Graefe’s Arch Clin Exp Ophthalmol (2000) 238:143–148 © Springer-Verlag 2000

Hans Mittelviefhaus Karin Mittelviefhaus Jürgen Gerling

Received: 3 March 1998 Revised: 1 March 1999 Accepted 2 March 1999

H. Mittelviefhaus (✉) · K. Mittelviefhaus J. Gerling Department of Ophthalmology, University of Freiburg, Killianstrasse 5, D-79106 Freiburg, Germany Tel.: +49-761-2704021 Fax: +49-761-2704045

C L I N I C A L I N V E S T I G AT I O N

Transscleral suture fixation of posterior chamber intraocular lenses in children under 3 years

Abstract ● Background: Children who have undergone lentectomy for congenital or traumatic cataract do not have adequate capsular support for secondary posterior chamber intraocular lens (PC-IOL) implantation and thus will become severely amblyopic if contact lens intolerance occurs. In order to prevent amblyopia we fixed PC-IOLs by transscleral sutures in three children younger than 3 years. Clinical outcome, visual acuity and course of refraction were studied. ● Methods: Four eyes of three children with contact lens intolerance were operated. Posterior chamber lenses (PC-IOL) were sutured in the ciliary sulcus by transscleral sutures. Two children had monocular traumatic cataract and one child underwent surgery on both eyes for congenital cataract. To allow adjustment of refraction in situ without removing the primarily implanted and transsclerally fixed PC-IOL we used

Introduction Lentectomy and correction of the consecutive aphakic refractive error by contact lenses is the gold standard for treatment of congenital or traumatic cataract in young children [3, 13, 29, 30]. Lentectomy with complete removal of the entire capsule causes less postoperative inflammation than any extracapsular cataract extraction in children and only rarely gives rise to complications. Removing the entire posterior lens capsule prevents after-

the piggyback intraocular lens system for implantation. ● Results: Visual acuity improved in all four eyes. The two children with traumatic cataract achieved visual acuity of 0.7 and 1.0, respectively, and stereopsis. No complications related to the technique of transscleral suture fixation of the PC-IOL were observed. Postoperative changes in refractive power were caused by a myopic shift between –1.0 D and –9.0 D. Follow-up was 25–70 months. ● Conclusion: Transscleral suture fixation of PC-IOLs did not cause specific complications during follow-up of up to 70 months. This technique offers an important option for the correction of an aphakic refractive error which cannot be corrected otherwise. In future the piggyback intraocular lens system may help to rather atraumatically correct postoperative changes in refractive power.

cataract. This guarantees a permanently clear visual axis. Furthermore, contact lens fitting ensures that any change of refraction can be adjusted instantly. Both are mandatory to prevent amblyopia. However, lentectomy has one major disadvantage. Children who have undergone lentectomy do not have adequate capsular support for secondary posterior chamber intraocular lens (PC-IOL) implantation if this becomes necessary [27, 28, 39]. Thus children with contact lens intolerance and rejection of aphakic spectacles most certainly will become severely amblyopic [22].

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Fig. 1 The 10–0 polypropylene sling suture is symmetrically anchored to the haptic eyelet of the intraocular lens without any twisting. Both arms of the sling sutures are tied 3–5 mm from the original site of transscleral penetration and are well covered by a layer of Tenon’s capsule (arrow)

To prevent amblyopia, epikeratophakia has been used in such children as an alternative. However, epikeratophakia has proved not to be beneficial because the optic rehabilitation is slow and the postoperative refraction is unpredictable [8, 25, 26]. Anterior chamber intraocular lenses (AC-IOLs), on the other hand, display potential side effects and late complications of uveitis, glaucoma and endothelial decompensation [2, 8, 38]. Fixing a PCIOL by transscleral sutures, however, does also have some disadvantages. First, it is more difficult to achieve the desired postoperative refraction with transscleral suture fixation of the PC-IOL than with implantation of the PC-IOL onto the intact posterior capsule [19, 21]. Second, the refraction after PC-IOL implantation in children will change during follow-up [4, 5, 7, 9, 11, 12, 35]. This may require exchange of the IOL in at least some of the children. Although suture-fixed PC-IOLs can be removed the exchange might be traumatic. In order to allow adjustment of the refraction in situ without removing the primarily implanted and transsclerally fixed PCIOL we developed the piggyback intraocular lens system [18]. In this study we present our operation technique and we report for the first time the visual results and early changes of refraction during follow-up from 2 to more than 5.5 years after transscleral suture fixation of PCIOLs in three children less than 3 years old at the time of operation.

