Changes of the accommodative amplitude and the anterior chamber depth after implantation of an accommodative intraocular lens

Background

Modern cataract surgery is interested in recovery of the accommodative power. This investigation aimed at determining pseudophakic accommodation in subjects implanted with the accommodative Human Optics 1 CU intraocular lens after drug-induced ciliary muscle stimulation by measuring the objective refraction and the changes in anterior chamber depth in comparison with a PMMA intraocular lens with rigid haptics.

Methods

The studied sample involved 30 eyes of 30 patients undergoing cataract surgery due to age-related cataract. Patients were between 50 and 77 years of age (67.71±8.0). No randomization was performed. The 1 CU accommodative intraocular lens and the PMMA intraocular lens were implanted in 15 eyes of patients with an expected visual acuity of at least 0.7. Objective refraction under pilocarpine-stimulated ciliary muscle contraction was determined with a Hartinger coincidence refractometer. The anterior chamber depth was measured with Jäger’s Haag–Streit slit-lamp attachment. The accommodative amplitude and the anterior chamber flattening were calculated from the measured values.

Results

Twelve weeks after surgery the average accommodative amplitude in eyes with a 1 CU intraocular lens calculated from the refractive change under drug-induced stimulation was 0.48±0.36 D (with a maximum of 1.25 D). The measured change of anterior chamber depth under drug-induced stimulation was 0.3±0.32 mm (at a maximum of 0.9 mm). In the reference group with PMMA lenses, the mean accommodative amplitude derived from the refractive changes under drug-induced stimulation was 0.34±0.27 D (at a maximum of 0.85 D). The measured change in anterior chamber depth under drug-induced stimulation was 0.18±0.09 mm (at a maximum of 0.31 mm). No statistically significant differences were found between the two groups of lenses concerning change in anterior chamber depth and accommodative amplitude.

Conclusions

This investigations indicate a mean anterior 1 CU shift of only 0.32 mm and a maximum of 0.9 mm. The accommodative amplitudes measured with the Hartinger coincidence refractometer (mean value 0.47 D) correspond to these values. Similar conclusions may be drawn from existing investigative results of the reference group, which are on the same order of magnitude as those of the 1 CU group. Objective accommodation measurements are needed to evaluate commercially available accommodative intraocular lenses in a scientifically satisfactory manner. Objectively measurable parameters include changes of the anterior chamber depth as well as refraction, as determined for instance by coincidence refractometry and streak retinoscopy. Future studies should also consider the IOL properties, astigmatism, and pupillary diameter. This is the only way to identify pseudoaccommodation and a decisive factor for further development of accommodative artificial lenses.     

超声生物显微镜观察弹性开放襻前房型人工晶状体对眼前段结构的影响

目的 评价弹性开放襻一体型前房型人工晶状体（anter chamber intraocular lens,AC-IOL)植入式的疗效及其安全性。方法 应用超声生物显微镜观察20例（20只眼）弹性开放襻一体型AC-IOL植入术后患者IOL襻的位置,以及其与虹膜及房角结构的关系,从而评价IOL对眼前段结构的影响。随访时间6～20个月。结果 40个IOL襻中,26个襻固定于房角隐窝;14个襻（8只眼）穿过虹膜侵入至睫状体实质内,并伴有反复发作的葡萄膜炎。术后8只眼虹膜前粘连与IOL襻有关。结论 超声生物显微镜检查是动态了解IOL对眼前段结构影响的有效方法。AC-IOL襻的设计有待进一步改进。     

