Comparison of iris-fixated foldable lens and scleralfixated foldable lens implantation in eyes with insufficient capsular support

AIM： To compare the outcomes of vision using two different intraocular lens（IOL） replacement techniques,iris-fixated foldable intraocular lens（IF-IOL） and scleralfixated foldable intraocular lens（SF-IOL） in patients with insufficient capsular support.METHODS： Total 63 eyes（62 patients） with insufficient posterior capsule support underwent replacement of IF-IOL or SF-IOL between January 2008 and August 2011.Outcome measures included changes in visual acuity, slit lamp examination, refractive indices and corneal curvatures. RESULTS： The mean improvement of uncorrected visual acuity（UCVA） was greater in IF-IOL group compared to the SF-IOL group（0.43 D±0.19 D vs 0.35 D±0.18 D, P 〈0.05）. Moreover, 12（38.71%） eyes in IF-IOL group and 4（12.50%） in SF-IOL group had a higher postoperative UCVA than preoperative best corrected visual acuity（BCVA） while 9（29.03%） eyes in IF-IOLgroup and 18（56.25%） in SF-IOL group had a lower postoperative UCVA than preoperative BCVA. The myopic mean manifest sphere and mean cylinder magnitude were lower in the IF-IOL group than that in the SF-IOL group（-0.47 D±0.58 D vs 0.50 D±0.43 D, P 〈0.01; 0.84 D ±0.53 D vs 1.23 D ±0.70 D, P 〈0.05）. No difference of corneal astigmatism and surgically induced astigmatism was found between the two groups. In addition, fewer complications were observed in IF-IOL eyes. CONCLUSION： IF-IOL implantation can give a significant improvement in vision with fewer complications than SF-IOL in patients with insufficient capsular support.

Visual performance after implantation of two types of phakic foldable intraocular lenses for correction of high myopia

AIM: To compare Visian lens(model V4 c) and Artiflex lens regarding quality(contrast sensitivity) and quantity(efficacy, predictability, safety and stability) of vision in correcting high myopia with recording and analysis of complications. METHODS: The comparative prospective study included 39 eyes of 23 patients with high myopia, 19 eyes had Visian lens implantation(model V4 c) and 20 eyes had Artiflex lens implantation. The inclusion criteria were high myopia(higher than 6.0 D) and stable refraction(<0.5 D change over one year). Outcomes included assessment of safety and efficacy indices, predictability, stability, contrast sensitivity and analysis of complications at postoperative 1 d, 1 wk and 1, 3, 6 and 12 mo. Selection of the type of phakic intraocular lens for patients was based on surgeons' preferences, which was no specific selection criteria. RESULTS: After 12 mo of follow up, difference in uncorrected and corrected distant visual acuity(CDVA) between both groups was statistically insignificant(UDVA for VisianV4 c and Artiflex lens were 0.33±0.2 logMAR and 0.37±0.2 logMAR respectively, P=0.59, CDVA for VisianV4 c and Artiflex lens were 0.155±0.1 logMAR and 0.147± 0.1 logMAR respectively, P=0.87). The efficacy index was 1.25 for VisianV4 c lens and 0.8 for Artiflex lens, 78.9% of eyes were within one diopter spherical equivalent in Visian V4 c lens group compared to 70% in the Artiflex lens group. No eye lost lines of CVDA proving a good safety index for both lenses(safety index was 1.67 for VisianV4 c lens and 1.34 for Artiflex lens). Difference in contrast sensitivity between both groups was statistically insignificant(P=0.15, 0.88, 0.27, 0.32 and 0.82 at five spatial frequencies). CONCLUSION: Both Visian ICL V4 c and Artiflex lensesare safe and effective with stable and predictable refraction and they have comparable contrast sensitivity outcomes with no vision threatening complications.