Materials and methods From April 1993 to January 1996 four eyes of three children were operated. Two children had traumatic monocular aphakia (cases 1 and 2). One child had binocular aphakia after lentectomy for congenital cataract (case 3). In this third child contact lenses had to be discontinued after 27 months of successful treatment. This child had no nystagmus or abnormal head posture that could explain the rejection of glasses. Keratometry was carried out with an ophthal-

mometer (Zeiss) and an automated keratometer (Alcon). Biometry was done with a Sonomed A Scan A 2500 (Technomed). The intraocular lens power was calculated by the SRK II formula. An IOL with a power 1–2 D less than that calculated for emmetropia was implanted. We added 0.5 D according to our study on the postoperative refraction after transscleral suture fixation of posterior chamber lenses [19, 21]. Informed consent was obtained from all parents. All operations were performed by the same surgeon (H.M.). Surgical technique Fornix-based conjunctival flaps were prepared at the 12 o’ clock and 6 o’ clock positions. A 6.5-mm-wide corneoscleral incision was made at the superior surgical limbus. Because all children already had anterior vitrectomy, during primary lentectomy only limited vitrectomy had to be performed. Viscoelastic substance (Healon, Pharmacia, Uppsala) was used in order to deepen the anterior chamber and to inflate the ciliary sulcus and the posterior chamber. One-piece polymethylmethacrylate (PMMA) IOLs were used as the basic PC-IOLs of the piggyback IOL system [18]. Both haptics of the lenses had small eyelets. The 10–0 polypropylene sling sutures which were used for transscleral suture fixation were easily hitched to each haptic eyelet without knots (Fig. 1) [18, 20]. We preferred the 16.0-mm spatula needle (CTC-6L Prolene EH 7896, Ethicon, Hamburg) for the 6 o’ clock position and the shorter 5.5mm spatula needle (GS-14 Prolene EN 5631 S, Ethicon, Hamburg) for the 12 o’ clock position. Both needles were passed under the iris and through the sclera via the ciliary sulcus. The tips of the needles were placed slightly less than 1 mm posterior to the surgical limbus. A radial scleral slit was cut, 0.5 mm long and of half scleral thickness, while the needle was in place. The PC-IOL was laid down onto the iris plane before it was guided beneath the iris and into the ciliary sulcus, while the sling suture was drawn tight. The corneoscleral wound was closed and, after tonization of the eye, the sclera was entered a second time with the needle, within the scleral slit. The needle was guided intrasclerally towards the equator and ocular muscle insertion. Because of the small size of the lid aperture in children a direction slightly oblique to the lateral insertion of the muscle was preferred. The sling sutures were drawn tight until they slipped into the scleral slit. Finally they were tied after taking another small bite of scleral tissue. Thus the knots were placed 3–5 mm from the place of transscleral penetration towards the ocular muscle insertion. Here they were covered by Tenon’s membrane and conjunctiva (Fig. 2). Subconjunctival antibiotics and steroids were given. Corticosteroid ophthalmic drops were

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Fig. 2 a The needle reenters the sclera within a scleral slit and is guided intrasclerally towards the ocular muscle insertion. b The sling sutures are drawn tight until they slip into the scleral slit. After another bite of scleral tissue is taken, one arm of the suture is cut. The suture is drawn tight and both arms of the suture are tied

Table 1 Patient data (HM hand motion, Ecc. fix. eccentric fixation) Patient Eye Etiology Age at of cataract cataract extraction (months)

Age at Preoperative Final secondary visual visual IOL acuity acuity insertion (months)

Lens power (D)

Postoperative refraction, operated eye (D)

Postoperative Stereopsis Follow-up refraction, (months) fellow eye (D)

1 2 3 3

28 26 35 35

+27.5 +25.0 +25.50 +23.5

–6.5 –0.25 –3.0 –1.0

–0.5 +1.25

a Due

OD OS OD OS

Trauma 26 Trauma 25 Congenital 8 Congenital 8

>HM >HM Ecc. fix. Central fix.