Accommodative intraocular lenses: current status

PURPOSE OF REVIEW: The possibility of using a monofocal IOL with accommodative ability allows refractive cataract surgery with a clearly decreased potential of photic phenomena. Three IOLs of different designs and materials have demonstrated accommodative ability, but the degree of accommodative amplitude has been reported to different extents and variabilities. The plate-haptic CrystaLens has a hinged design that might permit forward movement of the optic as a result of pressure changes in the vitreous cavity. The 1CU has modified haptics that bend in the bag as the lens capsule contracts, which are supposed to cause anterior displacement of the lens optic. With the dual-optic one-piece Synchrony, springlike haptics separate a high-plus anterior lens from a posterior minus lens. With accommodative effort, the capsular bag expands and the springs express kinetic energy, which might allow the optics to separate as the anterior lens moves forward. RECENT FINDINGS: This article seeks to clarify and distinguish the concepts of true accommodation and pseudo accommodation. Current designs of accommodative IOLs are supposed to work by the focus-shift principle to allow true pseudophakic accommodation. Studies that biometrically assessed optic shift found no or only low amplitudes of forward movement. The amount of forward movement, if present, was highly variable between patients. To date, most studies present psychophysical data for the proof of concept, which alone seems insufficient. Capsule bag performance and posterior capsule opacification with accommodative IOLs seem worse than those with standard intraocular lenses. SUMMARY: The potential clinical benefits of accommodative IOL technology for both cataract patients and refractive patients may place accommodative IOLs in a competitive position with multifocal IOL technology.     

Anterior segment changes during accommodation in eyes with a monofocal intraocular lens: high-frequency ultrasound study

PURPOSE: To analyze anterior segment structure changes during accommodative stimuli after monofocal intraocular lens (IOL) implantation using 2 ultrasound biomicroscopy (UBM) systems. SETTING: Department of Ophthalmology, University of Verona, Verona, Italy. METHODS: Twenty-six eyes (23 patients) with 1 of 4 monofocal IOL types were studied. Five to 9 months postoperatively, the patients were examined by high-frequency UBM using the HiScan system (Optikon 2000 SpA) and UBM 840 system (Carl Zeiss Meditec). Anterior chamber depth (ACD), iris-zonule distance, anterior chamber angle (ACA), scleral-ciliary process angle, and iris-ciliary process angle were measured using both systems. The iris-ciliary process distance and scleral spur perpendicular-sulcus distance were measured with the UBM 840 system and the sulcus-sulcus distance and capsular bag-IOL position with respect to ciliary process apex, with the HiScan system. Two experienced examiners performed all measurements. RESULTS: All parameters except the horizontal iris-ciliary process distance and vertical ACA measured by the UBM 840 system and horizontal ACA by the HiScan system showed significant variation during accommodation. An anterior shift of the IOL-capsular bag ciliary processes--sulcus-zonular iris complex was observed. A simultaneous centripetal shift of ciliary bodies and processes, shown by a reduction in sulcus and capsular bag diameter, was also observed. CONCLUSION: Anterior segment structures demonstrated accommodative movement on UBM after implantation of standard monofocal IOLs.     

A dual optic accommodating foldable intraocular lens

AIM: To design an accommodating intraocular lens with extended accommodative range that can be adapted to current standard phacoemulsification and endocapsular implantation technique. METHOD: Ray tracing analysis and lens design; cadaver eye implantation. RESULTS: Ray tracing analysis indicated that axial movement of an exaggerated converging anterior optic linked by spring loaded haptics to a compensatory static diverging posterior optic produced greater change in conjugation power of the eye compared to axial movement of a single optic lens. A dual optic one piece foldable silicone lens was constructed and implanted via a 4 mm corneal incision into the capsular bag of two cadaver eyes. CONCLUSION: A dual optic intraocular lens design can increase the optical effect of a given displacement and suggests improvements for accommodating intraocular lenses.     

