Corneal astigmatic outcomes after femtosecond laser-assisted cataract surgery combined with surface penetrating arcuate keratotomies

AIM:To evaluate corneal astigmatic outcomes of femtosecond laser-assisted arcuate keratotomies(FAKs)combined with femtosecond-laser assisted cataract surgery(FLACS)over 12mo follow-up.METHODS:Totally 145 patients with bilateral cataracts and no ocular co-morbidities were recruited to a singlecentre,single-masked,prospective randomized controlled trial(RCT)comparing two monofocal hydrophobic acrylic intraocular lenses.Eyes with corneal astigmatism(CA)of>0.8 dioptres(D)received unpaired,unopened,surface penetrating FAKs at the time of FLACS.Visual acuity,subjective refraction and Scheimpflug tomography were recorded at 1,6,and 12mo.Alpins vectoral analyses were performed.RESULTS:Fifty-one patients(61 eyes),mean age 68.2±9.6y[standard deviation(SD)],received FAKs.Sixty eyes were available for analysis,except at 12mo when 59 attended.There were no complications due to FAKs.Mean pre-operative CA was 1.13±0.20 D.There was a reduction of astigmatism at all post-operative visits(residual CA 1mo:0.85±0.42 D,P=0.0001;6mo:0.86±0.35 D,P=0001;and 12mo:0.90±0.39,P=0.0001).Alpins indices remained stable over 12mo.Overall,the cohort was under-corrected at all time points.At 12mo,61%of eyes were within±15 degrees of pre-operative astigmatic meridian.CONCLUSION:Unpaired unopened penetrating FAKs combined with on-axis phacoemulsification are safe but minimally effective.CA is largely under-corrected in this cohort using an existing unmodified nomogram.The effect of arcuate keratotomies on CA remained stable over 12mo.

Non-Penetrating Femtosecond Laser Intrastromal Astigmatic Keratotomy Performed during Laser-Assisted Cataract Surgery: Results on Keratometric Astigmatism

Purpose: To investigate the efficacy of non-penetrating femtosecond laser intrastromal astigmatic keratotomy (ISAK) in terms of topographic and refractive changes. Methods: Retrospective study including 42 eyes (35 patients) with a corneal astigmatism between 0.5 and 1.5 D. All eyes underwent femtosecond laser-assisted cataract surgery with ISAK for astigmatism management using the Catalys laser system (Johnson & Johnson Vision). Visual acuity, refraction, as well as corneal topographic and corneal endothelial cell density (ECD) changes were evaluated during a 12-month follow-up. Astigmatic changes were analyzed using the Alpins vector method. Results: A significant reduction in manifest cylinder was observed at 1 month postoperatively (p = 0.03), with no significant changes afterwards (p = 0.90). A total of 38.1%, 52.4% and 59.2% of eyes had a manifest cylinder of 0.50 D or lower preoperatively and at 1 and 12 months after surgery, respectively. A significant reduction was found in topographic astigmatism at 1 month postoperatively (p < 0.01), with an additionally small but statistically significant reduction afterwards (p < 0.01). No significant changes in postoperative uncorrected (p = 0.97) and corrected visual acuities (p = 0.40) were observed during the follow-up. There was a trend to undercorrection of corneal astigmatism that decreased significantly over time. This led to some variability in changes of refractive astigmatism. A small but significant reduction in ECD was observed at 1 month postoperatively (p Conclusions: Femtosecond laser assisted ISAK is an effective and safe option to reduce corneal astigmatism during cataract surgery and consequently refractive astigmatism.

Electromagnetic Resonance of Astigmatic Gaussian Beam to the High Frequency Gravitational Waves

The high frequency gravitational waves （around lOS-lO12 Hz） could interact with a specially designed electro- magnetic resonance system. It is found that the power of transverse perturbative photon flux （PPF） of an electromagnetic resonance system can be improved significantly by virtue of an astigmatic Caussian beam. Cor- respondingly the signal-to-noise ratio （SNR） would also be improved. When the eccentric ratio of waist satisfying w0x ： w0y 〉 1, the peak value of signal photon flux could be raised by 2-4 times with typical systematic parameters, while the background photon flux would be depressed. Therefore, the ratio of transverse PPF to background photon flux （i.e., SNR） can be further improved 3-8 times with dimensionless amplitude of relic gravitational wave ht = 10-36.

