Scanning electron microscopic characteristics of phakic intraocular lenses

OBJECTIVE: To analyze the surface quality of new generation phakic intraocular lenses (IOLs). DESIGN: Experimental materials study. MATERIALS: Three different new generation phakic IOLs: angle-fixated anterior chamber lens Chiron Vision NuVita MA20 (polymethylmethacrylate [PMMAD, iris-fixated anterior chamber lens Ophtec Artisan Iris-Claw (PMMA), posterior chamber lens Staar ICM (polymer from porcine collagen and 2-hydroxyethyl methacrylate [HEMA]). METHODS: Representative samples of three different phakic IOLs underwent surface and edge-finish examination with light microscopy (LM). The phakic IOLs were then examined by use of scanning electron microscopy (SEM), and particular attention was given to optic surface quality, edge finish, haptic, and optic/haptic junction. RESULTS: In all IOLs the LM examination showed a smooth and homogeneous surface. No irregularities, particularly at the optic front and back surface, optic edge, haptic, and the optic/haptic junctions, were detected by SEM. One exception was a minor surface roughness at the claws of an Artisan iris-fixated anterior chamber IOL. CONCLUSIONS: Phakic IOLs are implanted either in the anterior or posterior chamber of healthy eyes, and high standards for their surface quality are required. The evaluation of surface properties with LM and SEM did not reveal any defects that contraindicate the implantation of phakic IOLs.     

Ultrasound biomicroscopy of ZSAL-4 anterior chamber phakic intraocular lens for high myopia.

PURPOSE: To evaluate the intraocular location and anatomic relationship to other structures of the ZSAL-4 angle-supported anterior chamber phakic intraocular lens (IOL) for high myopia using ultrasound biomicroscopy (UBM). SETTING: Clínica de Nuestra Se?ora de la Concepción, Fundación Jiménez Díaz, and Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Madrid, Spain. METHODS: Eight phakic myopic eyes corrected by ZSAL-4 angle-supported anterior chamber phakic IOLs were examined by UBM. The distance between the corneal endothelium and the IOL at the central and peripheral cornea and between the phakic IOL and the iris was measured. RESULTS: The mean distance between the central cornea and the IOL was 2361.37 microm +/- 109.62 (SD); between the edge of the IOL optic and the endothelium, 1646.24 +/- 27.06 microm; and between the IOL and the iris, 354.46 +/- 41.61 microm. The IOL footplates appeared to be correctly positioned in the anterior chamber angle in all eyes. CONCLUSION: The space between the IOL and the endothelium was greater in eyes with the ZSAL-4 angle-supported phakic IOL than in eyes with other angle-supported phakic IOLs. The possibility of intermittent contact between the IOL edge and the midperipheral cornea plays a minor role in the mechanism of endothelial damage with this lens model.     

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.     

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.     

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.     

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.     

Intraocular lenses for the correction of refraction errors. Part II. Phakic posterior chamber lenses and refractive lens exchange with posterior chamber lens implantation

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.     

Scheimpflug biometry of the anterior segment after implantation of foldable iris-fixated lenses

PURPOSE: To evaluate intraocular dimensions of the anterior segment of myopic phakic eyes after implantation of foldable iris-fixated lenses. METHODS: Seventeen myopic eyes that received a foldable iris-fixated phakic intraocular lens (PIOL) were assessed. Distances between the cornea and the IOL-optic edge and between the IOL optic and the crystalline lens were evaluated using Scheimpflug photography 3 months postoperatively. RESULTS: The average postoperative distance between the central corneal endothelium and the anterior surface of the IOL was 2.01 +/- 0.26 mm. The distance between the corneal endothelium and the peripheral edge of the IOL averaged 1.32 +/- 0.18 mm at the 12 o'clock position and 1.34 +/- 0.21 mm at the 6 o'clock position. The distance between the crystalline lens and the posterior surface of the IOL averaged 0.73 +/- 0.09 mm. CONCLUSIONS: The high quality of the three-dimensional Scheimpflug images allowed measurements of intraocular distances in PIOL implanted eyes. Distances between the foldable iris-fixated IOL and crucial surrounding tissues could be determined 3 months postoperatively.     

