OBJECTIVE: To investigate the effect of anterior capsule polishing on postoperative capsule opacification and capsular bend in patients with age-related cataract displaying normal axial length.
METHODS: Eye Hospital of Wenzhou Medical University at Hangzhou.
METHODS: Prospective self-controlled trial.
METHODS: Patients with age-related cataracts aged 56 to 84 years displaying normal axial length were enrolled. Before surgery, a coin-toss method was used to randomly select 1 eye for intraoperative 360 degrees anterior capsule polishing (polishing group); the contralateral eye received no treatment (control group). Capsular bend index (CBI), anterior capsule opacification (ACO), posterior capsule opacification (PCO), and anterior capsule opening area (ACOA) were recorded at 1 week, 1 month, 3 months, 6 months, and 12 months postoperatively using swept-source optical coherence tomography and slitlamp examination.
RESULTS: 21 patients (42 eyes) were enrolled. Within-group comparisons showed that both groups had significant differences in CBI between 1 week and 1 month postoperatively, and between 6 months and 12 months postoperatively ( P < .05). Between-group comparisons revealed a significant difference in CBI at 1 week postoperatively ( P < .05); at 12 months postoperatively, there was a significant difference in ACOA ( P < .05). There were no significant between-group differences regarding ACO or PCO at any timepoint ( P > .05).
CONCLUSIONS: For patients with age-related cataracts and normal axial length, 360 degrees anterior capsule polishing can delay early capsular bag deformation without increasing the risks of ACO and PCO. This approach can also limit contraction of the anterior capsule opening.

Objective: To investigate the disparity between the set value of the capsulorhexis ring diameter in ophthalmic surgical navigation systems and the actual capsulorhexis ring diameter projected onto the lens surface. Methods: It was a cross-sectional study. Based on the Gullstrand eye model, the theoretical diameter of the capsulorhexis ring projected onto the lens plane through the cornea was calculated using the law of refraction in the Callisto Eye System. When the anterior chamber depth (ACD) ranged from 2.0 to 4.0 mm and the corneal curvature ranged from 40.00 to 48.00 D, the capsulorhexis ring diameters were calculated after projecting capsulorhexis rings with set diameters of 5.5 mm and 6.0 mm onto the lens plane. Additionally, 40 patients (40 eyes) aged 40 to 85 years who underwent cataract phacoemulsification combined with intraocular lens implantation at the Sixth People\'s Hospital of Shanghai Jiao Tong University School of Medicine were selected to validate the theoretical calculations. Among them, 15 were male, and 25 were female, and they were divided into three groups based on the ACD: group A (13 eyes) with ACD<3.0 mm; group B (16 eyes) with 3.0 mm≤ACD<3.5 mm; group C (11 eyes) with ACD≥3.5 mm. One week after surgery, anterior segment images of the eyes were taken, and the actual capsulorhexis ring diameter was measured using the Photoshop image processing software and compared with the set and calculated values. Results: When the capsulorhexis ring diameters were set at 5.5 mm and 6.0 mm and the corneal curvature was calculated based on the Gullstrand Eye model at 43.05 D, a linear negative correlation was found between ACD and the capsulorhexis ring diameter projected onto the lens plane (P<0.001). When the ACD was set at 2.5, 3.0, and 3.5 mm, and the capsulorhexis ring diameters were set at 5.5 and 6.0 mm, a linear negative correlation was observed between corneal curvature and the capsulorhexis ring diameter projected onto the lens plane (P<0.001). When the capsulorhexis ring diameter was set at 5.5 mm and the patient ACD and corneal curvature data were used for calculations, the capsulorhexis ring diameters projected onto the lens plane for groups A, B, and C were (5.09±0.05) mm, (4.97±0.05) mm, and (4.91±0.07) mm, respectively. When the capsulorhexis ring diameter was set at 6.0 mm, they were (5.56±0.05) mm, (5.44±0.05) mm, and (5.37±0.08) mm, respectively. One week after surgery, the actual measurements of capsulorhexis ring diameters for groups A, B, and C were (5.44±0.20) mm, (5.27±0.28) mm, and (5.25±0.41) mm, respectively, and the differences compared to the calculated values were not statistically significant (all P>0.05), but the differences compared to the set values were statistically significant (all P<0.001). Conclusion: The capsulorhexis ring diameter projected onto the lens surface by the Callisto Eye system was reduced by 7.33% to 10.48% compared to the set value, and the degree of reduction increased with the increase of ACD and corneal curvature.
目的： 探讨眼科手术导航系统中的撕囊环直径设定值与实际投影至晶状体表面的撕囊环直径的差异。 方法： 横断面研究。基于Gullstrand眼模型，依据折射定律计算Callisto Eye眼科手术导航系统中通过角膜投射至晶状体平面上的撕囊口理论直径。在前房深度（ACD）为2.0~4.0 mm和角膜曲率为40~48 D范围变化时，计算设定为直径5.5和6.0 mm的撕囊环投射至晶状体平面后的撕囊环直径。另选取40例（40只眼）于上海交通大学医学院附属第六人民医院眼科行白内障超声乳化吸除联合人工晶体植入术的40~85岁患者对理论计算结果进行验证，其中男性15例，女性25例，并按ACD分为3组：A组（13只眼），ACD<3.0 mm；B组16只眼，3.0 mm≤ACD<3.5 mm；C组11只眼，ACD≥3.5 mm。术后1周拍摄术眼眼前节图像，利用Photoshop图像处理软件测量实际撕囊口直径，并与设定值和计算值进行比较。 结果： 撕囊环直径分别设定为5.5和6.0 mm时，代入Gullstrand眼模型的角膜曲率43.05 D进行计算，发现ACD与投射至晶状体平面上的撕囊环直径均呈线性负相关（P<0.001）；设定ACD分别在2.5、3.0和3.5 mm时，撕囊环直径分别设定为5.5和6.0 mm，角膜曲率与投射至晶状体平面上的撕囊环直径均呈线性负相关（P<0.001）。撕囊环直径设定为5.5 mm时，代入患者术眼的ACD及角膜曲率数据进行计算，系统投射至A、B、C 3个组术眼晶状体平面上的撕囊环直径分别为（5.09±0.05）、（4.97±0.05）、（4.91±0.07）mm；撕囊环直径设定为6.0 mm时则分别为（5.56±0.05）、（5.44±0.05）、（5.37±0.08）mm。术后1周，实际测量A、B、C组撕囊口直径分别为（5.44±0.20）、（5.27±0.28）、（5.25±0.41）mm，与理论计算值的差异均无统计学意义（均P>0.05），但与设定值的差异均有统计学意义（均P<0.001）。 结论： Callisto Eye眼科手术导航系统投射至晶状体表面的撕囊环直径较设定值存在缩减现象，其程度随ACD及角膜曲率的增加而增加，可达7.33%~10.48%。.

