Oxidative stress and mitochondrial dysfunction of retinal ganglion cells injury exposures in long-term blue light

AIM: To investigate the clinical efficacy and safety of femtosecond laser-assisted steepest-meridian clear corneal incisions for correcting preexisting corneal astigmatism performed during cataract surgery. METHODS: This prospective case series study comprised consecutive age-related cataract patients with corneal regular astigmatism (range: +0.75 to +2.50 D) who had femtosecond laser-assisted steepest-meridian clear corneal incisions (single or paired). Corneal astigmatism was measured by the Pentacam preoperatively and 3 mo postoperatively. Total corneal astigmatism and steepest-meridian measured in the 3-mm central zone were used to guide the location, size and number of clear corneal incision. The vector analysis of astigmatic change was performed using the Alpins method. RESULTS: Totally 138 eyes of 138 patients were included. The mean preoperative corneal astigmatism was 1.31±0.41 D, and was significantly reduced to 0.69±0.34 D (equivalent to difference vector) after surgery (P<0.01). The surgically-induced astigmatism was 1.02±0.54 D. The correction index (ratio of target induced astigmatism and surgically-induced astigmatism: 0.72±0.36) as well as the magnitude of error (difference between surgically-induced astigmatism and target induced astigmatism: -0.29±0.51) represented a slight under correction. For angle of error, the arithmetic mean was 1.11±13.70, indicating no significant systematic alignment errors. CONCLUSION: Femtosecond-assisted steepest-meridian clear corneal incision is a fast, customizable, adjustable, precise, and safe technique for the reduction of low to moderate corneal astigmatism during cataract surgery.     

Effect on astigmatism of the location of clear corneal incision in phacoemulsification of cataract

PURPOSE: To investigate the refractive results of clear corneal incision performed at the steepest meridian of pre-existing corneal astigmatism. METHODS: One hundred eighty-two patients with astigmatism > 0.75 diopters (D) were evaluated. Superior, temporal, nasal, superotemporal, or superonasal clear corneal incisions were performed at the steep meridian. Refraction, visual acuity, and topography values were evaluated, and changes in surgically induced astigmatism were calculated by vector analysis using the Fourier formula. Paired t test was used to compare mean values. RESULTS: Postoperative cylinder values showed minor changes in all groups, except the nasal group. Nasal incision increased preoperative cylinder from 1.13 D to 1.83 D 6 months after surgery. Temporal and superotemporal incisions resulted only in small astigmatic changes. Conversely, superior, superonasal, and nasal incisions induced more pronounced astigmatism. CONCLUSIONS: Performing clear corneal incision for phacoemulsification of cataract at the steep meridian resulted in small changes with temporal incisions, whereas nasal incisions resulted in higher surgically induced astigmatism.     

Clear corneal incision of 2.75 mm for cataract surgery induces little change of astigmatism in eyes with low preoperative corneal cylinder

PURPOSE: To assess the early astigmatic effect induced by 2.75 mm clear cornea incisions with different locations for cataract surgery. METHODS: A total of 146 eyes of different patients were studied prospectively. Cataract surgery was performed by three surgeons, two using a temporal approach and one using a superior approach. For both approaches, the site of the 2.75 mm incision was allowed to vary slightly according to the characteristics of the eye and orbit. Computerized videokeratography was used to measure corneal astigmatism before surgery and after 1, 4, and 12 weeks. Corneal astigmatism was recorded as cylinder and axis and it was then converted to 2 power vector. Model based prediction and comparisons were made for the most commonly used corneal incision sites: 12 (both eyes), 2 (left eye), and 8 (right eye) o'clock meridian. RESULTS: After 3 months the differences in corneal astigmatism (JCC 0 ) between the incisions performed at 12 and 2 o'clock were not statistically significant (-0.08, 95% CI: -0.19, -0.02); the differences in JCC 0 between incisions at 12 and 8 o'clock were -0.17 (95% CI: -0.30, -0.05; p<0.01). After 3 months the change in JCC 0 for the patients with 0.5 D with-the-rule preoperatively were -0.32 (95% CI: -0.44, 0.21; p<0.01) for incisions at 12; -0.24 (95% CI: -0.36, 0.13; p<0.01) for incisions at 2; and -0.15 (95% CI: -0.27, -0.03; p<0.05) for incisions at 8. After 3 months the changes of JCC 0 for the patients with -0.5 D against-the-rule pre-operatively were 0.10 (95% CI: 0.04, 0.23) for incision at 12; 0.18 (95% CI: 0.04, 0.32; p<0.05) for incisions at 2; and 0.27 (95% CI: 0.14, 0.40; p<0.01) for incisions at 8 o'clock. The oblique astigmatic vector (JCC 45 ) was very modest in this sample before surgery and underwent minimal and nonsignificant change after it. CONCLUSIONS: This study has shown that a 2.75 mm clear corneal incision causes a small change of corneal cylinder regardless of incision site.     

