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 Table of Contents  
ORIGINAL ARTICLE
Year : 2018  |  Volume : 111  |  Issue : 2  |  Page : 63-69

Comparing the outcome of intraocular lens implantation with or without posterior optic capture in pediatric cataract surgery


1 Ophthalmology Department, Research Institute of Ophthalmology, Cairo, Egypt
2 Ophthalmology Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt

Date of Submission01-May-2018
Date of Acceptance07-May-2018
Date of Web Publication30-Aug-2018

Correspondence Address:
Mohamed G Aly
Ophthalmology Department, Faculty of Medicine, Ain Shams University, El Abbaseya, Cairo, 11566
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ejos.ejos_25_18

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  Abstract 

Purpose To evaluate the outcome of intraocular lens (IOL) implantation with posterior optic capture versus in-the-bag implantation in pediatric cataract surgery.
Setting Ain Shams University Hospital and Research Institute of Ophthalmology.
Design It is a prospective, comparative clinical study.
Patients and methods Thirty eyes with developmental cataract underwent primary cataract extraction and IOL implantation of hydrophobic acrylic multipiece Sensar IOL AR40e. In all cases, anterior and posterior continuous curvilinear capsulorrhexis, lens aspiration, and anterior vitrectomy were performed. IOL was implanted in the ciliary sulcus, and the optic was captured in both anterior and posterior capsulorrhexis in group A (15 eyes) and implanted in the bag without capture in group B (15 eyes). Visual acuity, visual axis opacification, red reflex, intraocular pressure, centration, and complications were all assessed.
Results The mean age of children was 5.3±2.93 years. At 6 months of follow-up, the mean postoperative corrected distant visual acuity was 0.69±0.19 and 0.65±0.23 in groups A and B, respectively. The mean clear central zone was 4.29±0.24 and 3.6±0.55 mm in groups A and B, respectively (P=0.001). The mean IOL decentration measured in mm was 1.61±1.17 and 0.86±0.28 SD in groups A and B, respectively (P=0.003). There were no postoperative complications in all cases.
Conclusion Placement of IOL haptics in the ciliary sulcus while capturing the optic through the posterior continuous curvilinear capsulorrhexis provides more central clarity of the visual axis, however IOL decentration was more common.

Keywords: optic capture, pediatric cataract, posterior capsular opacification


How to cite this article:
El-Meshad NM, Aly MG, Galal AS, Risk AA, Ismail ZF. Comparing the outcome of intraocular lens implantation with or without posterior optic capture in pediatric cataract surgery. J Egypt Ophthalmol Soc 2018;111:63-9

How to cite this URL:
El-Meshad NM, Aly MG, Galal AS, Risk AA, Ismail ZF. Comparing the outcome of intraocular lens implantation with or without posterior optic capture in pediatric cataract surgery. J Egypt Ophthalmol Soc [serial online] 2018 [cited 2018 Nov 12];111:63-9. Available from: http://www.jeos.eg.net/text.asp?2018/111/2/63/240159


  Introduction Top


Over the past few years, improvements in technology and adjustments in surgical procedures have brought pediatric cataract surgery to a new horizon. Automation of the surgery, and the use of intraocular lenses (IOLs) had improved both the anatomical and functional outcomes [1]. However, posterior capsular opacification occurs in 51–100% of those who do not have a primary posterior capsulotomy, and remains the main obstacle for proper visual rehabilitation in children [2]. A neodymium yttrium aluminum garnet (Nd:YAG) capsulotomy does not provide a long-lasting clear visual axis because lens epithelial cells can find their way to the posterior surface of the lens, not to mention the technical difficulty in children [3]. The transformation of residual lens epithelial cells can result in dense membranes on the anterior hyaloid surface, visual axis opacification, haptic displacement, and iris capture [4]. Posterior curvilinear continuous capsulorrhexis (PCCC) with optic capture is a technique initially described by Gimbel in 1994 to maintain a clear visual axis after pediatric cataract surgery [5]. The technique encompasses capturing the IOL optic through a PCCC, while keeping the haptics within the capsular bag. This technique was shown to prevent posterior capsular opacification and maintain IOL centration for children with developmental cataract of 6 years of age or less [1].

