Hydrophobic Acrylic Intraocular Lens in Both Eyes

 PURPOSE: To report on the clinical findings of a case of late opacification of the hydrophobic acrylic intraocular lens (IOLs) in both eyes after cataract surgery. METHODS: A 79-year-old man with a history of decreased visual acuity and complaints of glare and blurred vision in both eyes over the past 3 years. He had received an uneventful phacoemulsification combined with posterior chamber IOL implantation for senile cataract in both eyes 13 years ago, and had undergone neodymium:YAG(Nd:YAG) laser posterior capsulotomy on both eyes 6 years ago, for posterior capsular opacification (PCO). The optical portion of the IOLs showed uniform gray haze. Binocular posterior capsular laser holes were clearly noted. RESULTS: IOL exchange was performed by the same surgeon on both eyes, three days apart. Postoperatively, the patient's visual acuity was elevated to 6/12 (OD) and 6/9 (OS) at 6 months, and intraocular pressure (IOP) reached 16.8 mmHg (OD) and 18.4 mmHg (OS). Neither glare or blurred vision were observed in either eye. CONCLUSION: IOL exchange can be used to effectively manage clinically significant optic opacification.       

Posterior Capsule Opacification in Pseudophakic Eyes

Posterior capsule opacification following extracapsular cataract extraction is a manifestation of proliferation of anterior lens epithelium onto the posterior capsule. In addition to Elschnig pearl formation, vision is decreased in two ways. Multiple layers of proliferated epithelium produce a frank opacity. Also, the lens cells show myofibroblastic differentiation and their contraction produces numerous tiny wrinkles in the posterior capsule resulting in visual distortion. Because the cells that proliferate are anterior lens epithelial cells and because proliferation begins at the site of apposition of anterior capsular flap and the posterior capsule, a wide anterior capsulectomy should help reduce the risk of and delay the onset of visual loss from this complication of extracapsular surgery. Polishing the posterior capsule at the time of surgery will not help in this regard unless there is a complicated cataract with pre-existing posterior migration of lens epithelium. The presence of a potential cleavage plane between the proliferating epithelium and the posterior capsule provides a therapeutic alternative to surgical or laser discission.     

Decentration and Tilt of Intraocular Lens after Posterior Capsulotomy

Purpose: To assess the effect of posterior capsular opacification (PCO) and Neodymium-doped:Yttrium Aluminium Garnet (Nd:YAG) laser capsulotomy on tilt and decentration of intraocular lens (IOL) at vertical and horizontal meridians.

Methods: The study included 64 eyes of 64 patients. IOL decentration and tilt were measured using a Scheimpflug camera before and 1 month after Nd:YAG capsulotomy. Corrected distance visual acuity (CDVA) and manifest refraction were also determined. Between-group differences of IOL position change and the effect of Nd:YAG laser capsulotomy were analyzed.

Results: In the PCO group, before capsulotomy, CDVA was significantly lower than that after capsulotomy and of the control group values (p = 0.001 for both). No significant difference was observed in CDVA between the control group and the PCO group after capsulotomy (p = 0.854). Before capsulotomy, the angle of tilt and decentration at both meridians was significantly higher than that in the control group (tilt: p < 0.001; for both decentrations: p = 0.001, p = 0.003, respectively). A significant decrease was observed in the angle of tilt at both meridians (horizontal p = 0.001, vertical p = 0.001) from before to after capsulotomy in the PCO group. Although decentration was increased after capsulotomy, no significant position change was observed (horizontal p = 0.350, vertical p = 0.107). The angle of tilt and decentration at both meridians was significantly higher in the PCO group after capsulotomy compared to the control group (p < 0.001 for all).

Conclusions: PCO is associated with not only axial displacement, but also tilt and decentration of IOL at the vertical and horizontal meridians. Laser capsulotomy decreased IOL tilt but had no effect on decentration. However, these changes did not significantly change the visual acuity between the control group and the PCO group after capsulotomy.     

