Intraocular lenses for the correction of refraction errors. Part 1: phakic anterior chamber lenses

In this overview, the current status of intraocular lens surgery to correct refractive error is reviewed. The interventions are divided into additive surgery with intraocular lens implantation without extraction of the crystalline lens (phakic intraocular lens, PIOL) or the removal of the crystalline lens with implantation of an IOL (refractive lens exchange, RLE). Phakic IOLs are constructed as angle-supported or iris-fixated anterior chamber lenses and posterior chamber lenses that are fixated in the ciliary sulcus. The implantation of phakic IOLs has been demonstrated to be an effective, safe, predictable and stable procedure to correct higher refractive errors. Complications are rare and differ for the three types of PIOL; for anterior chamber lenses these are mainly pupil ovalization and endothelial cell loss.     

Intraokularlinsen zur Korrektur von Refraktionsfehlern

In this overview, the current status of intraocular lens surgery to correct refractive error is reviewed. The interventions are divided into additive surgery with intraocular lens implantation without extraction of the crystalline lens (phakic intraocular lens, PIOL) or removal of the crystalline lens with implantation of an IOL (refractive lens exchange, RLE). Phakic IOLs are constructed as angle-supported or iris-fixated anterior chamber lenses and posterior chamber lenses which are fixated in the ciliary sulcus. The implantation of phakic IOLs has been demonstrated to be an effective, safe, predictable and stable procedure to correct higher refractive errors. Complications are rare and differ for the three types of PIOL; for posterior chamber lenses these are mainly cataract formation and pigment dispersion. RLE is preferable in cases of high ametropia in which the natural lens has lost its accommodative effect. The main complications for myopic RLA include retinal detachment, while hyperopic refractive lens exchange may be associated with surgical problems in the narrower anterior eye segment.     

Intraokularlinsen zur Korrektur von Refraktionsfehlern

In this overview, the current status of intraocular lens surgery to correct refractive error is reviewed. The interventions are divided into additive surgery with intraocular lens implantation without extraction of the crystalline lens (phakic intraocular lens, PIOL) or the removal of the crystalline lens with implantation of an IOL (refractive lens exchange, RLE). Phakic IOLs are constructed as angle-supported or iris-fixated anterior chamber lenses and posterior chamber lenses that are fixated in the ciliary sulcus. The implantation of phakic IOLs has been demonstrated to be an effective, safe, predictable and stable procedure to correct higher refractive errors. Complications are rare and differ for the three types of PIOL; for anterior chamber lenses these are mainly pupil ovalization and endothelial cell loss.     

Scheimpflug photographic imaging following implantation of anterior and posterior chamber phakic intraocular lenses: preliminary results

BACKGROUND: For the correction of refractive errors lenticular procedures are increasingly used in addition to corneal refractive surgery. One of those techniques is the implantation of intraocular lenses into phakic eyes (pIOL). Due to the close neighborhood of the implant to delicate intraocular structures, exact positioning and high postoperative stability are required. Scheimpflug photography has been shown to be a suitable instrument for the biometry of the anterior eye segment and the examination of IOL position. PATIENTS AND METHODS: Four anterior chamber phakic IOLs (pIOLs) (Bausch & Lomb NuVita) and 7 posterior chamber pIOLs (Staar ICL) were examined 1 week, 1 month and 3-6 months following implantation. At each examination 1 Scheimpflug slit image and 1 infrared retroillumination image were taken using the anterior eye segment analysis system EAS-1000 (Nidek Co., Gamagori, Japan). Evaluation of the images was performed with a personal computer and the software provided by the manufacturer. The distance of the pIOL to cornea and human lens was calculated and incidence and amount of pIOL rotation around the optical axis and potential crystalline lens opacification were assessed. RESULTS: The distance between the anterior chamber pIOL and the cornea 1 week after implantation was 1.61 +/- 0.10 mm. The distances between the myopic posterior chamber pIOL and the human lens were 0.34 +/- 0.11 mm and between the hyperopic posterior chamber pIOL and the human lens 0.26 and 0.29 mm, respectively. The values were constant over a period of 3-6 months. The pIOL showed no movement or change of position around the optical axis. There was no detectable cataract formation in the human lens. CONCLUSIONS: All implanted phakic anterior and posterior chamber IOLs showed a stable position in the eye within the observation period. Scheimpflug photography is proved to be a useful technique for the postoperative evaluation of the positioning of phakic IOLs.     

