- Email: [email protected]
Single-piece acrylic intraocular lens implantation in children
Single-piece acrylic intraocular lens implantation in children Rupal H. Trivedi, MD, M. Edward Wilson Jr., MD Purpose: To assess the short-term outcomes of single-piece acrylic intraocular lens (IOL) implantation in children by determining the incidence of postoperative visual axis opacification and the need for a second procedure to clear the axis, cell deposits on the IOL optic, posterior synechias, and IOL decentration. Setting: Miles Center for Pediatric Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. Methods: This retrospective case review comprised 43 consecutive implantations (33 patients) of a single-piece hydrophobic acrylic IOL (AcrySof姞 SA30AL or SA60AT, Alcon). An analysis of 42 eyes with posterior capsulectomy and vitrectomy was performed. Eyes with traumatic cataract and secondary IOLs were excluded. Results: Single-piece acrylic IOLs were implanted in 42 eyes. The mean age was 33.5 months ⫾ 28.9 (SD) (range 0.5 to 110 months) and the mean follow-up, 12.0 ⫾ 8.2 months (range 1.0 to 27.5 months). Postoperative opacification of the visual axis occurred in 7 eyes (16.7%). Secondary surgical procedures were required in 5 eyes (11.9%). Lens deposits were observed in 8 eyes (19.0%) and synechias, in 5 eyes (11.9%). All IOLs were well centered postoperatively. Conclusion: The short-term data suggest implantation of the AcrySof singlepiece hydrophobic acrylic IOL is safe in the pediatric eye. J Cataract Refract Surg 2003; 29:1738 –1743 © 2003 ASCRS and ESCRS
T
o our knowledge, Epstein implanted the first intraocular lens (IOL) in a pediatric eye in 1951.1 However, IOL implantation in children did not become common practice until the 1990s, probably because of frequent secondary complications caused by the IOL material and design and the enhanced inflammatory response in these small eyes. Primary IOL implantation in young children has continued to become more popular as surgical techniques and biocompatible IOL materials and designs improve. Until recently, pediatric ophthalmologists were implanting poly(methyl methacrylate) (PMMA) IOLs exclusively. However, in a worldwide survey we conducted in 2001, 69.0% of respondents reported using hydrophobic acrylic IOLs Accepted for publication May 5, 2003. Reprint requests to M. Edward Wilson Jr., MD, MUSC–Storm Eye Institute, 167 Ashley Avenue, Charleston, South Carolina 29425-5536, USA. E-mail: [email protected]. © 2003 ASCRS and ESCRS Published by Elsevier Inc.
(unpublished data). The trend away from PMMA toward acrylic for childhood IOL implantation has been driven by the desire for a proven biocompatible material that can be inserted through a smaller incision. Until recently, the most popular acrylic IOL (AcrySof威, Alcon) was available only in a 3-piece design with PMMA haptics. Difficulties that can occur with the 3-piece design include haptic kinking and inadvertent sulcus fixation, which can be minimized with the use of the newer single-piece, all-acrylic AcrySof SA series IOLs. We2 and others3,4 recently reported good outcomes of 3-piece acrylic IOL implantation in children. Although the literature reflects the short-term results of single-piece acrylic IOL implantation in adult cataract surgery,5,6 to our knowledge, the short-term results of single-piece acrylic IOL implantation in infants and children have not been reported. In August 2000, 1 of us (M.E.W.) began implanting single-piece acrylic IOLs (AcrySof model SA30AL 0886-3350/03/$–see front matter doi:10.1016/S0886-3350(03)00468-1
SINGLE-PIECE ACRYLIC IOLS IN CHILDREN
initially and then model SA60AT) in pediatric cases at the time of cataract removal. We report the short-term outcomes in these cases, including any form of postoperative visual axis opacification with or without a second procedure to clear the axis, the incidence of cell deposits on the IOL optic, the presence of posterior synechias, and IOL centration.