Progress on Intraocular Lens Surface Modification for Posterior Capsular Opacification Prevention

Cataract is the main cause of blinding diseases. Phacoemulsification combined with intraocular lens (IOL) implantation is a commonly used clinical treatment. Visual acuity recovers well after the operation. However, since the IOL is an extrinsic implant, a high incidence of complications may occur postoperatively. In addition to acute inflammation, long-term in vivo biocompatibility problems-posterior capsular opacification (PCO, which is also called a secondary cataract) may occur over time and decrease vision again. The improvement of surgical methods and the design and processing of the IOL can reduce the incidence of PCO. However, PCO still occurs due to the intrinsic compatibility of the IOL materials. This review summarizes the IOL surface modifications used to inhibit PCO from the perspective of the science of materials.     

人工晶状体表面改性抑制后发性白内障的研究进展

白内障是目前最主要的致盲性眼病,临床上通常采用超声乳化联合人工晶状体（IOL）植入对其进行治疗。该手术术后视力恢复良好。但是所植入的IOL是一种外来性异物,术后除了急性炎症反应之外,存在着远期的体内生物相容性问题,即后发性白内障,严重影响术后的视觉质量。虽然手术方式改进、IOL设计加工改良等能降低后发性白内障的发生率,但由于材料本身的相容性问题并未获得改善,仍能导致后发性白内障的发生。笔者从材料学的角度对材料表面性能改性抑制后发性白内障作一综述。     

Two‐year follow‐up of posterior capsule opacification after implantation of a hydrophilic or hydrophobic acrylic intraocular lens

Purpose: To evaluate posterior capsule opacification (PCO) 2 years after cataract surgery following implantation of a hydrophilic or a hydrophobic single‐piece acrylic intraocular lens (IOL) with a sharp edge. Methods: Phacoemulsification cataract surgery was performed in one eye of 120 patients with senile cataract in this prospective study. They were randomized to implantation of either a hydrophilic acrylic IOL (BL27; Bausch & Lomb, Rochester, NY, USA) or a hydrophobic acrylic IOL (AcrySof^® SA60AT; Alcon Laboratories, Fort Worth, TX, USA). Two years after surgery, retroillumination images were obtained and PCO area and severity were evaluated using pocoman software. Best corrected visual acuity (VA) (both high‐contrast [100%] and low‐contrast [2.5%]), glare, laser flare and intraocular pressure were measured. Capsulotomy rates were recorded. Results: Patients implanted with the hydrophilic IOL had a greater percentage area and severity of PCO compared with patients with the hydrophobic IOL (p < 0.001). There was no difference in PCO between men and women in the hydrophilic group. However, in the hydrophobic group, women had significantly more PCO than men (p < 0.05). Patients with the hydrophobic acrylic IOL had better high‐ and low‐contrast visual activity (VA) (p < 0.01) and less glare (p < 0.001) than those with a hydrophilic acrylic IOL. Of the patients with the hydrophilic IOL, 42% underwent capsulotomy, compared with 10% in the hydrophobic group (p < 0.001). Conclusions: Two years after surgery, patients with the SA60AT hydrophobic acrylic IOL had less PCO and better high‐ and low‐contrast VA than patients with the BL27 hydrophilic acrylic IOL.     

Hydrophobic versus hydrophilic acrylic intraocular lens on posterior capsule opacification: a Meta-analysis