Silicone posterior chamber phakic intraocular lens dislocated into the vitreous cavity

PURPOSE: To report two highly myopic patients with silicone posterior chamber phakic intraocular lenses (Phakic Refractive Lens; CIBA Vision, Duluth, Ga) that luxated into the vitreous cavity without history of ocular trauma. METHODS: Two patients with posterior chamber phakic intraocular lenses (PIOLs) that luxated into the vitreous cavity of the right eye were examined. Each eye underwent pars plana vitrectomy and removal of the posterior chamber PIOL under retrobulbar anesthesia. RESULTS: Both patients were treated successfully. In the first patient, the posterior chamber PIOL luxated into the anterior vitreous cavity whereas in the second patient, the posterior chamber PIOL lay on the posterior pole. No ocular complications developed postoperatively. CONCLUSION: Luxation into the vitreous cavity is a rare, but potentially severe complication of posterior chamber PIOL refractive surgery in highly myopic eyes. Successful management includes pars plana vitrectomy and removal of the posterior chamber PIOL.     

Decentration and cataract formation 10 years following posterior chamber silicone phakic intraocular lens implantation

PURPOSE: To report a 10-year follow-up for bilateral implantation of a Chiron Adatomed silicone posterior chamber phakic intraocular lens (PIOL). METHODS: A 32-year-old man presented with bilateral blurred vision and monocular diplopia in the left eye of 2 years' duration. RESULTS: Slit-lamp microscopy showed bilateral anterior subcapsular cataract and temporal PIOL decentration, and no visible space between the PIOL and crystalline lens in the right eye. After explantation of the posterior chamber PIOL, lens aspiration, and IOL implantation, uncorrected visual acuity improved to 20/15 in the right eye. Scanning electron microscopy examination showed denser deposits on the central portion of the back surface when compared with the edges. CONCLUSIONS: Long-term follow up of certain designs of posterior chamber PIOLs may reveal late occurrence of complications. Cataract formation may be related to direct contact between the implanted and crystalline lenses.     

Phakic posterior chamber lenses for high myopia: functional and anatomical outcomes

PURPOSE: To evaluate the functional and the anatomical outcomes after implantation of phakic posterior chamber intraocular lenses (IOLs) in highly myopic eyes. SETTING: Service d'Ophtalmologie, H?pital Purpan, Toulouse, France. METHODS: Fifty-eight eyes of 46 patients that had implantation of phakic posterior chamber lenses for high myopia were evaluated. Predictability, efficiency, safety, and subjective and objective quality of vision were evaluated preoperatively and at least 6 months postoperatively. The effect of the procedure on the cornea, aqueous humor, pupil, anterior chamber angle, crystalline lens, and retina were studied. RESULTS: Mean preoperative myopia was -13.85 diopters (D) +/- 3.1 (SD) (range -8.00 to -19.25 D). Mean postoperative spherical equivalent was -1.22 +/- 0.83 D (range +0.75 to -3.50 D); 56.9% of eyes were within +/-1.00 D of the predicted result, and 77.6% gained 1 or more lines of best corrected visual acuity. All contact-lens-intolerant patients had improved quality of vision for day and night driving, distance vision, and vision under dim illumination. The mean postoperative level of contrast sensitivity without correction was higher than the mean preoperative level with correction. Adverse events were 2 cases of crystalline lens opacification 16 and 18 months after surgery and 2 cases of pigment deposits in the angle with increased intraocular pressure, which was controlled by beta-blockers. CONCLUSION: Implantation of posterior chamber phakic IOLs is effective and predictable; however, long-term follow-up is needed.     

Phake Intraokularlinsen

Refractive surgical procedures are generally divided into additive procedures with, e.?g. implantation of an artificial lens and subtractive procedures with ablation of corneal tissue. In this article the current status of phakic intraocular lens (IOL) implantation for correction of refractive errors is reviewed. Phakic IOLs are constructed as angle-supported or iris-fixated anterior chamber lenses and sulcus-fixated posterior chamber lenses. The implantation of phakic IOLs has been demonstrated to be an effective, safe, predictable and stable procedure to correct higher refractive errors. Complications are rare and depend to a large extent on the location. For anterior chamber lenses the main concern is critical endothelial cell loss and for posterior chamber lenses early cataract formation.     