Case report:simultaneous femtosecond laser astigmatic keratotomy and toric intraocular lens implantation in femtosecond laser-assisted cataract surgery in a patient with surgically induced high corneal astigmatism

Background:Femtosecond laser astigmatic keratotomy(FSAK)and toric intraocular lens(IOL)implantation have been studied individually for comparison to treat astigmatism at cataract surgery.We report a case of surgically induced high corneal astigmatism by laser thermal keratoplasty(LTK)in a patient with cataract who was successfully treated with simultaneous combination of FSAK and toric IOL implantation with femtosecond laser-assisted cataract surgery(FLACS).This is the first report of both procedures combined simultaneously,with or without history of LTK.Case Description:A 68-year-old male presented with a history of LTK with two enhancements each eye in 2004,with subsequent surgically induced high corneal astigmatism,and with age-related nuclear cataract of both eyes.IOL master demonstrated+7.71 diopters of astigmatism at 163 degree right eye and+3.29 diopters of astigmatism at 4 degree left eye.After extensive discussion of the risks and benefits,the patient agreed to undergo FLACS with FSAK with two 61 degrees of relaxation incisions(RIs)and toric IOL(Alcon SN6AT9)right eye;FLACS with toric IOL(Alcon SN6AT7)alone left eye.At 2-year follow-up,uncorrected visual acuity was 20/30 right eye,20/25 left eye.His best corrected visual acuity was 20/25(+0.25+1.00 axis 21)right eye and 20/20(plano+0.25 axis 90)left eye;his best corrected near visual acuity was J1+with add+2.50 diopters right eye and left eye.Conclusions:Patients with age-related cataract and LTK induced high corneal astigmatism can hardly be sufficiently treated with FSAK or toric IOL alone at the time of cataract surgery.An effective way is to combine large FSAK and toric IOL of the highest cylindrical power of T9,in our case,simultaneously,which can achieve an excellent long term visual outcome.

Comparative analysis of the efficacy of astigmatic correction after wavefront-guided and wavefront-optimized LASIK in low and moderate myopic eyes

AIM： To evaluate and compare the efficacy of the astigmatic correction achieved with laser in situ keratomileusis（LASIK） in eyes with myopic astigmatism using wavefront-guided（WFG） and wavefront-optimized（WFO） ablation profiles.METHODS： Prospective study included 221 eyes undergoing LASIK： 99 and 122 eyes with low and moderate myopic astigmatism（low and moderate myopia groups）.Two subgroups were differentiated in each group according to the ablation profile： WFG subgroup,109 eyes（45/64,low/moderate myopia groups） treated using the Advanced Custom Vue platform（Abbott Medical Optics Inc.）,and WFO subgroup,112 eyes（54/58,low/moderate myopia groups） treated using the EX-500 platform（Alcon）.Clinical outcomes were evaluated during a 6-month follow-up,including a vector analysis of astigmatic changes.RESULTS： Significantly better postoperative uncorrected visual acuity and efficacy index was found in the WFG subgroups of each group（P≤0.041）.Postoperative spherical equivalent and cylinder were significantly higher in WFO subgroups（P≤0.003）.In moderate myopia group,a higher percentage of eyes with a postoperative cylinder ≤0.25 D was found in the WFG subgroup（90.6% vs 65.5%,P=0.002）.In low and moderate myopia groups,the difference vector was significantly higher in the WFO subgroup compared to WFG（P〈0.001）.In moderate myopia group,the magnitude（P=0.008） and angle of error（P〈0.001） were also significantly higher in the WFO subgroup.Significantlyless induction of high order aberrations were found with WFG treatments in both low and moderate myopia groups（P≤0.006）.CONCLUSION： A more efficacious correction of myopic astigmatism providing a better visual outcome is achieved with WFG LASIK compared to WFO LASIK.