Evaluation of suturless scleral fixation with posterior chamber foldable intraocular lens implantation

AIM: To assess the sutureless scleral fixation technique for posterior chamber foldable intraocular lens(PCIOL) implantation in aphakic eyes with insufficient or no capsular support. METHODS: A technique for sutureless intrascleral fixation of the haptics of a standard 3-piece PCIOL was used which ensures sutureless fixation by permanent incarceration of the haptics in a scleral tunnel parallel to the limbus. All patients were evaluated for preoperative status [visual acuity, refractive error, K readings, intraocular pressure(IOP) measurement, slit lamp examination, fundus examination and optical biometry], postoperative status and complications. Ultrasound biomicroscopy(UBM) was done for 10 cases to evaluate optic tilt. RESULTS: The study evaluated 42 eyes of 42 patients. The follow-up period was 6 mo. Improvement of best corrected visual acuity(BCVA) one line occurred in 10 cases(23.8%) and loss of one line in 3 cases(7.1%). Intraoperative complications included: haptic kink in 4 cases(9.5%), haptic breakage in 1 case(2.4%), haptic dislocation in 1 case(2.4%), haptic slippage in 3 cases(7.1%), IOL dislocation in 1 case(2.4%) and sclerotomy related bleeding in 1 case(2.4%). Postoperative complications included: transient mild vitreous hemorrhage in 3 cases(7.1%), choroidal detachment in 1 case(2.4%), cystoid macular edema(CME) in 1 case(2.4%), optic capture in 1 case(2.4%), subconjunctival haptic in 2 cases(4.8%), ocular hypotony in 4 cases(9.5%) and ocular hypertension in 1 case(2.4%). There were no cases of retinal detachment or endophthalmitis. UBM showed optic tilt in 3 cases(30%). CONCLUSION: Fixation of three-piece foldable IOL haptics in scleral tunnel parallel to the limbus-providedaxial stability and proper centration of the IOL with minimal or no tilt in most cases and a low complication rate during the follow up period which lasted 6 mo.

Comparison of Trans-scleral Fixation of PMMA and Foldable Intraocular Lens in Children

Purpose: To observe the difference of the effects of PMMA and foldable intraocular lenses (IOLs) trans-sclerally fixed in pediatric eyes. Methods: Thirty-two children (43 eyes) who had undergone trans-scleral fixation of IOL were retrospected, of whom 5 children were implanted PMMA IOL in both eyes, 6children were implanted PMMA IOL in one eye and foldable IOL in the other eye, 12children were implanted foldable IOL in one eye and 9 chilrden were implanted PMMA IOL in one eye. Mean age was 5.3 years ( range 2.5 ～ 12 years ). Twelve children had traumatic cataract and the others congenital cataract before lens extraction. Results: Foldable group (18 eyes ): Mean follow-up was 12.1 months. Visual acuity (VA): compared with the best corrected VA before IOL fixation, postoperative best corrected VA improved in 16 eyes, remained unchanged in 2 eyes. In 14 eyes, one or two stitches were needed to seal the incision. Complications: Severe anterior chamber reaction was seen in 3 eyes. Intraocular bleeding was found in 3 eyes. IOL decentration was detected in 1 eye. Iris capture of IOL was seen in one eye. PMMA group (25 eyes ):Mean follow-up was 20.3 months. Visual acuity (VA): compared with the best corrected VA before IOL fixation, postoperative best corrected VA improved in 19 eyes,remained unchanged in 5 eyes and got worse in one eye. In 24 eyes, one to three stitches were needed to seal the incision. Complications: Severe anterior chamber reaction was seen in 5 eyes. Intraocular bleeding was found in 4 eyes. IOL decentration was seen in one eye. Iris capture of IOL was seen in 3 eyes. Intraocular pressure elevated in one eye. Conclusion: Our study shows that trans-scleral fixation of IOL is a safe procedure in pediatric eyes. Foldable IOL showed similar effect compared with PMMA IOL in pediatric trans-scleral fixation. Eye Science 2001; 17:61 ～ 64.