Pseudo-accommodation with intraocular lenses implanted in the bag

PURPOSE: To evaluate the accommodation potential in eyes after intraocular lens in-the-bag implantation. METHODS: Fifty-one consecutive patients were included in the study. Group 1 included 26 eyes that had phacoemulsification with continuous curvilinear capsulorhexis and in-the-bag implanted foldable IOL. Twenty-five eyes in Group 2 had capsulotomy with extracapsular cataract extraction and were implanted with polymethylmethacrylate IOL. Time elapsed from surgery was at least 6 months. There was no significant difference for age or gender between groups (P > .05). We measured accommodation amplitude and depth of the anterior chamber at distance and near fixation with an ultrasonic biometry device. The results were compared using the unpaired Student t-test. RESULTS: The anterior chamber depths while fixating at a distant object were not significantly different between groups (P>.05), however, at near the difference was statistically significant (P=.008). The change in depths between far and near fixation was significantly different (P=.002) and was more pronounced in the the capsulorhexis group (P < .001). The accommodation amplitudes in this group were significantly greater than in the capsulotomy group (P = .025). CONCLUSION: Patients who had uncomplicated small incision phacoemulsification surgery with continuous curvilinear capsulorhexis and in-the-bag implanted lens seemed to preserve some pseudo-accommodation after surgery.     

Tetraflex可调节人工晶状体临床应用的初步观察

目的 观察白内障超声乳化联合囊袋内可调节人工晶状体植入术的效果.方法 病例对照研究.全部患者行白内障超声乳化联合囊袋内人工晶状体植入术,根据植入人工晶状体的不同分为试验组:22例(30只眼)植入可调节人工晶状体,对照组:22例(29只眼)植入单焦点人工晶状体.观察并记录术后6个月和12个月时术眼远、近视力,主观调节幅度,应用OCULUS Pentacam三维前段分析仪测量2%毛果芸香碱眼液诱导前后的前房深度变化值.各观察指标数据以均数±标准差表示.使用SPSS13.0软件对数据进行分析.采用两组独立样本t检验比较两组各观察指标,以P<0.05为差异有统计学意义.结果 术后随访期间,试验组患者的裸眼近视力和最佳远视力矫正后的近视力与对照组患者相比,有统计学差异(P=0.000),两组患者的最佳矫正视力差异无统计学意义(P>0.05);术后6个月时,应用主观移近法测得的主观调节幅度,试验组为(1.60±0.57)D,对照组为(1.10±0.70)D.前房深度变化值试验组为(0.50±0.37)mm,对照组为(0.08±0.06)mm.术后12个月时,应用主观移近法测得的主观调节幅度,试验组为(1.38±0.52)D,对照组为(1.06±0.61)D.前房深度变化值试验组为(0.30±0.27)mm,对照组为(0.10±0.09)mm.结论 与传统的单焦点人工晶状体相比,Tetraflex可调节人工晶状体可以为患者提供较好的近视力和主观调节幅度,但远期疗效有下降趋势.     

Simultaneous measurements of refraction and A-scan biometry during accommodation in humans.

PURPOSE: Accommodation is a dioptric change in power of the crystalline lens resulting from ciliary muscle contraction that leads to an increase in lens surface curvatures and thickness and changes in the position of lens surfaces. Previous studies have used A-scan ultrasound to measure changes in the position of lens surfaces with voluntary accommodation, but have not simultaneously measured the change in refraction. The goal of this study is to simultaneously measure and correlate refractive and biometric changes in the lens during voluntary accommodation in humans. METHODS: Refraction was measured off-axis in the right eye and biometry on-axis in the left eye simultaneously during voluntary accommodation in 22 human subjects between the ages of 21 and 30 years (mean +/- standard deviation: 25.8 +/- 2.3 years). Subjects viewed a distant target and four near targets spanning the full accommodative range available to evaluate refraction and lens surface position at each accommodative state. RESULTS: Maximum objectively measured accommodative amplitude of all subjects was 5.64 +/- 0.21 D (mean +/- standard error of mean). Biometric and refractive changes during accommodation were linearly correlated. The mean +/- standard error of mean decrease in anterior chamber depth was 0.051 +/- 0.008 mm/D, increase in lens thickness was 0.067 +/- 0.008 mm/D, and increase in anterior segment length was 0.017 +/- 0.005 mm/D during accommodation. There was a net anterior movement of the lens center of 0.017 +/- 0.005 mm/D. CONCLUSION: Anterior chamber depth, lens thickness, and anterior segment length change linearly with refraction during accommodation. Per-diopter changes in the lens were greater in the current study compared with previous studies in which only accommodative demand was measured, which overestimates the accommodative response.     