AIM: To conduct a Meta-analysis pooling randomized controlled trials (RCTs) to compare hydrophobic with hydrophilic acrylic intraocular lenses in terms of posterior capsule opacification (PCO) development. METHODS: Electronic databases including PubMed, Embase, and the Cochrane Library were queried from their starting till January 2020. RCTs investigating the impact of hydrophobic versus hydrophilic acrylic intraocular lenses on PCO were considered eligible in this study. The pooled effect estimates were calculated using the random-effects model. RESULTS: Thirteen RCTs comprising of 939 patients (1263 eyes) were covered in this study. Patients with hydrophobic acrylic intraocular lenses had a lower PCO score than those with a hydrophilic acrylic intraocular lenses [standard mean difference: -1.80; 95% confidence interval (CI): -2.62 to -0.98; P<0.001]. Moreover, the frequency of neodymium-doped yttrium aluminum garnet (Nd:YAG) capsulotomy in patients with hydrophobic acrylic intraocular lenses was significantly lower than patients with hydrophilic acrylic intraocular lenses (relative risk: 0.38; 95%CI: 0.20-0.71; P=0.003). CONCLUSION: These findings suggest that hydrophobic acrylic intraocular lenses are superior to hydrophilic acrylic intraocular lenses in patients after cataract surgery due to lower PCO score and reduced Nd:YAG capsulotomy. While similar studies are conducted by other researchers, the present study conducted subgroup analyses that show superior results with hydrophobic lenses in trials conducted in western countries.     

Primary Posterior Chamber Intraocular Lens Implantation in Traumatic Cataract With Posterior Capsule Breaks

Background: In patients with incomplete posterior capsule support, posterior chamber intraocular lenses (PC-IOLs) were implanted with both haptics transs-cleral fixation. This causes more damage to the eye and may result in more complications. In patients with small posterior breaks, non-fixation or single haptic fixation may be adequate.Methods: Thirty-two consecutive patients of traumatic cataract with posterior capsule breaks caused by penetrating eye trauma were retrospected. Posterior chamber intraocular lenses were implanted in all these patients with three techniques, ie, without fixation, with single haptic fixation and with both haptics fixation. The selection of the technique was based on the position and size of the posterior capsule. The follow-up period was 21 days to 28 months (mean, 15. 2 months).Results: Intra-operative problems included ciliary body bleeding ( two patients, 6. 25% ) and enlargement of posterior capsule breaks (2 patients, 6. 25%). Postoperative visual acuity was 0. 5 or     

白内障囊外摘除人工晶体植入术中不同截囊方式与其后囊混浊发生率的观察比较

对白内障83眼，施行白内障囊外摘除及人工晶体植入术。按前囊截开方式不同分为三组，分别施行开罐式截囊、连续撕囊及线形截囊。术后随访观察12～24个月，后囊混浊发生率分别为：开罐组28％，撕囊组15％，线形截囊组7％。与开罐组相比，线形截囊组与其差异有显著性（P＜0．05），撕囊组与其差异无显著性（P＞0．05）。提示：选用一种既能有效地清除晶体上皮细胞，又能确保人工晶体袢完全植入囊袋内的截囊方式，如线形截囊，对防止后囊混浊是一种有效而实用的方法。     

Comparison of posterior capsular opacification in heparin-surface-modified hydrophilic acrylic and hydrophobic acrylic intraocular lenses

Purpose  To compare posterior capsular opacification (PCO) in a heparin-surface-modified (HSM) hydrophilic acrylic intraocular lens (IOL) and a hydrophobic acrylic IOL. Methods  Seventy-eight patients with simple cataract were randomized to receive either the BioVue 3 HSM hydrophilic acrylic IOL (Ophthalmic Innovations International, Ontario, CA, USA) (n = 38) or the Sensar AR40e hydrophobic acrylic IOL (AMO, Santa Ana, CA, USA) (n = 40). Another 99 patients with complicated cataract received either the BioVue 3 (n = 49) or the Sensar AR40e IOL (n = 50). Twelve months after surgery, POCOman software was used to analyze digital retroillumination photographs of the PCO. Results  In the simple cataract group, the respective PCO areas, expressed as a percentage and PCO severity scores at 12 months were 6.12% and 0.081 in the BioVue 3 group and 5.91% and 0.075 in the Sensar AR40e group. There was no statistically significant difference in the PCO area or the PCO severity score between the two IOLs (P = 0.631, P = 0.495, respectively). In the complicated cataract group, the respective PCO areas and PCO severity scores were 35.80% and 0.181 in the BioVue 3 group and 27.17% and 0.110 in the Sensar AR40e group. There was no statistically significant difference between the two IOLs (P = 0.147, P = 0.162). Conclusion  There was no difference in the degree or severity of PCO between the HSM hydrophilic acrylic IOL and the hydrophobic acrylic IOL groups.     