Bivariate polar value analysis of surgically induced astigmatism

PURPOSE: To demonstrate the use of bivariate polar value analysis of surgically induced astigmatism following various cataract incisions. METHODS: In a prospective study, we investigated surgically induced astigmatism following cataract surgery through 9.0-mm, 5.5-mm, and 4.0-mm superior corneal incisions. Autokeratometry was performed preoperatively and during the first year. All net astigmatisms were converted to polar values with reference to the 90 degrees meridian. Univariate and bivariate polar value analyses were performed. RESULTS: After 1 year, univariate polar value analysis disclosed flattening averaging 1.02 D for 9.0-mm incisions, 0.71 D for 5.5-mm incisions, and 0.64 D for 4.0-mm incisions. The induced torque was 0.46 D counterclockwise for the 9-mm incision and close to zero for the 5.5 and 4-mm incisions. Bivariate polar value analysis disclosed a statistically significant (P < .05) difference in surgically induced astigmatism between the 9.0-mm incisions and the two smaller incisions at all follow-up points. CONCLUSION: Univariate polar value analysis demonstrated the surgically induced steepening and torque. Bivariate analysis demonstrated the joint variation in these entities and therefore always yielded the correct result. Univariate and bivariate polar values may be used for analysis of surgically induced astigmatism following cataract surgery in any meridian.     

Astigmatism outcomes of horizontal temporal versus nasal clear corneal incision cataract surgery

PURPOSE: To compare the short- and long-term astigmatism outcomes after cataract surgery using temporal clear horizontal corneal incisions and nasal horizontal clear corneal incisions. SETTING: Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, Maryland, USA. METHODS: This retrospective study included a consecutive series of eyes having phacoemulsification with implantation of a 6.0 mm foldable acrylic intraocular lens through a 3.5 mm horizontal clear corneal incision at 180 degrees (temporal incision in right eyes, nasal incision in left eyes). Astigmatism was measured by keratometry readings before surgery and 6 weeks and 12 months postoperatively. RESULTS: The mean preoperative astigmatism in the 178 eyes (94 right, 84 left) of 161 patients was 0.78 diopter (D); 54.5% of eyes had against-the-rule (ATR) astigmatism, 22.5% had with-the-rule (WTR) astigmatism, and 14.0% were astigmatically neutral. A significant shift toward WTR astigmatism occurred postoperatively. At 6 weeks, 48.3% of eyes had WTR astigmatism and 23.0% had ATR astigmatism. At 12 months, 43.8% had WTR astigmatism and 25.8% had ATR astigmatism. Vector analysis revealed a mean surgically induced astigmatism (SIA) of 1.17 D at 6 weeks and 1.04 D at 12 months. The side of the incision significantly affected SIA. At 6 weeks, temporal incisions yielded a mean SIA of 0.74 D and the nasal incisions, of 1.65 D. This trend in SIA persisted at 12 months: 0.71 D for temporal incisions and 1.41 D for nasal incisions. CONCLUSIONS: Cataract surgery using a horizontal clear corneal incision induced WTR astigmatism 6 weeks and 12 months postoperatively. Temporal incisions induced significantly less astigmatism than nasal incisions.     

非球面和球面人工晶状体植入术后视功能观察

目的 分析白内障患者术前角膜散光情况评估经不同位置透明角膜切口行超声乳化术后的角膜散光变化情况.方法 218例(295只眼)白内障患者分为三组,第一组选择颞侧切口,第二组选择颞上方切口,第三组选择上方切口,三组患者通过透明角膜切口行白内障超声乳化及折叠式后房型人工晶体植入术.术前及术后一周、一月、三月分别检测患者角膜散光情况,并通过Holladay-Cravy-Koch方法 计算术源性散光.结果 术前角膜散光0.5至1.5D的占60.68%,大于等于1.5D的占11.86%,顺归散光占29.49%,逆归散光占51.19%,其余为斜轴散光.术后三次随访颞侧切口组的术源性散光最低,上方切口组的术源性散光最高,具有统计学差异(P<0.05).另外,在上方切口组中发现患者术后角膜散光有向逆归散光转变的趋势.结论 白内障患者术前大多存在小于1.5D的角膜散光.在白内障术后早期阶段,颞侧透明角膜切口引起的术源性散光较小,而上方透明角膜切口不仅可引起较显著的术源性散光,并且术后角膜散光有向逆归散光转变的趋势.