晶状体超声乳化吸除及人工晶状体植入术对闭角型青光眼眼压及前房深度的影响

目的评价品状体超声乳化吸除及后房型折叠式人工晶状体植入术或联合小梁切除术，治疗合并有自内障的闭角型青光眼，观察其术后眼压、前房深度及视力等的变化。方法回顾分析27例（30只眼）闭角型青光眼合并白内障患者。经综合降眼压治疗3～4d，眼压低于25mmHg者21只眼，即行巩膜隧道切口晶状体超声乳化吸除及后房型折叠式人工晶状体植入术，眼压高于25mmHg者9只眼，即行巩膜隧道切口晶状体超声乳化吸除及后房型折叠式人工晶状体植入联合抗代谢药物及小梁切除术。随访3—6个月。结果所有患者术中、术后没有出现严重的并发症，术后视力均有提高，术后眼压都得到控制。平均眼压由术前的20．28mmHg降至11．07mmHg；中央前房深度由术前的2．14mm加深到3．43mm。术后眼压、中央前房深度与术前相比均有显著性差异。术后前房角开放均≥180°。结论晶状体超声乳化吸除及后房型折叠式人工晶状体植入术或联合小梁切除术，是治疗合并有白内障的闭角型青光眼的有效方法。     

青少年近视在不同阅读距离调节状态下眼前段结构的变化

目的分析和探讨不同程度青少年近视在不同阅读距离诱导的调节状态下眼前段结构的变化。方法收集我院屈光门诊14～18岁间青少年近视95例（95眼），正视眼34例（34眼）作对照，其中男66例，女63例。所有被试者行主觉验光、调节幅度测定，眼前节OCT测量在不同阅读距离诱导的调节状态下（OD、3D、6D）的前房深度、晶状体厚度及瞳孔直径，采用SPSS11．5forWindows行统计学分析。结果①在调节放松情况下，随着近视度数增加，暗瞳直径明显减小（P〈0．05），各组间晶状体厚度差异无显著性，前房深度差异有显著性（P〈0．05）。（D随着阅读距离的减小，调节运用的增加，各组前房深度变浅值、晶状体厚度变厚值、暗瞳直径变小值均显著增加（P〈0．01）。③随着近视度数增高，诱发3D调节时前房深度变浅值显著增加（P〈0．01），晶状体厚度变厚值明显增加（P〈0．05），暗瞳直径变小值差异无显著性。④随着近视度数增高，诱发6D调节时前房深度变浅值显著增加（P〈0．01），晶状体厚度变厚值明显增加（P〈0．05），暗瞳直径变小值显著增加（P〈0．01）。结论在青少年中，随近视程度加深，阅读距离减小，运用调节量的增加可引起眼前房显著变浅，晶状体明显变厚：暗瞳直径缩小值在诱发6D调节时随近视度数增高而增大。     

