Estimation of surgically induced astigmatism after small-incision cataract surgery done by junior residents

Purpose: To estimate the postoperative astigmatism after small?incision cataract surgery (SICS) done by junior residents at the end of 1 and 3 months. Methods: This observational longitudinal study was conducted at the Department of Ophthalmology of a tertiary eye care hospital and research center. 50 patients enrolled in the study underwent manual small incision cataract surgery by junior residents. Preoperative detailed ocular examination was done, which included keratometric estimation using autokeratometer (GR?3300K). Incision length, distance of incision from the limbus, and type of suturing technique were noted. Postoperatively, keratometric readings were noted at 1 and 3 months. Astigmatism (surgically induced astigmatism [SIA]) was estimated using Hill’s SIA calculator version 2.0. All the analyses were performed using Statistical Package for the Social Sciences (SPSS) ver. 26.0 (IBM Corp., USA) software, and the statistical significance was tested at a 5% level. Results: Out of 50 patients, 54% had SIA between 1.5 and 2.5 D and 32% had SIA of more than 2.5 D. Only 14% had SIA less than 1.5 D at the end of 1 month. While 52% had SIA between 1.5 and 2.5 D, 22% had SIA between 1.5 and 2.5 D and 26% had SIA less than 1.5 D at the end of 3 months. Conclusion: The SIA in most of the SICS done by junior residents was above 1.5 D. It depended mainly on the incision length, its distance from the limbus, and the suturing technique.

Comparison of surgically induced astigmatic changes after cataract surgery in post-Laser in situ keratomileusis corneas versus virgin eyes / Comparação de alterações astigmáticas induzidas cirurgicamente após cirurgia de catarata em córneas ceratomileusis in situ pós-Laser versus olhos virgens

ABSTRACT Purpose: Postoperative refraction in modern mi­croincision cataract surgery gained extra importance in patients with the previous laser-assisted in situ keratomileusis (LASIK) surgery. The surgically induced astigmatic changes in those eyes may differ not only in magnitude but also in direction compared to virgin corneas. This study aimed to compare the surgically induced astigmatic changes after microscopic cataract surgery between post-LASIK corneas and virgin eyes. Methods: Cases that underwent microincision cataract surgery in eyes with and without previous LASIK surgery were reviewed. The demographics, the axial length at cataract surgery, the central corneal thickness, spheric and cylindric values, keratometry readings, and postoperative posterior corneal astigmatism were retrospectively evaluated. A modified Alpins method was used for astigmatic vector analysis, and baseline astigmatism, surgically induced astigmatism, difference vector, flattening effect, and torque were assessed. Results: A total of 42 eyes from 24 subjects was evaluated. Group I consisted of 14 eyes with the previous LASIK, and Group II included 28 eyes without any refractive surgery. Preoperative mean central corneal thickness in Group I was significantly thinner (p=0.012). There was no significant difference in baseline astigmatism between the groups regarding magnitude and power vectors. After microincision cataract surgery, there were no significant differences in mean spheric and cylindric values and mean keratometry readings (all p>0.05). However, surgically induced astigmatism and difference vector were significantly higher on J45 vector component in post-LASIK eyes and microincision cataract surgery steepening effect on post-LASIK corneas was significantly higher than those in virgin eyes (p=0.001, p=0.002 and p=0.018, respectively). Conclusions: Cataract surgery has steepened the corneas in both groups with a significantly higher steepening effect in post-LASIK eyes. Certainly, corneal topography cataract surgery is particularly helpful to provide more precise surgically induced astigmatism interpretations.