Abstract：

Objective To analyze the corneal astigmatism before cataract surgery and evaluate the astigmatism changes after cataract surgery performed using clear corneal incisions with different locations.Methods: This randomized prospective clinical study comprised 295 eyes of 218 patients having phacoemulsification and implantation of foldable intraocular lens through a corneal tunnel incision. Patients were randomly divided into three groups depending on the different locations of the incision: temporal, superotemporal and superior. Corneal topography was performed preoperatively and 1 week, 1 month, and 3 months postoperatively. Surgically induced changes were calculated by vector analyses using the Holladay-Cravy-Koch method. Results: Preoperatively, in 60.68% of eyes, corneal astigmatism was between 0.5 and 1.5 diopters (D) and in 11.86%, it was 1.5 D or higher. Meanwhile, about 29.49 percent of eyes had with-the-rule (WTR) astigmatism, while 51.19% had against-the-rule (ATR) astigmatism, and the others had oblique astigmatism. At three follow-up visits postoperatively, the mean magnitude of surgically-induced astigmatism (SIA) was lowest in the temporal incision group and highest in the superior incision group. In addition, an ATR shift was found in the superior incision group. Conclusions: Corneal astigmatism less than 1.5 D was present in most cataract surgery candidates. Cataract surgery using temporal clear corneal incision induced significantly less SIA in the early postoperative period. Superior incision may lead to an ATR astigmatism shift.     

Limbal relaxing incisions to correct astigmatism in clear corneal cataract surgery.

PURPOSE: To prevent surgically induced astigmatism following clear corneal cataract surgery. METHODS: Limbal relaxing incisions of 6- or 8-mm length and 0.55-microm depth were performed in 52 patients (52 eyes) with a spherical cornea (20 eyes) or mean with-the-rule astigmatism (32 eyes) of 0.80 +/- 0.30 D after temporal corneal cataract incision. A control group (47 eyes; 19 spherical and 28 with-the-rule astigmatism) underwent the same surgical procedure without limbal relaxing incisions. RESULTS: Six months after surgery, mean with-the-wound change using the Holladay analysis was -0.08 +/- 0.50 D in spherical eyes with limbal relaxing incisions and +0.50 +/- 0.70 D in control eyes. Patients with preoperative with-the-rule astigmatism showed a mean with-the-wound change of -0.09 +/- 0.50 D after limbal relaxing incisions; in corresponding control eyes, mean change was +0.39 +/- 0.70 D. CONCLUSION: Limbal relaxing incisions are a reliable and safe procedure to reduce postoperative astigmatism.     

Enlargement of the temporal clear corneal cataract incision to treat pre-existing astigmatism

PURPOSE: To evaluate the effect of enlarging the temporal clear corneal cataract incision on pre-existing against-the-rule astigmatism. METHODS: We performed a prospective study of 21 eyes of 21 consecutive patients with astigmatism greater > or = 1.75 D, who underwent temporal clear corneal cataract surgery by phacoemulsification. Patients were divided into two groups. The first group, with medium astigmatism, consisted of 14 patients (14 eyes) with 1.75 to 2.74 D of against-the-rule astigmatism, and had an incision enlarged to 4.5 mm. The second group, with higher astigmatism, consisted of seven patients (seven eyes) with 2.75 to 3.75 D of against-the-rule astigmatism and had an incision enlarged to 5.5 mm. Corneal topography was performed preoperatively and 24 months postoperatively on all eyes. Surgically induced cylinder changes were compared by examining preoperative and postoperative keratometric power using vector analysis. RESULTS: Mean preoperative cylinder in the medium against-the-rule astigmatism group was 2.10 +/- 0.23 D and mean postoperative cylinder at 3 months was 1.17 +/- 0.29 D. Using vector analysis, mean change in cylinder in the medium group was 0.93 +/- 0.42 D (P < .001). In the higher against-the-rule astigmatism group, mean preoperative cylinder was 2.85 +/- 0.10 D and mean postoperative cylinder at 3 months was 1.63 +/- 0.38 D. Mean change in cylinder in the higher astigmatism group was 1.34 +/- 0.58 D (P < .001). For both groups, Student's t-test showed that the postoperative decrease in cylinder was statistically significant (P = .005). CONCLUSION: By enlarging the size of the standard (2.8 to 3.5 mm) temporal clear corneal cataract incision, pre-existing against-the-rule astigmatism was reduced.     

