REVIEW
An overview of phakic intraocularlenses Albert C. M. Wong,' FCOphHK, FHKAM, Dimitri Az((J;2 MD, Chi Cheong Wong,' FCOphHK, FHKAM, Clement W N. Chan, 1 FCOphHK, FHKAM 1 Lo Ka Cliow Oplitlialmic Memorial Centre, 1img \\Till Eastem Hospital, Hong Kong, Cliina. 1lllinois Eye and Ear b1jir111aiy, Cliicago, USA.
Correspondence and reprint requests: Albert C. M . .ll'ong, 9/F Lo Ka C/iow Oplit/ialmic Memorial Centre, 1img \foll Eastem Hospital, Causeway Bay, Hong Kong, Cliina. Tel: (852) 2162 6888; Fax: (852) 2882 9909; F:-mail: drnlbertc111w@1:111ail.co111
3 6 9 addition to those used for correcting myopia • · and hyper 10 12 Abstract opia, · certain lenses are used to correct astigmatism 13•14 and presbyopia.15 The purpose of this article is to review There are 3 types of phakic intraocular lenses: angle the different PIOLs and the associated complications. The supported, iris-fixated, and posterior chamber. Implan reference articles quoted in this review are collected from tation of phakic intraocular lenses has been common a Medline database search using the key word 'phakic practice in Europe fo r the past decade. With the recent intraocular lens' plus 'complications', 'endothelial loss', approvals by the USA Food and Drug Administration ' pigment dispersion', 'cataract', 'vitreoretinal complication', for the Verisyse and Staar lenses, phakic intraocular lens 'surgical technique', and 'visual outcome'. implantation is expected to increase worldwide. Unlike Indications and contraindications the power calculation for conventional intraocular lenses using axial length and keratometry, the power of phakic Indications for PIOL implantation arc moderate to high intraocular lenses is calcul ated from keratometry myopia or hyperopia. The refraction should be stable so readings, anterior chamber depth, refractive error, and PIOLs are usually indicated for patients older than 20 years. ve1tex distance. In this review, different models of phakic For the implantation of anterior chamber lenses, the ante intraocular lenses and their indications are addressed. rior chamber depth should be at least 3.0 mm (measured Complications of implanting these lenses include endo from the inner part of the cornea). The endothelial cell count thelial cell loss, cataract, pigment deposits, iridocyclitis, should be at least 2000/mm2 preoperatively. For patients with and vitreoretinal complications. T hese complications more than -15.0 D refracti ve error, bioptics can be consid should be noted by surgeons before considering the use ered by adding an additional corneal procedure (usually 16 7 of these lenses for refractive cotTection. LASIK). .1 Limitations of the Verisyse toric IOL (Advanced Medical Optics, lnc, Santa Ana, USA) are a cylindrical power of up to 7 .00 D only and an optical zone of 5.00 mm. 13 Key words: lenses, intmocular; l ens implantation. intraocular; Postoperatil'e complications General contraindications for all types of PIOL implanta tion include ocular conditions such as corneal dystrophy, Introduction cataract, history of iritis, glaucoma, pigment dispersion syndrome, pseudoexfoliation of the lens capsule, excess iris A phakic intraocular lens (PlOL) is an intraocular lens de convexity, large scotopic pupils, ocular hypertension, con sig ned for implantation into an eye with phakia. ln 1954, tact sports, presbyopic age (in which refractive lens exchange Strampelli reported the first implantatio n of a minus power is preferred), and ocular conditions associated with diabetes. phakic intraocular lens (PJOL) in the anterior chamber. 1 Small pupil size is a relative contraindication fo r posterior Thereafter, newer and be tte r desig ns of PlOLs we re chamber lens implantation. 18 developed. There are 3 types of PIOL: the angle-supported/ angle-fixated lens (AS PlOL),2 iris-fixated/iris-claw lens With the development of anterior chamber optical coherence 3 4 5 (IF Pl OL), and posterior chamber lens (PC PlOL). • In tomography, a new parameter called crystalline lens rise,
28 HKJOphthalmol ® Vol.10 No.1 REVIEW which is defined by the distance between the anterior pole models,24 the parameters affecting the deviation of IOL of the crystalline lens and the horizontal plane joining the power from the desired power occurred in the following opposite iridocorneal recesses, has been proposed.'9 This order: refraction, vertex distance, ELP, keratometry, and parameter is used to predict the chance of developing pig refractive index. PlOLs showed high predictability in eyes ment dispersion after AS PIOL implantation. The safety level with preoperative refractive error between +1 5.0 D to -15.0 has been suggested to be <600 ~un . D. Thus, accurate measurements of preoperative refraction and the corresponding vertex distance, which may often be Power calculations for phakic intraocular neglected in conventional cataract surgery, are important for lens providing accurate desired postoperative refractions.