Comparison of the outcome of implantation of hydrophobic acrylic versus silicone intraocular lenses in pediatric cataract: prospective randomized study

Objective: To compare the postoperative performance of hydrophobic acrylic and silicone square-edge intraocular lenses in pediatric cataract.Design: Prospective randomized study.Participants: Forty-one eyes of 41 children (age 1 month to 8 years) with congenital or developmental cataract.Methods: Children were randomly divided into 2 groups. All participants underwent phacoaspiration, primary posterior capsulotomy, and anterior vitrectomy. Group A (n = 21) eyes were implanted with acrylic hydrophobic AcrySof SA60AT intraocular lenses (IOLs), and those of Group B (n = 20) were implanted with silicone Tecnis Z9000 IOLs. The children were evaluated for anterior chamber reaction, IOL position, posterior capsular opacifica-tion (PCO), intraocular pressure, best-corrected visual acuity (BCVA), corneal status, and refractive errors.Results: Postoperatively, 2 eyes in each group had significant anterior chamber reaction with fibrin membrane formation. IOLs were in the capsular bag in all but 1 eye in both groups. Seven eyes in the acrylic group and 6 eyes in the silicone group achieved visual acuity of 20/40 or better. None of the eyes showed glaucoma. BCVA at 1 year was similar in both groups. In the acrylic hydrophobic group, 14 eyes needed hypermetropic correction and 7 eyes were myopic, and in the silicone group 10 eyes had myopia and 10 eyes had hypermetropia at 1 year postoperatively. PCO at 1 yearfollow-up was more common in eyes implanted with acrylic hydrophobic IOLs (5 eyes) than silicone IOLs (2 eyes).Conclusions: Both square-edge hydrophobic acrylic and silicone IOLs were found to be compatible and safe for use in pediatric cataract surgery with similar visual axis clarity and postoperative outcome.     

人工晶状体的设计对后囊膜混浊的影响

后囊膜混浊是白内障囊外摘除术后最主要的并发症之一。后囊膜混浊的发生是多因素参与的结果,手术方式的改进、人工晶状体的改良、术后炎症反应的控制都可以减少后囊膜混浊的发生。本文就人工晶状体的设计对后囊膜混浊的影响作一综述。     

Adhesion of lens capsule to intraocular lenses of polymethylmethacrylate, silicone, and acrylic foldable materials: an experimental study

AIMS—To investigate the adhesion characteristics of several intraocular lenses (IOLs) to the simulated and rabbit lens capsule.
METHODS—Adhesive force to bovine collagen sheets was measured in water with polymethylmethacrylate (PMMA), three piece silicone, and acrylic foldable IOLs. In rabbit eyes, phacoemulsification and IOL implantation were performed. Three weeks later, adhesion between the anterior/posterior capsules and IOL optic was tested, and the capsule was examined histologically.
RESULTS—The mean adhesive force to the collagen sheet was 1697 (SD 286) mg for acrylic foldable, 583 (49) mg for PMMA, and 0 mg for silicone IOLs (p=0.0003, Kruskal-Wallis test). Scores (0-5) of adhesion between rabbit anterior capsule and IOL optic were 4.50 (0.55) for acrylic foldable, 3.20 (0.84) for PMMA, and 0.40 (0.55) for silicone IOLs (p=0.004). Scores between rabbit posterior capsule and IOL optic displayed a similar tendency; 4.50 (0.84) for acrylic foldable, 3.00 (1.00) for PMMA, and 0.40 (0.55) for silicone IOLs (p=0.021). Histological observation indicated that the edge of IOL optic suppressed the migration of lens epithelial cells towards the centre of the posterior capsule. This inhibitory effect was most pronounced with acrylic foldable IOL and least with silicone IOL.
CONCLUSIONS—The acrylic foldable IOL adhered to the lens capsule more than the PMMA IOL, and the silicone IOL showed no adhesiveness. These differences seem to play a role in preventing lens epithelial cells from migrating and forming posterior capsule opacification.