RESUMO Objetivo: A refração pós-operatória na cirurgia mo­derna de catarata por microincisão ganha ainda mais importância em pacientes com cirurgia prévia de ceratomileuse in situ assistida por laser (LASIK). As alterações astigmáticas induzidas cirurgicamente nesses olhos podem diferir não apenas em magnitude, mas também em direção em comparação com córneas virgens. O objetivo deste estudo foi comparar as alterações astigmáticas induzidas cirurgicamente após cirurgia de catarata por microincisão entre córneas pós-LASIK e olhos virgens. Métodos: Foi revisada uma série de casos de cirurgia de catarata por microincisão em olhos com e sem cirurgia LASIK anterior. Os dados demográficos, o comprimento axial no momento da cirurgia de catarata, a espessura central da córnea, os valores esféricos e cilíndricos, as leituras da ceratometria e o astigmatismo corneano posterior pós-operatório foram avaliados retrospectivamente. O método Alpins modificado foi usado para análise vetorial astigmática e foram avaliados o astigmatismo basal, o astigmatismo induzido cirurgicamente, o vetor de diferença, o efeito de achatamento e o torque. Resultados: Ao todo, 42 olhos de 24 indivíduos foram avaliados. O Grupo I consistiu em 14 olhos com LASIK prévio; o Grupo II incluiu 28 olhos sem qualquer cirurgia refrativa. A média da espessura corneana central pré-operatória no Grupo I foi significativamente mais fina (p=0,012). Não houve diferença significativa no astigmatismo basal entre os grupos em termos de magnitude e vetores de potência. Após a cirurgia de catarata por microincisão, não houve diferenças significativas nos valores médios esféricos, cilíndricos e leituras médias de ceratometria (todos com p>0,05). No entanto, o astigmatismo induzido cirurgicamente e o vetor de diferença foram significativamente maiores no componente do vetor J45 em olhos pós-LASIK, e o efeito de aumento da inclinação pela cirurgia de catarata por microincisão nas córneas pós-LASIK foi significativo em comparação com olhos virgens (p=0,001, p=0,002 e p=0,018, respectivamente). Conclusões: A cirurgia de catarata aumentou a inclinação das córneas em ambos os grupos, sendo esse aumento significativamente maior nos olhos pós-LASIK. Certamente, a topografia da córnea antes da cirurgia de catarata é particularmente útil para fornecer interpretações mais precisas do astigmatismo induzido cirurgicamente.

The influencing factors of surgically induced astigmatism in phacoemulsification / 西安交通大学学报(医学版)

【Objective】 To investigate the influencing factors of surgically induced astigmatism (SIA) in phacoemulsification. 【Methods】 Cataract phacoemulsification was performed in 69 patients with regular corneal astigmatism from December 2021 to March 2022. SIA of the anterior corneal surface, posterior corneal surface and simulated keratometry (SimK) in the diameter range of 3 mm, 5 mm and 7 mm centered at the apex of the cornea was observed. Pearson correlation analysis was used to analyze SIA with age, axial length (AL), anterior chamber depth (ACD), white-to-white (WTW), and central corneal thickness (CCT). Multiple linear regression was used to analyze the influencing factors of SIA. 【Results】 The mean age of the 69 patients was (63.25±14.74) years old, and 28 (40.58%) were male. The analysis found that the |SIA| of SimK was negatively correlated with WTW (r=-0.265, P=0.028), the |SIA| of 3 mm, 5 mm, 7 mm anterior surface was negatively correlated with WTW (r=-0.320, P=0.007; r=-0.337, P=0.005; r=-0.287, P=0.017), and the |SIA| of 3 mm, 5 mm, 7 mm posterior surface was negatively correlated with AL (r=-0.390, P=0.001; r=-0.352, P=0.003; r=-0.317, P=0.008). Multiple regression analysis showed that WTW was negatively correlated with |SIA| of SimK, 3 mm, 5 mm, 7 mm anterior surface and 3 mm posterior surface (B=-0.261, P=0.047; B=-0.387, P=0.016; B=-0.323, P=0.009; B=-0.297, P=0.041; B=-0.085, P=0.049). WTW was positively correlated with XSIA of 3 mm anterior surface, YSIA of 5 mm, and 7 mm anterior surface (B=0.347, P=0.040; B=0.318, P=0.034; B=0.403, P=0.010). AL was negatively correlated with |SIA| on the posterior surface of 3 mm and 5 mm (B=-0.023, P=0.021; B=-0.034, P=0.030). 【Conclusion】 During cataract surgery, the effect of ocular biological parameters such as axial length and corneal diameter on SIA should be considered.

Correction of pre-existing astigmatism by on-axis incision size modulation in manual small-incision cataract surgery

Purpose: To study the effect of wound size modulation on pre?existing astigmatism by on?axis placement of incision in manual small?incision cataract surgery (MSICS). Methods: In this prospective interventional study conducted at a tertiary care centre, 40 eyes of 40 consecutive senile cataract patients with 1.00�00 D corneal astigmatism were enrolled for the study. MSICS by modified Blumenthal抯 technique was performed through 6.0, 6.5, and 7.0 mm on?axis incision in 1.0�49 D (group A), 1.50�99 D (group B), and 2.00�00 D (group C) astigmatism, respectively. Surgically induced astigmatism (SIA) was calculated by vector analysis and double angle plots (DAP) at 12 weeks postoperatively. Results: There were 22 males and 18 females with mean age of 58.12 � 1.18 years. The mean SIA at 12 weeks was 0.85 � 0.28 D in group A (17 eyes), 1.32 � 0.65 D in group B (10 eyes), and 1.91 � 0.69 D in group C (13 eyes). The overall median uncorrected visual acuity was 0.18 (IQR = 0 to 0.2). The mean astigmatism decreased from 1.95 � 0.74 D to 1.04 + 0.57 D (P = 0.00) in superior incision and from 1.70 + 0.50 D to 0.92 � 0.45 D (P = 0.00) in temporal incision group with central shift of centroid in all cases. Conclusion: The customization of on?axis external incision size can be used to manage pre?existing corneal astigmatism of less than 3.00 D using both temporal and superior incisions effectively