Astigmatic correction with implantation of a light adjustable vs monofocal lens: a single site analysis of a randomized controlled trial

AIM: To evaluate the light adjustable lens(LAL) vs a standard monofocal lens in achieving target astigmatic refraction and improving postoperative uncorrected distance visual acuity(UDVA). METHODS: This randomized controlled clinical trial included 40 patients with pre-existing astigmatism and visually significant cataract. Twenty-eight patients received the LAL and 12 control patients received a monofocal intraocular lens(IOL) after cataract extraction at a single institution. The patients with the LAL underwent adjustment by ultraviolet(UV) light postoperatively plus subsequent lock-in procedures and all patients returned to clinic for follow up of study parameters at 6, 9, and 12 mo. Manifest refraction, distance visual acuity, and adverse events were recorded at each visit.RESULTS: The mean cylinder before adjustment in eyes with the LAL was-0.89±0.58 D(-2.00 to 0.00 D) and-0.34±0.34 D(-1.25 to 0.00 D) after lock-in(P=1.68 x10-8). The mean cylinder in patients with the monofocal lens was-1.00±0.32 D(-1.50 to-0.50 D) at 17-21 d postoperatively, which was statistically different from the LAL cylinder postlock-in(P=1.43 x10-6). UDVA in the LAL group was 20/20 or better in 79% of patients post lock-in with good stability over 12 mo compared with 33% of the control patients with UDVA of 20/20 or better. CONCLUSION: These results demonstrate that the LAL is more effective in achieving target refractions and improving postoperative UDVA in patients with pre-existing corneal astigmatism than a standard monofocal lens.

AB008:Structural and molecular changes in cornea and sclera of highly myopic-astigmatic chicks

Myopia and astigmatism, two common refractive errors frequently co-exist, are degrading vision at all working distances in populations worldwide. Eyeballs having high degrees of myopia and astigmatism are known to exhibit abnormal eye shape at the anterior and posterior eye segments, but whether the outer coats of these abnormal eyeballs, cornea anteriorly and sclera posteriorly, are regulated by region-specific molecular mechanism remains unclear. Here we presented the changes in eye shape and mRNA expression levels of three genes (MMP2, TIMP2, and TGFB2), all known to participate in extracellular matrix organization, at five regions of the cornea and sclera in chickens developing high myopia and astigmatism induced by form deprivation. Our results showed that, compared to normal chicks, the highly myopic-astigmatic chicks had significantly astigmatic cornea, deeper anterior chamber, longer axial length, and higher expressions of all three genes in the superior sclera. These results imply that local molecular mechanism may manipulate the eye’s structural remodeling across the globe during refractive eye growth.

Focusing properties of Gaussian Schell-model beams by an astigmatic aperture lens

This paper studies the focusing properties of Gaussian Schell-model （GSM） beams by an astigmatic aperture lens. It is shown that the axial irradiance distribution, the maximum axial irradiance and its position of focused GSM beams by an astigmatic aperture lens depend upon the astigmatism of the lens, the coherence of partially coherent light, the truncation parameter of the aperture and Fresnel number. The numerical calculation results are given to illustrate how these parameters affect the focusing property.

Femtosecond laser-assisted astigmatic keratotomy: a review

Background:Astigmatic keratotomy(AK)remains an accessible means to correct surgically induced or naturally occurring astigmatism.The advantages of femtosecond laser-assisted astigmatic keratotomy(FSAK)over conventional methods have been recognized recently.Main text:This review evaluates the efficacy,complications,and different methods of FSAK for correction of astigmatism in native eyes and those that underwent previous penetrating keratoplasty(PKP).The penetrating and intrastromal FSAK(IFSAK)techniques can reduce post-keratoplasty astigmatism by 35.4%to 84.77%and 23.53%to 89.42%,respectively.In native eyes,the penetrating and IFSAK techniques reduce astigmatism by 26.8%to 58.62%and 36.3%to 58%respectively,implying that the magnitude of the astigmatic reduction is comparable between the two FSAK procedures.Nonetheless,IFSAK offers the additional advantages of almost no risk of infection,wound gape,and epithelial ingrowth.The use of nomograms,anterior-segment optical coherence tomography,and consideration of posterior cornea and corneal biomechanics are helpful to enhance the efficacy and safety of FSAK.The complications of FSAK in eyes that underwent PKP include overcorrection,visual loss,microperforations,infectious keratitis,allograft rejection,and endophthalmitis.The reported difficulties in native eyes include overcorrection,anterior gas breakthrough,and suction loss.Conclusions:In eyes that underwent PKP,FSAK effectively reduces high regular or irregular astigmatism,with rare and manageable complications.Nevertheless,the drawbacks of the procedure include the potential loss of visual acuity and low predictability.For native eyes undergoing femtosecond laser-assisted cataract surgery,IFSAK is a good choice to correct low astigmatism(<1.5 diopters).The refractive effect of astigmatism from the posterior cornea needs to be considered in the nomograms for native eyes undergoing refractive cataract surgery.To further improve the efficacy of FSAK,more large-scale randomized studies with longer follow-up are needed.