Pseudophakic accommodation with translation lenses – dual optic vs mono optic

PURPOSE: To investigate the pseudophakic accommodation effect in dual and mono optic translation accommodative intraocular lenses (AIOL) using linear matrix methods in the paraxial space. METHODS: Dual (anterior optic of power +32 D linked to a compensatory posterior optic of negative power) and mono lens power was determined in the non-accommodated state using linear geometric optics based on the Gullstrand model eye. The position of the AIOL was calculated from a regression formula. Pseudophakic accommodation was assessed with three systems: (1) forward shift of the mono optic lens, (2) anterior translation of the anterior optic in the dual optic lens system with an unchanged position of the posterior minus lens and (3) symmetrical anterior and posterior translation of the anterior and posterior lens. The Gullstrand model eye was modified by changing the axial length (and proportionally changing the phakic anterior chamber depth) to investigate the accommodative effect in myopic and hyperopic eyes. RESULTS: The dual optic lens system (2) yields a nearly constant accommodation amplitude of 2.4-2.5 D mm(-1) movement over the total range of axial lengths. The mono optic lens (1) provides a higher accommodative effect only in extremely short eyes (high refractive power of the lens), whereas for normal eyes (1.4-1.5 D mm(-1) movement) and for long (myopic) eyes the accommodative effect is much less than the dual optic lens. The dual optic lens system under condition (3) yields less accommodation amplitude compared with the dual optic system under condition (2) over the total range of axial length but provides higher accommodation amplitude compared with the mono optic lens system (1) with axial lengths greater than 22.3 mm (lens power 25.5 D). In the accommodated state, with lens translation of 1 mm, the absolute value of the lateral magnification increases with the refractive power of the mono optic lens (1) and decreases in both dual optic lens systems (under conditions 2 and 3). CONCLUSIONS: A mathematical strategy is presented for calculation of the accommodative effect of mono-optic and dual optic AIOL. The dual optic lens yielded a nearly constant accommodation amplitude of about 2.4-2.5 D mm(-1) translation, whereas the mono optic lens yielded an accommodative response of <2 D mm(-1) translation in long myopic or normal eyes. Only in extremely short eyes is the accommodative amplitude of the mono-optic lens higher than the dual optic lens.     

Dynamic accommodative changes in rhesus monkey eyes assessed with A-scan ultrasound biometry.

PURPOSE: Prior studies in humans measured time constants of biometric accommodative changes as a function of amplitude, and prior studies in monkeys used slit lamp videography to analyze dynamic lenticular accommodative movements. Neither of these studies related biometric changes to refractive changes. We wished to develop and test methodology to begin to test the hypothesis that ocular biometric changes are well correlated with accommodative refractive changes in rhesus monkeys. METHODS: Methodology is described to dynamically measure biometric accommodative changes with A-scan ultrasonography. Lens thickness, anterior chamber depth, and anterior segment length (anterior chamber depth plus lens thickness) were measured dynamically during Edinger-Westphal-stimulated accommodation in two eyes of one rhesus monkey. In addition, dynamic accommodative refractive changes were measured with infrared photorefraction. Functions were fit to the accommodative and disaccommodative responses to obtain time constants. Derivatives of these functions allow peak velocities to be determined for each amplitude. Dynamic changes in lens thickness and anterior chamber depth measured with A-scan biometry were compared with dynamic measures of accommodation using infrared photorefraction. RESULTS: Lens thickness and anterior segment length increase and anterior chamber depth decreases during accommodation. The biometric changes are well correlated with the accommodative optical changes. Peak velocities of accommodative changes in lens thickness and anterior chamber depth increase with amplitude and peak velocities for disaccommodation were higher than those for accommodation. CONCLUSIONS: Dynamic A-scan provides a method for dynamic analysis of the accommodative biometric changes during Edinger-Westphal-stimulated accommodation in monkeys, although the measurement resolution of this approach is limited.     

Refraktion, Vorderkammertiefe, Dezentrierung und Tilt nach Implantation monofokaler und multifokaler Silikonlinsen

BACKGROUND: We prospectively investigated changes in refraction, anterior chamber depth, decentration and tilt after implantation of multifocal (MIOL) and monofocal (MONO) intraocular lenses (IOL). PATIENTS AND METHODS: We examined 103 cataractous eyes from 103 patients receiving either a three-piece monofocal or multifocal silicone IOL. Anterior chamber depth (ACD), amount of IOL decentration, and degree of IOL tilt were quantified using retroillumination and Scheimpflug photographs. Examinations, including subjective refraction, were performed preoperatively, one week and 6 months postoperatively. RESULTS: All eyes were within 2 dpt (spherical equivalent) from the target refraction, and 93% of eyes with a MIOL were within 1 dpt. No significant refractive shift or ACD change occurred during the postoperative course. Median tilt in the MIOL group at 6 months was 1.1 degrees (0-2.6) and that in the MONO group 1.0 degree (0-2.5). There was no statistically significant change in intraindividual IOL decentration or tilt. CONCLUSION: Three-piece silicone MIOLs and MONOs with polymethylmethacrylate haptics implanted in the capsular bag after circular capsulorhexis provide good centration and very little tilt without statistically significant change up to 6 months after surgery. Postoperative refractive shift is of minor concern for 6 months after surgery.     