Evaluation of scleral incisions and their effects on corneal curvature in manual small-incision cataract surgery

Purpose: Incisions in cataract surgery can be modified in various ways in terms of size, shape, and axis to reduce or tailor astigmatism. This study was conducted to examine the effect of site (superior vs, temporal) and shape (frown vs. V?shaped, chevron) of scleral incisions for cataract surgery on corneal curvature. Methods: The prospective study was carried out on 200 consecutive patients with senile cataract and who were planned for surgery at a tertiary eye hospital in north India. The placement of the incision was decided by the steeper corneal meridian梬hether superior or temporal梐nd then patients of these two groups were randomized for frown and V?shaped incision; in this way, four groups of 50 patients each were formed. Follow?up was done on day 1, at 2 weeks, 4 weeks, 8 weeks, and 12 weeks. At each follow?up, post?operative keratometry with routine postoperative examination was done. The results were statistically analyzed by using student抯 t?test, Chi?squared test, and the Pearson correlation coefficient. Results: In all the four groups, the difference of preoperative astigmatism and surgically?induced astigmatism was statistically highly significant. The analysis of uncorrected visual acuity (UCVA) was statistically significant (P < 0.05) on postoperative day 1 and at 2, 4, and 12 postoperative weeks; it was statistically insignificant (P > 0.05) at postoperative week 8. Conclusion: Temporal incisions result in lesser postoperative surgically induced astigmatism (SIA) than superior incisions. Chevron incisions result in minimal change in corneal curvature. This effect can be utilized to tailor the postoperative astigmatism.

Customized incision cataract surgery: Astigmatism modulation techniques in manual small-incision cataract surgery

Advanced instrumentation and intraocular lenses (IOL) allow great refractive and visual outcome control to permit excellent correction of refractive aberrations. Residual astigmatism can be modified to provide depth of focus using an appropriate incision in the steepest meridian in manual small-incision cataract surgery (MSICS). The authors describe the nomogram for surgically correcting astigmatism (SCA). This technique can handle preoperative astigmatism of about 2.25 DCyl with the standard incisions梥traight incision of 5, 6, and 7 mm in length, the minimally curved frown incision, the frown incision, the frown incision with an accentuated frown, and the U incision placed on the steep axis in the superior or the temporal quadrant depending on the axis of pre-operative astigmatism.

Visual outcome after manual small-incision cataract surgery by viscoexpression technique

Purpose: Globally, cataracts have remained the major cause of blindness. Cataract accounts for 62.6% of blindness affecting 9� million people. The only treatment for cataracts is surgical removal of cataracts. The surgical procedures include phacoemulsification and extracapsular cataract extraction (ECCE). In India, there is a huge backlog of cataract patients. Phacoemulsification is preferred nowadays for early visual rehabilitation, but in developing countries like ours, where facilities are not widely available, small-incision cataract surgery (SICS) is a cost-effective alternative as no machine is required. Also, it provides early visual rehabilitation as it is sutureless when compared to ECCE. So, manual SICS has emerged as a substitute for phacoemulsification and ECCE. The aim of the study was to evaluate the visual acuity and surgically induced astigmatism in patients more than 40 years of age, undergoing manual SICS with nucleus management by viscoexpression technique. Methods: This was a prospective study that included 50 patients over the age of 40 years undergoing manual SICS at a tertiary health-care center in North India by viscoexpression technique. Only those patients whose functional visual disability could be attributed to cataracts were included in the study. Preoperative and postoperative astigmatism were analyzed in the first, fourth, and sixth weeks. Results: Fifty patients who were undergoing manual SICS were analyzed. Preoperative best-corrected visual acuity (BCVA) and astigmatism were compared to postoperative BCVA and astigmatism. Of 50 patients, 48 (96%) patients were able to gain good vision after 6 weeks. Conclusion: This study showed early visual rehabilitation with less surgically induced astigmatism following manual SICS by viscoexpression technique.