Application of Foldable Intraocular Lens in Multiple Types of Cataract

Objective: To evaluate the clinical results of implantation of foldable intraocular lens inmultiple types of cataract.Methods: This retrospective study comprised 162 eyes of 148 patients undergoingphacoemulsification and implantation of foldable intraocular lens, some of whom under-went combined pars plana vitrectomy or trabeculectomy or silicone oil removal. Theperiod of follow-up was from 3 months to 17 months.Results: There is slight reaction postoperatively in all cases. The postoperative uncorrectedvisual acuites was from 0. 05 to 1.2, patient with 0.6 or above acuity were 70.98%. Aneodymium: YAG capsulotomy was required in 5 eyes. Posterior capsule ruptured in 1eyes, and a PMMA intraocular lens was implanted in ciliary sulcus. In one eye, a lenswas removed because of recurrence of retina detachment.Conclusions: The application of foldable intraocular lens in multiple types of cataract issafe, and there is a slight postoperative reaction. less complications , and fast visualacuity recovery.

Guidelines for the application of artificial intelligence in the diagnosis of anterior segment diseases(2023)

The landscape of ophthalmology has obser ved monumental shifts with the advent of artificial intelligence(AI)technologies.This article is devoted to elaborating on the nuanced application of AI in the diagnostic realm of anterior segment eye diseases,an area ripe with potential yet complex in its imaging characteristics.Historically,AI’s entrenchment in ophthalmology was predominantly rooted in the posterior segment.However,the evolution of machine learning paradigms,particularly with the advent of deep learning methodologies,has reframed the focus.When combined with the exponential surge in available electronic image data pertaining to the anterior segment,AI’s role in diagnosing corneal,conjunctival,lens,and eyelid pathologies has been solidified and has emerged from the realm of theoretical to practical.In light of this transformative potential,collaborations between the Ophthalmic Imaging and Intelligent Medicine Subcommittee of the China Medical Education Association and the Ophthalmology Committee of the International Translational Medicine Association have been instrumental.These eminent bodies mobilized a consortium of experts to dissect and assimilate advancements from both national and international quarters.Their mandate was not limited to AI’s application in anterior segment pathologies like the cornea,conjunctiva,lens,and eyelids,but also ventured into deciphering the existing impediments and envisioning future trajectories.After iterative deliberations,the consensus synthesized herein serves as a touchstone,assisting ophthalmologists in optimally integrating AI into their diagnostic decisions and bolstering clinical research.Through this guideline,we aspire to offer a comprehensive framework,ensuring that clinical decisions are not merely informed but transformed by AI.By building upon existing literature yet maintaining the highest standards of originality,this document stands as a testament to both innovation and academic integrity,in line with the ethos of renowned journals such as Ophthalmology.

Foldable Lens Explantation and Exchange: The Reason and Solution

Objective: To report the explantation and exchange of Hydrophilic Acrylic foldable intraocular lens (IOL) on 14 patients who had visual disturbances caused by the change of transparence on optic. Methods: Sixteen Hydrophilic Acrylic foldable intraocular lenses from 14 patients who presented with decreased visual acuity from 6 months to 1 year after normal phacoemulsification and IOL implantation associated with extensive transparent change on optic of the lens. The lenses were explanted with the bisection technique. All the eyes were reinserted with Acrysof foldable lenses. Results: Sixteen lenses were removed successfully and exchanged with the new lens in the capsule. The posterior capsular rupture and vitreous loss were found in the first two cases. One of them had the zonulysis due to the radial tear of the anterior capsule during the enlargement of the capsular opening. The anterior vitrectomy was performed with IOL fixed on the ciliary sulcus. The visual acuity of all the patients improved obviously without posterior complication. Conclusion: Foldable lens explantation with the bisection technique and exchange had a successful outcome with improvement of ocular condition. Eye science 2001; 17:54 ～56.