In situations where access to YAG lasers is difficult, this technique could be considered as a method to reduce the need for dissection of the posterior capsule as a second procedure. Moreover, optic capture has the advantage of preventing vitreous herniation [6]. However, Vasavada and Trivedi [7] reported that optic capture predisposes the eye to an increased postoperative uveal inflammatory response, as evidenced by a larger proportion of posterior synechiae and IOL deposits. The aim of this study is to evaluate the outcome of the sulcus IOL implantation with posterior optic capture compared to the commonly used ‘in the bag implantation’ without optic capture.


  Patients and methods Top


This prospective study included 30 eyes of 24 patients with congenital cataract who underwent primary cataract surgery and IOL implantation. The age of the patients was 1.5–10 years. Only children with congenital cataract who had a significant block of the visual axis and diminished red reflex were included in the study. Eyes with cataract associated with corneal opacity, glaucoma, iris, coloboma, or accompanying uveitis were excluded from the study. The study protocol was approved by the Ain Shams University hospital research ethics committee. All patients’ parents received a thorough explanation of the study design and aims, and were provided with and signed a written informed consent. Cases were recruited from the pediatric ophthalmology clinics in both the Research Institute of Ophthalmology and Ain Shams University hospital. Patients were randomly divided into two groups. Group A included 15 eyes that underwent primary cataract surgery, anterior vitrectomy, and IOL implantation in the ciliary sulcus with capture of the optic through the anterior and posterior capsulorrhexis. Group B included 15 eyes that also underwent primary cataract surgery, anterior vitrectomy, and IOL implantation within the capsular bag but without optic capture.

All patients had a detailed preoperative evaluation, including history taking, visual acuity assessment, anterior segment, and fundus examination. Visual acuity was assessed using the decimal chart in verbal children (tumbling E, lea symbols, and forced preferential looking in selected cases). In eyes where objective visual assessment was not possible the fixation pattern was noted. A thorough anterior segment slit-lamp examination for the assessment of corneal clarity, anterior chamber depth, iris, shape, and density of cataract was done. Intraocular pressure (IOP) was measured by applanation tonometry using Haag-Streit applanation tonometer. Perkins handheld tonometer was used to measure IOP under general anesthesia in uncooperative or younger children. Dilated fundus examination for the evaluation of the vitreous, optic nerve head, macular area, and retinal periphery was carried out. Ultrasonography was done in cases where there was no clear fundus view. In patients with suspected low visual potential, flash electroretinogram, flash, and pattern visual evoked potential were done for estimation of retinal and optic nerve functions. All patients were referred to the general pediatric clinic for clinical assessment and evaluation of any associated systemic problems and preoperative consultation. IOL power calculation was carried out by preoperative assessment of axial length and keratometric readings. The power of the IOL calculated using SRK-II intended for emmetropia, was then under-corrected in percentage according to age, as recommended by Dahan and Salmenson equally for both groups [2].

Surgical technique

All eyes were dilated using tropicamide 1% eye drops. Surgeries were performed under general anesthesia. Two clear corneal side-port incisions were performed at 3 and 9 O’clock positions using a 20-G blade. A viscoelastic substance (Healon; Abbott Medical Optics: Santa Ana, CA) was injected into the anterior chamber. A 2.4-mm superior clear corneal incision was performed using a 2.4-mm keratome. A 5-mm anterior capsulorrhexis was performed under a viscoelastic substance. Staining of the anterior capsule with trypan blue stain was done when needed. Multiquadrant hydrodissection and automated irrigation aspiration of all lens material using the phacoemulsification machine was carried out in all cases. A 4 mm posterior capsulorrhexis was then completed using capsulorrhexis forceps. Cases in which anterior and posterior capsulorrhexis was not completed were excluded in the study. Anterior vitrectomy using a vitreous cutter was then done through the PCCC in all cases. This was followed by implantation of the hydrophobic acrylic multipiece IOL (Sensar AR40e; Abbott Medical Optics, Santa Ana, California, USA). In group A, the IOL was implanted in the ciliary sulcus, and the optic was captured posteriorly in both the anterior and posterior capsulorrhexis. Capture was confirmed by ovalization of both anterior and posterior capsulorrhexis ([Figure 1]). In group B, the IOL was implanted in the capsular bag without posterior capturing. The main incision and side ports were closed using one 10–0 nylon. At the completion of surgery, all patients received subconjunctival injection of dexamethasone at a concentration of 4 mg/ml and cefuroxime at a concentration of 1 mg/ml.
Figure 1 Ovalization of both anterior and posterior capsulorrhexis in the case of group A with optic capture.