Comparison between toric and spherical phakic intraocular lenses combined with astigmatic keratotomy for high myopic astigmatism

Background:To compare the outcomes of a toric phakic intraocular lens(PIOL)and a spherical PIOL combined with astigmatic keratotomy(AK)for the correction of high myopic astigmatism.Methods:This study enrolled patients with high myopic astigmatism,including 30 eyes(22 patients)that received a toric PIOL implantation(TICL group),and 32 eyes(24 patients)that received combined AK and a spherical PIOL implantation(AK+ICL group).The outcomes were compared between the two groups before surgery,and at the following time points after surgery:1 week,1,3,6 months,and 1,2 years.Results:Preoperatively,the mean manifest spherical equivalent(SE)was−14.14±2.12 D in the TICL group and−14.83±2.79 D in the AK+ICL group(P=0.28),and the mean manifest refractive cylinder,−2.87±1.09 D and−2.58±0.85 D,respectively(P=0.28).Two years postoperatively,the mean safety index was 1.53±0.55 in the TICL group and 1.60±0.70 in the AK+ICL group(P=1.00),and the mean efficacy index,1.18±0.45 and 1.38±0.52,respectively(P=0.86).The mean manifest refractive cylinder correction was 1.94±1.07 D in the TICL group and 1.39±0.71 D in the AK+ICL group(P=0.02).The mean changes in SE and refractive cylinder from 1 week to 2 years were less than 0.50 D in both groups.Conclusions:Both TICL implantation and AK+ICL implantation are a good alternative for correction of astigmatism in addition to high myopia.TICL implantation has better predictability in correction of high myopic astigmatism.

Refractive outcomes after V4c Toric collamer lens implantation over 1y of follow-up

AIM:To evaluate refractive outcomes and corneal astigmatism changes after Toric implantable collamer lens with a central port(V4c T-ICL)implantation over 1y of follow-up.METHODS:A retrospective study was performed including 50 eyes of 50 patients that underwent V4c T-ICL implantation.Uncorrected(UDVA)and corrected(CDVA)distance visual acuities,refraction,refractive and corneal astigmatism changes and corneal coupling correction were evaluated preoperatively,1 and 12mo postoperatively.Vector analysis was used for astigmatism changes.Coefficient of adjustment(CAdj)was calculated for corneal coupling analysis.RESULTS:The mean UDVA achieved was 0.03 logMAR at 1mo and remained unchanged throughout the whole follow-up(P=0.193).At the last visit,84%of the eyes achieved a CDVA of 0.00 logMAR or better.Regarding spherical equivalent refraction(SEQ),96%of eyes were ranges of±1.00 D and 84%of them within±0.50 D.Also,94%of eyes had a remaining refractive cylinder within±1.00 D and 78%of them within±0.50 D.Both,SEQ and refractive cylinder,remain stable over the postoperative follow-up(P=1.000 and P=0.660,respectively).In terms of surgically induced astigmatism(SIA),no statistically significant differences were found over the follow-up(P=0.102)and under correction was found with a correction index lower than the unit at each visit.A keratometric astigmatism induced of 0.59±0.53(vector mean:0.26×73º)D was reached at the last visit.No significant changes in terms of corneal astigmatism orientation were reported over post-surgery visits(P=0.129 and P=0.097 at 1 and 12mo respectively).No clinical significance was found for CAdj on with-the-rule astigmatism.No postoperative complications resulting from the surgery were found.CONCLUSION:Refractive outcomes suggest that the V4c T-ICL implantation for correction of myopic astigmatism was satisfactory in terms of effectiveness,safety,and stability during 1y of follow-up.Corneal astigmatism induced by the incision around 0.5 D is achieved according to the remaining refractive cylinder found at one-year post-surgery.Corneal coupling analysis results in no unexpected spherical change.

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.