UNASSIGNED: The lens zonule, a circumferential system of fibres connecting the ciliary body to the lens, is responsible for centration of the lens. The structural, functional, and positional abnormalities of the zonular apparatus can lead to the abnormality of the intraocular structure, presenting a significant challenge to cataract surgery.
UNASSIGNED: The lens zonule is the elaborate system of extracellular fibers, which not only centers the lens in the eye but also plays an important role in accommodation and lens immunity, maintains the shape of the lens, and corrects spherical aberration. The zonules may directly participate in the formation of cataract via the immune mechanism. Abnormal zonular fibers that affect the position and shape of the lens may play an important role in the pathogenesis of angle closure disease and increase the complexity of the surgery. Capsular tension rings and related endocapsular devices are used to provide sufficient capsular bag stabilization and ensure the safety of cataract surgery procedures. Better preoperative and intraoperative evaluation methods for zonules are needed for clinicians.
UNASSIGNED: The microstructure, biomechanical properties, and physiological functions of the lens zonules help us to better understand the pathogenesis of cataract and glaucoma, facilitating the development of safer surgical procedures for cataract. Further studies are needed to carefully analyze the structure-function relationship of the zonular apparatus to explore new treatment strategies for cataract and glaucoma.

OBJECTIVE: To report how to manage posterior capsule abnormalities (PCAs) in pediatric cataracts and evaluate the influence of PCAs during intraocular lens (IOL) optic implantation in Berger space surgeries.
METHODS: Qingdao Eye Hospital of Shandong First Medical University, Qingdao, China.
METHODS: Retrospective case series study.
METHODS: Pediatric patients with PCAs who underwent cataract surgery were evaluated. A video-based analysis of the surgical interventions included the type of crystalline lens opacification, types and management of PCAs, complications during primary posterior continuous curvilinear capsulorhexis (PCCC), need for anterior vitrectomy (AV), and feasibility of IOL optic capture.
RESULTS: There were 227 pediatric cataract surgeries performed during the study period, and 76 eyes of 66 children with PCAs were evaluated (33.5%, 76/227). Unilateral cataract with PCAs were found in 50 eyes (22.0%, 50/227) and bilateral were found in 26 eyes (11.5%, 26/227). The PCAs were posterior capsule plaque (19.8%, 45/227), posterior capsule defect (6.2%, 14/227), posterior lenticonus (3.1%, 7/227), and persistent fetal vasculature (4.4%, 10/227). In the PCA cases, primary PCCC was successful in 44.7% of the cases (34/76). An unplanned AV during the surgeries was performed in 47.4% (36) of the 76 eyes. IOL optic implantation in Berger space was achieved in 63.2% of the eyes (48/76).
CONCLUSIONS: PCAs are often encountered during pediatric cataract surgeries, especially in unilateral cases. The presence of PCAs may complicate a primary PCCC procedure, resulting in an unplanned AV in some cases. IOL optic implantation in Berger space can also be performed fortunately with well-designed and skilled operation.