Keywords: intraocular lens; lens capsule; posterior capsule opacification; adhesion     

Comparison of posterior capsule opacification at 360-degree square edge hydrophilic and sharp edge hydrophobic acrylic intraocular lens in diabetic patients

AIM:To compare posterior capsule opacification (PCO) degree and visual functions after phacoemulsification in eyes implanted with 360-degree square edge hydrophilic acrylic intraocular lens (IOL) (570C C-flex, Rayner) and sharp edge hydrophobic acrylic IOL (Sensar AR40e, AMO) in diabetic patients.METHODS:Sixty diabetic patients underwent uneventful phacoemulsification and randomly implanted one of the two IOLs. The PCO value was measured by retroillumination photographs and Evaluation of Posterior Capsule Opacification (EPCO) 2000 image-analysis software at 1, 6, 12, and 24mo after surgery. Visual acuity, and contrast sensitivity in photopic and mesopic conditions were also examined at each follow up time point. The incidence of eye that required Nd:YAG laser posterior capsulotomy were also compared.RESULTS:There was not any statistically significant difference in PCO scores between Rayner C-flex 570C group and Sensar AR40e group at each follow up time point. Visual acuity, Nd:YAG capsulotomy incidence and contrast sensitivity also had no significant difference during the 24mo follow-up.CONCLUSION: For diabetic patients, Rayner 570C C-flex and Sensar AR40e IOLs are same effective for prevent PCO. The 360-degree square edge design maybe is a good alternative technique to improve PCO prevention.     

Posterior Capsule Opacification and Nd:YAG Rates with Two Acrylic Intraocular Lenses after Age-Related Cataract Treatment: Three-year Results

Objective: To compare the incidence and intensity of posterior capsule opacification (PCO) between two intraocular lenses (IOLs) over three years. Methods: Eighty-three patients underwent cataract surgery with implantation of Acreos Adapt AO or Acrysof SA60AT. PCO values were assessed using a photographic image analysis system (EPCO 2000) and the amount of PCO at the slit lamp. Results: Mean PCO score was 2.78 ± 1.55 for the Acreos Adapt AO and 2.32 ± 1.20 for the Acrysof SA60AT (P=.229). There were no significant differences in the median EPCO values in the entire IOL optics area (0.60 ± 0.26 vs 0.58 ± 0.23; P=.745) and in the central 3-mm zone (0.28 ± 0.13 vs 0.27 ± 0.12; P=.638). Neodymium:YAG capsulotomy was performed in 28% of eyes with Acreos Adapt AO and 23.33% with Acrysof SA60AT (P=.692). Conclusion: Both IOLs had comparable PCO and Nd:YAG rates three years postoperatively.     

人工晶体植入术中晶体后囊破裂的原因分析及处理

分析白内障摘除并后房型人工晶体植入术中发生晶体后囊破裂的原因和讨论处理方法。分析５５例（５５眼）白内障摘除并后房型人工晶体植入术中发生晶体后囊破裂的原因，裂口形态，大小及部位。根据具体情况采用不同处理方法。该术中合并症好发于抽吸晶体皮质及植入人工晶体时，各２１例（３８．２％），后囊破裂大小约３ｍｍ的３９例（７０．９％），５ｍｍ的１３例（２３．６％）。大于６ｍｍ的３例（５．５％）。后囊破裂的部位及形     