The formula used for the power calculation for PIOL is based Sizing of phakic intraocular lenses on vergence equations: the object vergence is equal to the refractive index of the object medium divided by the object The origi nal design of the Worst-Fechner biconcave iris claw distance (L = n/ I). In 1988, van der Heijde et al published a lens is standardized to 8.5 mm in size, but 7.5-mm or 8.5-mm 3 10 25 26 formu la to determine the IOL power needed for phakic myo lenses can now be obtained (Verisyse lens). • · • Other 21 pia and aphakia (hyperopia).20• Holladay later included the lenses such as angle-fixated and posterior chamber lenses desired postoperative refraction (DPostRx) in the equation.22 are available in 3 different sizes with a 0.5-mm step. Accu In both formulae, the following parameters were needed: rate sizing of PIOLs is important to minimize complications. the expected/effective lens position (ELP; distance from Limbal white-to-white diameter is usually used to determine corneal vertex to principal plane of IOL), the net corneal the size of the PIOL. The length of anterior chamber PIOLs power (K), the preoperative refraction in D (PreRx), and the (AC PIOLs) is approximated by adding 0.5 mm or 1.0 mm vertex distance (V) [Figure 1). Usually, the manufacturer to the horizontal w hite-to-white diameter for myopia or 6 27 28 calculates the desired power of the lens for the surgeons who hyperopia according to different Jens models. • · For PC provide the parameters. The effective lens position depends PIOLs, 0.5 mm or 1.0 mm is added to the horizontal white on the type of Jens and is estimated from the anterior cham to-white diameter for myopia, and 0.5 mm is subtracted for 9 11 29 ber depth, measured from the corneal vertex to the anterior hyperopia. • • .JO I 00 MHz ultrasound biomicroscopy (UBM) surface of the lens, rather than using the anatomical anterior and OCT may be helpful for assessing the preoperative and 11 38 chamber depth, which is measured from the corneal endo postoperative anatomical conditions. - thelium to the anterior surface of the lens. The white-to-white diameter can be measured by various Holladay's formula works well for all types of lenses. The instruments. The usual manual device is a surgical measur Staar Company (Monrovia, USA) has its own software for ing caliper with a scale from 0 to 20.0 mm in 1.0-mm steps. power calculations, but the exact equation was not found in The Holladay-Godwin Cornea Gauge is a hexagonal plate any published articles. Other formulae such as the Olsen with a half-circle scale from 9.0 mm to 14.0 mm in 0.5-mm 11 12 Feingold formula9• • ·18•23 have been used for the power increments, and can be held 1.0 mm from the cornea for calculation of PC PIOLs. The basic concept of this fo rmula measurement. Optical devices such as Orbscan II (Orbtek is to take account of the relative position of the PIOL to the Inc, Salt Lake City, USA) and JOLMaster (Carl Zeiss, biometric anterior segment measurements by considering Meditec, Jena, Germany) can detect the border between white the geometric featu res, refractive index, and elasticity of sclera and the darker iris image. lOLMaster shows the best the IOL material. Clinicall y, this formula shows less pre correlation with the measurements of video images and has dictability fo r myopia than for hyperopia.23 The accuracy of the highest reliability. 39 the power calculations is mainly governed by the accurate measurements of each parameter. Using mathematical Angle-supported phakic intraocular lenses
Examples of AS PIOLs include BaikoffZB (Domilens, Lyon, France), ZB5M (Domilens, Lyon, France), Nu Vita (Bausch 1336 1336 640 lOLe = ------and Lomb Surgical, Irvine, USA), • ZSAL-4 (Morcher GMBH, 136 136 Stutgart, Germany),41 phakic 6H (Ophthalmic Innovations -- - ELPo - - - ELPo 28 2 1000 1000 International [OII] Inc, Ontario, USA), .4 GBR (IOLTECH, - - - +Ko ---+ Ko LaRochelle, France)NIVARTE foldable (CIBA-Vision AG, 1000 1000 41 - --V - - - - V Embrach, Switzerland), - Kelman Duet (Tekia, Irvine, USA),.w Pre Rx DPostRx I-CARE lens (Corneal, Paris, France), and Thinlens (ThinOptX, Abingdon, USA) LFigure 2]. The Baikoff lenses are polymethyl methacrylate (PMMA) biconcave lenses Figure 1. The power determination of phakic intraocular lens using Holladay's formula.22 that have evolved from the first-generation ZB and second Abbreviations: IOL, = expected power of the intraocular lens; generation ZB5M to become the thi rd-generation NuVita DPostHx = postoperative refraction; ELP0 = effective lens implant by altering the size and thickness of the optic.2 The position; 1<0 = net corneal power; PreRx = preoperative refrac angulation of the haptics have been reduced from 25° to 20°, tion in D; V = vertex distance. and the optic edge has been thinned to provide an additional