Patients and Methods A database of pediatric IOL implantations was queried to allow review of consecutive eyes implanted with a single-piece acrylic IOL. Eyes with traumatic cataract or secondary implantation were excluded from the study. All surgeries were performed by a single surgeon (M.E.W.). An AcrySof SA30AL IOL (5.5 mm optic, 12.5 mm overall size) or AcrySof SA60AT IOL (6.0 mm optic, 13.0 mm overall size) was implanted. Both models are foldable and single-piece. The SA30AL IOL was used between August 2000 and April 2001 (eyes 1 to 14 and eye 17), and the SA60AT IOL was used between March 2001 and July 2002 (eyes 15 to 16 and eyes 18 to 43). All patients had keratometry and immersion A-scan ultrasonography for axial length measurement. The Holladay formula was used to calculate IOL power. The target postoperative refraction was based on the patient’s age and fellow-eye status. In general, the target refraction in cases of single IOL implantation early in life was hyperopia. The younger the child, the higher the postoperative refraction target. For instance, in the first month of life, it was ⫹12.0 diopters (D); in the second to third month, ⫹8.0 to ⫹10.0 D; in the fourth to sixth month, ⫹6.0 D; and in the sixth to twelfth month, ⫹4.0 D. In the second to sixth year of life, the target gradually decreased from ⫹4.0 to ⫹1.0 D and after the sixth year of life, the aim was emmetropia. When the eye was microphthalmic, the target refraction was sometimes not reached even with the highest power (⫹30.0 D) available in the IOL style used. When the piggyback technique was used, the target refraction was plano or mild myopia in the early postoperative period. When piggyback lenses were implanted in the first 2 months of life, the target was ⫹2.0 or ⫹3.0 D because this mild hyperopia would likely disappear in the early postoperative period. The power of the temporary anterior-most IOL was chosen based on how much refractive change was anticipated during growth and development. It often amounted to approximately one third of the total IOL power. A standard surgical technique7 was used. For IOL insertion, a forceps was used in the first 12 eyes; the Monarch II injector (Alcon Laboratories) was used after January 2001. The postoperative treatment was standardized.7 When possible, a follow-up examination was performed 1 and 7 days and 4 and 8 weeks postoperatively, every 3 months during the first year, and every 6 months thereafter.
Postoperative parameters assessed were any form of media opacification (visually significant or not), the need for secondary intervention to clear the visual axis, the presence of synechias or cell deposits, and IOL centration. Data were analyzed using the Student t test.
Results Of the 328 consecutive pediatric IOL implantations in the database at the time of the review, 43 eyes of 33 patients received a single-piece acrylic IOL. With 1 exception (eye 22), all received primary posterior capsulectomy and anterior vitrectomy at the time of cataract surgery. Eye 22 had an intact posterior capsule and will be discussed separately. Of the remaining 42 eyes of 32 patients, 15 had implantation of an SA30AL IOL and 27, an SA60AT IOL. The mean age of the 21 boys and 11 girls at the time of treatment was 33.5 months ⫾ 28.9 (SD) (range 0.5 to 110 months). The mean follow-up was 12.0 ⫾ 8.2 months (range 1.0 to 27.5 months). A corneal tunnel incision was made in 32 eyes and a scleral tunnel incision in 10 eyes. Thirty-eight eyes received a vitrectorhexis and 4, a manual capsulorhexis. In 3 eyes (7, 10, 27), an anterior capsule tear occurred during IOL insertion; a posterior capsulectomy was performed using the vitrectorhexis technique in all cases. Twenty-three eyes received a posterior capsulectomy and an anterior vitrectomy from the pars plana approach, and 19 eyes received it from the limbal approach. In addition to bag-fixated single-piece IOL implantation, 4 eyes had implantation of an SA30AL piggyback IOL (eyes 13, 14) or an MA60BM (eyes 17, 26) in the ciliary sulcus. Postoperative Visual Axis Opacification Five eyes (11.9%) required a second surgical procedure for opacification of the visual axis (Table 1). The mean age at surgery was 7.9 ⫾ 6.6 months in patients requiring a secondary procedure and 37.0 ⫾ 29.0 months in those who did not (P ⫽ .0001). Three of 11 eyes (27.3%) with IOL implantation during the first year of life required surgical intervention. Five of 17 eyes (29.4%) operated on before 18 months of age required a second surgery to clear the visual axis; none of the 25 eyes operated at or after 18 months of age required a second surgery. Two eyes with piggyback IOLs required surgery for postoperative visual axis opacification. Both
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Table 1. Characteristics of eyes requiring a second procedure because of visual axis opacification. Age at Cataract Surgery (Mo)
Interval to 2nd Procedure (Mo)
5
14.1
12.0
Cortex reproliferation
Posterior
Pars plana, with vitrector
7
10.8
21.9
Elschnig pearls
Posterior
Limbal, with vitrector
13
0.9
9.7
Fibrous (anterior capsule closure)
Anterior
Capsulorhexis, with forceps
17
0.5
4.4
Cortex reproliferation
Predominately posterior; also anterior
Pars plana and limbal, with vitrector
33
13.0
5.5
Cortex reproliferation
Predominately anterior; also posterior
Limbal and pars plana, with vitrector
Eye
Type of Opacification