Paired opposite clear corneal incisions to correct preexisting astigmatism in cataract patients

PURPOSE: To evaluate the astigmatic correcting effect of paired opposite clear corneal incisions on steep axis in cataract patients. SETTING: Sligo General Hospital, Sligo, Ireland. METHODS: Fifteen eyes of 14 cataract patients with a mean age of 78.4 years +/- 6.38 (SD) (range 69 to 90 years) were recruited for the study. Inclusion criterion was topographic astigmatism of more than 2 diopters (D) in the cataractous eye. Preoperative refraction, autokeratometry, and topography were performed. The steep axis was marked before sub-Tenon's anesthesia was given. Paired 3-step self-sealing opposite clear corneal incisions were made 1 mm anterior to limbus on the steep axis with a 3.2 mm keratome. One incision was used for standard phacoemulsification, and the other was left unused for astigmatic correction. All the patients had day-case surgery. The first follow-up was at 1 month. Postoperative topography, keratometry, and refraction were performed on all patients. RESULTS: Mean preoperative and postoperative topographic corneal astigmatism were 3.26 +/- 1.03 D (range 2.30 to 5.80 D) and 2.02 +/- 1.04 D (range 0.20 to 4.00 D), respectively. Mean astigmatic correction was 1.23 +/- 0.49 D (range 0.30 to 2.20 D). Mean surgically induced astigmatism by vector analysis was 2.10 +/- 0.79 D (range 0.80 to 3.36 D). There were no incision-related complications. CONCLUSION: Paired opposite clear corneal incisions on the steep axis is a useful way to correct astigmatism in cataract patients, requiring no extra skill or instrumentation.     

飞秒激光弧形角膜切开术对白内障合并角膜散光患者的矫正效果

目的　探讨飞秒激光弧形角膜切开术对白内障合并角膜散光患者的矫正效果。方法　选取33例（36眼）白内障合并角膜散光≥0.75 D的患者作为研究对象,均行飞秒激光弧形角膜切开术来矫正角膜散光。术前测患者裸眼远视力、最佳矫正远视力,用Pentacam三维眼前节分析系统测量角膜散光。行飞秒激光辅助的超声乳化白内障手术,术中弧形切口直径为9 mm,深度为90%。术后3个月时复查患者角膜散光、裸眼远视力、最佳矫正远视力,并用Alpins矢量分析法进行散光分析,主要观察以下矢量数据,即目标诱导散光向量、手术诱导散光向量、差异向量和矫正指数。结果　术前患者角膜散光为（1.16±0.35）D,术后3个月下降到（0.54±0.22）D,差异有统计学意义（P＜0.01）。术前裸眼远视力为0.81±0.42,术后3个月提高到0.26±0.24,差异有统计学意义（P＜0.01）。术前最佳矫正远视力为0.76±0.30,术后3个月提高到0.09±0.12,差异有统计学意义（P＜0.01）。对患者术前术后角膜散光的变化进行矢量分析显示,目标诱导散光向量为0.80～2.20（1.16±0.35）D,手术诱导散光向量为0.40～1.80（1.07±0.40）D,差异向量为0.20～1.00（0.54±0.22）D。矫正指数为0.89±0.35,理想值为1,提示总体为少许欠矫。大部分患眼（32眼）角度误差在15°范围内。成功指数平均值为0.47,提示还残留部分散光未得到矫正。通过公式计算可以得到散光矫正的成功率为53.0%。变平效果平均值为0.94,变平指数平均值为0.83。结论　飞秒激光弧形角膜切开术能有效矫正白内障合并角膜散光患者的角膜散光。     

Astigmatism outcomes of scleral tunnel and clear corneal incisions for congenital cataract surgery