HKJOphthalmol ® Vol.10 No.1 29 REVIEW
Figure 2. Angle-supported phakic intraocular lenses. (a) Vivarte; (b) Nu Vita MA; and (c) ZSAL-4. Reproduced courtesy of Dr H Bmkhard Dick (Training VerisyseTM Phakic Intraocular Lens) and Advanced Medical Optics, Inc.
45 49 51 0.6 mm of lens-cornea spacing. The modi lied Kelman Duet and PC PIOLs showed si milar predictabilities. - Complica has a similar design and the lens is in 2 pieces: a PMMA tions such as corneal endothelial loss, damage to the irido haptic with a silicone optic.44 Other lenses include the ZSAL corneal angle and glaucoma, pupil ovalization (Figure 3), and Phakic 6 lenses. The first-generation ZSAL-1 lens was IOL rotation, cataract formation, chronic low-grade iritis, 6 28 31 9 5 53 convex-concave and this has evolved to piano-concave for and retinal detachment have been reported. · · A . i - the fourth-generation ZSAL-4 o r ZSAL-4/plus. The phakic AS PIOLs appeared to be well tolerated by the corneal 6 and 6H lenses are biconcave PMMA lenses that are also endothelium, with a low rate of other complications, in a modi lied from the Baikoff lenses. Foldable AS PJOLs such 7-year study. 54 However, pupil ovalization is a common 4 1 as th e GBR/VIVARTE · have now been introduced to de complication with this type of lens (5.9%). Moreover, halos 28 6 crease the size of the corneo-scleral incision. A and glare arc the most annoying visual disturbance after AS PJOL implantation (27.8%).6 However, lenses with a larger Surgical technique optical zone (ZSAL-4 compared with ZB5M/ZB5MF) have The implantation of an AS PIOL can be performed under signifi cantly lower halo incidence (p < 0.05). general, peribulbar, or retrobulbar anesthesia, depending on a patient's needs and the surgeon's preference. The recom In a review of AS PIOLs, the endothelial cell loss after im mended anesthesia is peribulbar. Topical anesthesia can be plantation ranged from 16% to I 9% at I year and from 20% to used but the surgery may be more painful and complications 28% after 2 years for the Baikoff ZB lens. The endothelial may result. Baikoff et al suggested that the operation be per cell loss ranged from 4.5% to 5.5% at I year, from 5.6% to formed with the eyes in tight miosis using pilocarpine.6 6.8% at 2 years and from 5.5% to 7 .5% at 3 ycru·s for the ZB5M phakic IOL. Ultrasound biomicroscopy was used to exam A 6- or 7-mm incision is made in the lateral nasal or tempo ine the position of the footplates, the anatomy of the angle, ral cornea parallel to the iris plane and the anterior chamber and the anatomic relationships of AC PIOLs.55 The ZSAL-4 is filled with a viscoelastic substance. The implant, held with AS PIOL was found to have space between the IOL and the pincers or forceps, is introduced with a circular movement endothelium greater than other AS PlOL'>; the intermittent con following the scleral curve and envelops the curve of the tact between the IOL edge and the mid-peripheral cornea may pupil. The distal loops or the leading haptic should be fitted be responsible for the endothelial damage with this lens.56 into the iridocorneal angle without causing any pupil distortion. Once the leading haptic is properly positioned, additional viscoelastic is added as needed, and the trailing haptic is then placed in the iridocorneal angle on the oppo site side of the eye. Pupillary block is common with non patent iridectomies with AC PJOLs.6.47 lridectomies should be pe1formed on all eyes. In case of 360° posterior synechiae, iridectomy allows aqueous circulation. To obtain small, patent iridectomies, pigment vacuum iridectomy by remov ing the pigment layer of the iris using vacuum aspiration with a 25-gauge cannula after removing the stromal layer by surgical excision has been suggested.48 The surgery is completed after exchanging viscoelastics with balanced salt solution (BSS) and wound closure with 2 to 5 inter rupted I 0-0 nylon sutures. Figure 3. Pupil ovalization in an eye with an angle-supported Visual results, outcomes, and complications phakic intraoculai· lens. Reproduced comtesy of Dr H Ilmklmrcl Studies have been conducted to evaluate the safety, effective Dick (Training VcrisyscTM Phakic l11traocuh11· Lens) and ness, predictability, and stability of AC PIOLs. The AS PJOLs Adyanced Medical Optics, Inc.