虹膜夹型人工晶状体矫正高度近视的前节OCT检查分析

目的:使用前节OCT分析高度近视植入虹膜夹型人工晶状体后眼内的结构变化。方法:植入前房晶状体矫正高度近视6眼(11.5D至22.0D),使用前节OCT采集前节图像测量术前前房深度,术后人工晶状体与角膜内皮间距离(内皮—晶状体距离),人工晶状体与正常晶状体间距离。结果:术前前房深度为3.27～3.91mm,术后内皮—晶状体距离为2.07～2.24mm。人工晶状体后表面与正常晶状体间的距离为0.82～1.32mm。图像显示虹膜色素层没有明显改变。结论:前房深度较术前减少36.1%～44.6%。前节OCT对于检测虹膜夹型前房晶状体的位置有帮助。     

小眼球高度远视眼透明晶状体摘除联合后房型Piggyback人工晶状体植入

目的：探讨小眼球高度远视眼的透明晶状体摘除联合后房型Piggyback人工晶状体植入术的疗效及人工晶状体度数的计算方法。方法：1例双眼极短眼轴合并高度远视、慢性闭角型青光眼患者行透明晶状体摘除联合后房型二片 30.0D Piggyback人工晶状体植入,术前双眼行YAG激光虹膜周切,术后一周右眼眼压高,行小梁切除术。术后一周、一月和三月分别视力、屈光状态,眼压和前房深度。利用光路追迹法计算人工晶状体度数。结果：术后三月最佳矫正视力与术前一致,屈光状态等效球镜度右 2.75D、左 2.88D,前房深度右眼、左眼分别由术前1.87mm、1.93mm加深到术后3.02mm和3.20mm,眼压正常。结论：对小眼球合并高度远视、慢性闭角型青光眼行透明晶状体手术联合二片后房型IOL植入,不仅能较好地解决屈光问题,而且有利于控制青光眼的发作和发展。利用光路追迹法计算IOL度数的方法是可取。     

Phakic posterior chamber plate intraocular lenses for high myopia.

PURPOSE: Refractive correction of high myopia with phakic minus power intraocular lenses (IOLs) may give dramatic visual results. Various types of lenses developed for this purpose have not gained widespread use due to complications. Long-term results and complications of phakic posterior chamber lenses are yet unknown. The purpose of this study was to evaluate long-term refractive results and complications of early design phakic posterior chamber lenses. METHODS: Thirty-four high myopic eyes implanted with phakic posterior chamber IOLs designed by Fyodorov were evaluated retrospectively. Follow-up time ranged from 36 to 62 months. Corneal endothelial cell counts were made at the central cornea preoperatively and in the sixth month in 18 eyes and in the twelfth month in 14 eyes. RESULTS: Preoperative refractions were between -7.75 and -21.00 D; refractions at the end of the follow-up period were between -5.75 and +3.00 D. Sixty-three percent of eyes were in the +/-2.00-D range. Endothelial cell loss was 9% at 6 months and 10.22% at 12 month. The difference in endothelial cell counts at 6 and 12 months was not statistically significant. CONCLUSIONS: Early design phakic posterior chamber IOLs implanted in this study were developed by Fyodorov and are not used currently. These IOLs provided a stable and reversible refractive correction without leading to cataract formation. Endothelial loss was limited to surgical trauma. Moderate predictability of refractive correction and frequent decentrations with these lenses were linked to the early design of these IOLs.     

有晶状体眼前房角固定型人工晶状体植入术的进展

有晶状体眼前房角固定型人工晶状体植入术是近年来发展起来的矫正高度和超高度近视的一项新技术，随着晶状体材料的改良和临床经验的积累，这种屈光手术逐渐显示出了安全、有效、预测性好、可逆性、保留调节功能和对角膜内皮损伤小等优点。因此，在未来的几年里，前房角固定型人工晶状体植入术作为一种屈光手术将会扩大它的临床应用范围。就该手术的历史、人工晶状体的设计、手术适应证与禁忌证、手术技术、并发症及其防治等方面进行综述。     

Contrast sensitivity after posterior chamber phakic intraocular lens implantation for high myopia.

PURPOSE: To evaluate contrast sensitivity after posterior chamber phakic intraocular lens (PIOL) implantation for the correction of high myopia. METHODS: Twenty eyes of ten patients had a posterior chamber phakic intraocular lens (Staar ICL) implanted to correct high myopia. Mean preoperative myopia was -14.10+/-2.70 D. Follow-up was 24 months for all patients. Contrast sensitivity was tested with best spectacle-corrected visual acuity preoperatively and 3, 6, 12, 18, and 24 months postoperatively. RESULTS: Contrast sensitivity increased after surgery in all spatial frequencies. Normal values were achieved for low and intermediate spatial frequencies (3 and 6 c/deg). However, in spite of the improvement, values were still below normal for high spatial frequencies (12 and 18 c/deg). When the first postoperative examination was not considered, there were no statistically significant differences in contrast sensitivity values at different postoperative periods. CONCLUSION: Contrast sensitivity increased after posterior chamber phakic intraocular lens implantation (Staar ICL) in all spatial frequencies when compared to preoperative contrast sensitivity (best spectacle-corrected).     