三种手术方式治疗闭角型青光眼临床前期及先兆期的疗效观察

目的:探讨超声乳化晶状体摘除并人工晶状体植入术治疗急性闭角型青光眼临床前期、先兆期的疗效。方法:选择原发性闭角型青光眼临床前期或先兆期患者66例66眼,随机分为3组,A组行激光周边虹膜造孔术,B组行单纯超声乳化,C组行超声乳化联合虹膜周边切除术(各22眼)。并比较观察3组术后眼压、中央前房深度、视力、房角Scheie分级等的变化。平均随访11.72±0.96mo。结果:术后最终随访时发现:A,B,C组患者的前房角(Scheie分级法)均显著增宽(P<0.05),3组间的房角Scheie分级无显著性差异;A组中央前房深度无明显变化,B、C组中央前房深度较术前均显著加深(P<0.05),A组的中央前房深度明显低于B、C组(P<0.05),B、C组间的中央前房深度无显著性差异;3组平均眼压无明显变化,三组间的平均眼压无明显差异(P<0.05);A组暗室激发试验的阳性率无显著变化,B,C组暗室激发试验的阳性率均显著小于术前。A,B,C3组暗室激发试验的阳性率无显著差异;A组患者最佳矫正视力无明显提高,B,C组患者最佳矫正视力较术前均显著提高(P<0.05)。结论:在加深中央前房深度、降低术后暗室激发试验的阳性(潜在的可能)及提高术后视力的效果方面,超声乳化晶状体摘除并人工晶状体植入术优于激光周边虹膜造孔术;超声乳化晶状体摘除并人工晶状体植入术中不需要进一步做周边虹膜切除术。     

植入可调节人工晶状体和多焦点人工晶状体后视功能的对比研究

目的比较超声乳化白内障吸除术后植入可调节人工晶状体和多焦点人工晶状体的视功能。方法32例年龄相关性白内障患者根据自愿原则,采用非随机对照方式分成两组,试验组13例患者（24只眼）植入1CU可调节人工晶状体,对照组19例患者（30只眼）植入Array多焦点人工晶状体。术后3个月使用标准对数视力表检测患者最佳矫正视力及在最佳矫正视力基础上获得的近视力、近点及调节幅度、立体视觉。检查结果以年龄作为协变量,进行成组设计定量资料一元协方差分析。结果随诊期间所有患者均无明显的术后并发症。术后3个月试验组最佳矫正视力为4．96±0．15,对照组为5．02±0．08,两组比较差异无统计学意义（P=0．085）。试验组术后最佳矫正视力基础上获得的近视力为4．65±0．15,对照组为4．60±0．10,两组比较差异无统计学意义（P=0．398）。试验组术后主观近点为（56±9）cm,对照组为（61±11）cm,两组比较差异无统计学意义（P=0．80）。试验组术后调节幅度为（1．30±0．40）D,对照组为（1．20±0．36）D,两组比较差异无统计学意义（P=0．093）。试验组术后立体视觉为43．24”±18．25”,对照组为60．00”±23．09”,两组比较差异无统计学意义（P=0．543）。结论植入1CU可调节人工晶状体的患者术后可在保持最佳远视力的同时获得一定的近视力。两种人工晶状体在矫正远视力、远矫下近视力、主观近点、术后调节幅度及近距矫正基础上的立体视觉检查方面均无统计学意义。     

Ultrasound biomicroscopy examination of intraocular lens haptic position after phacoemulsification with continuous curvilinear capsulorhexis and extracapsular cataract extraction with linear capsulotomy.