Effect of low-degree astigmatism on the objective visual quality

AIM:To evaluate the effect of low-degree astigmatism on objective visual quality through the Optical Quality Analysis System(OQAS).METHODS:This study enrolled 46 participants(aged 23 to 30y,90 eyes)with normal or corrected-to-normal vision.The cylindrical lenses(0,0.5,0.75,1.0,and 1.25 D)were placed at the axial direction(180°,45°,90°,and 135°)in front of the eyes with the best correction to form 16 types of regular low-degree astigmatism.OQAS was used to detect the objective visual quality,recorded as the objective scattering index(OSI),OQAS values at contrasts of 100%,20%,and 9%predictive visual acuity(OV100%,OV20%,and OV9%),modulation transfer function cut-off(MTFcut-off)and Strehl ratio(SR).The mixed effect linear model was used to compare objective visual quality differences between groups and examine associations between astigmatic magnitude and objective visual quality parameters.RESULTS:Apparent negative relationships between the magnitude of low astigmatism and objective visual quality were observed.The increase of OSI per degree of astigmatism at 180°,45°,90°,and 135°axis were 0.38(95%CI:0.35,0.42),0.50(95%CI:0.46,0.53),0.49(95%CI:0.45,0.54)and 0.37(95%CI:0.34,0.41),respectively.The decrease of MTFcut-off per degree of astigmatism at 180°,45°,90°,and 135°axis were-10.30(95%CI:-11.43,-9.16),-12.73(95%CI:-13.62,-11.86),-12.75(95%CI:-13.79,-11.70),and-9.97(95%CI:-10.92,-9.03),respectively.At the same astigmatism degree,OSI at 45°and 90°axis were higher than that at 0°and 135°axis,while MTFcut-off were lower.CONCLUSION:Low astigmatism of only 0.50 D can significantly reduce the objective visual quality.

Prevalence and Factors Associated with Refractive Errors among University Students at Mbarara University of Science and Technology, Uganda

Introduction: WHO estimated that uncorrected refractive errors are the leading cause of visual impairment and second leading cause of blindness globally. University students are prone to developing refractive errors due to their curriculum that requires a lot of near work affecting their performance and quality of life unknowingly. Genetic and environmental factors are thought to play a role in the development of refractive errors. This study addresses the paucity of knowledge about refractive errors among university students in East Africa, providing a foundation for further research. Objectives: To determine the prevalence and factors associated with refractive errors among students in the Faculty of Medicine at Mbarara University of Science and Technology. Methodology: This was a cross-sectional descriptive and analytical study in which 368 undergraduate students selected using random sampling were assessed for refractive errors from March 2021-July 2021. Eligible participants were recruited and their VA assessment done after answering a questionnaire. Students whose VA improved on pin hole had subjective retinoscopy and results were compiled and imported to STATA 14 for analysis. Results: The prevalence of refractive errors was 26.36% with (95% CI) among university students especially myopia. Myopia is most predominant at 60%, followed by 37% Astigmatism and hyperopia of 3% among medical students. Astigmatism consisted of largely myopic astigmatism 72% (26) and 28% (10) compound/mixed astigmatism only. Student positive family history of refractive error was found to have a statistically significant relationship with refractive errors with AOR 1.68 (1.04 - 2.72) (95% CI) and P (0.032). Conclusion: The prevalence of refractive errors among university students, especially myopia, was found to be high and family history was associated with students having refractive errors.

Progression of Corneal Astigmatism after Phaco-Alternative at the University Hospital Center of the Oueme-Plateau Department in Porto-Novo

Objective: To study the postoperative evolution of corneal astigmatism following phaco-alternative at the University Hospital Center of Ouémé-Plateau (UHC-OP) in Porto-Novo. Method: This was a prospective, cross-sectional study with a descriptive and analytical purpose conducted from April 19 to September 20, 2021;a period of 6 months. The study included all patients presenting with senile or non-senile cataracts without a history of corneal trauma and who underwent phaco-alternative during the study period. Results: A total of 62 eyes underwent phaco-alternative. The average age was 63 ± 12 years with a male predominance of 59.7%. Phaco-alternative was performed with 74.2% linear incision and 25.8% smile incision. Perioperative incidents were mainly capsular ruptures with vitreous loss occurring in 8.1% of cases. The mean preoperative astigmatism was 1.29 ± 1.5 D with an axis of 180˚ ± 20˚, indicating with-the-rule astigmatism. The mean postoperative astigmatism was 2.2 ± 1.5 D with an axis of 90˚ ± 20˚, indicating against-the-rule astigmatism. The mean induced astigmatism at Day 30 was 1.4 ± 1.2 D for smile incision and 1.8 ± 1.2 D for linear incision. Conclusion: Phaco-alternative yields good results with few complications but remains astigmatogenic. The smile incision appears to be less astigmatogenic.