PURPOSE: To evaluate astigmatism outcomes after congenital cataract surgery with intraocular lens implantation using clear corneal or scleral tunnel incisions. METHODS: We retrospectively reviewed the medical records of 46 children (67 eyes), aged 2 months to 12 years, who had undergone nontraumatic cataract extraction and intraocular lens implantation between 1996 and 2001, using a scleral tunnel incision (group 1), or a clear corneal incision (group 2). Refractive astigmatism was measured at 1 week, 3 months, and 5 months after surgery. Paired t-test was used to compare those variables, and Spearman's correlation was used to determine their relation to patient's age. RESULTS: Mean+/-SD astigmatism at 1 week postoperatively was 3.1+/-2.8 Diopter (D) and 2.1+/-1.7 D in groups 1 and 2, respectively. It significantly reduced to 1.1+/-1.2 D and 0.9+/-1.0 D, respectively, in the two groups at 5 months postoperatively (P<0.007). In both groups patients' age was significantly correlated with 1-week postoperative astigmatism (group 1: r=0.64; P=0.001; group 2: r=-0.58; P=0.003), and with the change in cylinder magnitude between 1 week and 3 months postoperatively (group 1: r=-0.67; P=0.001; group 2: r=0.50; P=0.013). CONCLUSION: Children who underwent congenital cataract surgery using clear corneal or scleral tunnel incisions showed high postoperative astigmatism at 1 week postoperatively, which spontaneously reduced during 5 months follow-up. Therefore, suture removal is not necessary in those cases.     

Toric intraocular lenses for correcting astigmatism in 130 eyes

OBJECTIVE: This study evaluated the results after implantation of toric intraocular lenses (IOLs) to correct preexisting corneal astigmatism in patients undergoing either cataract or clear lens extraction surgery. DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: One hundred thirty eyes of 99 patients who underwent phacoemulsification and posterior chamber toric IOL implantation from January 1997 through February 1998 were included in the study. INTERVENTION: Implantation of a toric IOL was performed after cataract surgery (122 eyes) or clear lens extraction surgery (eight eyes). Both preoperative corneal cylinder and refractive cylinder powers were more than 1.50 diopters (D) for all the eyes included in this study. To provide a comparison, we also studied 51 eyes of 45 patients meeting the same preoperative criteria for degree of corneal and refractive cylinder who underwent implantation of a spherical (nontoric) IOL combined with limbal relaxing incisions. The data for both study and comparison groups were analyzed retrospectively. The selection for the two groups was arbitrary. MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA), mean spherical equivalent, residual refractive cylinder, and toric IOL axis. RESULTS: In the toric IOL group, 84% of eyes achieved 20/40 or better UCVA. In the spherical IOL group, 76% achieved 20/40 or better UCVA. The mean postoperative refractive cylinder was -1.03 +/- 0.79 D in the toric IOL group and -1.49 +/- 0.75 D in the spherical IOL group. CONCLUSIONS: Our results indicate that phacoemulsification and posterior chamber toric IOL implantation is a largely predictable new surgical option to correct preexisting corneal astigmatism in cataract or clear lens extraction surgery.     

角膜缘松解切开术治疗白内障患者术后角膜散光

目的 研究角膜缘松解切开术治疗白内障患者术后角膜散光的临床疗效.方法 前瞻性队列研究.纳入2018年1月至2020年11月期间,既往行6.0 mm切口白内障手术3个月以上且术后伴有明显角膜散光拟行视力增效手术者61例(71眼)进行研究,按患眼角膜散光大小分为A组(≤1.50 D)和B组(＞1.50 D),所有患眼数据在...     

Limbal relaxing incisions versus on-axis incisions to reduce corneal astigmatism at the time of cataract surgery

PURPOSE: To compare limbal relaxing incisions (LRIs) with placement of the corneal cataract incision on the steepest keratometric axis for the reduction of preexisting corneal astigmatism at the time of cataract surgery. SETTING: The Queen Elizabeth Hospital, Adelaide, South Australia, Australia. METHODS: In a prospective single center study, patients having 1.5 diopters (D) or more of keratometric astigmatism were randomly assigned to 2 surgical techniques: on-axis incisions (OAIs) consisting of a single clear corneal cataract incision centered on the steepest corneal meridian or LRIs consisting of 2 arcuate incisions straddling the steepest corneal meridian and a temporal clear corneal incision. Vector analysis of the target axis flattening effect was used to assess the efficacy of treatment. RESULTS: Seventy-one eyes of 71 patients were evaluated, 33 in the OAI group and 38 in the LRI group. Six weeks postoperatively, the flattening effect was 0.41 D (median and interquartile range 0.15 to 0.78 D) in the OAI group and 1.21 D (range 0.43 to 2.25 D) in the LRI group (P = .002). After 6 months, the flattening effect was 0.35 D (range 0.00 to 0.96 D) and 1.10 D (range 0.25 to 1.79 D), respectively (P = .004). CONCLUSION: The amount of astigmatism reduction achieved at the intended meridian was significantly more favorable with the LRI technique, which remained consistent throughout the follow-up period.     