Re-inventing the straight incision with a single central suture in manual small-incision cataract surgery to minimize surgically induced astigmatism

Purpose: To calculate the surgically induced astigmatism (SIA) in MSICS through a superiorly placed straight scleral incision closed with a single, central, perpendicular 10?0 polyamide suture and to document any suture?related complaints and complications. Methods: A retrospective, hospital?based study was carried out in 50 cases of uncomplicated senile cataract (>50 year) with nuclear sclerosis ? grade 4, 搘ith the rule� astigmatism who underwent MSICS through a superior, straight incision with a single, central, perpendicular 10?0 nylon suture. Patients with 揳gainst the rule� astigmatism, keratoconus, pre?existing corneal opacity, astigmatism >2D, distorted or oblique mires, and previous ocular surgeries and unwilling to participate were excluded. Results: The mean age of the patients was 64.81 + 2.824 years, with a male: female ratio of 1.38:1. The mean SIA at day 7, week 6, and 12 weeks was 0.539 + 0.118, 0.529 + 0.134, and 0.524 + 0.129, respectively. Only 6 patients (12%) complained of foreign body sensation. No patient developed any suture?related complications. Conclusion: SIA is significantly reduced in straight incision by applying a single, central, and perpendicular 10?0 polyamide suture, as compared to a straight incision without a suture.

Comparison of surgically induced astigmatism in chevron, straight, and frown incisions in manual small-incision cataract surgery

Purpose: The study was conducted to calculate and compare the surgically induced astigmatism (SIA) in chevron, frown, and straight incisions in manual small-incision cataract surgery (MSICS). Methods: A prospective, hospital-based study was conducted on 90 patients aged 50 years and above with nuclear sclerosis of grade 4 or more. Each group had 30 patients, divided into Group V (chevron incision), Group S (straight incision), and Group F (frown incision). Patients who had with-the-rule (WTR) astigmatism were operated on through a chevron or straight incision superiorly, while patients who had against-the-rule (ATR) astigmatism underwent MSICS through a temporal frown incision. The patients were followed up post-operatively on days 1, 7, 6 weeks, and 12 weeks, and at each visit, the uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), and SIA were calculated and compared. Results: The mean age of all the patients was 66.22 � 8.05 years. BCVA of at least 6/18 or better at 12 weeks post?operatively was achieved in 29 patients (97%) in Group V, 28 patients (93%) in Group F, and 29 patients (97%) in Group S. The mean SIA in Group V was 0.34D � 0.22D, in Group S was 0.97D � 0.29D, and in Group F was 0.575D � 0.25D. Conclusion: SIA by chevron incision is the least followed by the frown incision and straight incision. The superiorly placed chevron incision in WTR astigmatism provided optimal results for the best UCVA and minimal SIA. The temporal frown incision in ATR astigmatism also had good results.

Surgically induced astigmatism and refractive outcomes following phacotrabeculectomy

Purpose: To objectively evaluate surgically induced astigmatism (SIA) after phacotrabeculectomy using keratometry and topography and to compare the magnitude of SIA and the refractive outcomes of single-site and twin-site phacotrabeculectomies. Methods: Forty prospective subjects were enrolled in the study and were randomized into single-site and twin-site cohorts. SIA was objectively assessed using keratometry and Orbscan before and at three months after surgery. For both cohorts, the changes in SIA were assessed using power vector analysis compared at the third month after surgery. Results: Each cohort consisted of 20 eyes. The preoperative parameters and postoperative IOP were comparable and similar, respectively, in both the cohorts (P = 0.1). Majority of the patients in both the cohorts had preoperative against-the-rule (ATR) astigmatism. The median change in SIA at the three-month postoperative visit was similar in both the cohorts, with a small increase in ATR astigmatism. Although the SIA change measured by keratometry in the J0 component was similar in both the groups (P = 0.54), that of J45 was significantly different (P = 0.01). However, the median change in SIA was similar in both the groups for both the J0 (P = 0.52) and J45 components (P = 0.94) when measured by Orbscan. The SIA in both the groups measured with keratometry (P = 0.62) and topography (P = 0.52) were clinically and statistically similar. In both the groups, the refraction was similar at 1 month and 3 months. Conclusion: The SIA as measured with keratometry and topography was similar in the single-site and twin-site phacotrabeculectomy cohorts at the end of 3-months. The postoperative refraction was stabilized in 1-month in both the groups.

