作者：叶向彧，曹景，陶津华，王于蓝，盛耀华
作者单位：1200092 中国上海市，上海交通大学医学院附属新华医院眼科；2266100 中国山东省青岛市第八人民医院眼科
【摘要】本文报道了两例在植入时出现镊子夹痕的AcrySof ReSTOR IOL患者。病例1进行了IOL置换，电镜扫描结果显示AcrySof ReSTOR IOL衍射结构保持良好。病例2术后视力、对比敏感和波前相差检查未见明显异常。我们的结论是AcrySof ReSTOR IOL光学区上的镊子夹痕不会导致视力下降。
【关键词】 镊子夹痕；人工晶状体；多焦
Forceps imprint in the AcrySof ReSTOR IOL Optic XiangYu Ye, Jing Cao, JinHua Tao, YuLan Wang, Yao Hua Sheng
Department of Ophthalmology, Xinhua Hospital Affiliated to Medical School of Shanghai Jiaotong University, Shanghai 200092, China Department of Ophthalmology, Qingdao Eighth Peoples Hospital, Qingdao 266100, Shandong Province, China
Abstract
We describe two cases in which a forceps imprint developed in the AcrySof ReSTOR IOL optic while inserting these IOLs into the cartridge with straight clamping forceps. In case 1,the AcrySof ReSTOR IOL was explanted and observed under scanning electron microscopy (SEM). The SEM showed that the step design of ReSTOR Multifocal IOL was well maintained. In case 2, visual acuity, contrast sensitivity and wavefront measurements were performed and no specific changes were found. Strong evidence does not exist that suggests the onaxis forceps imprint can significantly compromise visual acuity.
KEYWORDS: forceps imprint; intraocular lens; multifocal
INTRODUCTION
AcrySof ReSTOR (Alcon) is the most widely used diffractive multifocal IOL(MIOL). Recent studies[15] have found that the results of both uncorrected distance visual acuity and uncorrected near visual acuity in eyes with the ReSTOR intraocular lens (IOL) were satisfactory. Its optic is composed of the same proprietary acrylic material that has been used in AcrySof lenses since 1995. This material has been shown to provide excellent clinical benefits through its high refractive index (1.55), flexibility, and biocompatibility. ReSTOR IOL has a 6.0mm diameter biconvex optic, including refractive zones for distance vision and diffractive zones for near vision. Twelve diffractive discontinuities or steps have been incorporated in the central 3.6mm region.
We describe two cases in which a forceps mark developed in the AcrySof ReSTOR IOL optic while inserting these IOLs into the cartridge with straight clamping forceps.
CASE 1
A 56yearold woman was admitted on June 25, 2006, with progressive decrease of visual acuity (VA) in both eyes that was more pronounced in the OD. At that time, bestcorrected visual acuity (BCVA) was 20/40 (OD) and 20/30 (OS). Laser interferential VA was 20/30 (OU) evaluated with a Heine retinometer (Heine, Herrsching, Germany). Slitlamp examination revealed the presence of agerelated cataracts in both eyes. The patient underwent uneventful phacoemulsification in the right eye under topical/intracameral anesthesia (June 28, 2006), performed by one of us (C.J.). A 3.0mm scleral tunnel incision was created at 12 oclock. The size of the anterior capsulotomy was about 5.0mm. The AcrySof ReSTOR IOL (+20 diopters [D]) was loaded into the Monarch II Injector System (Alcon) with straight clamping forceps and was slowly injected into the capsular bag with no additional resistance felt. At the completion of the surgery, it was confirmed that the IOL was well centered in the capsular bag and no abnormalities were noted.