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Postoperatively, all patients received topical moxifloxacin (Vigamox 0.5%; Alcon Laboratories, Fort Worth, TX) for 2 weeks and topical steroids prednisolone acetate ophthalmic suspension (Predforte 1%; Allergan, Inc., Irvine, CA). Topical steroids were tapered gradually over 6 weeks.

Patients were followed up at 1 day, 1 week, 1 month, and 6 months after surgery. At each visit, the measurement of visual acuity, cycloplegic refraction, measurement of IOP, slit-lamp biomicroscopy, and fundus examination were performed. Any anterior segment reaction, synechiae formation, IOL decentration, or visual axis opacification were recorded. Visual axis opacification was graded using a red reflex with grade I, indicating a bright-red reflex, grade II a slightly dimmed reflex, and grade III a grayish reflex. The area of a clear zone was evaluated by measuring its longest axis in mm by slit-lamp biomicroscopy. Ultrasound biomicroscopy (UBM) by Sonomed Escalon (Lake Success, NY) by probe 35 in 90° orientation to evaluate the lens position and centration was done in all patients at 6 months of follow-up.

Statistical analysis

Data were summarized as the mean and SD for continuous variables and frequencies for categorical variables. Change over time was analyzed using Friedman two-way analysis of variance. Differences were evaluated using Chi square-test or Fisher’s exact test for noncategorical variables and t-test for continuous variables. Statistical analysis was performed using SPSS for Windows version 20 (SPSS Inc., Chicago, Illinois, USA).


  Results Top


A total of 30 eyes of 24 patients were included in the study. The mean age of the patients at the time of surgery was 5.3±2.93 years (range: 1.5–10 years). The mean preoperative corrected distant visual acuity (CDVA) was 0.11±0.1 in group A and 0.11±0.08 in group B. The mean postoperative CDVA was 0.55±0.2 and 0.51±0.2 at 1 month after surgery, and improved to 0.69±0.19 and 0.65±0.23 at 6 months postoperatively in groups A and B, respectively. The improvement of visual acuity was statistically significant in both groups (P=0.0001 and 0.0002 in groups A and B, respectively) ([Figure 2]). However, there was no statistically significant difference in the CDVA when comparing both the groups (P=0.34).
Figure 2 Preoperative and postoperative corrected distance visual acuity in both groups.

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The mean spherical equivalent (SE) was 1.43±3.37 D in group A and 1.64±1.92 D in group B at the end of the postoperative follow-up (hypermetropic). The difference was not statistically significant (P=0.45).

The mean longest diameter of the central clear zone was 4.9±0.24 mm in group A and 3.67±0.55 mm in group B. The difference was statistically significant (P=0.001).

The postoperative clarity of the red reflex was better in group A than in group B. Seventy-three percent of patients in group A and 40% in group B had grade I (bright-red reflex). None of the patients in group A had grade-III red reflex (retrolental opacity), whereas 13% of group B had grade-III red reflex ([Figure 3]).
Figure 3 Red reflex grading among both groups.

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Comparing IOL centration at 6-month follow-up, the difference between group A and group B was statistically significant (P=0.03). The mean decentration measured in mm was 1.61±1.17 SD and 0.86±0.28 SD in groups A and B, respectively. There were no postoperative complications in all cases ([Figure 4]).
Figure 4 Intraocular lens decentration as measured by UBM.

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[Figure 5] shows the ultrasound biomicroscopy (UBM) of two cases of groups A and B. It shows that the IOL was perfectly centered in group B, whereas it was decentered in group A.
Figure 5 (a): UBM picture of the case of group A with optic capture showing intraocular lens (IOL) decentration. (b): UBM picture of the case of group B without optic capture showing well-centered IOL in the capsular bag.