Retrospective Case Series on The Enduring Rotational Stability of The AcrySof IQ Toric Intraocular Lens in Cataract Patients Suffering from Myopia

Objective:To analyze the enduring rotational steadiness of AcrySof IQ Toric intraocular lens(IOL)in cataract patients suffering from myopia in a long-term study.Methods:A retrospective study was conducted on a case series involving 78 patients.A total of 120 eyes with an axial length(AL)ranging from 24-30 mm and corneal astigmatism≥1.50 D underwent implantation of AcrySof IQ Toric IOL guided by the version navigation system.The eyes were divided into two groups based on AL.Group A included 60 eyes with high myopia(AL≥26 mm),while Group B consisted of eyes with low to moderate myopia(24 mm≤AL<26 mm).Data on the preoperative AL were collected.Measurements were taken for residual astigmatism,the best corrected visual acuity(BCDVA),corneal astigmatism,and IOL rotation occurring between 24-and 48-months post-surgery.The percentage of eyes with an IOL rotation of under 5°and 10°was analyzed.Results:The mean length of follow-up times was recorded as 34.27±4.98,and the average rotation was 2.73±1.29°.Group A exhibited a slightly higher average rotation of 2.87±1.31°,compared to the rotation of 2.59±1.27°observed in Group B.At both the 24-36 month and 26-48 month post-operation marks,the degree of IOL rotation did not show a statistically significant difference between the two groups,with none of the patients experiencing a rotation exceeding 10°(P>0.05).The percentage of rotation degrees under 5°was recorded as 98.22%.After the procedure,the BCDVA was 0.1322±0.03 LogMAR.There was a substantial increase in theχvalue after the operation as compared to the pre-operativeχ^(2) value(χ^(2)=76.79).The standard deviation of preoperative corneal astigmatism was statistically significant(P<0.05)at 2.17±1.08 D.Following the surgical procedure,the remaining astigmatism was measured at 0.41±0.26 D.The data showed a notable gap in statistical significance(t=4.281,P<0.05).Conclusion:The AcrySof Toric IOL was a reliable solution for managing corneal astigmatism in cataract patients with myopia,demonstrating excellent long-term rotational stability.

Clinical Effect Analysis of Posterior Chamber Intraocular Lens Implantation for Correcting High Myopia and Astigmatism

Objective:To explore the corrective effect of posterior chamber intraocular lens implantation with phakic eyes in the treatment of high myopia and astigmatism.Methods:From May 2023,the hospital began to collect the case data of diagnosis and treatment of high myopia and astigmatism.By May 2024,310 cases were included,all of which were treated with posterior chamber intraocular lens implantation.The visual acuity,astigmatism and axial position of the intraocular lens were observed before and after treatment.Results:At different time points after the operation,the patient’s vision was significantly improved compared with that before the operation(P<0.05),and the vision level was equal to or greater than the best-corrected vision before the operation.At different time points after the operation,the average rotation of the intraocular lens was less than 5 degrees.Astigmatism was significantly lower than that before the operation(P<0.05).After the operation,the intraocular pressure increased in 11 cases,accounting for 3.55%,with no adverse complications such as lens turbidity,glare and obvious halo occurring.Conclusion:The posterior chamber intraocular lens implantation with phakic eyes has an ideal correction effect in the treatment of high myopia and astigmatism,which can effectively improve the vision level of patients and reduce the degree of astigmatism,and has high effectiveness and safety.

Investigation of a real-time location system of corneal astigmatic axis

Background:To construct a real-time computerized location system(RCLS)to analyze and display the axis of corneal astigmatism and to compare its accuracy with the Scheimpflug method.Methods:Fifty-seven eyes of 39 volunteers with corneal astigmatism more than 1.00 diopter(D)were recruited.The RCLS was composed of a circular light-emitting diode(LED)light source,surgical microscope,surgical video system,computer and self-programming image analysis software.Scheimpflug imaging measurements(Pentacam HR,Oculus,Wetzlar,Germany)were performed on all subjects to determine the axis and power of corneal astigmatism.Thereafter,the axis of corneal astigmatism was analyzed in real-time and displayed by the RCLS on supine position,and videos were recorded.The MB-Ruler 4.0 software was used to measure the astigmatic axis.The accuracy of the RCLS was compared with the Scheimpflug method.Results:The RCLS was able to display the axis of corneal astigmatism in real-time.The axial deviation of corneal astigmatism between the two methods was 0.63±3.78°when astigmatism was 1.00 to 2.00 D and decreased to 0.06±1.38°when astigmatism was greater than 2.00 D.A linear correlation of astigmatic axis was noted between the two methods:Axis_(RCLS)=1.01×Axis_(Scheimpflug)−1.02(R^(2)=0.998,P<0.001).The Bland-Altman analysis revealed that the RCLS agreed sufficiently well with the Scheimpflug method.Conclusions:The RCLS can accurately analyze and display the axis for corneal astigmatism greater than 1.00 D in real-time.The RCLS simplifies marking procedures and may have potential clinical application to improve the postoperative visual outcomes in surgical correction of corneal astigmatism.