Pigment dispersion and Artisan phakic intraocular lenses: crystalline lens rise as a safety criterion

PURPOSE: To validate the theory that crystalline lens rise can be used as a safety criterion to prevent pigment dispersion in eyes with an Artisan phakic intraocular lens (IOL) (Ophtec BV). SETTING: Monticelli Clinic, Marseilles, France. METHOD: A comparative analysis of crystalline lens rise in 9 eyes with pigment dispersion and 78 eyes without dispersion was performed. All eyes had previous implantation of an Artisan IOL. Anterior segment imaging was done using an anterior chamber optical coherence tomography (AC OCT) prototype. Crystalline lens rise was defined by the distance between the anterior pole of the crystalline lens and the horizontal plane joining the opposite iridocorneal recesses. RESULTS: The study confirmed that crystalline lens rise can be considered a safety criterion for implantation of Artisan-type phakic IOLs. The higher the crystalline lens rise, the greater the risk for developing pigment dispersion in the area of the pupil. This complication occurred more frequently in hyperopic eyes than in myopic eyes. Results indicate there is little or no risk for pigment dispersion if the rise is less than 600 microm; 67% of eyes with a rise of 600 microm or more developed pupillary pigment dispersion. In some cases in which the IOL was loosely fixated, there was no traction on the iris root and dispersion was prevented or delayed. CONCLUSIONS: Crystalline lens rise should be considered a new safety criterion for Artisan phakic IOL implantation and should also be applied to other types of phakic IOLs. The distance remaining between the crystalline lens rise and a 600 microm theoretical safety level allows one to calculate how long the IOL can safely remain in the eye.     

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.     

Biometry of phakic intraocular lens using Scheimpflug photography

PURPOSE: To examine lateral and axial positioning of phakic intraocular lenses (IOLs) with iris fixation in the anterior chamber and to examine short-term stability of the IOL position. SETTING: The Netherlands Opthalmic Research Institute, Amsterdam, the Netherlands. METHODS: Thirty patients participated in the study. Thirty-one eyes were implanted with the 204 type myopia IOL, 14 eyes with the 206 myopia IOL, and 8 eyes with the 203 hyperopia IOL. Scheimpflug slitlamp photographs were made through the optical axis along 4 meridians of the eyes. Ray tracing was used to obtain the lateral and axial position of the IOLs. RESULTS: Centration of the IOL with respect to the pupil's center and the tilt angle of the IOL with respect to the optical axis of the eye were measured. Standard deviation of decentration was 0.21 mm vertically and 0.16 mm horizontally. Standard deviation of tilt was 1.30 degrees vertically and 0.90 degrees horizontally. Tilt and decentration are proportional to each other. Vaulting, the distance between the crystalline lens and the IOL, was constant over a period of 24 months, ranging from 0.2 to 0.8 mm, depending primarily on the radius of curvature of the crystalline lens. A geometric model for this dependence was formulated. CONCLUSION: Phakic IOLs with iris fixation can be positioned in the eye with submillimeter precision. Axial position of iris-fixated phakic IOLs over time is excellent. Axial position and vaulting can be predicted when the radius of curvature of the crystalline lens is known. The IOL behaves as if mounted slightly above a sphere-the anterior surface of the crystalline lens.     

Blendempfindlichkeit und Halos nach “phakic IOL”-Operation zur Behandlung einer hohen Myopie

BACKGROUND: Phakic IOLs are currently under clinical investigation for the correction of high myopia with acceptable postoperative refractive results. Although daytime vision is usually very good some patients complain of visual disturbances, described as glare and halos, during the night time, leading to difficulties in driving vehicles. PATIENTS AND METHODS: The quality of vision after phakic IOL surgery was investigated pre- and postoperatively using various tests for objective measurements of glare and halo in 40 myopic eyes (-9.0 to -20.0 D). Based on the implanted phakic IOL, eyes were divided into 4 groups of 10 eyes each where an Artisan 5.0 was implanted, an Artisan 6.0, a NuVita, and an ICL. RESULTS: All patients were happy with the postoperative refractive outcome and during daytime no visual discomfort was reported. In contrast, most patients reported visual disturbances during dim light conditions and at night time, described as glare and halos. The objective measurements showed in most eyes increased glare and halos which was most prominent in eyes with an ICL, followed by the NuVita IOL. In contrast, patients with an Artisan 6.0 reported significantly less glare and halo problems. CONCLUSIONS: All currently available phakic IOLs, in particular the ICL and the NuVita lead to a decreased visual performance during night time. Therefore, this phenomenon must be explained to the patient prior to surgery. An increase in the size of the optic should lead to an improvement with reduction of postoperative glare and halos.     

