Foldable iris-fixated intraocular lens implantation in children

Introduction

Refractive surgery is rarely performedin children and is controversial.Photorefractive keratectomy (PRK)(Astle et al. 2002) and laser intrastro-mal keratectomy (LASIK) (O’Keefe &Nolan 2004) have been the main sur-gical techniques. Single case reportsand a few case series have beenreported with rigid phakic intraocular

lenses (pIOLs) (Chipont et al. 2001;Saxena et al. 2003; Lifshitz & Levy2005; Assil et al. 2007; Pirouzian & Ip2010; Alio et al. 2011), but there areno literature reports on the use offoldable pIOLs in children.

The purpose of this study was toprospectively follow and report theoutcome of foldable pIOL insertion ina series of children with high bilateraland unilateral myopia who were func-

tioning poorly with spectacle correc-tion and intolerant of contact lenswear.

Materials and Methods

All children undergoing iris-fixatedanterior chamber (AC) pIOL insertionin The Children’s University HospitalTemple Street, Dublin, Ireland wereprospectively followed from October2009 to August 2011. Selected chil-dren had high bilateral or unilateralmyopia. They were intolerant to spec-tacle or contact lens correction orwere functioning poorly with high-powered spectacles.

Written informed consent wasobtained from the parents for surgery.Institutional approval and parentalconsent was given to publish thisstudy. The study was conducted inaccordance with the Tenets of theDeclaration of Helsinki. One surgeon(M. O’K.) performed all procedures.

Preoperative measures were age-appropriate corrected distance visualacuity (CDVA), ocular alignment withcover ⁄uncover testing, cycloplegicrefraction (Minims Cyclopentolatehydrochloride 1%, Bausch & LombInc., Surrey, UK), full anterior andposterior segment examination withslit-lamp, indirect ophthalmoscopy orexamination under anaesthesia andendothelial cell density (ECD) (Cell-Chek, Model NSP 9900; KonanMedical, Irvine, CA, USA) if feasiblegiven the age and level of co-opera-tion of the child. The CDVA wasmeasured with an ETDRS chart forco-operative children. For youngerchildren and those with developmentaldelay, a Sheridan–Gardiner test was

Foldable iris-fixated intraocularlens implantation in children

Andrea Ryan, Claire Hartnett, Bernadette Lanigan andMichael O’Keefe

Department of Ophthalmology, Children’s University Hospital, Dublin, Ireland

ABSTRACT.

Purpose: To describe the results of foldable iris-fixated intraocular lens (IOL)

implantation in children.

Methods: Children with high bilateral or unilateral myopia who were intoler-

ant of spectacle or contact lens correction were implanted with an iris-fixated

foldable IOL and prospectively followed. We measured pre- and postoperative

visual acuity, refraction, endothelial cell density (ECD) and National Eye

Institute Visual Functioning Questionnaire-25.

Results: Eleven eyes of six children were implanted. Indications were high

bilateral myopia in children with comorbid neurobehavioural disorders, high

anisometropia and high myopic astigmatism. Mean preoperative spherical

equivalent (SE) refraction was )14.6 dioptres (D) ± 4.2 SD. Mean follow-up

was 15 months. Postoperative SE refraction was )2.40 D ± 2.40 SD. Cor-

rected distance visual acuity (CDVA) improved from mean logMAR

0.84 ± 0.4 SD to postoperative 0.67 ± 0.34 SD (p = 0.005). CDVA was

reduced because of coexistent ocular disorders and amblyopia. Vision-related

quality of life (QOL) measures improved significantly. There were no intraop-

erative or postoperative serious complications.

Conclusion: Foldable iris-fixated IOL insertion can give a significant improve-

ment in vision and in vision-related QOL in a subset of paediatric patients

with special refractive needs who are intolerant to conventional treatment.

Long-term follow-up is required for monitoring of ECD.