30 HKJOphthalmol ® Vol.10 No.1 REVIEW
Figure 4. Iris-claw phakic intrnocular lenses. (a) Verisyse lens; (b) lens in sltu; and (c) tol'ic lens. Reproduced courtesy of Dr H Burkhard Dick (Training Verisyseni Phakic Intrnocular Lens) and Advanced Medical Optics, Inc.
Vitreoretinal complicatio ns can occur after AC PIOL approach depends on the predetermined implant location and implantation. In a retrospecti ve study of the incidence of the cylindrical axis as 2 models of lens are available: model retinal disease following refractive surgery,57 294 eyes cor AT PIOL has the torus axis identical to the target enclavation rected by AC PIOL were reviewed. Epiretinal membrane axis and model B T PIOL has the enclavation axis 90° to appeared in I patient 19 months after AC PIOL implantation. the torus axis. Thus, for eyes with a cylinder axis between The in cidences of retinal detachment and choroidal neo 0° and 45° or between 135° and 180°, model A is recom vascul arization (CNV) were 4.08% and 2.38%, respectively. mended, while for eyes with a cylinder axis between 45° Implantation of AS PIOLs to correct myopia in patients and 135°, model B is recommended. A clear corneal, limbal, with kcratoconus stage l to II have been reported. Short corneosclcral, or scleral wound can be constructed, depend term clinical results were acceptable, but astigmatism could ing on the surgeon's preference. To decrease the chance of not be corrected by wound incision.52 endothelial damage, a 'sandwich technique' is recommended for IF PIOL implantation. This method involves injecting a Iris-fixated phakic intraocular lenses bolus of a high-viscosity ophthalmic viscosurgical device over the optic after PIOL insertion and before performing 35859 The initial design of IF PIOLs was biconcavc · but this was enclavation. &1 later modified to a large convex-concave optic to decrease corneal endothelial damage, glare, and halos.00 In 1998, the Visual results, outcomes, and complications name of the Worst-Fechner IOL was changed to the Artisan T he iris-claw lenses achieve postoperative refraction within 8 62 63 65 66 lens (Ophtec, The Netherlands) although the design remained +/- 1 D in 60% to 80% of eyes. · · · · Eyes implanted with 26 29 unchanged. · The lens is also known as the Verisysc (Figures the Verisyse lens were studied under UB!vl. Adequate space 4a and b).6 1 As well as correcting myopia, the lens can be was found between the Vcrisyse hyperopic IOL and the 26 6 6 2 used to correct hyperopia and astigmatism (Figure 4c). · 1. corneal endothelium, angle, and crystalline lens. Haptic The Verisyse (At1isan) myopic lens (size range, -5.0 to -20.0 D) indentation of the iris, which can lead to pigment erosion, is a 5- or 6-mm concave-convex optic with an 8.5-mm wide was observed, tlms, possible complications include transient elliptical carrier, which is used to grip the outer edge of the iritis and chronic subclinical inllammation.67 To decrease the iris for lens fi xation. The Verisyse lens is the first PIOL to chance of inflammation, shortening the haptics or increas 32 33 receive USA Food and Drug Administration (FDA) approval. ing the lens vault has been suggested. • Detached enclavations can occur in eyes with the IC PIOL (Figure 5). Surgical technique Also, late endotheli al damage and corneal decompensation For the implantation of the Verisyse lens, a 2-plane, 5- to 6- are of concern after IF PIOL implantation. Although no mm posterior corneal incision can be constructed superiorly sig nificant endothelial cell loss was found in the 2- to 68 10 with 2 paracenteses at 2 o'clock and 10 o'clock. After an 3-year evaluation of the Veri sysc in eyes with myopia, · intracameral injection of acetylcholine and viscoelasti c a negative correlation between anterior chamber depth and material, the lens is introduced and rotated 90° into a hori endothelial cell loss was found in eyes with hyperopia.62 zontal position. The PIOL is fixed by pushing the iris into Therefore, it is recommended that eyes indicated