Corneal astigmatism induced by superior versus temporal corneal incisions for extracapsular cataract extraction

Purpose : We tested the hypothesis that superior corneal sections induce a shift to 'against-the-rule' astigmatism and temporal corneal sections lead to
Methods : We conducted a prospective randomised trial of superior versus temporal corneal incisions in extracapsular cataract surgery in a hospital practice. Thirty nine eyes of 37 patients were included. The induced astigmatism was analysed by three methods.
Results : When analysed by Cravy's method of induced astigmatic cylinders, the superior incision induced a greater degree of 'with-the-rule' astigmatic cylinder prior to sutures removal on day 77 ( P <0.049). Long term, the temporal incision produced 1.44 dioptre of 'with-the-rule' astigmatism, while the superior section produced 0.08 dioptre of 'against-the-rule' astigmatism ( P <0.001).
Conclusion : The results of this small trial indicates that the superior corneal incision produces significantly less astigmatism than the temporal incision. The temporal incision induces a moderate degree of 'with-the-rule' astigmatism.     

Surgically induced astigmatism after micro and small clear temporal corneal incision in cataract surgery

PURPOSE: To compare surgically induced astigmatism among 3 sizes of temporal corneal incisions in cataract surgery. PATIENTS AND METHODS: A retrospective review was carried out of case records of 48 patients (64 eyes) who underwent cataract surgery. The length of the corneal incision was 1.6 mm in five eyes, 2.2 mm in 33 eyes, and 3.0 mm in 26 eyes. Astigmatism was measured by keratometry readings before and 1 week, 1 month, and 3 months after surgery. Surgically induced astigmatism was calculated by vector analyses using the Cravy method. RESULTS: One week postoperatively, the mean surgically induced astigmatism was 0.00 +/- 0.69 diopter(D) in the 1.6 mm group, -0.05 +/- 0.61 D in the 2.2 mm group and 0.44 +/- 0.57 D in the 3.0 mm group. Three months after surgery, the mean surgically induced astigmatism was -0.05 +/- 0.08 D in the 1.6 mm group, -0.04 +/- 0.47 D in the 2.2 mm group and 0.47 +/- 0.59 D in the 3.0 mm group. The surgically induced astigmatism was significantly less in the 2.2 mm group than in the 3.0 mm group. CONCLUSION: The amount of induced astigmatism was significantly less in temporal corneal micro-incision cataract surgery than in small incision surgery.     

Astigmatism after small-incision clear corneal cataract extraction and intraocular lens implantation in children

PURPOSE: To investigate the magnitude of postoperative astigmatism in children having cataract extraction with intraocular lens (IOL) implantation through a 3.0 mm superior clear corneal incision. SETTING: Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, USA. METHODS: This retrospective chart review comprised all pediatric patients having cataract surgery with IOL implantation through a 3.0 mm clear corneal incision from 1997 to 2002. One hundred two eyes of 75 patients were included. All refractions were performed manually by an experienced pediatric ophthalmologist. RESULTS: The mean postoperative retinoscopic cylinder in all patients was 0.63 diopter (D) (range 0.0 to 4.50 D) at 1 month, 0.40 D (range 0.0 to 1.75 D) at 6 months, and 0.51 D (range 0.0 to 2.50 D) at 1 year. Patients aged 0 to 36 months at the time of surgery had a mean postoperative cylinder of 0.22 D at 1 month, 0.03 D at 6 months, and 0.21 D at 1 year. Patients between 36 months and 6 years of age at surgery had a mean refractive cylinder of 0.50 D, 0.38 D, and 0.75 D, respectively. Patients older than 6 years at surgery had a mean refractive cylinder of 0.94 D, 0.75 D, and 0.76 D, respectively. CONCLUSIONS: Small-incision clear corneal cataract extraction with IOL implantation in children led to minimal postoperative astigmatism that remained stable over time. Less astigmatism was observed in children having surgery before they were 36 months old.     