AcrySof phakic angle-supported intraocular lens for the correction of high to extremely high myopia:one-year follow-up results

AIM: To assess the safety, efficacy and predictability of the AcrySof phakic angle-supported intraocular lens (IOL) (Alcon Inc., U.S.A.) for correction of high-to-extremely high myopia in adults. METHODS: In this prospective study performed in Tianjin Medical University Eye Center & College of Optometry, Tianjin, China, 25 eyes of 13 patients were implanted with AcrySof phakic angle-supported IOLs and followed for 1 year postoperatively. Preoperative manifest refractive sphere was (-12.08 +/- 2.44) diopters (D) and cylinder was (-1.35 +/- 0.62)D. Visual acuity, predictability and stability of manifest refraction spherical equivalent (MRSE), adverse events, and endothelial cell density were analyzed during 1-year of follow-up. RESULTS: After 1 year of follow-up, no eyes lost 1 line (best spectacle-corrected visual acuity)BSCVA; an uncorrected visual acuity (UCVA) of 20/20 or better was achieved in 60% of eyes; 100% had an UCVA of 20/40 or better; a BSCVA of 20/30 or better was achieved by 100% of eyes; 84% had a BSCVA of 20/20 or better. The overall mean percentage change in endothelial cell density 1 year after surgery was (-0.27 +/- 3.60)%. Two eyes (8%) had increased intraocular pressure (IOP) on the day of surgery. No pupil ovalization, pupillary block, or retinal detachment events were observed. CONCLUSION: After 1 year of follow-up, the implantation of AcrySof phakic angle-supported IOL is proved to be safe, effective and predictable with minimal complications in patients with high-to-extremely high myopia. Due to the limitation of visiting time, long-term of clinical investigation is necessary to verify the safety and efficacy of this IOL.

Corneal injection track: an unusual complication of intraocular lens implantation and review

Phacoemulsification is the main gold standard for cataract operation in the developed world together with foldable intraocular lens(IOL) implantation by injection,allowing for stable wound construction and less postoperative astigmatism. It is a safe procedure with high success rate with the advancement in machines,improvement of IOL injection systems and further maturation of surgeons’ techniques. Despite the large number of operations performed every day, foldable IOL injection leading to an intra-stromal corneal track is a very rare complication. We report a case of this unusual finding in a 70-year-old gentleman who has undergone cataract operation in November 2011 in our hospital and will review on the complications related to foldable IOL injection.

Optical performance of toric intraocular lenses in the presence of decentration

· AIM: To evaluate the optical performance of toric intraocular lenses(IOLs) after decentration and with different pupil diameters, but with the IOL astigmatic axis aligned.· METHODS: Optical performances of toric T5 and SN60 AT spherical IOLs after decentration were tested on a theoretical pseudophakic model eye based on the Hwey-Lan Liou schematic eye using the Zemax ray-tracing program. Changes in optical performance were analyzed in model eyes with 3-mm, 4-mm, and 5-mm pupil diameters and decentered from 0.25 mm to 0.75 mm with an interval of 5° at the meridian direction from0° to 90°. The ratio of the modulation transfer function(MTF) between a decentered and a centered IOL(MTFDecentration/MTFCentration) was calculated to analyze the decrease in optical performance.· RESULTS: Optical performance of the toric IOL remained unchanged when IOLs were decentered in any meridian direction. The MTFs of the two IOLs decreased,whereas optical performance remained equivalent after decentration. The MTFDecentration/MTFCentrationratios of the IOLs at a decentration from 0.25 mm to 0.75 mm were comparable in the toric and SN60 AT IOLs. After decentration, MTF decreased further, with the MTF of the toric IOL being slightly lower than that of the SN60 AT IOL. Imaging qualities of the two IOLs decreased when the pupil diameter and the degree of decentration increased, but the decrease was similar in the toric and spherical IOLs.· CONCLUSION: Toric IOLs were comparable to spherical IOLs in terms of tolerance to decentration at the correct axial position.