Safety and efficacy of fibrin glue versus infinity suture in SICS with extended scleral flap

Purpose: To study the safety and efficacy of biologic fibrin glue (FG) in comparison with infinity suture in SICS with compromised scleral flap. Methods: A retrospective comparative study of patients who were treated with FG (Group A) with 10�nylon (Group B) as sealing agent for intraoperative compromised tunnels in SICS. Parameters noted were postoperative inflammation, wound integrity, anterior chamber (AC) depth, intraocular pressure (IOP), and surgically induced astigmatism (SIA) at postoperative day 1, 4 weeks, 6 weeks, and 6 months, respectively. Epi Info 7 software and SIA calculator, Version 2.1 were used to analyze the result. Results: We reviewed the two groups of 18 patients each and noted that there was no statistically significant difference in postoperative inflammation (P > 0.05), AC depth (P > 0.05), and IOP (P > 0.05) between both groups at each postoperative visit. One patient in Group A showed postoperative shallow AC and subconjunctival bleb. Exposed sutures causing foreign body sensation had to be removed in five patients in Group B. At the end of 6-month postoperative period, no statistically significant difference was found in SIA (P = 0.92) between the two groups. Conclusion: Biologic FG can be safely used in securing the compromised scleral incisions in SICS. It also avoids suture-related complications.

Effects of femtosecond laser-assisted cataract surgery on corneal astigmatism and SIA in patients with age-related cataract / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM:To explore the effects of femtosecond laser-assisted cataract surgery(FLACS)on corneal astigmatism and surgically induced astigmatism(SIA)value in patients with age-related cataract. <p>METHODS: Totally 152 cases of age-related cataract patients(233 eyes)admitted to our hospital were divided into the study group(<i>n</i>=70, 107 eyes, given the FLACS)and the control group \〖<i>n</i>=82, 126 eyes, given the traditional phacoemulsification cataract surgery(TS)\〗 according to the economic conditions and voluntary principles. Corneal astigmatism degree and SIA value were compared between the two groups. <p>RESULTS: The effective ultrasound time, average ultrasound energy, and total operative time in the study group were less than those in the control group(<i>P</i><0.05). There was no significant difference in the intraocular pressure between the two groups before operation and at 1 and 3mo after operation(<i>P</i>>0.05). The difference in intraocular pressure was statistically significant of the two groups at different time points(<i>P</i><0.05). The two groups showed a downward trend in intraocular pressure(<i>P</i><0.05). There were statistically significant differences in the accumulated energy complex parameter(CDE)values of phacoemulsification between the two groups of grade Ⅱ nuclear and grade III nuclear surgery, and the intraoperative CDE value of grade Ⅲ nuclear in the two groups was higher than that of grade Ⅱ nuclear(<i>P</i><0.05). The difference in visual acuity and best corrected visual acuity between the two groups at different time points was statistically significant(<i>P</i><0.05). The uncorrected visual acuity and best corrected visual acuity were significantly improved in the two groups(<i>P</i><0.05). The uncorrected visual acuity and best corrected visual acuity in the study group were better than those in the control group at 1mo after operation(<i>P</i><0.05), but there was no significant difference at 3mo after operation(<i>P</i>>0.05). There was no significant difference in corneal astigmatism between the two groups and at different time points(<i>P</i>>0.05). There was no significant difference in surgical astigmatism between-groups at 1 and 3mo after operation(<i>P</i>>0.05).The surgical astigmatism at 3mo after operation was lower than that at 1mo after operation(<i>P</i><0.05). There were significant differences in corneal endothelial cell counts between the two groups at different time points(<i>P</i><0.05). There was no significant difference in corneal endothelial cell counts in the study group before operation and at 1mo after operation(<i>P</i>>0.05). The corneal endothelial cell counts in control group at 1mo after operation was lower than that before operation(<i>P</i><0.05). There was no significant difference in the corneal endothelial cell counts between the two groups before operation and at 1mo after operation(<i>P></i>0.05). The corneal endothelial cell counts in the study group were significantly more than those in the control group at 3mo after operation(<i>P</i><0.05). The corneal endothelial loss rate was significantly lower in the study group at 1 and 3mo after operation than that in the control group(<i>P</i><0.05). <p>CONCLUSION: FLACS can effectively improve the postoperative visual acuity in patients with age-related cataract, and it will not increase the postoperative corneal astigmatism and SIA.