Intermittent myopic shift of 4.0 diopters after implantation of an Artisan iris-supported phakic intraocular lens

A 45-year-old man with bilateral high myopia and myopic astigmatism had uneventful implantation of a -10.5 diopters (D) Artisan iris-fixated anterior chamber phakic intraocular lens (PIOL) (Ophtec) in both eyes. In the first days after surgery, uncorrected visual acuity (UCVA) was 20/16 in the right eye and 20/16 in the left; the position of the PIOL was stable. Ten days after surgery, the left eye developed a myopic shift of 4.0 D. Further examination showed that the myopia disappeared when the pupil was medically dilated. After the pupil returned to a natural position, the myopic shift reappeared. Because there were no changes in the subsequent 4 months, we decided to exclavate the IOL, rotate it by 10 degrees, and reenclavate it with less tissue. The myopic shift did not return over the following 20 months, and the UCVA was 20/20. In rare cases, iris-fixated anterior chamber IOLs may induce refractive changes related to effects on the surrounding anatomic structures. This may be corrected by phakic IOL rotation or reenclavation of the phakic IOL with less tissue.     

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.     

Intraocular lens implantation in phakic rabbit eyes

Three sizes (13.5 mm, 17.5 mm, and 18.5 mm) of open loop, one piece, poly(methyl methacrylate) anterior chamber intraocular lenses (IOLs) were implanted in 12 phakic rabbit eyes to evaluate the effect of the IOL on the crystalline lens and the anterior chamber. Six eyes were used as a control group. Minimum follow-up was four weeks. All the IOLs touched the crystalline lenses, and on the first postoperative day, round subcapsular lens opacities were found in all eyes in the area of IOL contact. The lens opacities became more dense with time. Only one eye in the control group showed a subcapsular opacity, which was linear rather than round. Anterior chamber inflammation was 1+ to 2+ in ten eyes (80%) in the IOL group during the first and second weeks, whereas minimal inflammatory changes occurred in the control group. These results suggest that with current IOL technology, IOL insertion in the phakic eye to correct refractive errors results in a high incidence of cataract if IOL-to-lens touch occurs.     

Position of rigid and foldable iris-fixated myopic phakic intraocular lenses evaluated by Scheimpflug photography

PURPOSE: To evaluate the postoperative intraocular positional stability of 1 rigid poly(methyl methacrylate) (PMMA) phakic intraocular lens (pIOL) model and 2 foldable polysilicone-PMMA iris-fixated pIOL models. SETTING: Department of Ophthalmology, Johann Wolfgang Goethe-University Frankfurt am Main, Germany. METHODS: One of 3 iris-fixated pIOL models (Artisan, Artiflex I, and Artiflex II, Ophtec BV) was implanted in 45 eyes of 26 patients with myopia or myopic astigmatism. The central distance between the pIOL and corneal endothelium and between the pIOL and anterior surface of the crystalline lens was evaluated using Scheimpflug photography 6 and 12 months after surgery. RESULTS: The mean preoperative spherical equivalent was -9.32 diopters +/- 1.78 (SD) (range -6.5 to -13.5 D). Each IOL model was implanted in 15 eyes. The median distance from the central corneal endothelium to the anterior surface of the pIOL at 6 months and 12 months was 2.65 mm and 2.64 mm, respectively, in the Artisan group, 2.47 mm and 2.50 mm, respectively, in the Artiflex I group, and 2.48 mm and 2.52 mm, respectively, in the Artiflex II group. The median distance between the posterior surface of the pIOL and the anterior surface of the crystalline lens at 6 months and 12 months was 0.40 mm and 0.48 mm, respectively, in the Artisan group, 0.53 mm and 0.55 mm, respectively, in the Artiflex I group, and 0.68 mm and 0.66 mm, respectively, in the Artiflex II group. At 12 months, the distance between the pIOL and crystalline lens was statistically significantly greater in the Artiflex II group than in the Artisan group (P<.01). CONCLUSION: The intraocular position of rigid pIOLs and foldable silicone iris-supported pIOLs showed a difference between the 3 pIOL models in space to the crystalline lens and the corneal endothelium, which may affect long-term results in terms of IOL interaction with surrounding tissue.     