OBJECTIVE: To evaluate the effect of primary posterior continuous curvilinear capsulorrhexis (PPCCC) on the positional stability of IOLs.
METHODS: This study is a prospective intra-individual comparative randomized controlled trial including 31 patients (62 eyes). Eyes of the same patient were randomly assigned to the PPCCC group (18 right eyes and 13 left eyes) or group without PPCCC (NPCCC group). Eyes in both groups were implanted with a one-piece foldable hydrophobic acrylic IOL via routine cataract surgery. Patients in the PPCCC group underwent additional manual PPCCC before IOL implantation. Examinations were performed 1 day, 1 week, 1 month and 3 months postoperatively. IOL tilt (x, y), decentration (x, y), anterior chamber depth (z) and refractive prediction error data were collected and analyzed with Pentacam.
RESULTS: Postoperatively, the range of IOL position change over 3 months in PPCCC group was comparable to NPCCC group, which indicated smaller value in every tilt and decentration index. PPCCC eyes showed comparable tilt and decentration with NPCCC eyes in this study endpoint: mean tilt (x, y), decentration (x, y) and anterior chamber depth (ACD) were 1.04 ± 0.56°, 0.90 ± 0.64°, 0.239 ± 0.140 mm, 0.233 ± 0.133 mm and 4.01 ± 0.32 mm, respectively, in the PPCCC group vs. 1.09 ± 0.76°, 1.10 ± 0.82°, 0.252 ± 0.153 mm, 0.244 ± 0.155 mm and 4.01 ± 0.38 mm, respectively, in the NPCCC group. Refractive prediction error in the PPCCC group demonstrated a mild hyperopic shift vs. the NPCCC group (0.13 ± 0.50 vs. 0.05 ± 0.39; p = 0.208), and corrected distance visual acuity (CDVA) did not differ between the two groups (0.027 ± 0.014 vs. 0.059 ± 0.185; p = 0.377).
CONCLUSIONS: Comparable IOL tilt, decentration, ACD and refractive prediction error were observed in PPCCC eyes with that underwent routine cataract surgery. Little IOL position fluctuation and good visual acuity were shown in PPCCC group over time.
BACKGROUND: The study was registered at the Chinese Clinical Trial Register Center on May 27th, 2020 (protocol code ChiCTR2000033304, 27/05/2020).

OBJECTIVE: Continuous curvilinear capsulorhexis (CCC), as a prerequisite for successful cataract surgery, is one of the most important and difficult steps in phacoemulsification. In clinical practice, the size and circularity of the capsular tear and eccentricity with the lens are often employed as indicators to evaluate the effect of CCC.
METHODS: We present a neural network-based model to improve the efficiency and accuracy of evaluation for capsulorhexis results. The capsulorhexis results evaluation model consists of the detection network based on U-Net and the nonlinear fitter built from fully connected layers. The detection network is responsible for detecting the positions of the round capsular tear and lens margin, and the nonlinear fitter is utilized to fit the outputs of the detection network and to compute the capsulorhexis results evaluation indicators. We evaluate the proposed model on an artificial eye phantom and compare its performance with the medical evaluation method.
RESULTS: The experimental results show that the average detection error of the proposed evaluation model is within 0.04 mm. Compared with the medical method (the average detection error is 0.28 mm), the detection accuracy of the proposed evaluation model is more accurate and stable.
CONCLUSIONS: We propose a neural network-based capsulorhexis results evaluation model to improve the accuracy of evaluation for capsulorhexis results. The results of the evaluation experiments show that the proposed results evaluation model evaluates of the effect of capsulorhexis better than the medical evaluation method.