白内障术后后囊膜混浊的发生因素

晶状体后囊膜混浊是白内障摘除联合后房型人工晶状体植入术后最常见的并发症,其发生率与人工晶状体的材料、镜片的式样,手术技术等因素均有关。新型的亲水丙烯酸和疏水丙烯酸AcrysofTM人工晶状体由于材料有良好的生物相容性及粘附性能,从而降低了后囊膜混浊的发生率。后凸型的人工晶状体、矩形锐利直角的光学边缘的人工晶状体、小切口白内障超声乳化摘除术、连续环形撕囊可以减少后囊膜混浊的发生率。     

Effect of intraocular lens asphericity on posterior capsule opacification between two intraocular lenses with same acrylic material: a fellow‐eye study

Purpose: To evaluate intra‐individual differences in posterior capsule opacification (PCO) and visual performance between spherical AcrySof SN60AT and an aspheric AcrySof SN60WF intraocular lens (IOL) with a posterior aspheric surface, both of which are made of same hydrophobic acrylic material. Setting: Ophthalmology Department, St Thomas’ Hospital, London, UK. Methods: In this prospective randomized, fellow‐eye comparison, an aspheric IOL, which is 9% thinner in comparison with the spherical IOL, was randomized to the first eye of 47 patients and fellow‐eye surgery was performed within 3 weeks. Follow‐up was at 1, 3, 6, 12 and 24 months. Corrected logMAR visual acuity (CDVA) was measured at 100% and 9% contrast. After pupil dilation, digital retroillumination photographs were taken and the mean PCO percentage was calculated using poco software at each follow‐up visit. Results: At 1, 3, 6, 12 and 24 months, 47 (94 eyes), 44 (88 eyes), 42 (84 eyes) and 41 (82 eyes) patients were followed‐up respectively. Hundred per cent and 9% of LogMAR CDVA was not significantly different between the two IOLs (p = NS at all time‐points). Percentage area PCO scores (mean ± SD) at 1, 3, 6, 12 and 24 months with the spherical IOL was 5.82 ± 9.89, 7.76 ± 16.83, 7.21 ± 12.46, 9.29 ± 18.25 and 14.39 ± 25.42, respectively, and with an aspheric IOL was 8.91 ± 12.79, 5.97 ± 10.32, 5.15 ± 7.92, 7.68 ± 11.18 and 12.18 ± 20.10, respectively (p = NS at all time‐points). Conclusions: Posterior capsule opacification was not significantly different between the spheric and aspheric IOLs in this fellow‐eye, randomized comparison. Additional asphericity on the existing model of IOL does not influence PCO performance.     

Lens epithelial cell proliferation, migration, and metaplasia following capsulorhexis

AIM—To study the behaviour of residual lens epithelial cells after capsulorhexis and expression of material from the isolated lens.
METHODS—Human and bovine lens capsules were isolated, sterile non-toxic silicone rings inserted, and the preparations placed in organ culture for up to 12 weeks. Cell coverage of the posterior lens capsule was recorded and the capsules were examined, both pre- and post-coverage, for (a) proliferative activity and (b) cytoskeletal components.
RESULTS—After a lag period outgrowth was observed across the posterior capsule. The rate of cell coverage was dependent upon both species and the presence or absence of serum. The proliferative activity of the cells was greatest at or near the leading edge and decreased once covered. Wrinkles became visible in the posterior capsule during the late stages of pre-coverage and increased in both number and complexity. All cells on both the human and bovine posterior capsules contained F-actin and vimentin and the majority were immunolabelled for α-smooth muscle actin (α-SMA).
CONCLUSIONS—This model exhibits many of the in vivo characteristics of the lens capsule after extracapsular surgery and may prove useful in further elucidating the cellular mechanisms of posterior capsule opacification.

Keywords: lens epithelial cells; posterior capsule opacification; capsulorrhexis