Iris Repair after Long-Term Complications of Angle-Supported Phakic Intraocular Lenses

We report the case of a high myopic patient who had been implanted with angle-supported phakic intraocular lenses (pIOL) in 1990 and who subsequently and gradually developed complications in both eyes including endothelial cell loss, chronic glaucoma, cataract, pupil ovalization and severe iris atrophy. The patient was impaired by photophobia, glare, halo, loss in visual acuity and concerned about the cosmetically deforming aspect of her eyes. Cataract surgery was performed after explantation of the pIOL followed by combined implantation of a standard IOL in the capsular bag and a Dr Schmidt artificial iris in the sulcus. There were no intraoperative and postoperative complications except slight bilateral corneal oedema which resolved completely within 1 month after surgery. Uncorrected and corrected visual acuity improved progressively to reach 0.3 and 0.6 at the last follow-up visit (±1 year), respectively. The patient was very satisfied with the functional and aesthetical outcomes.

Clinical Application of the Sapphire Unfolder Lens Injection System

Purpose: To summarize the clinical experience of 300 cases using the Sapphire unfloder intraocular lens (IOL) injection system.Methods: After the standard phacoemulsification, an AR40e IOL was implanted using the Sapphire Unfolder. The involved problems during and after the operation were observed and analyzed.Results:The complications occurred during the operation including the crack at the haptic-optic junction in 2 cases, slight kink in the haptic in 5 cases, IOL clamp into the cartridge in 2 cases, posterior capsular rupture in 2 cases and endothelium damage in the central small area in 4 cases. All the patients recovered successfully with IOLs in good position.Conclusion: IOL implantation with the Sapphire Unfolder led to no serious complications and got the satisfactory results.

超声乳化吸除联合人工晶体植入术治疗白内障的疗效分析

目的分析白内障患者行超声乳化吸除联合人工晶体植入术的临床治疗效果及安全性。方法选取2022年7月—2023年本院收治的白内障患者42例为研究对象。比较治疗前、后视力恢复效果,视觉质量评分,角膜散光度、眼轴长度变化差异,分析手术并发症发生率。结果(1)患者术后视力较术前均显著提升,术后1周时患者术眼视力测评结果高于术前,差异有统计学意义(P<0.05);术后1个月时术眼视力测评结果较术前、术后1周升高,差异有统计学意义(P<0.05)。(2)术后康复期间受白内障摘除及人工晶状体植入影响,患者视觉质量均逐步恢复,患者术后1个月时夜间视物、看电视、阅读书写及精细操作质量评分较术前提升,差异有统计学意义(P<0.05)。(3)患者术后角膜散光度及眼轴长度较术前均呈下降趋势变化,且术后1个月时角膜散光度低于术前,差异有统计学意义(P<0.05);术前、术后1个月时眼轴长度比较差异无统计学意义(P>0.05)。(4)患者术后手术并发症发生率为9.52%,含高眼压2例、角膜水肿1例、前房反应1例,经对症处理后均缓解或自愈。结论超声乳化术联合人工晶状体植入治疗白内障临床效果确切,患者术后视力、视觉质量改善效果确切,且可起到角膜散光度改善效果,临床安全性确切。

多焦点非球面人工晶体在老年性白内障手术患者中的应用效果及安全性分析

目的 研究多焦点非球面人工晶体在老年性白内障手术患者中的应用效果及安全性。方法 选取2021年10月—2023年5月在本院就诊的94例老年性白内障手术患者为研究对象,根据植入晶体的不同进行分组,对照组、观察组分别植入单焦点球面人工晶体、多焦点非球面人工晶体,每组47例。对比两组的治疗情况。结果 术后1周、3个月时的裸眼近视力与远视力、最佳矫正近视力与远视力,均是观察组高于对照组(P<0.05);观察组术后角膜散光度小于术前,术后VF-14评分以及明视环境中不同空间频率时的敏感度均高于对照组,暗视环境下8cpd、12cpd时的敏感度低于对照组,差异具有统计学意义(P<0.05);近视脱镜率、视觉干扰发生率组间对比,观察组居更高水平;并发症发生率方面,观察组低于对照组(P<0.05)。结论 在老年性白内障手术患者中应用多焦点非球面人工晶体更有助于其视力、对比敏感度的改善,促使患者术后对眼镜的依赖性下降,提升了视觉质量以及安全性。