Current treatment of cataract widely used in clinics is by removal of the opacified content from the lens capsule which is followed by insertion of an artificial intraocular lens (IOL). The IOL needs to remain stabilized in the capsular bag for the eye to achieve desired optical quality. The present study aims to investigate how different design parameters of the IOL can influence the axial and rotational stabilities of IOLs using Finite Element Analysis.
Eight designs of IOL with variations in types of optics surface, types of haptics and haptic angulation were constructed using parameters obtained from an online IOL databank (IOLs.eu). Each IOL was subjected to compressional simulations both by two clamps and by a collapsed natural lens capsule with an anterior rhexis. Comparisons were made between the two scenarios on axial displacement, rotation, and distribution of stresses.
The clamps compression method set out by ISO does not always produce the same outcome as the in-the-bag analysis. The open-loop IOLs show better axial stability while the closed-loop IOLs show better rotational stability when compressed by two clamps. Simulations of IOL in the capsular bag only demonstrate better rotational stability for closed-loop designs.
The rotational stability of an IOL is largely dependent on its haptic design whilst the axial stability is affected by the appearance of the rhexis to the anterior capsule which has a major influence on designs with a haptic angulation.

To evaluate intraocular lens (IOL) tilt and decentration and their effects on higher-order aberrations (HOAs) after cataract surgery with and without primary posterior continuous curvilinear capsulorhexis (PPCCC).
Fujian Provincial Hospital, Fujian, China.
Prospective, intraindividual, randomized, comparative clinical trial.
64 eyes of 32 patients with age-related cataract who underwent bilateral cataract surgery and IOL implantation were enrolled in this study. In randomized order, all patients had phacoemulsification cataract surgery with PPCCC in 1 eye (PPCCC group) and routine cataract surgery in the contralateral eye (NPCCC group). IOL decentration, tilt, HOAs, modulation transfer function, and point spread function were measured at 1 day, 1 week, 1 month, and 3 months after surgery using OPD-Scan III.
52 eyes of 26 patients were available for analysis. The mean overall decentration in the NPCCC group was significantly higher than in the PPCCC group at 3 months (0.302 ± 0.157 mm vs 0.187 ± 0.099 mm, P < .001). Under 3 mm pupil, internal spherical aberration (SA) 1 day after surgery and coma 1 week after surgery were lower in the PPCCC group compared with the NPCCC group (0.15 ± 0.10 μm vs 0.30 ± 0.21 μm, P < .001, and 0.34 ± 0.18 μm vs 0.47 ± 0.31 μm, P = .03, respectively). IOL decentration was significantly correlated with ocular and internal coma, ocular and internal SA, and internal HOAs at 5 mm pupil ( R = 0.083 and R = 0.099, R = 0.650 and R = 0.613, and R = 0.418, respectively, all P < .01).
Less IOL decentration was observed in the PPCCC group at 3 months after surgery, indicating that PPCCC may result in better IOL centrality.

BACKGROUND: There are some techniques for disassembly of hard nuclear. It is challenging in hard cataract surgery through microincision. The classic chop or prechop techniques often do not succeed,resulting in incomplete nuclear segmentation. The authors describe a new chop technique for removing hard nucleus cataracts in coaxial microincisional cataract surgery.
METHODS: We create a deep hole (drill) in the central nucleus with the phaco tip and divide the nucleus (prechop) with the Nagahara chopper and the modified capsulorhexis forceps inside the hole. The chopper and the modified capsulorhexis forceps are spread apart laterally after they approach at the center of the nucleus, to create a complete fracture across the entire nucleus. Since January 2022, we have completed 27 eyes of 25 patients with hard nucleus cataract using this technique.
RESULTS: Complete segmentation of the hard nuclear into two hemispheres was implemented with this drill and prechop technique in all cases. The effective phaco time and ultrasound energy decreased. No intraoperative complication such as iris injury, anterior capsule tears, zonulysis, or posterior capsule rupture with vitreous loss occurred during surgery.
CONCLUSIONS: This technique simplifies the previous prechop techniques especially for hard nucleus in microincisional cataract surgery. The technique is efficient, safe and simple.

BACKGROUND: Continuous curvilinear capsulorhexis (CCC) is a delicate ophthalmic procedure which may benefit from robot technology. Measuring the behaviours (physiological tremor, operation force) of surgeons provides baseline data to develop assistive CCC robot.
METHODS: A forceps with fibre bragg grating and inertial sensors is used to measure the surgeons\' behaviours while experts/novices perform CCC on ex-vivo pig eyes, in-vivo rabbit eyes and ex-vivo human lens.
RESULTS: In pig/rabbit tests, the root-mean-square (RMS) tremor amplitude is 35.26/59.04 μm (expert/novice, transverse), 13.3/20.55 μm (axial). The RMS voluntary force (VF) and involuntary force (IF) are 8.97/17.16 mN, and 0.66/1.90 mN, respectively. In human lens test, the RMS tremor amplitude is 24.0 μm (transverse, expert only), 9.88 μm (axial). The RMS VF and RMS IF are 9.04 mN (expert only) and 0.17 mN, respectively.
CONCLUSIONS: The expert surgeons have better precision and less operation force.