had been operated on in the first month of life. The secondary procedures were required a mean of 10.7 months (range 4.4 to 21.9 months) after cataract surgery. Two other eyes had off-center opacification of the visual axis not requiring surgical intervention. Eye 24 had cortex reproliferation not occluding the visual axis. Eye 32 had peripheral Elschnig pearls. Cell Deposits on IOL Optic Eight eyes (19.0%) had IOL deposits. Six eyes (3, 4, 5, 19, 20, 35) had a few deposits, and 2 eyes (6, 7) had more numerous deposits. None of the deposits was visually significant. Posterior Synechias Posterior synechias were seen in 5 eyes (13, 17, 24, 27, 39) (11.9%). None produced enough correctopia to cause a noticeable cosmetic deformity. In most cases, the synechias were pinpoint adhesions of the iris to the anterior capsulotomy edge. No adhesions were seen between the iris and the IOL. IOL Centration All eyes maintained a clinically centered IOL
Discussion Since its introduction in 1994, the acrylic IOL has assumed a prominent role in adult cataract surgery.2– 4,6 In a survey of practice patterns for pediatric cataract surgery, the acrylic IOL was also the most popular for implantation in children. Recent reports2– 4 show these 1740
Plane of Opacification in Relation to IOL Optic
Surgical Approach
lenses to be biocompatible with the pediatric eye. However, the 3-piece design of the most commonly used acrylic IOL (AcrySof MA series) predisposed to haptic kinking on entry into the eye. Inadvertent sulcus implantation could also occur when this IOL is used in small pediatric eyes. More recently, a single-piece, all-acrylic AcrySof IOL (SA series) became available. It can be inserted into the smallest capsular bags using the Monarch II injector. The soft haptics can be manually placed in position if necessary using an intraocular hook or push–pull instrument. The haptics unfold slowly yet retain enough memory after placement to resist equatorial lens capsule fibrosis. In our series, we did not detect haptic deformation caused by compression from capsule fibrosis, a complication that occurs in children. Based on their implantation characteristics, we believe single-piece AcrySof SA series IOLs are ideal for children. Our early results show the lens has clinical biocompatibility, stays well centered, and has a low incidence of postoperative opacification of the visual axis. All but 1 eye in the series had a primary posterior capsulectomy and anterior vitrectomy; therefore, we cannot comment on the incidence of posterior capsule opacification with this new lens when the posterior capsule is left intact. Laboratory investigation at Storm Eye Institute indicates that the flexible haptic design of the single-piece acrylic AcrySof IOL minimizes ovaling of the capsulorhexis opening and capsule bag in children compared to the 3-piece design (S.K. Pandey, MD, et al., “Evaluation of IOL Sizing and Capsular Bag Stretch in Pediatric Eyes,” presented at the ASCRS Symposium on Cataract,
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Figure 1. (Trivedi) Postoperative photographs. A: Eye 6 (right eye) at 22.1 months in a patient who had surgery at 10.6 months of age. The visual axis is clear and the IOL well centered. B: Left eye (7) of the same child, which had surgery when the patient was 10.8 months old. There is visual axis opacification with Elschnig pearls, and the edge of the IOL is exposed at 3 o’clock.
Figure 2. (Trivedi) Postoperative photograph of eye 33 5.5 months after surgery, which was performed when the patient was 13.0 months old. Cortex reproliferation (arrow) can be seen.
IOL and Refractive Surgery, Philadelphia, Pennsylvania, USA, June 2002). Haptic deformation (ie, haptics bending behind the optic), occasionally observed with other lenses, can develop when using such a soft IOL. However, this has not occurred with the single-piece acrylic lens in our clinical practice. Extremely flexible haptics, combined with excellent memory, make this IOL easy to implant and not prone to deformation (S.S. Lane, MD, “Comparison of the Biomechanical Behavior of Foldable IOLs,” presented at the ASCRS Symposium on Cataract, IOL and Refractive Surgery, San Diego, California, USA, April 2001). Despite primary removal of the center of the posterior capsule and the anterior vitreous, 5 eyes (11.9%)
required a second procedure to clear postoperative visual axis opacification a mean of 10.7 months postoperatively. The age at surgery was younger on average than when no second surgery was needed (7.9 months versus 37.0 months). One patient (eyes 6, 7) had SA30AL IOL implantation at the age of 10.6 months and 10.8 months, respectively. The right eye (6) had uneventful surgery. In the left eye (7), a tear was noted in the anterior capsule during IOL manipulation. At the follow-up at 22.1 months and 21.9 months, respectively, the right eye had a clear visual axis with the anterior capsule completely covering the optic (Figure 1, A). The left eye had visual axis opacification caused by Elschnig pearls. This opacification was visually significant and required a second procedure. In this eye, the anterior capsule edge no longer completely covered the optic for 360 degrees, which exposed the IOL edge for 1 clock hour at the 3 o’clock position (Figure 1, B). The relationship of the anterior capsule to the IOL optic may have led to the need for the second procedure by allowing Elschnig pearls to migrate into the visual axis. Although 1 case is not sufficient to draw a conclusion, this possible explanation concurs with a report in the literature on adult cataract surgery.8 Cortex reproliferation after cataract surgery is typical in very young eyes. This easily aspirated material can escape the capsule fornix and block the visual axis (Figure 2), even when the anterior capsule edge overlaps the IOL optic for 360 degrees. The relationship between the anterior capsule and IOL optic and its connection to