白内障撕囊口控制环的临床应用价值分析

目的 评价白内障撕囊口控制环的临床应用效果。方法 选取60例(60眼)年龄相关性白内障患者为研究对象,按照随机数字表法分为A组与B组,每组30例(30眼)。A组行常规连续环形撕囊白内障超声乳化+折叠式人工晶状体植入术, B组在白内障撕囊口控制环辅助下行连续环形撕囊白内障超声乳化+折叠式人工晶状体植入术。比较两组撕囊口合格率、人工晶状体轻度偏移情况、视力、眼压,以及术中和术后并发症发生情况。结果 两组均顺利完成连续环形撕囊。A组撕囊口合格24眼(80.0%), B组合格30眼(100.0%)。B组撕囊口合格率高于A组,差异有统计学意义(P<0.05)。两组术后1个月人工晶状体轻度偏移率比较差异无统计学意义(P>0.05)。两组术后1 d、1周视力>0.5占比比较,差异无统计学意义(P>0.05)。术前, A组眼压为(14.17±2.47)mm Hg(1 mm Hg=0.133 kPa), B组为(14.60±2.97)mm Hg;术后A组眼压为(15.37±3.59)mm Hg, B组为(15.63±3.05)mm Hg。手术前后两组眼压比较差异无统计学意义(P>0.05)。术中两组无一例发生前房出血、虹膜损伤及后囊膜破裂。术后两组无一例发生前房渗出,两组角膜水肿及前房闪辉发生率比较差异无统计学意义(P>0.05)。两组角膜水肿均在1周内消退。结论 白内障撕囊口控制环可明显提高撕囊口合格率,有助于手术顺利完成,使人工晶状体处于完美位置,并提高手术的安全性。

动态透镜成像学习人工兔优化算法及应用

针对基本人工兔优化(Artificial Rabbits Optimization, ARO)算法在解决复杂优化问题时存在收敛慢、精度不高和容易陷入局部最优等缺陷,本文提出一种改进的ARO算法(记为IARO算法)。IARO算法中的基于正弦函数的非线性递减能量因子能够帮助算法实现从探索阶段到开发阶段的良好过渡,从而提高算法的收敛速度和解的质量。此外,为了提高算法跳出局部最优的概率,IARO算法引入了一种动态透镜成像学习策略。为了证明IARO算法的优越性,首先选取了6个基准测试函数进行数值实验,然后用其求解2个工程设计优化问题和1个包括15个数据集的特征选择问题,并与灰狼优化(GWO)算法、鲸鱼优化算法(WOA)、正弦余弦算法(SCA)和基本ARO算法进行对比。结果表明,IARO算法有着比其他对比算法更优越的性能。

太赫兹超表面透镜综述

本文综述了基于人工微结构的太赫兹超表面透镜的最新研究进展,通过仿真分析了人工微结构单元与太赫兹波的相互作用,阐述了共振相位、几何相位和传输相位3种主要的相位调控机理及相应的相位调制效果.根据透镜相位的空间分布规律,通过合理的人工微结构布局实现对入射太赫兹波波前的调控,从而实现太赫兹超表面透镜的聚焦和成像功能.太赫兹超表面透镜具有设计灵活、厚度超薄、功能多样等诸多优势,在太赫兹波无损检测、高速通信和公共安全等领域具有广阔的应用前景.本文根据太赫兹波聚焦效率这一重要技术指标,介绍了基于单层结构、多层结构、全介质结构以及可调谐太赫兹超表面透镜的研究成果,并对太赫兹超表面透镜的未来发展前景进行了展望.