for PIOL both claws with a bl end-tip enclavation needle; the iris can implantation have a minimum anterior chamber depth of be also enclavated by special forceps. A peripheral slit iri 3.2 mm. Eyes with crystalline lens rise of 600 ~un o r more dectomy is performed at 12 o'clock and the viscoelastic have a 67% chance of developing pupillary pigment material is exchanged with BSS. The wound can be closed dispersion. Thus, it is suggested that crystalline lens ri se with 5 or 6 interrupted 10-0 nylon sutures.63 should be used as a selection criterion.19 Yilreoretinal com plications have been found after implantation of an IF PIOL. Similar to the spherical Yerisyse PIOL, patients undergoing CNY was found in an eye 3 years after lens implantation.7 1 toric implantation (T PIOL) should be prepared with miotic T his patient was subsequently treated by photodynamic drops to reduce the risk of Jens touch. The site of the therapy with visuclyne.
HKJOphthalmol ~ Vol.10 No.1 31 REVIEW
Surgical technique For the implantation of a PC PIOL, a neodymium:YAG laser iridotomy is performed in the upper peripheral iris at least 2 weeks before implantation to allow inflammation to subside. 18 Two iridotomies are placed 90° apart to preclude the possibility of pupil block after IOL insertion. On the day of surgery, maximal mydriasis is required. After preparation, two 0.8-mrn paracenteses are placed 90° from the clear cor neal tunnel incision to facilitate immediate replacement of aqueous humor. The use of a viscosurgical device protects the surrounding tissues and allows the IOL to be unfolded slowly in a controlled manner. Each footplate is levered into position behind the iris through the pupil with a long spatula, Figure 5. Detached cnclavation in an eye with an iris-claw phakic intraocular lens. Reproduced courtesy of Dr H Burkhard Dick without placing pressure on the crystalline lens. The opera ('n·aining Vcris)·seTM Phakic lntraocular Lens) and Advanced tion is completed after the removal of the viscoelastic. Medical Optics, Inc. Postoperatively, steroid/antibiotic combination eye drops arc recommended 3 times daily for I week. Posterior chamber phakic intraocular lens Examples of PC lOLs are Chiron-Adatomed (Chiron GmbH, Visual results, outcomes, and complications Ratingen, Germany), Staar, Phakic Refractive Lens (PRL; As PC PIOLs are also called prelens lOLs, pigment dis CIBA Vis ion, Duluth, USA), Sticklens (IOLTECH, persion, cataract formation (Figure 7), and vitreoretinal 30 76 LaRochelle, France), and Thinlens. The PC PlOLs were first complications are important issues for these lenscs. • As introduced by Fyodorov (Moscow, Russia).4 2 The original previously mentioned, the AS PIOLs and PC PlOLs showed 49 51 design was a collar-button optic located in the anterior cham similar predictabilities. - ber with haptics behind the iris.72 Later, Chiron-Adatomed silicon lenses were used. This Jens is a single-piece boat shaped biconcave lens with piano haptics and is made of a silicon elastomer approved by the USA FDA. The optic diameter was originally 4.0 mm but, in 1994, it was changed to 5.5 mm. Haptic thickness has varied between 0.14 and 0.25 mm and ultimately became 0.18 mm. The overall length ranged from 10.5 mm to 12.0 mm with 0.5 mm steps.73 This implant has become less popular due to a high cataracto genesis rate. Today, the PRL-Medennium silicon lens74 and the Staar collamer implantable contact Jens are more usually used. The Staar lens is a foldable convex-concave lens made of porcine collagen hydroxyethylmethacrylatc copolymer (<0. l % collagen).75 The Staar lens vaults over the anterior lens capsule and provides space for the aqueous.37 The lens is designed for the surgical correction of moderate to high hyperopia and myopia with a range of correction Figure 7. Subcapsular catarnct iu an eye with a posterior cham from+ 10.00 to -20.00 D. The Staar lens became the second ber phakic intraocular lens. Reproduced courtesy of STAAR FDA-approved PIOL (Figure 6). Surgical AG.