1.0 0.7 >0.063a >0.4a

+ + – –

70 46 25 25

to poor cooperation. Binocular visual acuity 0.63 (Cardiff test)

administered 5 times per day and tapered over 4–6 weeks. Occlusion therapy was restarted 2 days postoperatively. The frequency of occlusion differed between 2 h every 2nd day and 50% of waking hours, depending on the child’s fixation behavior. Children were followed up monthly for the first postoperative year and every 2–6 months thereafter. Refraction was measured by retinoscopy. Visual acuity was determined according to the compliance and to the children’s age by LH symbol charts, Sheridan-Gardner test, E-symbols, Landolt rings, Cardiff test or Freiburg visual acuity test [24]. Fusion was confirmed by cover-uncover test and with 10-cm/m base out prism test. Stereopsis was examined by Titmus test and Lang test. Eye examinations were performed under a short-acting anesthetic (ketamine) 6, 12, 18 and 24 months postoperatively and without anesthetic thereafter.

Results Two children had transscleral suture fixation of PC-IOLs after penetrating eye injuries with laceration of the cor-

nea, the iris and the lens, requiring primary lentectomy (Table 1, cases 1 and 2). In one of these two children, both gas-permeable and extended-wear soft contact lenses were tried unsuccessfully for 2 months (case 1). The second child refused any attempt for contact lens fitting (case 2). Preoperative visual acuity could not be evaluated. The third child had transscleral suture fixation of PCIOLs in both eyes (case 3). Unfortunately in this child congenital cataract was not diagnosed before strabismus occurred. Bilateral lentectomy was performed at the age of 8 months. The aphakic refractive error was corrected with extended-wear soft contact lenses. Treatment was complicated by poor compliance. After 27 months contact lenses were refused. Aphakic spectacles were rejected, due to poor visual acuity and lack of compliance. In none of the children were intraoperative or postoperative complications observed. The IOLs were well centered

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Fig. 3 Refraction after transscleral suture fixation of the basic posterior chamber intraocular lens of the piggyback intraocular lens system (n=4 eyes)

without any tilt. All children had normal intraocular pressure and normal fundus examination. Although no scleral flaps were used the 10–0 polypropylene sutures fixating the PC-IOL remained well covered beneath Tenon’s membrane and conjunctiva. The knots were located several millimeters distant from the location of scleral penetration and did not cause conjunctival irritation. Visual acuity improved in all children (Table 1). Both children with traumatic cataract had stereopsis. They had fusional movements confirmed with 10 cm/m base out prism test, and a positive Titmus test (ring 1–3). Lang test remained negative. Occlusion therapy was accepted from the 3rd–5th postoperative day on. In the third child occlusion therapy remained a problem for 10 months postoperatively, but it was better accepted thereafter. Postoperative refraction of the first child was almost 1 D more hyperopic than precalculated. In the second child we exactly achieved the desired refraction. Both eyes of the third child were more myopic than expected. Due to the postoperative astigmatism of almost 6 D the overcorrection in this child initially increased to 3 and 5 D spherical equivalent. Within 2 months the astigmatism disappeared and the refraction changed to emmetropia. Figure 3 shows the postoperative changes in refractive power of all children ranging from –1.0 D to –9.0 D. The axial length of the eye of our first patient increased from 21.54 mm to 23.56 mm, of our second patient from 21.32 mm to 22.37 mm and of our third patient from 20.54 mm to 22.3 mm (OD) and from 20.63 mm to 21.35 mm (OS).