Key words: artiflex – foldable iris-fixated lens – paediatric refractive surgery – phakic intraocular

lens

Acta Ophthalmol.ª 2012 The Authors

Acta Ophthalmologica ª 2012 Acta Ophthalmologica Scandinavica Foundation

doi: 10.1111/j.1755-3768.2011.02367.x

Acta Ophthalmologica 2012

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used. Biometric measurements of ACdepth, axial length and keratometryreadings were taken with the IOLMaster 500 (Carl Zeiss Meditec, Jena,Germany) in co-operative children orwith ultrasound biometry (OcuscanRxP; Alcon Laboratories, Inc., Irvine,CA, USA) and handheld keratometry(KM-500 Auto Keratometer, NidekCo. Ltd., Gamagori, Alchi, Japan)under general anaesthesia. Selectioncriteria were a minimum AC depth of3.2 mm for foldable pIOL insertion,absence of anterior or posterior seg-ment inflammation, normal intraocu-lar pressure and normal irisarchitecture. Intraocular lens powercalculations were made with the Vander Heijde formula according to themanufacturer’s guidelines.

The pIOL used was the Artiflexmyopia lens (Ophtec BV, Groningen,The Netherlands) with 6 mm opticand 8.5 mm total diameter. This lensis made of a flexible polysiloxaneoptic and rigid PMMA haptics. Thetarget was emmetropia or as close toemmetropia as possible. In eyes withmyopic refractive error >)14.5 diop-tres (D), the maximum availablepower Artiflex lens of )14.5 D wasinserted. The Artiflex toric intraocularlens (Ophtec BV) 6 mm optic ⁄ 8.5 mmtotal diameter was used in eyes withhigh astigmatism ‡2.5 D. This lenshas a maximum cylindrical correctionof )5.0 D.

Surgical technique

Preoperative topical pilocarpine wasinstilled to constrict the pupil. The cor-nea was marked at the 3 and 9 o’ clockpositions, and two sideport incisionswere made at the 10 and 2 o’ clockpositions. Sodium hyaluronate visco-elastic (Healon OVD, Abbott MedicalOptics, Inc., Santa Ana, CA, USA) wasinstilled to the AC. A superior poster-ior corneal incision of 3.2 mm wasmade. The IOL was inserted using theinsertion spatula and enclavated to themid-peripheral iris stroma at the 3 and9 o’ clock positions using the enclavat-ing needle. For toric Artiflex insertion,the IOL was positioned based on theaxis of astigmatism. A peripheral iri-dectomy was made. The cornealwound was closed with a single 10 ⁄ 0vicryl suture. Intravenous acetazola-mide 1 mg ⁄kg was given intraopera-tively followed by oral acetazolamide

at 5 hours postoperatively. Topical reg-imen postoperatively was prednisoloneacetate 1% (Pred Forte; Allergan, Inc.,Irvine, CA, USA) and chlorampheni-col 0.5% (Chloromycetin Redidrops;Goldshield Pharmaceuticals, Surrey,UK) four times daily tapering over1 month. In bilateral cases, surgerywas performed 2 weeks apart.

Patients were seen postoperativelyat 1 day, 1 week, 2 weeks, 1 month,3 months, 6 months and 6 monthlythereafter or sooner if deemed appro-priate by the follow-up examination.Postoperative measures were uncor-rected visual acuity (UCVA) in thosepatients in whom emmetropia was tar-geted, CDVA in those in whom themyopic error was reduced but noteliminated because of limitations ofthe available lens power, cycloplegicrefraction and ocular alignment inaddition to complete ophthalmicexamination. Endothelial cell density(ECD) measurements were obtainedin co-operative children at 1 year and18 months postoperatively.

Parents completed the National EyeInstitute Visual Functioning Question-naire-25 (NEI VFQ-25) version 2000preoperatively and at 6 months post-operatively. This survey measures theinfluence of visual disability on gen-eric health domains such as emotionalwell-being and social functioning aswell as task-oriented domains relatedto daily visual functioning (Mangioneet al. 2001). The NEI VFQ-25 con-tains 25 questions each of which areassigned to one of 12 subscales – gen-eral health, general vision, near activi-ties, distance activities, peripheralvision, colour vision, ocular pain,vision-specific social functioning, men-tal health, role difficulties, dependencyand driving. For each question, theanswer is converted into a scorebetween 0 and 100 (100 being thebest, 0 being the worst), and itemswithin each subscale are averagedtogether to create 12 subscale scores.An overall composite score is achievedby averaging the vision-targeted sub-scale scores, excluding the generalhealth rating question. Owing to theage of the subjects in this study, thedriving subscale was excluded.

