCVA equal to or one line better or lower than the preoperative BCVA,respectively.In group B,after 10 days,1,3,6 and 12 months,UCVA equal to or one line better or lower than the preoperative BCVA occurred in 35.9%,83.0%,87.0%,86.0% and 84.0% of the patients respectively. Most of the haze showed 0.5～1 grades except 3 eyes with the haze of 2 grade at 3 or 6 months and it changed to l and 0.5 grade respectively at one year.after 10 days and 1,3,6,12 months postoperatively,the corneal haze was noted in 32.9%,84.8%,62.8%,9.0%and 2.8% of the treated eyes respectively.Conclusion We found that the 193nm excimer laser PRK is a predictable,safe,stable,and effective refractive surgery for correcting myopia up to-10.00D in Chinese patients,and the effect is better in myopia lower than -6.00D.

CLINICAL ANALYSIS OF EXCIMER LASER PHOTOREFRACTIVE KERATECTOMY FOR TREATMENT OF MYOPIA AND MYOPIC ASTIGMATISM / 药物分析学报

To evaluate the efficacy and accuracy of photorefractive keratectomy (PRK) for myopia and myopic astigmatism .SVS APEX excimer laser with a wave length of 193 nm(Sumit Technology Inc. Waltham, Mass, USA) was applied. 316 myopic eyes of 168 patients were treated with PRK between September, 1996 and October, 1997, and 260 eyes (84%) of 150 patients were followed for more than three months, including male 68(116 eyes, 40.1%) and female 82(144 eyes, 59.9%). The preoperative spherical equivalent refractive errors ranged from -1.25D to -10.00 (mean -4.67±1.63D), and astigmatism ranged from 0 to -2.00D (means -0.33±0.45D). We divided the patients into two groups according to the referaction: group A (from -1.25D to -5.90D) and group B(from -6.00 to -10.00D). The number of eyes in the two groups were 220 and 40 respectively. In group A, on the 10th day, 68.9% has the uncorrected visual acuity (UCVA) equal to or one line better or lower than the preoperative best corrected visual acuity (BCVA). In 1,3,6 and 12 months, 90%, 96%, 95% and 94% had the UCVA equal to or one line better or lower than the preoperative BCVA respectively. In group B, on the 10 th day, in 1,3,6 and 12 months, UCVA equal to or one line better or lower than the preoperative BCVA occurred in 35.9%, 83%, 87%, 86%, and 84% of the cases respectively. Most of the haze showed 0.5～1 grades except 3 eyes with the haze of 2 grade in 3 or 6 months and it changed to 1 and 0.5 grade respectively within one year. In 10 days and 1,3,6,12 months postoperatively, the corneal haze was noted in 32.9%, 84.8%, 62.8%,9.0% and 2.8% of the treated eyes respectively. We found that 193 nm excimer laser PRK was a predictable, safe, stable, and effective refractive surgery for correcting myopia up to -10.00D in Chinese patients, and the effect was better in myopia lower than -6.00D.

Excimer Laser Photorefractive Keratectomy for the Correction of Compound Myopic Astigmatism: One Year Follow-Up

To prospectively examine the predictability of excimer laser photorefractive keratectomy for compound myopic astigmatism, we treated 107 eyes of 70 patients with a VisX Twenty/Twenty excimer laser and followed them up for 12 months. Patients were divided into three groups with preoperative myopia: group 1 with diopters of -6.00 or less, group 2 with diopters between -6.01 and -10.00, and group 3 with diopters greater than -10.00. Also, two groups of patients were evaluated with preoperative astigmatism: group I with -2.00 diopters or less and group II with greater than -2.00 diopters. At 12 months group1, with amean preoperative refractive error of -4.332D, changed to -0.19D, group 2 changed from -7.35D to -0.66D, and group 3 changed from -11.72D to -1.23D. Group I with a mean preoperative refractive error of -1.22D changed to -0.55D, while group II changed from -2.63D to -0.77D. Finally, 85% of eyes with preoperative spherical equivalent diopters of -6.00 or less, 65% of eyes between -6.01 and -10.00D, and 42% of eyes greater than -10.00D were corrected within 1D of intended refraction, respectively.

Clinical Result of Excimer Laser Park

We evaluated the effectiveness of photoastigmatic refractive Keratectomy(PARK) by excimer laser on patients with compound myopic astigmatism. Spherocylindrical PARK was performed on 181 myopic eyes with astigmatism(mean spherical equivalent : -6.61 D, range : -1.88~-14.5 D) using the visx excimer laser. The eyes were divided into three groups according to the amount of desired astigmatic correction : Group 1(-0.5~-1.0 D), Group 2(-1.25~3.0 D), and Group 3(-3.25~-5.5 D). Patients were followed up for 6 months. Uncorrected visual acuity at postoperative 6 month, was 0.80+/-0.27 in Group 1, 0.79+/-0.19 and 0.71+/-0.21bin Group 2 and 3 respectively. The mean spherical equivalent refraction was -0.24 D 6 months after PARK. Mean astigmatism was reduced from preoperative -0.85+/-0.51 D to postoperative -0.34+/-0.38 D in Group 1, from -2.08+/-0.65 D to -0.43+/-0.64 D and from -4.42+/-0.63 D to -1.23+/-1.25 D in Group 2 and 3 respectively. We also analyzed the angle of error, magnitude of error, index of success, and coefficient of afjustment by vector analysis. No significant complications were observed during the follow-up period. These results show that PARK by excimer laser was effective in correction of astigmatism. The effect of astigmatic correction in Group 2 and 3 were better than that of Group 1. Group 1 showed overcorrected tendency and Group 2 and 3 showed undercorrected tendency.

Clinical Result of Excimer Laser Park

We evaluated the effectiveness of photoastigmatic refractive Keratectomy(PARK) by excimer laser on patients with compound myopic astigmatism. Spherocylindrical PARK was performed on 181 myopic eyes with astigmatism(mean spherical equivalent : -6.61 D, range : -1.88~-14.5 D) using the visx excimer laser. The eyes were divided into three groups according to the amount of desired astigmatic correction : Group 1(-0.5~-1.0 D), Group 2(-1.25~3.0 D), and Group 3(-3.25~-5.5 D). Patients were followed up for 6 months. Uncorrected visual acuity at postoperative 6 month, was 0.80+/-0.27 in Group 1, 0.79+/-0.19 and 0.71+/-0.21bin Group 2 and 3 respectively. The mean spherical equivalent refraction was -0.24 D 6 months after PARK. Mean astigmatism was reduced from preoperative -0.85+/-0.51 D to postoperative -0.34+/-0.38 D in Group 1, from -2.08+/-0.65 D to -0.43+/-0.64 D and from -4.42+/-0.63 D to -1.23+/-1.25 D in Group 2 and 3 respectively. We also analyzed the angle of error, magnitude of error, index of success, and coefficient of afjustment by vector analysis. No significant complications were observed during the follow-up period. These results show that PARK by excimer laser was effective in correction of astigmatism. The effect of astigmatic correction in Group 2 and 3 were better than that of Group 1. Group 1 showed overcorrected tendency and Group 2 and 3 showed undercorrected tendency.