On the first postoperative day, the uncorrected distance visual acuity (UCDVA) was 20/40 and the uncorrected near visual acuity (UCNVA) was J5. Slitlamp examination revealed a clear cornea, the pupil was dilated to 5.0mm, and the IOL was perfectly centered. There was a 3mm long imprint of the forceps observed on the lens central anterior surface where the apodized, diffractive concentric rings were located (Figure 1). We informed the patient about the imprint and recommended her to come back for a follow
up examination. Two weeks later, the UCDVA, bestcorrected distance visual acuity (BCDVA), UCNVA, and best distancecorrected near visual acuity (BDCNVA) were 20/40, 20/30, J5, and J3, respectively. The imprint of the forceps was still present. No retinal complications, such as cystoid macular edema, were detected by fundus fluorescein angiography and fundus examination. The patient reported no optical symptoms such as glare or halo postoperatively.
Because the patient was dissatisfied with vision both at near and far, the IOL exchange was done on July 12, 2006. A new AcrySof ReSTOR lens (+20D, SA60D3, Alcon ) was folded meticulously and inserted into the capsular bag. Two days after the IOL exchange, examinations of the cornea, AC, pupil, and fundus were normal. The IOL was well centered. The UCDVA was 20/40, the UCNVA was J5. One month later, the eye was quiet. The UCDVA, BCDVA, UCNVA and BDCNVA were 20/30, 20/25, J4, and J3, respectively.
After explantation, gross photographs of the explanted lenses were taken using a camera (Canon IXUS 500) fitted to a slitlamp microscope (NIDEK 150) ( Figure 2). For surface analyses, the specimens were also observed under scanning electron microscopy (SEM) (Electron Microscopy Center of Qingdao University of Science & Technology, China)(Figure 3,4).
Figure 1A slitlamp photograph of case 1 shows an opaque, obliquely orientated forceps mark in the area compressed by the forceps. （略）
Figure 2Slitiamp appearance of forceps imprint after explantation by bisection technique.（略）
Figure 3The presence of multiple fine granular substances covering the optical surface of the IOL and forceps mark were found in the diffractive refractive zones (original magnification ×80)（略）
CASE 2
A 72yearold man, who was a high myope, had cataract in both eyes. Laser interferential VA was 20/40 (OS) when evaluated with a Heine retinometer. Ascan ultrasound biometry showed an axial length of 25.46mm in the left eye. On August 23, 2007, uneventful phacoemulsification was performed by one of us (Sheng YH) on the left eye. A +16.0D AcrySof ReSTOR IOL was loaded into Monarch II Injector System (Alcon) with straight clamping forceps and slowly injected into the capsular bag through a 3.0mm corneal incision.
On the first day after surgery, the UCDVA was 20/40. The slitlamp examination revealed a clear cornea and the IOL was centered. An approximately 3mm imprint of the forceps was observed on the lens anterior surface (Figure 5,6). One month after operation, the BCDVA was 20/30 with 1.50DC×85 and the UCNVA was J4. Wavefront measurements (NIDEK NAVEX platform) and contrast sensitivity (PelliRobson test) were performed in the left eye and no specific changes were found (Figure 6).
DISCUSSION
The ReSTOR MIOL, fabricated in the AcrySof (Alcon) foldable acrylic material, has an apodized diffractive refractive optic with a 3.6mm center of concentric diffractive steps and within this area is a ＋4.00D addition that equates to a ＋3.20D addition at the spectacle plane. Step heights decrease smoothly from 1.3μm in the central zone to 0.2μm at the diffractive periphery (apodization). The central 3.6mm functional region is very important to gradually changing the proportion of energy directed to the two images as the pupil diameter changes. AcrySof lens is made of a copolymer of 2phenylethyl acrylate and 2phenylethyl methacrylate. Its physical characteristics include a high refractive index; great flexibility; and low elasticity. However, these IOLs are more fragile and hence more susceptible to injury than silicone and PMMA IOLs[6,7].