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visual axis opacification (both Elschnig pearls and cortex reproliferation) in pediatric cataract surgery require further work. One patient had piggyback IOL implantation at the age of 0.9 month in the right eye (13) and at 1.2 month in the left eye (14). A pars plana vitrectomy was performed in the right eye. During the procedure, the leading haptic went behind the posterior capsule but was lifted manually to achieve in-the-bag IOL fixation. The left eye had uneventful surgery. The right eye required a second procedure 9.7 months postoperatively for removal of the fibrous opacification. The opacification appeared as a thin, taut sheet of cells that encased, but did not adhere to, the capsule-fixated IOL. No adhesion to the sulcus-fixated IOL was observed. We have seen this type of opacification on rare occasions with PMMA and 3-piece acrylic IOL implantation, but always in eyes having implantation within the first 6 months of life. After the ciliary sulcus-fixated IOL in the right eye was explanted, the fibrous membrane was removed in a capsulorhexis fashion. Opacification was not observed behind the IOL. The left eye had a clear visual axis at the time and required planned explantation of the piggyback IOL only. In a previous study,2 we found IOL deposits in 7 of 110 eyes (6.4%) with 3-piece acrylic lenses (MA30BA and MA60BM series) and in 26 of 120 eyes (21.7%) with PMMA lenses. In the present study, cell deposits occurred in 8 of 42 eyes (19.0%), although only 2 eyes had more than a few isolated deposits. In no case were the deposits visually significant. In the previous study, posterior synechias were seen in 5 eyes (4.5%) with 3-piece acrylic IOLs and 23 (19.2%) with PMMA lenses. In the present study, synechias occurred in 5 eyes (11.9%) with posterior capsulectomy and vitrectomy. Three eyes in our series (13, 14, 17) had explantation of an acrylic IOL placed in the ciliary sulcus anterior to the capsule-fixated single-piece IOL. The IOLs were explanted as a planned surgical procedure to compensate for the growth of the eye.7 They were removed without difficulty. Because IOLs in the sulcus do not fixate by scarring, the explantation procedures were unhampered. However, the single-piece AcrySof SA series IOLs are not recommended for sulcus fixation. Unlike the 3-piece design, the single-piece lenses are not posteriorly angulated and have broad haptics with bulbous tips. Decen1742
tration and iris chafing can occur with ciliary sulcus fixation. The 3-piece acrylic or a posteriorly angulated PMMA lens is recommended when capsule fixation is not possible. In 1 eye, removal of posterior capsule plaque resulted in a wide opening in the capsule. Implantation of a single-piece acrylic IOL was attempted with the haptics in the ciliary sulcus, and the optic was captured through the anterior capsulorhexis. However, the IOL did not maintain the captured position because of the soft haptic–optic junction. The lens was immediately explanted and exchanged for a 3-piece acrylic IOL, which remained captured. This eye was not part of the current study. In 1 eye (22) in a patient who had implantation of an SA60AT IOL at the age of 12.7 years, the posterior capsule was left intact; therefore, the case is discussed separately here. The visual axis remained clear and the IOL was well centered with no deposits or synechias 8.5 months postoperatively. In conclusion, single-piece acrylic AcrySof SA series lenses are well suited for implantation in the small capsular bag of children. The IOL can be placed in the eye through a 3.0 mm incision with good control using the Monarch II injector, even in very soft eyes. Although long-term clinical experience with these newer IOLs is necessary to draw firm conclusions regarding the biocompatibility of this material in pediatric eyes, our preliminary data suggest that the single-piece acrylic IOL can be safely implanted in the pediatric eye.
References 1. Letocha CE, Pavlin CJ. Follow-up of 3 patients with Ridley intraocular lens implantation. J Cataract Refract Surg 1999; 25:587–591 2. Wilson ME, Elliott L, Johnson B, et al. AcrySof acrylic intraocular lens implantation in children: clinical indications of biocompatibility. J AAPOS 2001; 5:377–380 3. Argento C, Badoza D, Ugrin C. Optic capture of the AcrySof intraocular lens in pediatric cataract surgery. J Cataract Refract Surg 2001; 27:1638 –1642 4. Stager DR Jr, Weakley DR Jr, Hunter JS. Long-term rates of PCO following small incision foldable acrylic intraocular lens implantation in children. J Pediatr Ophthalmol Strabismus 2002; 39:73–76 5. Caporossi A, Casprini F, Tosi GM, Baiocchi S. Preliminary results of cataract extraction with implantation of a single-piece AcrySof intraocular lens. J Cataract Refract Surg 2002; 28:652–655
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6. Davison JA. Clinical performance of Alcon SA30AL and SA60AT single-piece acrylic intraocular lenses. J Cataract Refract Surg 2002; 28:1112–1123 7. Wilson ME, Peterseim MW, Englert JA, et al. Pseudophakia and polypseudophakia in the first year of life. J AAPOS 2001; 5:238 –245 8. Hollick EJ, Spalton DJ, Meacock WR. The effect of capsulorhexis size on posterior capsular opacification: oneyear results of a randomized prospective trial. Am J Ophthalmol 1999; 128:271–279
From the Miles Center for Pediatric Ophthalmology, Storm Eye Institute, Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, USA. Supported in part by an unrestricted grant to MUSC–SEI from Research to Prevent Blindness, Inc., New York, New York, USA. Neither author has a financial or proprietary interest in any material or method mentioned. Mae Millicent Peterseim, MD, established and managed the pediatric database used, and Luanna R. Bartholomew, PhD, provided critical reading of and comments on the manuscript.