Different sized incisions for phacoemulsification combined with vitrectomy in the treatment of age- related cataract associated with maculopathy / 中国医师进修杂志

Objective To compare the clinical efficacy of different sized incisions for phacoemulsification combined with vitrectomy in the treatment of age-related cataract associated with maculopathy. Methods From January 2016 to October 2016, a total of 60 eyes of 60 senile cataract patients with maculopathy were prospectively divided into the micro incision group and the standard incision group according the random number table,with 30 cases in each group.The micro incision group received a 1.8 mm micro incision for phacoemulsification combined with 23G vitrectomy and the standard incision group underwent a 2.8 mm incision for phacoemulsification combined with 23G vitrectomy.The intraoperative conditions and the postoperative complications of the two groups at 1 d, 1 and 6 months after surgery were compared. The intraocular pressure (IOP), best corrected visual acuity (BCVA), surgically induced astigmatism (SIA), dry eye symptoms (Sx), break-up time (tBUT), schirmer test (ST)-Ⅱwere respectively measured at 1 and 6 months after surgery.Results The operation procedures were similar in two groups,and there were no significant differences in the operative time and the incidence of intraoperative complications(P>0.05).There were no significant differences in IOP and the incidence of postoperative complications between two groups at 1 d, 1 and 6 months after surgery (P>0.05). At the time point of 1 month after operation,there was no significant difference in BCVA between two groups,but the level of SIA in micro incision group was lower:0.4 ± 0.2 vs.0.6 ± 0.3,t=3.038,P=0.004;the level of Sx micro incision group was lower: (1.2 ± 0.8)score vs. (1.8 ± 1.1) scores, t = 2.416, P = 0.019; the level of tBUT was higher:(5.2 ± 1.6)s vs.(3.8 ± 1.3)s, t = 3.454,P = 0.001;the level of ST-Ⅱwas higher: (4.7 ± 2.1) mm vs. (3.5 ± 1.8), t = 2.376, P = 0.021; there were significant differences. At 6 months after operation,there were no significant differences in the indexes of BCVA,SIA,Sx,tBUT and ST-Ⅱbetween two groups(P>0.05).Conclusions The different sized incisions for phacoemulsification combined with vitrectomy in the treatment of senile cataract associated with maculopathy are similarly safe and effective. However, the micro incision surgery can improve the surgically-induced astigmatism and dry eye in the early stage,with a shorter postoperative recovery time.

Vector analysis and comparison of surgically induced astigmatism after coaxial phacoemulsification with 2.2-and 2.8-mm clear corneal incisions / 眼科新进展

Objective To evaluate the surgically induced astigmatism (SIA)caused by coaxial phacoemuisification and intraocular lens (IOL) implantation with different clear corneal incision.Methods Clinical data of 97 patients 97 eyes underwent phacoemulsification and IOL implantation with 2.2 mm (2.2 mm group,44 eyes) or 2.8mm (2.8 mm group,53 eyes) clear corneal incisions were retrospectively reviewed.The corneal curvature were measured before and four weeks after the surgery.Then SIA were calculated,followed by analysis of the differences in mean SIA and centroid SIA between the 2.2 mm and 2.8 mm groups.Results At 4 weeks after surgery,the centroid and mean SIA of the 2.8 mm group was (0.234 ± 0.423) D@105° and (0.552 ±0.349) D,respectively;the corresponding data was (0.174 ± 0.464) D@104° and (0.582 ±0.392) D in the right eyes,and (0.272 ±0.382)D@106° and (0.545 ±0.300) D in the left eyes,respectively.At 4 weeks after surgery,the centroid and mean SIA of the 2.2 mm group was (0.108 ±0.417)D@98°and (0.506 ±0.362) D,respectively;the corresponding data was (0.145 ±0.404)D@81° and (0.5182 ±0.332)D in the right eyes,and (0.127 ± 0.418) D@120° and (0.516 ± 0.418) D in the left eyes,respectively.There was no significant difference in centroid SIA and mean SIA,centroid SIA and mean SIA of the right and left eyes,as well as both eyes between the two groups (all P＞0.05);Atotal of 47 patients (48.5％) had SIA greater than 0.5 D,and 28 patients (52.8％) were in the 2.8 mm groups,including 12 patients (22.6％) in the right eyes and 16 patients (20.5％) in the left eyes;as well as 19 patients (43.2％) in the 2.2 mm group,including 10 patients (22.7％) in the right eyes and 9 patients (20.5％) in the left eyes.There was no significant difference in the proportion of SIA greater than 0.5 D and the proportion of SIA between the left and right eyes greater than 0.5 D between the two groups (all P ＞ 0.05).Conclusion The mean SIA and centroid SIA are not statistically different in the 2.2 mm group than in the 2.8 mm group,but SIA were more stable in the 2.2 mm group than in the 2.8 mm group.The axis of the SIA were closely related to the position of the incisions,which were the vertical direction of the incisions.