There are several reports, which mentioned that the forceps marks or imprints were induced on IOL optic surface while in folding or inserting process[812]. Rauz et al[8]noted visually insignificant “offaxis” scratch marks by the lensintroducing forceps that were detected in a total of 24 eyes (40.0%), most commonly on the acrylic (MA60BM) and hydrogel optics. The difference between the various biomaterials(acrylic, hydrogel, and silicone)was not significant. Gunenc et al[10], in their series of 91 eyes that had phacoemulsification and inthebag AcrySof IOL implantation (MA30BA or MA60BA), reported that 25 eyes (27.4%) were observed folding marks away from the central visual axis and there was no difference in visual acuity or contrast sensitivity between eyes with folding marks and those without.
Figure 4The step design within the forceps imprint is well maintained (original magnification×500)（略）
Figure 5Slitlamp examination of case 2 shows a forceps imprint in the central 3.6mm region 1 month postoperatively（略）
Figure 6Wavefront analysis revealed refractions similar to the manifest refraction and no particular aberrations related to the forceps imprint were observed in case 2 （略）
In our report, in case 1, a 3mm “onaxis” imprint of the forceps was observed on the lens anterior surface covered with granular substances. This is the first situation we met in which the functional zone of MIOL was “damaged”. Eventually, we opted for an IOL exchange for the following reasons: (1) The patient was subjectively not satisfied with the visual outcome. After 2 weeks followup, the UCDVA, BCDVA and BDCNVA were not significantly improved. (2) The characteristic material and design of ReSTOR MIOL is more fragile and its onaxis injury on the optic surface may compromise the visual function. (3) Many reports [9,13] showed that granular deposits on the optical surface were associated with a significant decrease in visual acuity. In our case, haze or granularity present on the surface of the lens optic corresponding to marks, theoretically should have an effect on the visual performance. (4) With the AcrySof lens, although its adhesiveness is associated with advantages such as low ACO and PCO rates, it rendered explantation of this singlepiece design more difficult with time[14]. (5) To evaluate whether or not; and if so, then to what extent, the apodized diffractive–refractive optic of the AcrySof ReSTOR IOL is altered when it is implanted in the wrong manner.
Scanning electron microscopy (SEM) is the gold standard for evaluating morphologic details of IOL surfaces[7,1517]. Studies of the surface quality of diffractive PMMA and refractive silicone (SA40N, Array) MIOLs have been published[18]. The results show that the MIOL surface structure is not more sensitive to manipulation during folding than that of monofocal IOL. Until now, no study of the surface quality of AcrySof ReSTOR IOL has been reported. In case 1, SEM showed that the step design of ReSTOR MIOL was well maintained and that the granular substances were less dense than that of other reports. It appears as though impairment of the optical qualities of the MIOLs is not to be expected. The vision dissatisfaction of case 1 might related to insufficient adaption of the lens or her high expectation.
Internal optic aberration in pseudophakic eyes consists of that of the posterior corneal surface, ocular media, and IOL. However, because the posterior corneal surface and ocular media generally have little aberration, what is derived from the IOL is thought to predominate in internal optic aberrations[1921]. The OPD (optical path difference) internal map displays the refractive status of the eye owing to internal aberrations by subtracting the effects of the corneal front surface from the total aberrometry. For intraocular surgery, the internal OPD map allows for determination of the centeration of the IOL and the optical effect of the surgery[22]. In case 2, there are no particular changes related to the forceps imprint observed on the OPD map.
The reason for the forceps imprint is that we grasped the IOL at the central optic zone unintentionally. We recommend implanting the AcrySof ReSTOR IOL carefully according to the companys instructions. The forceps should grasp the IOL at the junction of the optic and haptic. Recently, Evangelista et al[23] proposed the Sfold implantation technique for the AcrySof intraocular lens as a good alternative.
To our knowledge, this is the first report of forceps imprint in AcrySof ReSTOR IOL. Although the optical qualities of the IOLs were not specifically evaluated in this study, strong evidence does not exist that suggests the onaxis forceps imprint can significantly compromise visual acuity.
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