PURPOSE: Intraocular lens (IOL) haptic position in 35 eyes that had undergone cataract surgery was examined with ultrasound biomicroscopy (UBM). METHODS: In a prospective randomized study the patients were operated by phacoemulsification using continuous curvilinear capsulorhexis (CCC) (group I) or by extracapsular cataract extraction (ECCE) using linear capsulotomy (group II). Ultrasound biomicroscopy was used to localize both haptics of the implanted intraocular lenses and to measure anterior chamber depth (ACD), iris thickness and anterior chamber angle. The inflammatory reaction in the anterior chamber was assessed with laser flare photometry. Slit lamp examination was performed. RESULTS: Both IOL haptics were found in the lens capsule in all 18 eyes in group I. In group II one of the haptics was located out of the capsule in 7 of 17 eyes (41%). The difference is statistically significant (p=0.01). Postoperatively mean ACD measured with the UBM was 4.06+/-0.30 mm in group I and 3.64+/-0.24 mm in group II (p=0.00025). CONCLUSION: The UBM examinations indicate that phacoemulsification with continuous curvilinear capsulorhexis is a more reliable technique than ECCE with linear capsulotomy to achieve implantation of the intraocular lens haptics in the capsular bag.     

拟调节人工晶状体在眼内位移与调节力研究

目的 探讨拟调节人工晶状体在眼内位移与调节力的关系.方法 采用病例对照研究方法,将白内障患者20例(20只眼)分成两组:10只眼植入Lestec公司生产的福来视拟调节人工晶状体(TetraflexIOL)(福来视组);另外10只眼植入其他无调节功能的人工晶状体(单焦点组).检测患者术后的裸眼远、中、近视力及矫正远、中、近视力;矫正远视力的近视力;采用前段OCT定量测定1%pilocarpine诱导缩瞳后人工晶状体在眼内前后移动的幅度;同时观察患者调节力的变化.结果 所有患者随访3个月:两组的裸眼、矫正远视力及矫正近视力差异均无统计学意义(P＞0.05);福来视组的裸眼中、近视力及矫正远视力的近视力均优于对照组(P<0.05);福来视组人工晶状体移动度及调节力与对照组比较差异有统计学意义(P<0.05),而且人工晶状体移动度与调节力呈正相关(r=0.977.P=0.000).结论 福来视拟调节人工晶状体是安伞有效的,能使患者术后获得一定的调节力,与人工晶状体的移动度具有正相关性,提供良好的远、中、近视力.     

Synchrony dual-optic accommodating intraocular lens. Part 1: optical and biomechanical principles and design considerations

PURPOSE: To describe a dual-optic accommodating intraocular lens (IOL) based on theoretical considerations. SETTING: University and independent research group. METHODS: Ray-tracing analysis using optical modeling software (ZEMAXTM, Focus Software Inc., Tucson, Ariz) in a theoretical model eye was used to analyze lens configurations to optimize the accommodative and magnification effects of axial lens displacement. Finite-element modelling using a commercially available PC-based software package (COSMOS DesignSTAR) was applied to design the biomechanical parameters of the inter-optic articulations and optics. RESULTS: Ray-tracing analysis indicated that a dual-optic design with a high plus-powered front optic coupled to a minus posterior optic produced greater change in conjugation power of the eye compared to a single-optic intraocular lens and that magnification effects were unlikely to account for improved near vision. Finite-element modelling indicated that the 2 optics can be linked by spring-loaded haptics that allow anterior and posterior axial displacement of the front optic in response to changes in ciliary body tone and capsular tension. CONCLUSION: A dual-optic design linked by spring haptics increases the accommodative effect of axial optic displacement with minimal magnification effect and has promise for improving the performance of accommodative intraocular lenses.     

Accommodation-induced intraocular pressure changes in progressing myopes and emmetropes

Purpose

To investigate the changes of intraocular pressure (IOP) and anterior eye segment biometric parameters under different accommodative statuses in progressing myopes and emmetropes.