Measurement and clinical significant of posterior corneal astigmatism / 眼科新进展

Corneal astigmatism includes anterior astigmatism (AA) and posterior astigmatism (PA).According to the hterature,85.0％-96.1％ PA ranging from-0.01 to-1.10 D refers to astigmatism against the rule.With the age increasing,PA shows a significant trend from astigmatism against the rule to with the rule,while AA shows toward against-the-rule astigmatism.Therefore,PA often leads to partially decrease of total astigmatism (TA) in young adults,but the increase of TA in aged elderly.Clinically,ignorance of PA will lead to a false estimate of TA,thereby affecting visual quality after refractive cataract surgery.And this article aims to introduce the measurement of PA and its clinical significance for providing the reference in clinical practices.

Short-term efficacy of posterior chamber phakic intraocular lens implantation for moderate to high myopia / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To evaluate the short-term efficacy of posterior chamber phakic intraocular lens implantation for moderate to high myopia.METHODS:Fifty-three eyes of 27 patients with moderate to high myopia (-3.25 to-21.5D) were received posterior chamber phakic intraocular lens implantation with 2.8mm clear corneal incision.Changes of visual acuity, intraocular pressure(IOP), counts of endothelial cells and surgically induced astigmatism at 1mo after surgery were observed.RESULTS:The preoperative best corrected visual acuity (BCVA LogMAR) were 0.05±0.18, the postoperative BCVA at 1d were 0.02±0.14, the postoperative BCVA at 1wk were-0.05±0.11, the postoperative BCVA at 1mo were-0.07±0.10.The postoperative BCVA were statistically significant differences in different time(P<0.05).The preoperative endothelial cell count was 2932.5±270.8/mm2, the postoperative endothelial cell count at 1d was 2917.1±299.0/mm2;the postoperative endothelial cell count at 1wk was 2902.5±288.6/mm2;the postoperative endothelial cell count at 1mo was 2855.3±284.2/mm2.The postoperative endothelial cell count was not statistically significant differences in different time.The preoperative IOP was 15.8±2.5mmHg;the postoperative IOP at 1d was 15.3±2.9mmHg;the postoperative IOP at 1wk was 17.4±5.8mmHg;the postoperative IOP at 1mo were 15.8±2.6mmHg.The preoperative IOP was significantly different compared with postoperative IOP at 1d, 1wk and 1mo.The postoperative IOP at 1d and 1wk were statistically significant differences (P<0.05).The surgically induced astigmatism at 1d was 0.74±0.39D;the surgically induced astigmatism at 1wk was 0.57±0.28D;the surgically induced astigmatism at 1mo was 0.44±0.21D.The postoperative IOP were statistically significant differences in different time (P<0.05).The preoperative anterior chamber depth was 3.26±0.25mm;the postoperative central vault at 1d were 654.5±345.2μm;the postoperative central vault at 1mo were 683.0±211.7μm.The postoperative central vault were significantly different between that at 1d and 1mo after operations.Operations went without serious complications.CONCLUSION:Posterior chamber phakic intraocular lens implantation for moderate to high myopia were safe, effective and predictability.But long-term effect remains needed to be further follow-up.

Comparison of anterior chamber maintainer and viscoelastic agent on corneal astigmatism and endothelial cells after phacoemulsification / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To compare the influence of anterior chamber maintainer and viscoelastic agent on corneal astigmatism and endothelial cells after phacoemulsification.METHODS:Totally 70 patients(70 eyes) of cataract from April 2013 to April 2015 were randomly divided into the study group and the control group, with 35 cases in each group.The study group were treated with anterior chamber maintainer during phacoemulsification with support system approach, and the control group were treated with phacoemulsification under viscoelastic agent.RESULTS:The age (t=0.215, P=0.831), the density of corneal endothelial cells (t=-0.352, P=0.726) and corneal luminosity (t=-0.162, P=0.872) of two groups had no significant difference before surgery;there were no significant difference in preoperative visual acuity (t=0.463, P=0.599) and visual acuity (t=1.616, P=0.124) at 1mo after operation.And patients in the study group (t=-21.129, P<0.01) and the control group (t=-12.780, P<0.01) before surgery and 1mo postoperative when compared with the naked eye eyesight showed significant difference.The visual acuity after operations improved significantly.There were significant differences of corneal endothelial cells density (t=8.489, P< 0.01) and corneal astigmatism (t=-2.032, P=0.046) in the study group before surgery and 1mo after surgery;corneal endothelial cell density (t=8.999, P<0.01) and corneal astigmatism (t=-2.167, P=0.034) in the control group before surgery and 1mo after surgery also had significant differences.There was no significant difference in the rate of corneal endothelial cell loss between the two groups (t=0.410, P=0.683).CONCLUSION:Compared with viscoelastic agent, anterior chamber maintainer during phacoemulsification in patients with cataract won't increase the damage of postoperative surgically induced astigmatism and corneal endothelial cells, which mean the method of anterior chamber maintainer during phacoemulsification in the treatment of cataract is safe and effective.