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Anterior continuous curvilinear capsulorrhexis and PCCC were successfully executed in all cases. Significant visual axis opacification that needed Nd:YAG laser capsulotomy occurred in three patients in group B, whereas no patient in group A needed intervention. A single case in group A with intraoperative IOL slippage occurred during irrigation and aspiration after successful capture in posterior capsulorrhexis. The IOL was immediately and successfully repositioned in the bag intraoperatively and had no further complications and was excluded from the study. None of the patients had elevation of the IOP or other complications during the follow-up. [Table 1] summarizes the differences between group A and group B, as regards CDVA, IOP, and postoperative SE power.
Table 1 Comparison between both groups regarding corrected distance visual acuity, spherical equivalent refraction, and intraocular pressure along the follow-up period

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  Discussion Top


Visual axis opacification remains the most common complication of occurrence, preventing visual improvement after pediatric cataract surgery [8]. In an attempt to deal with this highly expected complication, in our study, we compared IOL implantation with posterior optic capture to ‘in the bag’ implantation, a choice adopted by many pediatric cataract surgeons [9]. We chose to evaluate visual axis opacification by grading the red reflex and found that there was a higher number of cases achieving grade-1 red reflex in the optic-capture group. We found severe visual axis opacification in three patients of group B who eventually needed Nd:YAG capsulotomy to improve the clarity of the central area and visual acuity, whereas no single case of group A was in need of such intervention. Our results are similar to those of Leysen et al. [10] whose results of the cumulative Nd:YAG laser rate after implantation using the IOL capture technique, were zero. The lower incidence of visual axis opacification in the optic-capture group in our study could be explained by the complete sealing of the anterior and posterior capsule leaflets. This capsular sealing closed the bag completely and prevented lens epithelial cells to migrate and form secondary opaque membranes. It has been shown in previous studies that other surgical techniques such as ‘bag in the lens implantation’ and vertical entrapment of IOL also decrease the incidence of late visual axis opacification by preventing the lens epithelial cell migration [11],[12]. We also assessed the size of the clear central zone as an end-point result at 6-month follow-up period and found that group A patients maintained a statistically significant larger clear central area than group B. This might be explained by the haptic optic capture halting the progress of contraction of the posterior capsule at the point of capture more than the in-the-bag group where continuous centripetal contracture of the capsular rim causes the clear zone to become progressively smaller. Both techniques were found to achieve improved visual acuity. There was no statistically significant difference in the postoperative CDVA between both the groups at any of the follow-up periods. We thought that the more posterior location of IOL in the optic-capture group compared to in-the-bag group might have an effect on the targeted IOL power. This could result in a difference in the SE between both the groups, however, postoperative SE showed no statistically significant difference between both the groups. The high SD in the postoperative SE could be attributed to the large age group of the studied patients with different amounts of intended undercorrection. There was no increase in IOP in both groups, suggesting that both techniques were equally safe regarding the risk of the development of glaucoma. Michaelides et al. [13] concluded that the higher rate of the incidence of postoperative glaucoma in his work might be owing to the lack of posterior capsulotomy that was done in all of our patients. Our data confirm his work that removal of the posterior capsule may be associated with a lower rate of acquired glaucoma. We also believe that the older age group of patients in our study was another reason for the absence of acquired postoperative glaucoma [13]. However, a longer period of follow-up is still needed to detect secondary glaucoma.

Centration of the IOL was observed at each postoperative visit and UBM was done at 6 months, and the results showed a statistically significant difference observed when comparing both groups. It has been proven that optic capture ensured good IOL centration [14]. However, our results differ from other studies that reported that mild decentration was being observed in the case of in-the-bag implantation and in no eye in the optic capture [7],[14]. Previous studies had concluded that the continuous capsule margins in the optic-capture group lock the IOL optic and prevent it from decentering. In our work, the results were similar earlier; however, in late postoperative period as the capsular contraction occurred; decentration was more evident in the optic-capture group. We concluded that the captured IOL moves sideways to become displaced due to unequal capsular contraction forces that occurred in the optic-capture group than in-the-bag implantation group whose contraction forces were centripetal without significant decentration. Another explanation for IOL decentration in the optic-capture group is the possible disparity regarding the location of the posterior capsulorrhexis relative to the anterior capsulorrhexis. For optimum centration of IOL, the posterior capsulorrhexis should always be smaller, centered, and contained within the circumference of the anterior capsulorrhexis. We had only a single case of intraoperative sudden partial IOL slippage into the vitreous cavity during the removal of a viscoelastic substance and after attempted optic capture in the posterior capsulorrhexis. This was explained by the increased pressure in the anterior chamber during irrigation and aspiration of the viscoelastic substance compared to the lower vitreous pressure due to anterior vitrectomy. Even though in this case the IOL was immediately retrieved and safely repositioned in the sulcus without further complications, this incident suggests that a certain degree of skills and great care are needed while performing this procedure. In this context, we disagree with Faramarzi who proposed that the technique was easier to perform than in-the-bag implantation. However, we agree with his conclusion that implanting IOL in the sulcus with optic capture through the PCCC provides complete fusion of the anterior and posterior capsule leaflets (sealed-bag technique), and lens epithelial cells migration then is not possible [14]. Anterior vitrectomy was done in our study in both groups, as previous studies have shown that the anterior vitreous can act as a scaffold for lens epithelial cells to migrate and form secondary membranes [15],[16]. A recent study comparing optic capture with or without anterior vitrectomy has shown that the incidence of visual axis opacification was the same [17]. Recently, a femtosecond laser has been tried with success for performing accurately sized anterior and posterior capsulorrhexis [18],[19],[20]. The utilization of femtosecond laser technology in pediatric cataract surgery eliminates the real challenge associated with creation of posterior capsulorrhexis that should be contained within the circumference limits of the anterior capsulorrhexis. We think that this will decrease the possibility of late IOL decentration. Furthermore, it might help to flatten the steep learning curve associated with the optic-capture technique and might help beginning surgeons to adopt such a difficult but a worthy-doing technique.