Discussion The implantation of PC-IOLs and the fixation of these lenses by transscleral sutures was technically more difficult in young children than in adults. This was obviously related to the smaller aperture of the lids and the smaller size of the eyes. However, we did not see any complications related to the technique of suture fixation, neither the more serious complications of vitreous or choroidal hemorrhage from the ciliary body or the major arterial circle of the iris, caused by needle stitches, nor the more frequently described complication of conjunctival irritation by the transscleral sutures. Fortunately we did not observe any of the other complications reported after suture fixation of PC-IOLs, such as IOL tilt or decentration, cystoid macular edema, retinal detachment, glaucoma, corneal decompensation, inflammation and endophthalmitis [16, 21, 32, 34, 36]. In our experience postoperative inflammation after transscleral suture fixation of the PC-IOL was less than after uncomplicated extracapsular cataract extraction in children of the same age. Use of sling sutures, which are hitched to the haptic eyelets without knots, most effectively prevents any torsion of the lens, which might be caused by the suture fixation as described recently for several other techniques [37]. Furthermore, the four-point support of the basic PC-IOL haptic facilitated high intraoperative stability and ideal postoperative centration without any tilt. This confirmed earlier results of a preliminary study in adult patients who had transscleral suture fixation of the basic PC-IOL of the piggyback system and simultaneous corneal trans-

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plantation [23]. Using the scleral slit technique [20], which transfers the prolene knot backward towards the ocular muscle insertion, where it is safely covered by a layer of Tenon’s membrane, prevents suture erosion and conjunctival irritation. Because the polypropylene sutures may become degraded with time the suture fixation of the PC-IOL may be destabilized. Fortunately we did not observe complications in eight adult patients in whom we had to remove some of the sutures [17]. We therefore believe that the long-term degradation of polypropylene will not cause late dislocation of the PC-IOL. Although all children were at risk of developing severe amblyopia we achieved rather good visual results and, in both trauma cases, even binocular vision. These very encouraging results are at least comparable to those seen after successful contact lens treatment [1, 6, 8, 14, 30, 31]. Our experiences are in line with the favorable results reported by Sharpe et al., who studied an inhomogeneous group of seven patients who had suture fixation of PC-IOLs between age 1 and age 19 years (mean 9 years 3 months) with a follow-up of 3–38 months [33]. However, the main challenge of transscleral suture fixation of PC-IOLs in children still remains the unpredictability of the postoperative refraction. Already preoperative keratometry is more difficult in small children. Children under 3 years cannot hold fixation long enough and eccentric measurements may result. Therefore, despite correct preoperative biometry and IOL power calculation, postoperative refraction after IOL implantation in children can differ significantly from the desired result [4, 15]. The postoperative anterior chamber depth can be another source of error, most likely because the chamber is deeper than after implantation of a PC-IOL onto an intact capsule, as shown in adult patients [19]. The role of postoperative astigmatism is still unclear. In our two cases with penetrating eye injuries, astigmatism occurred in the axis of corne-

al laceration. In our third case, astigmatism was caused by the tight closure of the corneoscleral wound and completely disappeared within 6–8 weeks. Sharpe et al. reported a rather high degree of astigmatism persisting in their patients [33]. It is not clear whether this phenomenon in children is due to the operative technique. Most importantly, eye growth will change refraction particularly in children younger than 3 years. Unfortunately the course of refraction cannot be predicted. Some authors base their decision as to which IOL power should be implanted on the growth curve of normal phakic eyes, others on the growth curve of aphakic eyes. Both will inevitably have to accept failures, because pseudophakic eyes behave differently [4, 9–12, 14, 35]. Kora observed myopization of up to 11 D even in children who received IOLs after the age of 7 years [12]. Gusek-Schneider et al. reported myopization of 5.8 D in 29 of 41 children who received IOLs before the age of 7 years [7] (personal communication), and Dahan and Drusedau published data on children under the age of 3 years and observed myopization of 2.7±1.4 D after 3.5 years of follow-up and 6.4±3.7 D in children who received the IOL before the age of 18 months and had 6.9 years of follow-up [4]. The large standard deviation shows that the myopic shift was much larger in individual cases. We therefore use the basic PC-IOL of our piggyback IOL system for IOL implantation in children, which require transscleral suture fixation of the lens. This will enable us to change the refraction without removing the primarily implanted lens. Although we report rather favorable results, and although we did not observe any surgery-related complications in our small series, transscleral suture fixation of posterior chamber lenses in children can not be recommended in general in the absence of even longer follow-up.

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