Surgically induced astigmatism after 3.0 mm temporal and nasal clear corneal incisions in bilateral cataract surgery

Aims:

To compare the corneal refractive changes induced after 3.0 mm temporal and nasal corneal incisions in bilateral cataract surgery.

Materials and Methods:

This prospective study comprised a consecutive case series of 60 eyes from 30 patients with bilateral phacoemulsification that were implanted with a 6.0 mm foldable intraocular lens through a 3.0 mm horizontal clear corneal incision (temporal in the right eyes, nasal in the left eyes). The outcome measures were surgically induced astigmatism (SIA) and uncorrected visual acuity (UCVA) 1 and 3 months, post-operatively.

Results:

At 1 month, the mean SIA was 0.81 diopter (D) for the temporal incisions and 0.92 D for nasal incisions (P = 0.139). At 3 months, the mean SIA were 0.53 D for temporal incisions and 0.62 D for nasal incisions (P = 0.309). The UCVA was similar in the 2 incision groups before surgery, and at 1 and 3 months post-operatively.

Conclusion:

After bilateral cataract surgery using 3.0 mm temporal and nasal horizontal corneal incisions, the induced corneal astigmatic change was similar in both incision groups. Especially in Asian eyes, both temporal and nasal incisions (3.0 mm or less) would be favorable for astigmatism-neutral cataract surgery.     

Surgically induced astigmatism after superotemporal and superonasal clear corneal incisions in phacoemulsification

PURPOSE: To evaluate surgically induced corneal astigmatism after small superotemporal and superonasal clear corneal incision cataract surgery. SETTING: Department of Ophthalmology, School of Medicine, University of Afyon Kocatepe, Afyon, Turkey. METHODS: This prospective study comprised 56 eyes of 28 patients who had bilateral phacoemulsification and implantation of a foldable intraocular lens (IOL) through a corneal tunnel incision. A superotemporal incision was used in all right eyes, and a superonasal incision was used in all left eyes. Topography was performed preoperatively and at 1 week, 1, 3, and 6 months, and 1 year. Surgically induced astigmatism (SIA) was calculated by vector analyses using the Holladay-Cravy-Koch method. The incision length was measured and was between 3.30 mm and 3.50 mm in all eyes. RESULTS: Although SIA did not differ significantly between the 2 incision groups (P>.05), decomposition of vectors showed that the horizontal component of SIA after superonasal incision was statistically significantly higher than superotemporal incision throughout the study (P<.05). Vertical components of SIA and the incision size after IOL implantation with the syringe/cartridge system between the 2 incision groups were not significantly different (P>.05). CONCLUSION: There was no statistically significant difference in SIA between superotemporal incisions in the right eyes and superonasal incisions in the left eyes 1 year after surgery for a surgeon who sits at the 12 o'clock. Superonasal clear corneal incisions can be used in left eyes and superotemporal clear corneal incisions in right eyes.     

Surgical approaches to correct corneal astigmatism at time of cataract surgery: a mini-review

Among refractive errors, astigmatism is the most common optical aberration, where refraction changes in different meridians of the eye. It causes blurred vision at any distance and includes corneal, lenticular, and retinal astigmatism. Cataract surgery used to cause a progressive increase in the pre-exisiting corneal astigmatism because of creating a surgically induced astigmatism, for example, a large size surgery incision. The development of surgical techniques during last decades has made cataract surgery interchange to treat preoperative corneal astigmatism at time of surgery. Nowadays, three surgical approaches can be used. By placing a sutureless clear corneal incision on the steep meridian of the cornea, a preoperative corneal astigmatism less than 1.0 D can be corrected. Single or paired peripheral corneal relaxing incisions (PCRIs) provide 1.0-3.0 D corneal astigmatism correction. PCRIs are typically used for treating 1.0-1.5 D of regular corneal astigmatism, if more than 2.0 D, the risk of overcorrection and irregular astigmatism is increased. When toric intraocular lenses (IOLs) are unavailable in markets, PCRIs are still a reasonable option for patients with up to 3.0 D of pre-existing corneal astigmatism. Toric IOLs implantation can correct 1.0-4.5 D of corneal astigmatism. Several IOLs are approved to correct a high degree of corneal astigmatism with cylinder power up to 12.0 D. These approaches can be used alone or in combination.