Bibliometric analysis of research relating to refractive cataract surgery over a 20-year period:from 2003 to 2022

AIM:To investigate the research trend on refractive cataract surgery,compare the contributions of different countries,institutions,journals,and authors in the past 20y,and explore its potential research hotspots.METHODS:All publications were extracted relating to refractive cataract surgery from 2003 to 2022 from Web of Science.Document types were limited to original articles and reviews,and the language was limited to English.Quantitatively and qualitatively of the publications were analyzed through Microsoft Excel and GraphPad Prism.VOSviewer and CiteSpace were used for bibliometric and visualized analysis.RESULTS:A total of 2090 publications were enrolled.The United States contributed the most publications(434,20.8%),followed by China(345,16.5%)and England(163,7.80%).Publications from the United States were cited more frequently(9552 citations)with the highest H-index of 48.China ranked second in the total number of publications,the papers were not cited that frequently(3237 citations),and the H-index ranked sixth(H-index=29).Journal of Cataract and Refractive Surgery published the most papers(333,15.9%),and the University of London had the highest number of publications(75,3.59%).Dick HB from Germany published the most papers.Corneal astigmatism-related research,cataract surgery methodrelated research,postoperative visual-quality relate to research,and postoperative complications-relate research are the hotspots in this field.The most significant limitation was that the database was updated frequently and the latest publications were not included.CONCLUSION:The bibliometric analysis shows a brief summarization of the contribution of the authors,institutions,countries,and journals.Corneal astigmatism,cataract surgery method,postoperative visual-quality and postoperative complications related researches have become the emerging hotspots,which can give a direction in the future researches.

Symmetrical femtosecond laser arc incision in correcting corneal astigmatism in cataract patients

AIM:To evaluate the effect of symmetrical arc incision correcting corneal astigmatism in femtosecond laserassisted phacoemulsification(FLACS).METHODS:This study enrolled patients with cataract combined with regular corneal astigmatism of>0.75 D,who underwent FLACS.Symmetrical arc incision was set at 8 mm diameter and 85%depth.The follow-up time was 3-24mo(4.92±3.49mo).Pentacam recorded the corneal astigmatism and higher-order aberration at pre-operation and post-operation.The changes in corneal astigmatism were analyzed by Alpins method.The correlation of astigmatism type,age,corneal horizontal diameter,corneal thickness,arc incision length,and correction index(CI)was analyzed,and the residual corneal astigmatism was compared with the residual whole eye astigmatism.RESULTS:Totally 79 patients(102 eyes)were enrolled,10 patients had corneal epithelial injury,1 patient occurred corneal epithelial hyperplasia.The corneal astigmatism was 1.23±0.38 D pre-operation,and decreased to 0.76±0.39 D post-operation(t=10.146,P=0.000).Corneal high-order aberration was 0.17±0.08μm pre-operation and 0.24±0.11μm post-operation(t=-5.186,P=0.000).The residual corneal astigmatism and residual whole eye astigmatism were no significant difference(t=-0.347,P=0.729).Using Alpin’s method,the following were determined:target-induced astigmatism(TIA)=1.23±0.38 D,surgeryinduced astigmatism(SIA)=0.77±0.45 D,difference vector(DV)=0.77±0.39 D,and CI=0.54±0.28.Age,astigmatism size,corneal horizontal diameter,corneal thickness,and arc incision length were not correlated with CI.The CI for against the rule astigmatism(ATR)was better than that for with the rule astigmatism(WTR;P=0.001).CONCLUSION:Femtosecond laser-assisted astigmatic keratotomy has better CI of ATR,but increase higher-order corneal aberration.CI is not ideal,it’s not a perfect choice if we pursue ideal correction effect.