Statistical analysis

Visual acuity data were converted tologMAR values to obtain geometric

means ± standard deviation (SD)pre- and postoperatively. A paired ttest was used to compare pre- andpostoperative values. For patients inwhom emmetropia was targeted, theUCVA was used, and in those inwhom myopic error was reduced, theCDVA was used.

For NEI VFQ-25 data, a two-tailedpaired t test was used to compare pre-and postoperative scores for each sub-scale and for the composite score. Ap value of £0.05 was considered signif-icant.

To better represent the magnitude ofchange in each NEI VFQ-25 scale, themean difference was converted to astandardized effect size (ES). The ESwas obtained by dividing the meanchange on each subscale by the baselineSD of scores for that scale. Accordingto Cohen’s criteria, an effect size of 0.8or greater is considered large, 0.5–0.79moderate, 0.2–0.49 small and <0.2trivial. (Kazis et al. 1989).

Results

Foldable pIOLs were implanted in 11eyes of six children of mean age10 years, range 8–15 years. The meanpostoperative follow-up was15 months, range 12–18 months.Table 1 shows the patient characteris-tics, preoperative and postoperativevision and refraction.

The main indications for pIOLinsertion were bilateral high myopiain children with behavioural, neuro-logical or developmental disorders(eight eyes of four children), highanisometropia where spectacle or con-tact lens correction was not tolerated(one eye) and bilateral high astigma-tism with poor visual functioning withspectacle correction (two eyes of onechild). The mean preoperative spherewas )13.80 D ± 5.3 SD and cylinder)1.64 D ± 2.1 SD. Excluding the onebilateral case performed for highastigmatism, the mean preoperativecylinder was 0.81 D ± 0.97 SD. Themean preoperative spherical equiva-lent (SE) refraction was )14.6 D± 4.4 SD. Mean postoperative SErefraction was )2.40 D ± 2.4 SD. Inpatients in whom emmetropia wastargeted (five of 11 eyes), the meanpostoperative SE refraction was0.03 D ± 0.68 SD. In patients inwhom myopic error was reduced (sixof 11 eyes), mean postoperative SE


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refraction was )4.40 D ± 0.92 SD.Mean postoperative cylinder was)0.66 D ± 0.84 SD.

Mean preoperative logMAR CDVAfor all patients was 0.84 ± 0.41 SD(Snellen equivalent 6 ⁄ 40 ± 4 lines).Mean postoperative logMAR CDVAwas 0.67 ± 0.34 SD (Snellen equiva-lent 6 ⁄ 28 ± 3.4 lines) (p = 0.005).This represents a mean gain in visualacuity of 0.17 logMAR (95% CI0.06–0.28) or 1.7 lines Snellen equiva-lent. For patients in whom emmetr-opia was targeted, mean preoperativelogMAR CDVA was 0.87 ± 0.6,postoperative UCVA was 0.64 ± 0.38

(p = 0.09), and postoperative CDVAwas 0.56 ± 0.45 (p = 0.01).

There were no intraoperative orserious postoperative complications.We observed transient raised intraocu-lar pressure in two eyes at 2 weekspostoperatively caused by steroidresponse. In both cases, the peripheraliridectomy was patent and there wasno evidence of pupil block. Both casesresponded to substituting fluorome-tholone 1% (FML Liquifilm; Aller-gan, Inc., Irvine, CA, USA) forprednisolone acetate with a taperingcourse. One eye showed pigment celldeposits on the IOL at 1 month. This

was treated with topical prednisoloneacetate 1% 6 times daily tapering over1 month and fully resolved.