Methods

Forty-six progressing myopes and 40 emmetropes participated in this study. All the subjects had their IOP and anterior eye segment biometric parameters (including corneal thickness, anterior chamber depth, anterior chamber angle width, and lens thickness) measured using iCare rebound tonometer and VisanteTM anterior segment-optical coherence tomography while accommodative stimuli of 0, 3, and 6D were presented.

Results

There was no significant difference in IOP between progressing myopes and emmetropes when no accommodation was induced (16.22±4.11 vs 17.01±3.72, respectively, t=−0.93, P>0.05). However, IOP significantly increased with accommodation in progressing myopes (mean change +1.02±2.07 mm Hg from 0D to 6D, F=5.35, P<0.01), but remained unchanged (mean change −0.76±3.22 mm Hg from 0D to 6D, F=1.46, P>0.05) in emmetropes. Meanwhile, we found that their anterior chamber depth decreased (P<0.01), anterior chamber angle narrowed (P<0.01), and lens thickened (P<0.01) significantly with accommodation, both in progressing myopes and emmetropes.

Conclusions

Although no difference was detected between the IOPs of progressing myopes and emmetropes without accommodation, accommodation could induce transient IOP elevation in progressing myopes. Simultaneously, we found that their anterior chamber depth decreased, anterior chamber angle narrowed, and lens thickened with accommodation. Although emmetropes showed the similar anterior eye segment structure changes, their IOPs did not increase with accommodation. Our study indicated that IOP elevation with accommodation in progressing myopes might be related to myopia progression.     

Visual outcomes after accommodating intraocular lens implantation

PURPOSE: To evaluate and compare the visual outcomes and accommodative amplitude in cataract patients after implantation of the Crystalens intraocular lens (IOL) (Eyeonics) versus standard monofocal IOLs. SETTING: Ten clinics in a nationwide multicenter study in the United States. METHODS: A multicenter comparative interventional case series with masked randomized postoperative examination of 224 eyes of 112 patients was performed by a single observer. Patients were divided into 2 groups (56 patients; 112 eyes each) depending on which IOL was implanted (Crystalens or monofocal). Accommodation was measured using 1 objective (dynamic retinoscopy) and 2 subjective methods (defocus and near point of accommodation). Visual acuity measurements were performed under the same conditions with standard visual acuity charts. RESULTS: Uncorrected monocular near vision was significantly better in the Crystalens group than in the standard monofocal group, with 101 of 112 eyes (90%) and 17 of 112 (15%), respectfully, reading J3 or better postoperatively. All 56 Crystalens patients had a binocular uncorrected near visual acuity of J3 or better compared with 16 of 56 (29%) standard monofocal patients. The mean postoperative monocular (0.85 +/- 0.30 [SD] versus 0.70 +/- 0.19, P<.01) and binocular (1.16 +/- 0.17 versus 1.01 +/- 0.14, P<.01) distance uncorrected visual acuities were also better in the Crystalens group than in the control group. All patients in the study achieved a corrected distance visual acuity of 20/20 or better. Measures of accommodation were significantly higher in Crystalens patients than in the monofocal IOL patients (dynamic retinoscopy 2.42 +/- 0.39 diopters [D] versus 0.91 +/- 0.24 D, P<.01; monocular defocus 1.74 +/- 0.48 D versus 0.75 +/- 0.25 D, P<.01; monocular near point of accommodation 9.5 +/- 3.1 inches versus 34.7 +/- 9.8 inches, P<.01). Perceived accommodation (5.79 D) was significantly greater than the measured accommodation (1.96 to 2.42 D) in Crystalens patients (paired t test, P<.01). CONCLUSIONS: The Crystalens IOL provided better uncorrected near and distance visual outcomes than standard monofocal IOLs in all analyses performed. Patients perceived a greater accommodation than measured. Understanding why this occurred could lead to valuable advances in accommodating IOL technology.