有晶状体眼人工晶状体尺寸选择的研究进展

有晶状体眼人工晶状体(ICL)植入术在治疗屈光不正中发挥着越来越重要的作用。从前房型ICL到后房型,再到中心孔型的ICL,给视界带来全新的改变。虽然目前ICL术后并发症发生率很低,但是在ICL的尺寸选择中仍会因为设备测量差异及ICL尺寸算法不同等导致植入不当的ICL,引发相关并发症。随着对ICL植入术认识地不断深入,以及眼科设备及技术地不断发展,特别是人工智能的出现,使得越来越多的指标如:睫状沟直径(STS)、晶状体矢高(CLR)、前房角直径(ATA)、虹膜色素端到虹膜色素端(PTP)、前房宽度(ACW)、前房角度数(ACA)等指标在ICL尺寸的选择中提供参考,本文就ICL尺寸选择进行综述。

不同浓度的人工泪液对合并中重度干眼的白内障患者角膜曲率测量和人工晶状体度数计算的影响

目的探讨不同浓度的人工泪液对合并中重度干眼的白内障患者角膜曲率测量和人工晶状体度数计算的影响。方法本研究共纳入合并中重度干眼的白内障患者80例80眼,依据患者所用人工泪液玻璃酸钠滴眼液的浓度将患者分为低浓度组和高浓度组各40例40眼。低浓度组患者采用1 g·L^(-1)玻璃酸钠滴眼液滴眼;高浓度组患者采用3 g·L^(-1)玻璃酸钠滴眼液滴眼。于用药前和用药后1、5、15 min测量受试眼平坦轴角膜曲率(K 1),计算患者所需人工晶状体度数,对比其变化情况。结果用药后1 min和5 min,低浓度组受试眼K 1均较用药前减小,差异均有统计学意义(均为P<0.05);用药后15 min,低浓度组受试眼K 1与用药前比较,差异无统计学意义(P=0.556)。高浓度组受试眼用药前后K 1变化情况与低浓度组相似。用药前两组受试眼K 1差异无统计学意义(P>0.05)。用药后1 min,低浓度组受试眼K 1较高浓度组升高(P<0.05)。用药后1 min和5 min,低浓度组受试眼人工晶状体度数均较用药前增大,差异均有统计学意义(均为P<0.05);用药后15 min,低浓度组受试眼人工晶状体度数与用药前比较,差异无统计学意义(P=0.160)。高浓度组受试眼人工晶状体度数变化情况与低浓度组相似。用药后1、5、15 min,两组受试眼人工晶状体度数差异均无统计学意义(均为P>0.05)。结论合并中重度干眼的白内障患者使用人工泪液短时间内会显著减小患眼K 1,增大人工晶状体度数;建议使用人工泪液后应超过15 min再进行白内障术前生物测量。

“可折叠性”在酶智能设计改造中的应用研究--以AlphaFold2为例

天然酶具有绿色环保、高效催化的优点,但由于工业环境的酸碱性、温度等条件不够适宜,天然酶在实际工业生产中往往存在错误折叠、功能受限等问题。使用人工智能技术辅助酶的改造设计,相比传统方法具有高效、快速、低成本的优势,但在这个过程中大部分工作没有考虑设计改造酶的“可折叠性”问题。同时,最近几年来,以AlphaFold2为代表的蛋白质结构预测工具借助人工智能技术取得了突破性的进展,已经具有原子级别的结构预测精度。这一工具的日益成熟,不仅有助于对蛋白结构功能机制的了解,同时可以丰富现有酶结构数据,用于后续的研究。因此,基于现有酶改造以及从头设计新酶过程中出现的错误折叠导致成功率不高、实验验证成本高的问题,我们认为结合蛋白质结构预测工具辅助酶的改造设计任务,可以增加设计可靠酶的数量,同时降低实验成本。本文首先梳理回顾人工智能技术在酶设计改造中的应用,主要从序列和结构两个角度展开。然后将现有蛋白质结构预测工具归纳成四种类型分别介绍其设计原理和预测能力。接着以AlphaFold2为代表性工作,归纳了三种在现有技术基础上利用结构预测工具进一步提高酶改造的合理性以及酶设计的“可折叠性”的方式:①结构“分析器”;②突变“筛选器”;③折叠“监督器”。最后在讨论部分总结并提出了一些现有算法的不足和缺陷。随着人工智能技术的逐渐发展以及人类对蛋白质作用机理的研究,酶的改造设计精度一定会有所提高,这将助力合成生物学的快速发展。