Pre- and postoperative ECD mea-surements were possible in three eyesof two patients (patients 5 and 6Table 1). The mean preoperativeECD was 2643 cells ⁄mm3, and meanpostoperative ECD at 18 months was2468 cells ⁄mm3, giving a cumulativeloss of 6.6%. The fellow nonoperatedeye of patient 5 showed 10.4% cumu-lative loss in the same time period(3543 cells ⁄mm3 to 3175 cells ⁄mm3).All 3 of these eyes had had previouscongenital cataract extraction with

Table 1. Patient characteristics, preoperative and postoperative vision and refraction.

Pt Sex

Age

(yrs) Eye

FU

(mths) Diagnosis

Preop

CDVA

Preop

refraction (D)

Postop

UCVA

Postop

CDVA

Postop

refraction (D)

1 M 9 R 17 Bilateral high myopia,

septo-optic dysplasia,

nystagmus, developmental

delay

2 ⁄ 60 )13.25 ⁄ )1.75 · 90 6 ⁄ 60 6 ⁄ 60 0 ⁄ )2.0 · 90

M 9 L 17 Bilateral high myopia,

septo-optic dysplasia,


delay

2 ⁄ 60 )14.0 6 ⁄ 60 6 ⁄ 60 +0.75 ⁄ )0.75 · 0

2 M 8 R 14 Bilateral high myopia

postretinopathy of

prematurity, nystagmus

autism

6 ⁄ 36 )18.0 6 ⁄ 36 )5.0

M 8 L 14 Bilateral high myopia

postretinopathy of

prematurity, nystagmus,

autism

6 ⁄ 36 )18.0 6 ⁄ 36 )5.0

3 M 8 R 14 Bilateral high myopia,


delay

5 ⁄ 60 )17.0 ⁄ )2.0 x180 6 ⁄ 60 )5.00 ⁄ )1.00 · 30

M 8 L 14 Bilateral high myopia,


delay

5 ⁄ 60 )15.0 6 ⁄ 60 )3.0

4 M 8 R 13 Bilateral high compound

myopic astigmatism,

refractive amblyopia

6 ⁄ 36 )4.50 ⁄ )6.50 · 2 6 ⁄ 24 6 ⁄ 24 +0.50 ⁄ )1.50 · 150

M 8 L 13 Bilateral high compound

myopic astigmatism,

refractive amblyopia

6 ⁄ 12 )5.25 ⁄ )4.25 · 160 6 ⁄ 9 6 ⁄ 7.5 +0.75

5 F 13 R 18 Unilateral high myopia

post congenital cataract

extraction with primary

PCIOL

6 ⁄ 12 )10.0 ⁄ )2.0 · 45 6 ⁄ 12 6 ⁄ 7.5 +1.25 ⁄ )2.00 · 50

6 M 15 R 18 Bilateral high myopia



PCIOL, Down’s

syndrome

6 ⁄ 24 )15.75 ⁄ )1.5 · 0 6 ⁄ 18 )4.0

M 15 L 18 Bilateral high myopia



PCIOL, Down’s

syndrome

6 ⁄ 24 )21.0 6 ⁄ 18 )4.0

UCVA is shown for patients in whom emmetropia was targeted. CDVA is shown for all patients. Pt = patient; yrs = years; mths = months;

D = dioptres; CDVA = corrected distance visual acuity; UCVA = uncorrected visual acuity; M = male; F = female; R = right; L = left;

PCIOL = posterior chamber intraocular lens.


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primary posterior chamber IOL. Oneyear postoperative ECD measurementwas possible in two eyes of patient 4,which showed healthy ECD of2985 cells ⁄mm3 and 3155 cells ⁄mm3

and no change in central cornealthickness from preoperative. ECDmeasurement was not possible in theremainder because of limitations ofage, comorbid disorders and fixationinstability caused by nystagmus.

Table 2 shows mean change in NEIVFQ-25 scores together with thecalculated effect size.