Evaluation of the Relationship between Incision Location and Change of Posterior Corneal Astigmatism

PURPOSE: To determine if there is a difference in surgically induced astigmatism (SIA) of the posterior corneal surface between superior and temporal incision and its effect on total corneal power in patients who underwent clear corneal incision cataract surgery. METHODS: A retrospective study of 81 patients (84 eyes) who underwent clear corneal incision phacoemulsification by one surgeon. Patients were divided into two groups according to the steep axis: the temporal and superior groups. Anterior, posterior and total corneal SIA (simulated keratometry [Sm K], posterior keratometry [PK] and total corneal power [TCP] respectively) were measured using autorefractive keratometry (ARK) and dual Scheimpflug imaging before and after surgery. RESULTS: There were 61 eyes with temporal incision and 23 eyes with superior incision. The mean SIA was larger in the superior incision group than in the temporal incision group according to ARK, Sm K, PK and TCP (p < 0.05). There were no significant cylindrical changes in ARK in the temporal incision group, however, there was a significant decrease in the superior incision group before and after the operation (p < 0.05). Change in the amount and axis of PK before and after operation were not significantly different, for both incision groups. There was a significant correlation between post-operative TCP and both pre-operative ARK and Sm K for both groups. However, there was no correlation between post-operative TCP and pre-operative PK. In all patients, when pre-operative PK was more than 0.5 D, SIA-ARK, SIA-Sm K and SIA-TCP were all significantly larger than when pre-operative PK was less than 0.5 D, whereas SIA-PK was not. When pre-operative PK was more than 0.5 D, there were no significant differences in SIA-ARK, SIA-Sm K, SIA-PK or SIA-TCP in the temporal incision group. However, SIA-ARK was significantly larger in the superior incision group. CONCLUSIONS: There was no significant cylindrical change in PK before and after operation in both the temporal and superior incision groups. Therefore, when predicting post-operative TCP, it might be meaningful to consider SIA-ARK and SIA-Sm K.

Comparison of changes in astigmatism after cataract surgery in temporal versus superior incisions.

Introduction- Patients undergoing cataract surgery develop astigmatism based on location of incision. This retrospective study investigated the “Pre & post operative astigmatism after cataract surgery based on incision”. Purpose of this study was to compare astigmatismobtained in temporal & superior incision. Material and Methods- Out of 50 cataract patients collected, 25 patients were in the temporal incision PHACO group and 25 were in the superior incision PHACO group. Corneal astigmatism and corrected visual acuity were assessed 30 and 90 days after cataract surgery. Results- against the rule astigmatism is more common after superior incision cataract surgery and with the rule astigmatism is more common after temporal incision cataract surgery. Conclusion: The study reveals temporal incision, increase with the rule & superior incision increase against the rule and also concluded astigmatism is least in temporal incision.

Comparative Study of Surgically Induced Astigmatism in One and Two Side Port 2.8mm Clear Corneal Temporal Phacoemulsification in Cataract Surgery.

Background: Surgically induced astigmatism (SIA) remains a common obstacle for achieving an excellent UCVA (Un Corrected Visual Acuity). The aim of this study is to compare surgically induced astigmatism (SIA) after one or two side ports with clear corneal temporal 2.8 mm phacoemulsification cataract surgery. Methods: Study comprised a multi-centric, nonrandomized prospective consecutive series of 358 eyes of 328 patients between age group of 9 to 71 years who had uneventful 2.8mm main temporal clear corneal incision and one or two side ports phacoemulsification cataract surgery with implantation of aspheric foldable intraocular lens (IOL). All surgery was performed by one experienced surgeon. Surgically induced astigmatism was calculated using Holladay-Carvy-Koch formula method. Results: At 1.5 months, the mean SIA was 0.51 diopter (D) for the one side port incisions and 1.50 D for two side port incisions (P = 0.04). At 3 months, the mean SIA were 0.41 D for one side port incisions and 1.25 D for two side port incisions (P = 0.03). Conclusion: The UCVA was far better in the one side port group, at 1.5 and 3 months post-operatively.