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T
o our knowledge, Epstein implanted the first intraocular lens (IOL) in a pediatric eye in 1951.1 However, IOL implantation in children did not become common practice until the 1990s, probably because of frequent secondary complications caused by the IOL material and design and the enhanced inflammatory response in these small eyes. Primary IOL implantation in young children has continued to become more popular as surgical techniques and biocompatible IOL materials and designs improve. Until recently, pediatric ophthalmologists were implanting poly(methyl methacrylate) (PMMA) IOLs exclusively. However, in a worldwide survey we conducted in 2001, 69.0% of respondents reported using hydrophobic acrylic IOLs Accepted for publication May 5, 2003. Reprint requests to M. Edward Wilson Jr., MD, MUSC–Storm Eye Institute, 167 Ashley Avenue, Charleston, South Carolina 29425-5536, USA. E-mail: [email protected]. © 2003 ASCRS and ESCRS Published by Elsevier Inc.
(unpublished data). The trend away from PMMA toward acrylic for childhood IOL implantation has been driven by the desire for a proven biocompatible material that can be inserted through a smaller incision. Until recently, the most popular acrylic IOL (AcrySof威, Alcon) was available only in a 3-piece design with PMMA haptics. Difficulties that can occur with the 3-piece design include haptic kinking and inadvertent sulcus fixation, which can be minimized with the use of the newer single-piece, all-acrylic AcrySof SA series IOLs. We2 and others3,4 recently reported good outcomes of 3-piece acrylic IOL implantation in children. Although the literature reflects the short-term results of single-piece acrylic IOL implantation in adult cataract surgery,5,6 to our knowledge, the short-term results of single-piece acrylic IOL implantation in infants and children have not been reported. In August 2000, 1 of us (M.E.W.) began implanting single-piece acrylic IOLs (AcrySof model SA30AL 0886-3350/03/$–see front matter doi:10.1016/S0886-3350(03)00468-1
SINGLE-PIECE ACRYLIC IOLS IN CHILDREN
initially and then model SA60AT) in pediatric cases at the time of cataract removal. We report the short-term outcomes in these cases, including any form of postoperative visual axis opacification with or without a second procedure to clear the axis, the incidence of cell deposits on the IOL optic, the presence of posterior synechias, and IOL centration.
Patients and Methods A database of pediatric IOL implantations was queried to allow review of consecutive eyes implanted with a single-piece acrylic IOL. Eyes with traumatic cataract or secondary implantation were excluded from the study. All surgeries were performed by a single surgeon (M.E.W.). An AcrySof SA30AL IOL (5.5 mm optic, 12.5 mm overall size) or AcrySof SA60AT IOL (6.0 mm optic, 13.0 mm overall size) was implanted. Both models are foldable and single-piece. The SA30AL IOL was used between August 2000 and April 2001 (eyes 1 to 14 and eye 17), and the SA60AT IOL was used between March 2001 and July 2002 (eyes 15 to 16 and eyes 18 to 43). All patients had keratometry and immersion A-scan ultrasonography for axial length measurement. The Holladay formula was used to calculate IOL power. The target postoperative refraction was based on the patient’s age and fellow-eye status. In general, the target refraction in cases of single IOL implantation early in life was hyperopia. The younger the child, the higher the postoperative refraction target. For instance, in the first month of life, it was ⫹12.0 diopters (D); in the second to third month, ⫹8.0 to ⫹10.0 D; in the fourth to sixth month, ⫹6.0 D; and in the sixth to twelfth month, ⫹4.0 D. In the second to sixth year of life, the target gradually decreased from ⫹4.0 to ⫹1.0 D and after the sixth year of life, the aim was emmetropia. When the eye was microphthalmic, the target refraction was sometimes not reached even with the highest power (⫹30.0 D) available in the IOL style used. When the piggyback technique was used, the target refraction was plano or mild myopia in the early postoperative period. When piggyback lenses were implanted in the first 2 months of life, the target was ⫹2.0 or ⫹3.0 D because this mild hyperopia would likely disappear in the early postoperative period. The power of the temporary anterior-most IOL was chosen based on how much refractive change was anticipated during growth and development. It often amounted to approximately one third of the total IOL power. A standard surgical technique7 was used. For IOL insertion, a forceps was used in the first 12 eyes; the Monarch II injector (Alcon Laboratories) was used after January 2001. The postoperative treatment was standardized.7 When possible, a follow-up examination was performed 1 and 7 days and 4 and 8 weeks postoperatively, every 3 months during the first year, and every 6 months thereafter.