Pigmentary dispersion syndrome induced by a posterior chamber phakic refractive lens

PURPOSE: To report a case of bilateral pigmentary dispersion syndrome (PDS) induced by the implantation of posterior chamber phakic refractive lenses (PRLs). METHOD: Case report. RESULTS: Following bilateral implantation of posterior chamber phakic refractive lenses in 38-year-old woman, unilateral elevated intraocular pressure (IOP) developed within months that was attributable to pigment dispersion within the anterior chamber. Findings consistent with PDS included bilateral transillumination defects of the iris in areas contacting the anterior surface of the PRLs, pigment deposits on the anterior surface of the PRLs, Krukenberg spindles, and bilateral dense pigmentation of the trabecular meshwork. The patient's IOP is presently under control and she has not developed glaucomatous damage. CONCLUSIONS: The development of PDS in this case demonstrates that posterior chamber phakic refractive lenses can make contact with the posterior iris and induce pigment dispersion syndrome in susceptible patients.     

ZB5M anterior chamber and Fyodorov's posterior chamber phakic intraocular lenses: long-term follow-up

PURPOSE: To compare the long-term complications of two outdated phakic intraocular lenses (PIOL) implanted in eyes with high myopia to aid development of better PIOL designs. METHODS: Sixty-two eyes of 37 patients implanted with the ZB5M anterior chamber PIOL (anterior chamber group) and 22 eyes of 14 patients implanted with Fyodorov's posterior chamber PIOL (posterior chamber group) were examined. Complications were compared after a mean follow-up of 71.15 +/- 32.17 months (range: 24 to 145 months) in the anterior chamber group and 84.14 +/- 26.43 months (range: 24 to 132 months) in the posterior chamber group (P = .07). RESULTS: At last follow-up, pupil ovalization was present in 32 (51.6%) eyes in the anterior chamber group and 1 (4.5%) eye in the posterior chamber group (P < .001), and cataract in 5 (8.1%) eyes in the anterior chamber group and 7 (31.8%) eyes in the posterior chamber group (P = .007). Phakic intraocular lens decentration, glaucoma, retinal detachment, corneal decomposition, and monocular diplopia were additional complications encountered in both groups, with no statistically significant difference. CONCLUSIONS: Proper understanding of these outdated PIOLs may be helpful in developing better PIOL designs.     

应用Pentacam三维眼前段分析仪对虹膜夹型人工晶状体植入术后的研究

目的 应用Pentacam术后追踪测量虹膜夹型有晶状体眼人工晶状体(PIOL)中央和周边部与角膜内皮和自然晶体之间的距离,倾斜度、偏心值以及前房深度的变化,评价其在前房的位置.方法 收集自2006年1月以来接受虹膜夹型人晶状体植入术的22例33只眼.术后6个月全部患者行Pentacam检查,测量VRSM50和VRSM60两组不同类型虹膜夹型PIOL中央和周边部与角膜内皮和自然晶体之间的距离,并测量术后1d、1、3及6个月人工晶状体的偏心量、倾斜度及前房深度值.结果 角膜内皮至PIOL光学部前表面距离为(1.94±0.36)mm.PIOL后表面与自然晶状体间的距离为(0.76±0.12)mm.分别比较各组在不同时期的平均偏心量与平均倾斜度,差异无统计学意义(P>0.05).在术后1d、1、3及6个月,比较2组的平均偏心量与平均倾斜度,差异无统计学意义(P>0.05).结论 Pentacam三维眼前段分析仪为PIOL植入术后提供高质量的Scheimpflug摄像,可以为有晶状体眼前房型人工晶状体提供精确的眼内定位,在这一方面具有重要的临床应用价值.     