Anterior segment OCT and phakic intraocular lenses: a perspective

Perfect tolerance is expected when one implants a phakic intraocular lens (pIOL) in the anterior segment. Not only should the material be compatible, but the pIOL must respect the anatomy of the anterior chamber. Based on 3 years of experience using an anterior segment optical coherence tomographer (Visante OCT, Carl Zeiss Meditec), I have defined numerous safety criteria for pIOLs. The internal dimensions of the anterior chamber must be considered along different meridians. I propose an objective measurement of the iris dome, the crystalline lens rise (CLR), which is the distance between the anterior pole of the crystalline lens and a line joining the 2 opposite iridocorneal angles. In a series with the Artisan IOL (Ophtec), pigment dispersion syndrome appeared in 70% of cases in which the CLR was greater than 600 microm. Angle-supported IOLs must be placed relative to the anterior chamber's largest diameter; in the same series of cases, the anterior chamber was oval with a large vertical axis in 74% of cases. The posterior face of an angle-supported IOL must have a 700 microm vault to respect the physiological modifications of the crystalline lens. It is difficult to know the posterior chamber's exact diameter as it varies with the horizontal or vertical axis. It also undergoes constant modifications due to accommodation and aging.     

三种有晶状体眼IOL植入矫正高度近视的临床评价

目的 评价3种有晶状体眼IOL植入矫正高度近视的有效性、安全性和稳定性.方法 选取2003年12月至2009年12月就诊高度近视患者110例(208只眼),平均年龄31岁,其中59例(113只眼)行房角支撑型IOL植入术,29例(53只眼)行虹膜夹持型IOL植入术,21例(41只眼)行后房型IOL植入术,平均随访时间分别为54个月(3～72个月)、15.7个月(3～24个月)和7.2个月(3～15个月).定义安全性指数为术后平均BSCVA与术前平均BSCVA的比值,定义有效性指数为术后平均UCVA与术前平均BSCVA的比值.对手术前后角膜内皮细胞计数比较采用配对t检验.结果 术后3个月和1年时有效性指数均大于1.只有植入房角支撑型IOL的患者随访至术后5年,有效性指数下降为0.85,但仍有16%的患眼裸眼视力≥1.0,85%的患眼≥0.5.所有患者术后的随访过程中,安全性指数始终大于1.植入房角支撑型IOL的患者随访术后5年时,46%的患眼实际屈光度数与预期矫正度数在±0.50 D以内,68%的患眼实际屈光度数与预期矫正度数在±1.00 D以内.植入虹膜夹持型IOL的患者随访至术后1年时,78%的患眼实际屈光度数与预期矫正度数在±0.50 D以内,100%的患眼的实际屈光度数与预期矫正度数在±1.00 D以内.植入后房型IOL的患者随访至术后3个月时,95%的实际屈光度数与预期矫正度数在±0.50 D以内,100%的实际屈光度数与预期矫正度数在±1.00 D以内.房角支撑型IOL植入术后5年时角膜内皮细胞计数的减少与术前相比具有统计学意义(t=9.769,P=0.000),而植入虹膜夹持型IOL的患者在术后1年和植入后房型IOL的患者在术后3个月时的角膜内皮细胞计数与术前相比无统计学意义(t=1.180,0.583;P=0.249,0.566).术后1个月内分别有16只眼出现高眼压,局部应用降眼压眼液后恢复正常.植入房角支撑型IOL的患者术后最主要的并发症是瞳孔失圆,虹膜夹持组为夹持处虹膜色素的脱失,植入后房型IOL的患者为自然晶状体的混浊.结论 有晶状体眼IOL植入治疗高度近视早期预测性好、安全,但手术长期并发症的发生需要引起关注.(中华眼科杂志,2011,47:531-538)