Postoperative parameters assessed were any form of media opacification (visually significant or not), the need for secondary intervention to clear the visual axis, the presence of synechias or cell deposits, and IOL centration. Data were analyzed using the Student t test.
Results Of the 328 consecutive pediatric IOL implantations in the database at the time of the review, 43 eyes of 33 patients received a single-piece acrylic IOL. With 1 exception (eye 22), all received primary posterior capsulectomy and anterior vitrectomy at the time of cataract surgery. Eye 22 had an intact posterior capsule and will be discussed separately. Of the remaining 42 eyes of 32 patients, 15 had implantation of an SA30AL IOL and 27, an SA60AT IOL. The mean age of the 21 boys and 11 girls at the time of treatment was 33.5 months ⫾ 28.9 (SD) (range 0.5 to 110 months). The mean follow-up was 12.0 ⫾ 8.2 months (range 1.0 to 27.5 months). A corneal tunnel incision was made in 32 eyes and a scleral tunnel incision in 10 eyes. Thirty-eight eyes received a vitrectorhexis and 4, a manual capsulorhexis. In 3 eyes (7, 10, 27), an anterior capsule tear occurred during IOL insertion; a posterior capsulectomy was performed using the vitrectorhexis technique in all cases. Twenty-three eyes received a posterior capsulectomy and an anterior vitrectomy from the pars plana approach, and 19 eyes received it from the limbal approach. In addition to bag-fixated single-piece IOL implantation, 4 eyes had implantation of an SA30AL piggyback IOL (eyes 13, 14) or an MA60BM (eyes 17, 26) in the ciliary sulcus. Postoperative Visual Axis Opacification Five eyes (11.9%) required a second surgical procedure for opacification of the visual axis (Table 1). The mean age at surgery was 7.9 ⫾ 6.6 months in patients requiring a secondary procedure and 37.0 ⫾ 29.0 months in those who did not (P ⫽ .0001). Three of 11 eyes (27.3%) with IOL implantation during the first year of life required surgical intervention. Five of 17 eyes (29.4%) operated on before 18 months of age required a second surgery to clear the visual axis; none of the 25 eyes operated at or after 18 months of age required a second surgery. Two eyes with piggyback IOLs required surgery for postoperative visual axis opacification. Both
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SINGLE-PIECE ACRYLIC IOLS IN CHILDREN
Table 1. Characteristics of eyes requiring a second procedure because of visual axis opacification. Age at Cataract Surgery (Mo)
Interval to 2nd Procedure (Mo)
5
14.1
12.0
Cortex reproliferation
Posterior
Pars plana, with vitrector
7
10.8
21.9
Elschnig pearls
Posterior
Limbal, with vitrector
13
0.9
9.7
Fibrous (anterior capsule closure)
Anterior
Capsulorhexis, with forceps
17
0.5
4.4
Cortex reproliferation
Predominately posterior; also anterior
Pars plana and limbal, with vitrector
33
13.0
5.5
Cortex reproliferation
Predominately anterior; also posterior
Limbal and pars plana, with vitrector
Eye
Type of Opacification
had been operated on in the first month of life. The secondary procedures were required a mean of 10.7 months (range 4.4 to 21.9 months) after cataract surgery. Two other eyes had off-center opacification of the visual axis not requiring surgical intervention. Eye 24 had cortex reproliferation not occluding the visual axis. Eye 32 had peripheral Elschnig pearls. Cell Deposits on IOL Optic Eight eyes (19.0%) had IOL deposits. Six eyes (3, 4, 5, 19, 20, 35) had a few deposits, and 2 eyes (6, 7) had more numerous deposits. None of the deposits was visually significant. Posterior Synechias Posterior synechias were seen in 5 eyes (13, 17, 24, 27, 39) (11.9%). None produced enough correctopia to cause a noticeable cosmetic deformity. In most cases, the synechias were pinpoint adhesions of the iris to the anterior capsulotomy edge. No adhesions were seen between the iris and the IOL. IOL Centration All eyes maintained a clinically centered IOL
Discussion Since its introduction in 1994, the acrylic IOL has assumed a prominent role in adult cataract surgery.2– 4,6 In a survey of practice patterns for pediatric cataract surgery, the acrylic IOL was also the most popular for implantation in children. Recent reports2– 4 show these 1740
Plane of Opacification in Relation to IOL Optic
Surgical Approach