Multifocal intraocular lenses

PURPOSE OF REVIEW: Multifocal intraocular lenses (IOLs) are growing in popularity among patients and surgeons, and opened the way to refractive lens exchange. Still they are not used routinely in cataract surgery, for reasons probably connected to the frequently observed reduction in contrast sensitivity. Recent papers with clinical study outcomes can help in understanding the advantages and the limits of multifocal IOLs. RECENT FINDINGS: Emerging from every published study, both refractive and diffractive multifocal IOLs usually provide good near visual acuity with distance correction. As many multifocal IOLs are distance-dominant, near vision can be improved by correcting for near the distance focus. The near contrast sensitivity thus obtained is similar to that of monofocal IOLs. Multifocal IOLs have been employed with success in complicated cataract surgery and in trauma cases, with the same outcome as in normal cataract cases. Presbyopic lens exchange remains controversial, with a high success rate in original ametropic eyes, but limited success in original emmetropic eyes. Secondary procedures to improve the refractive outcome are usually of little efficacy in improving patient satisfaction. A new anterior chamber phakic multifocal IOL has been designed to correct presbyopia and small refractive errors. The first clinical results indicate high patient satisfaction, with 7.3% explantation rate. SUMMARY: Multifocal IOLs can be more widely used after cataract surgery, but should be used with caution in almost emmetropic eyes with little or no cataract. Refractive lens exchange with multifocal IOL is especially worthwhile in hyperopic eyes. The new phakic multifocal IOL adds the concept of reversibility to presbyopic lens exchange.     

Implantation of posterior chamber lenses in eyes with phakodonesis and lens subluxation

Unilateral posterior chamber intraocular lens (IOL) implantation was performed after phacoemulsification or extracapsular cataract extraction in ten of 11 patients with phakodonesis or lens subluxation, which was bilateral in two cases. To facilitate placement of the IOL, the anterior capsule was opened with a YAG laser in nine patients. Intraoperative vitrectomy was performed in two patients, and posterior chamber IOL implantation was accomplished with fixation in the ciliary sulcus. Postoperative follow-up studies failed to demonstrate significant decentration or dislocation of the IOLs. Phakodonesis and lens subluxation are no longer considered absolute contraindications to implantation of posterior chamber IOLs.     

Bilateral giant retinal tear following posterior chamber phakic intraocular lens implantation

PURPOSE: To report a case of bilateral giant retinal tear following posterior chamber phakic intraocular lens (PIOL) implantation. METHODS: A patient with an ocular history of retinal detachment associated with giant retinal tear 4 months after a bilateral PIOL implantation was referred with a macula on retinal detachment associated with giant retinal tear in the fellow eye. The patient underwent vitrectomy with silicone oil tamponade and an encircling buckle. Five months later, a lensectomy with phakic IOL and silicone oil removal were performed. RESULTS: The retina was reattached and has remained stable during 3-year follow-up. CONCLUSIONS: Although it is unclear whether retinal detachment associated with giant retinal tear following refractive procedures occurs within the normal incidence in myopic eyes, prophylactic measures are mandatory in high-risk fellow eyes.     

Correction of high myopia with different phakic anterior chamber intraocular lenses: ICARE angle-supported lens and Verisyse iris-claw lens

Purpose To evaluate the efficacy, predictability and safety of implanting two models of anterior chamber IOLs for high myopia. Comparison of the refractive results between two groups of patients implanted with different IOLs.Materials and methods Forty eyes were implanted with phakic IOLs. The ICARE myopia lens was implanted in 20 eyes of 12 patients with preoperative myopia that ranged from −21.875 to −10.0. The mean patients‘ age was 30 years. The Verisyse IOL was implanted in 20 eyes of 12 patients with spherical equivalent of the refractive error from −21.625 to −10.375D, and the mean patients’ age was 32.25 years. The dioptric power of the intraocular lens was calculated by considering refraction, keratometry, and anterior chamber depth. The follow-up period was 12 months.Results Twelve months after surgery, the mean refractive error (SE) was −0.19D (100% of eyes were within ±1.0D of the target refraction) in the ICARE group, and −0.86D (95% of eyes were within ±1.0D of the target refraction) in the Verisyse group. The postoperative refraction remained stable during the entire follow-up period. The mean uncorrected visual acuity was 0.7 in the ICARE group, and 0.69 in the Verisyse group 1 year postoperatively. There was no loss in visual acuity 1 year after surgery in the ICARE implanted eyes, one patient in the Verisyse group lost 1 line of BCVA as compared to the preoperative state. Mean endothelial cell density loss was 6.12% and 6.79% in the ICARE and Verisyse groups, respectively. There were no statistically significant differences regarding the analyzed outcome parameters between the two study groups.Conclusion The implantation of both anterior chamber phakic intraocular lenses to correct high myopia resulted in a stable and predictable refractive outcome. Efficacy and safety of surgery for both implanted lens models are very high.This material was previously presented at the American Academy of Ophthalmology Annual Meeting in New Orleans, October 2004.The authors have no financial interest in this study. This was prospective randomized clinical trial.