Abstract：

Objective To evaluate the efficacy, safety and stability of three kinds of phakic intraocular lens implantation for the correction of high myopia. Methods This study included 208 eyes of 110 patients with a mean age of 31 years(21-53) from December 2003 to December 2009. Angle-supported lens(Phakic 6H, OII) were inserted into 113 eyes, iris-fixated lens(Artisan, OPHTEC) were inserted into 53 eyes and implantable contact lens(ICL) (V4, STAAR)were inserted into 41eyes. The average follow-up time of the three groups were 54.0 months(3-72 months), 15.7 months(3-24 months)and 7.2 months(3-15 months)respectively. Results At 3 months and 12 months, the efficacy indexes of the three groups were all above 1.00. Only the angle-supported group was followed up to 72 months postoperatively when the efficacy index dropped to 0.85, but still UCVA was 1.0 (20/20) or better in 16% eyes and 0.5 (20/40) or better in 85% eyes. The safety indexes of the three groups were always above 1.00 during the follow up. In the angle-supported group, 46% eyes were within ±0.50 D of the desired refraction and 68% eyes were within ±1.00 D at 5 years postoperatively. In the iris-fixated group, 78% eyes were within ±0.50 D of the desired refraction and 100% eyes were within ±1.00 D at 1 years postoperatively. In the ICL group, 95% eyes were within ±0.50 D of the desired refraction and 100% eyes were within ±1.00 D at 3 months postoperatively. No statistically significant differences were found between preoperative and 3-month postoperative endothelial cell density in the ICL group. Also, there was no statistically significant reduction in endothelial cell density at 1 years in the iris-fixated group. However, when preoperative and 5-year postoperative measurements were compared in the angle-supported group, the total decrease in cell density is statistically significant(t=9.769, P=0.000). 16 eyes developed high IOP within 1 month postoperatively which resolved after intervention. In the three groups(angle-supported, iris-fixated and ICL), the most common complications were pupil ovalization, iris atrophy plus pigment dispersion and lens opacification respectively. Conclusion Although phakic IOL implantation is predictable and safe for treatment of high myopia in short-term, the long-term complications should be concerned and treated well.     

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。     

Ultrasound biomicroscopy of the Artisan phakic intraocular lens in hyperopic eyes

PURPOSE: To study in situ the intraocular position of the Artisan iris-claw intraocular lens (IOL) (model 203) (Ophtec) in phakic hyperopic eyes using ultrasound biomicroscopy (UBM). METHODS: Echograms of the anterior chamber were taken preoperatively and 24 to 317 days postoperatively in 4 eyes implanted with the Artisan IOL (power +4.0 to +6.0 diopters). The preoperative anterior chamber depth (ACD) and the postoperative distance between the IOL and the corneal endothelium (endothelium-optic distance) and between the IOL and the lens were measured. The echograms were assessed for the effect of the IOL on iris tissue. RESULTS: The preoperative ACD ranged from 3.10 to 3.56 mm and the postoperative endothelium-optic distance, from 2.03 to 2.54 mm. The distance between the lens and the posterior surface of the IOL ranged from 0.35 to 0.79 mm. Several UBM echograms showed indentation of iris tissue by the IOL haptics and optic edge, although no pigmentary dispersion was noted. CONCLUSIONS: Adequate space was maintained between the Artisan hyperopic IOL and the corneal endothelium, angle, and crystalline lens. Haptic indentation of the iris, which could lead to pigment erosion, was observed. Preoperative gonioscopy and maintenance of normal intraocular pressure postoperatively suggest the indentation was secondary to inadequate lens vaulting relative to the high natural arch of the iris in hyperopic eyes. Shortening the haptics or increasing the lens vault might resolve this problem.