lenses to be biocompatible with the pediatric eye. However, the 3-piece design of the most commonly used acrylic IOL (AcrySof MA series) predisposed to haptic kinking on entry into the eye. Inadvertent sulcus implantation could also occur when this IOL is used in small pediatric eyes. More recently, a single-piece, all-acrylic AcrySof IOL (SA series) became available. It can be inserted into the smallest capsular bags using the Monarch II injector. The soft haptics can be manually placed in position if necessary using an intraocular hook or push–pull instrument. The haptics unfold slowly yet retain enough memory after placement to resist equatorial lens capsule fibrosis. In our series, we did not detect haptic deformation caused by compression from capsule fibrosis, a complication that occurs in children. Based on their implantation characteristics, we believe single-piece AcrySof SA series IOLs are ideal for children. Our early results show the lens has clinical biocompatibility, stays well centered, and has a low incidence of postoperative opacification of the visual axis. All but 1 eye in the series had a primary posterior capsulectomy and anterior vitrectomy; therefore, we cannot comment on the incidence of posterior capsule opacification with this new lens when the posterior capsule is left intact. Laboratory investigation at Storm Eye Institute indicates that the flexible haptic design of the single-piece acrylic AcrySof IOL minimizes ovaling of the capsulorhexis opening and capsule bag in children compared to the 3-piece design (S.K. Pandey, MD, et al., “Evaluation of IOL Sizing and Capsular Bag Stretch in Pediatric Eyes,” presented at the ASCRS Symposium on Cataract,
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Figure 1. (Trivedi) Postoperative photographs. A: Eye 6 (right eye) at 22.1 months in a patient who had surgery at 10.6 months of age. The visual axis is clear and the IOL well centered. B: Left eye (7) of the same child, which had surgery when the patient was 10.8 months old. There is visual axis opacification with Elschnig pearls, and the edge of the IOL is exposed at 3 o’clock.
Figure 2. (Trivedi) Postoperative photograph of eye 33 5.5 months after surgery, which was performed when the patient was 13.0 months old. Cortex reproliferation (arrow) can be seen.
IOL and Refractive Surgery, Philadelphia, Pennsylvania, USA, June 2002). Haptic deformation (ie, haptics bending behind the optic), occasionally observed with other lenses, can develop when using such a soft IOL. However, this has not occurred with the single-piece acrylic lens in our clinical practice. Extremely flexible haptics, combined with excellent memory, make this IOL easy to implant and not prone to deformation (S.S. Lane, MD, “Comparison of the Biomechanical Behavior of Foldable IOLs,” presented at the ASCRS Symposium on Cataract, IOL and Refractive Surgery, San Diego, California, USA, April 2001). Despite primary removal of the center of the posterior capsule and the anterior vitreous, 5 eyes (11.9%)
required a second procedure to clear postoperative visual axis opacification a mean of 10.7 months postoperatively. The age at surgery was younger on average than when no second surgery was needed (7.9 months versus 37.0 months). One patient (eyes 6, 7) had SA30AL IOL implantation at the age of 10.6 months and 10.8 months, respectively. The right eye (6) had uneventful surgery. In the left eye (7), a tear was noted in the anterior capsule during IOL manipulation. At the follow-up at 22.1 months and 21.9 months, respectively, the right eye had a clear visual axis with the anterior capsule completely covering the optic (Figure 1, A). The left eye had visual axis opacification caused by Elschnig pearls. This opacification was visually significant and required a second procedure. In this eye, the anterior capsule edge no longer completely covered the optic for 360 degrees, which exposed the IOL edge for 1 clock hour at the 3 o’clock position (Figure 1, B). The relationship of the anterior capsule to the IOL optic may have led to the need for the second procedure by allowing Elschnig pearls to migrate into the visual axis. Although 1 case is not sufficient to draw a conclusion, this possible explanation concurs with a report in the literature on adult cataract surgery.8 Cortex reproliferation after cataract surgery is typical in very young eyes. This easily aspirated material can escape the capsule fornix and block the visual axis (Figure 2), even when the anterior capsule edge overlaps the IOL optic for 360 degrees. The relationship between the anterior capsule and IOL optic and its connection to
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visual axis opacification (both Elschnig pearls and cortex reproliferation) in pediatric cataract surgery require further work. One patient had piggyback IOL implantation at the age of 0.9 month in the right eye (13) and at 1.2 month in the left eye (14). A pars plana vitrectomy was performed in the right eye. During the procedure, the leading haptic went behind the posterior capsule but was lifted manually to achieve in-the-bag IOL fixation. The left eye had uneventful surgery. The right eye required a second procedure 9.7 months postoperatively for removal of the fibrous opacification. The opacification appeared as a thin, taut sheet of cells that encased, but did not adhere to, the capsule-fixated IOL. No adhesion to the sulcus-fixated IOL was observed. We have seen this type of opacification on rare occasions with PMMA and 3-piece acrylic IOL implantation, but always in eyes having implantation within the first 6 months of life. After