Significant improvements wereobserved in all vision-specific sub-scales and in the composite score withthe exception of colour vision, whichwas unchanged. There was no changein general health or in ocular pain as

none of the subjects had ocular painpre- or postoperatively. The scale withthe greatest improvement in score wasperipheral vision. The effect size ofthe pIOL insertion on each of the sub-scale scores is shown graphically inFig. 1.

Discussion

The management of paediatric highbilateral ametropia and anisometropiais challenging. Spectacle correction ofsuch refractive errors is suboptimalbecause of image minification in highmyopia, constriction of visual field,prismatic effects and aniseikonia inanisometropia. Contact lens use in chil-dren can pose serious difficulties forparents and patients alike. Compliance

with spectacles or contact lenses can bea particular problem in children withneurobehavourial disorders.

Management options in such caseswhere spectacle or contact lens correc-tion is not tolerated or is unsuitableinclude corneal excimer laser ablativeprocedures, refractive lens exchangeand pIOL insertion.

Corneal excimer laser ablation car-ries the disadvantages of cornealhaze and regression with PRK, par-ticularly as many of the childrenhave high myopia (Tychsen et al.2005; O’Keefe & Kirwan 2010).Laser intrastromal keratectomy istechnically difficult in these children,requires general anaesthesia and car-ries the risk of long-term ectasia.Refractive lens exchange carries thedisadvantages of loss of accommoda-tion and increased risk of retinaldetachment, of glaucoma in children,and of posterior capsule opacification(Ali et al. 2007; Tychsen 2008).

Anterior chamber pIOL insertion ofthe iris-fixated type carries severaladvantages in many of these respects.In aphakic children, the advantages ofinsertion of a secondary IOL in thecapsular bag or as an iris-fixated IOL(in the absence of capsular support)have been reported (Kim et al. 2010;Cleary et al. 2011). Studies in phakicchildren are more limited, and all previ-ous studies using iris-fixated pIOLs inchildren have used the rigid Artisan(Ophtec BV) or Verisyse IOL (AbbottMedical Optics Inc.) (Chipont et al.2001; Saxena et al. 2003; Lifshitz &Levy 2005; Assil et al. 2007; Pirouzianet al. 2009; Alio et al. 2011). We reporton the outcome of foldable pIOL inser-tion in children in this study.

We observed a statistically signifi-cant improvement in corrected vision.Postoperatively, the CDVA of most ofour patients was still subnormal owingto coexisting ocular and neurologicalconditions such as septo-optic dyspla-sia, nystagmus and refractive amblyo-pia. Spectacles of much reducedpower were required in three patientspostoperatively to correct residualerror. This is because of the limitationin available power of the Artiflex lens(maximum )14.5 D). We found thatcompliance with the reduced-pow-ered spectacles was excellent. Impor-tantly, vision-related QOL measuresimproved significantly. The advantageof the foldable pIOL is the need for a

Table 2. Mean change in National Eye Institute Visual Functioning Questionnaire-25 (NEI

VFQ-25) score by subscale from preoperative to postoperative following phakic intraocular lens

insertion.

NEI VFQ Scale Mean change (SD) p-value* 95% CI

General health 0 (0) NS 0

General vision 20 (0) 0.03� 20

Near visual activities 20.8 (11.5) 0.007 8.8–33

Distance visual activities 27.8 (14.6) 0.006 12.5–43.1

Peripheral vision 41.7 (20.4) 0.004 20.2–63

Vision-specific social functioning 16.7 (10.2) 0.01 6–27.4

Vision-specific mental health 28.5 (10.4) 0.001 17.5–39.4

Vision-specific role difficulties 29.2 (23.3) 0.028 4.7–53.6

Vision-specific dependency 16.7 (16.7) 0.038 1.3–32

Colour vision 4.2 (10.2) 0.36 )6.5–14.9Ocular pain 0 (0) NS 0

Composite score 20.7 (8.5) 0.002 11.8–29.6

SD = standard deviation; CI = confidence interval; NS = not significant.

*p value based on paired t test.�p value based on Wilcoxon test paired sample.