  Conclusion Top


We found that the procedure of sulcus implantation with a sealed-bag technique using a three-piece acrylic-foldable IOL, although technically difficult, significantly decreases the posterior opacification and maintains clarity in pediatric cataract surgery that however can result in significant decentration from the visual axis.

Acknowledgements

The authors thank Layla Hamouda MD, PhD, Professor of Ophthalmology, Al Menya University Hospital for providing technical support and UBM imaging. Mohamed Khafagy MD, PhD, El Kasr El Einy Hospital for providing statistical analysis.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

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Gimbel HV. Posterior continuous curvilinear capsulorhexis and optic capture of the intraocular lens to prevent secondary opacification in pediatric cataract surgery. J Cataract Refract Surg 1997; 23(Suppl 1):652–656.  Back to cited text no. 5
    
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Koch DD, Kohnen T. A retrospective comparison of techniques to prevent secondary cataract formation following posterior chamber intraocular lens implantation in infants and children. Trans Am Ophthalmol Soc 1997; 95:351–360.  Back to cited text no. 9
    
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Leysen I, Coeckelbergh T, Gobin L. Cumulative neodymium: YAG laser rate after bag-in-the-lens and lens-in-the-bag intraocular lens implantation; comparative study. J Cataract Refract Surg 2006; 32:2085–2090.  Back to cited text no. 10
    
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Tassignon MJ, Gobin L, Mathysen D, van Looveren J, De Groot V. Clinical outcomes of cataract surgery after bag-in-the-lens intraocular lens implantation following ISO standard 11979-7:2006. J Cataract Refract Surg 2011; 37:2120–2129.  Back to cited text no. 11
    
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Grieshaber MC, Pienaar A, Stegmann R. Posterior vertical capsulotomy with optic entrapment of the intraocular lens in congenital cataracts − prevention of capsule opacification. J Cataract Refract Surg 2005; 31:886–894.  Back to cited text no. 12
    
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Michaelides M, Bunce C, Adams GW. Glaucoma following congenital cataract surgery − the role of early surgery and posterior capsulotomy. BMC Ophthalmol 2007; 7:13.  Back to cited text no. 13
    
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Faramarzi A, Javadi MA. Comparison of 2 techniques of intraocular lens implantation in pediatric cataract surgery. J Cataract Refract Surg 2009; 35:1040–1045.  Back to cited text no. 14
    
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Ellis FJ. Management of pediatric cataract and lens opacities. Curr Opin Ophthalmol 2002; 13:33–37.  Back to cited text no. 15
    
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Hosal BM, Biglan AW. Risk factors for secondary membrane formation after removal of. J Cataract Refract Surg 2002; 28:302–309.  Back to cited text no. 16
    
17.
Vasavada AR, Vasavada V, Shah SK, Trivedi RH, Vasavada VA, Vasavada SA et al. Postoperative outcomes of intraocular lens implantation in the bag versus posterior optic capture in pediatric cataract surgery. J Cataract Refract Surg 2017; 43:1127–1183.  Back to cited text no. 17
    
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Dick HB, Schultz T. Femtosecond laser-assisted cataract surgery in infants. J Cataract Refract Surg 2013; 39:665–668.  Back to cited text no. 18
    
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