the ciliary sulcus-fixated IOL in the right eye was explanted, the fibrous membrane was removed in a capsulorhexis fashion. Opacification was not observed behind the IOL. The left eye had a clear visual axis at the time and required planned explantation of the piggyback IOL only. In a previous study,2 we found IOL deposits in 7 of 110 eyes (6.4%) with 3-piece acrylic lenses (MA30BA and MA60BM series) and in 26 of 120 eyes (21.7%) with PMMA lenses. In the present study, cell deposits occurred in 8 of 42 eyes (19.0%), although only 2 eyes had more than a few isolated deposits. In no case were the deposits visually significant. In the previous study, posterior synechias were seen in 5 eyes (4.5%) with 3-piece acrylic IOLs and 23 (19.2%) with PMMA lenses. In the present study, synechias occurred in 5 eyes (11.9%) with posterior capsulectomy and vitrectomy. Three eyes in our series (13, 14, 17) had explantation of an acrylic IOL placed in the ciliary sulcus anterior to the capsule-fixated single-piece IOL. The IOLs were explanted as a planned surgical procedure to compensate for the growth of the eye.7 They were removed without difficulty. Because IOLs in the sulcus do not fixate by scarring, the explantation procedures were unhampered. However, the single-piece AcrySof SA series IOLs are not recommended for sulcus fixation. Unlike the 3-piece design, the single-piece lenses are not posteriorly angulated and have broad haptics with bulbous tips. Decen1742
tration and iris chafing can occur with ciliary sulcus fixation. The 3-piece acrylic or a posteriorly angulated PMMA lens is recommended when capsule fixation is not possible. In 1 eye, removal of posterior capsule plaque resulted in a wide opening in the capsule. Implantation of a single-piece acrylic IOL was attempted with the haptics in the ciliary sulcus, and the optic was captured through the anterior capsulorhexis. However, the IOL did not maintain the captured position because of the soft haptic–optic junction. The lens was immediately explanted and exchanged for a 3-piece acrylic IOL, which remained captured. This eye was not part of the current study. In 1 eye (22) in a patient who had implantation of an SA60AT IOL at the age of 12.7 years, the posterior capsule was left intact; therefore, the case is discussed separately here. The visual axis remained clear and the IOL was well centered with no deposits or synechias 8.5 months postoperatively. In conclusion, single-piece acrylic AcrySof SA series lenses are well suited for implantation in the small capsular bag of children. The IOL can be placed in the eye through a 3.0 mm incision with good control using the Monarch II injector, even in very soft eyes. Although long-term clinical experience with these newer IOLs is necessary to draw firm conclusions regarding the biocompatibility of this material in pediatric eyes, our preliminary data suggest that the single-piece acrylic IOL can be safely implanted in the pediatric eye.
References 1. Letocha CE, Pavlin CJ. Follow-up of 3 patients with Ridley intraocular lens implantation. J Cataract Refract Surg 1999; 25:587–591 2. Wilson ME, Elliott L, Johnson B, et al. AcrySof acrylic intraocular lens implantation in children: clinical indications of biocompatibility. J AAPOS 2001; 5:377–380 3. Argento C, Badoza D, Ugrin C. Optic capture of the AcrySof intraocular lens in pediatric cataract surgery. J Cataract Refract Surg 2001; 27:1638 –1642 4. Stager DR Jr, Weakley DR Jr, Hunter JS. Long-term rates of PCO following small incision foldable acrylic intraocular lens implantation in children. J Pediatr Ophthalmol Strabismus 2002; 39:73–76 5. Caporossi A, Casprini F, Tosi GM, Baiocchi S. Preliminary results of cataract extraction with implantation of a single-piece AcrySof intraocular lens. J Cataract Refract Surg 2002; 28:652–655
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6. Davison JA. Clinical performance of Alcon SA30AL and SA60AT single-piece acrylic intraocular lenses. J Cataract Refract Surg 2002; 28:1112–1123 7. Wilson ME, Peterseim MW, Englert JA, et al. Pseudophakia and polypseudophakia in the first year of life. J AAPOS 2001; 5:238 –245 8. Hollick EJ, Spalton DJ, Meacock WR. The effect of capsulorhexis size on posterior capsular opacification: oneyear results of a randomized prospective trial. Am J Ophthalmol 1999; 128:271–279
From the Miles Center for Pediatric Ophthalmology, Storm Eye Institute, Department of Ophthalmology, Medical University of South Carolina, Charleston, South Carolina, USA. Supported in part by an unrestricted grant to MUSC–SEI from Research to Prevent Blindness, Inc., New York, New York, USA. Neither author has a financial or proprietary interest in any material or method mentioned. Mae Millicent Peterseim, MD, established and managed the pediatric database used, and Luanna R. Bartholomew, PhD, provided critical reading of and comments on the manuscript.
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