Fig. 1. Effect size of phakic intraocular lens insertion on National Eye Institute Visual Func-

tioning Questionnaire-25 (NEI VFQ-25) subscale scores. An effect size of 0.8 or greater is con-

sidered large, 0.5–0.79 moderate, 0.2–0.49 small and <0.2 trivial.


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small corneal incision 3.2 mm versus6 mm for the rigid pIOL. It can cor-rect high degrees of myopia up to)14.5 D with the 6 mm optic size.The toric version can correct up to5 D of astigmatism. There is a rapidvisual recovery, and it is reversible. Itcan be performed in an operatingroom by paediatric surgeons who areskilled in doing cataract surgery.

We did not encounter any seriouscomplications following pIOL inser-tion in this study. The principalpotential concern for implantation ofthese pIOLs in children is possiblelong-term endothelial cell loss. This isimportant given the long-life expec-tancy of the child and the potentialfor eye rubbing. The normal annualrate of ECD loss has been reported tobe approximately 2.9% per year (1.5–4%) in children up to age 14 yearsand 0.3% per year (0.3–0.7%) thereaf-ter (Moller-Pedersen 1997).

As a result of the age and comorbidi-ties of our study patients, ECD mea-surements were not possible in allpatients. In three eyes that had pre-and postoperative ECD, the cumula-tive loss was 6.6%. This compares to10.4% loss in the fellow nonoperatedeye of one of these patients. A thirdpatient had healthy 1-year ECD mea-surements of 2985 and 3155 cells ⁄mm3.

Data in the literature on ECD lossin children following pIOL insertionare limited and pertain to a smallnumber of cases. Pirouzian & Ip(2010) found ECD loss of 6.5–15.2%at 3 years following AC pIOL inser-tion in seven children with anisometro-pic myopia. Alio et al. (2011) reportedthe outcome of 10 eyes of 10 childrenwith high anisometropia who under-went pIOL insertion (nine iris-fixated,one posterior chamber) 5 years aftersurgery and found that ECD was<2000 cells ⁄mm3 in two patients(20%) and more than 2000 cells ⁄mm3

in the remainder. Of the two patientswith ECD <2000 cells ⁄mm3, onereported frequent eye rubbing and theother had suffered ocular trauma. Amulticentre US FDA clinical trialfound mean ECD loss of 5% over3 years in adult patients followingVerisyse ⁄Artisan IOL implantation(Stulting et al. 2008), and a Europeanmulticentre study found mean ECDloss of 1.1% at 2 years followingArtiflex lens insertion (Dick et al.2009).

The majority of children in thisstudy had developmental delay or neu-robehavioural disorders similar to aprevious study using rigid pIOLs(Tychsen et al. 2008). Based on thatstudy, Waring concluded that thisensures that these children are notassigned to a life in a cocoon of blur,promoting fearfulness, reduced interestin the outside world and tainted socialinteractions (Waring 2009). Othershave questioned this and propose thatthese children should have child devel-opmental experts who could assesspatient behavioural response after sur-gery (Brown 2011). At present, vision-related QOL is the only practical wayof assessing this. Our study demon-strated significant postoperativeimprovement in all vision-specific sub-scales of NEI VFQ-25, which webelieve answers this criticism.

ConclusionWe acknowledge that our study has limita-tions and lacks long-term data. In the idealworld, a multicentre prospective study isthe gold standard. However, to co-ordi-nate such a study with appropriate centres,patient numbers, relevant personnel andfinancial backing is a logistical problemand unrealistic. Finally, based on ourexperience, we believe that foldable pIOLsoffer major advantages in this group ofchildren.

AcknowledgementsNone of the authors has a financial inter-est in the subject matter of this study.

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Received on September 2nd, 2011.

Accepted on December 3rd, 2011.

Correspondence:

Michael O’Keefe

Department of Ophthalmology

The Children’s University Hospital

Temple Street

Dublin 2

Ireland

Tel: 00 353 1 8858626

Fax: 00 353 1 8858490

Email: [email protected]


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Foldable iris-fixated intraocular lens implantation in children

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