Figure 6. Posterior chamber phakic intraocular lens. (a) Stam· lens; (b) Stam· lens in situ; and (c) toric lens. Reproduced courtesy of STAAR Surgical AG.
32 HKJOphthalmol ® Vol.10 No.1 REVIEW
38 76 78 Reports have shown that the chance of cataract formati on following PC PIOL implantation. · · T he so-called ' float after implantation of the Chiron Aclatomecl lens ranges from ing contact lens' has been found to have areas contacting 71 17 .8% to 33.3% after 6 and 32 months, respectively.30A5· · the surrounding tissues and requires a longer time for The Staar lens is associated with a 25% to 75% chance of evaluation. There is a higher incidence of lens clecentration cataract fo rmation within 18 to 32 months, although some and anteri or subcapsular cataract with the Adatomed lens 30 79 80 reports have shown no cataract formation d uring follow-up than with the Staar Jens. · Jn the study by Menezo et al, 30 76 77 of up to 24 months. · · Postoperative atonic pupil has been delayed cataract development and cataract type (nuclear) noted and has sometimes been described as Urrets-Zavalia were found in patients with an Ophtec lens and the variables sy n drome.~·73 This syndrome consists of a transient increase of patient age (older than 40 years) and axial length (>30 in IOP, iris stromal atrophy, and irreversible paretic mm) may be the prognostic factors. mydriasis. Ultrasound biomicroscopy has shown IOL-iris touch, IOL-crystalline lens touch, and anterior chamber In patients with the Adatomed and Staar PIOLs, other fac shallowing . This raises concerns about pigmentary tors such as lens design, material, and placement probably dispersion, cataractogenesis, and narrow angle glaucoma influenced cataract formation. Cataract formation, JOL
Table 1. Summary of angle-suptJorted tJlmkic intraocular lenses.
l\lodcl l\lanufocturer l\laterial 01>1k/o\'erall HatJtic Range (step) ID] Comments O u I comes ------diameter (mm) angle Baikoff (ZB) Domilens Biconca\'e 4.5 25' - No longer used - - First generation PivIMA endothelial damage Baikoff (ZB5l\ I) Domilens Biconcave 5.0 (4.0)/12.5, 20' -7 to -20.0 (1.0) Pupil ovalisation; halos/glare: 65% within Second PMMA 13.0, 13.5 t 2.3% endothelial cell loss ± 1.00 D at 2 years generation at 2 years; 21.05 to 23.50 photons/ms pigment at 2 years Baikoff (Nuvita) Bausch Biconcave 5.0 (4.5) - Only minus lens No longer used: - Third and Lomb PMMA significant endothelial - generation --- cell loss in the second year ZSAL-1 ( 1991) Morcher Convex-concave 5.5 15' - Failed in eye bank trials - PMMA ZSAL-2 ( 1992) Morcher PMMA 5.5 (5.0) 17' - No longer used - ZSAL-3 ( 1993) Morcher PMMA 5.5 (5.0) 18' - No longer used - -- ZSAL-4 (1994) Marcher Plano·concave 5.5 (5.0)/ 19'. -6 to -20.0 ( 1.0) No longer used: 4.18% -0.65 ± 0.65 D. PMMA 12.5, 13.0 z-shaped endothelial cell loss 82.6% within haptic at 24 months ± 1 D at 2 years ------ZSAL-4/plus Morcher Plano-conc:wc 5.8 (5.0-5.3)/ - -6 to -20.0 (0.5) lntraocular lens rotation - PMMA 12.0-1 3.0 - - - Phakic 6 Oil Biconcave 6.0 up to -10 D: - - Modified from Baikoff - PMMA 5.5 up to -25 DI ,__ 12.0-14.0 (0.5) Phakic 6H Oil Biconcave 6.0 up to -10 D; - - - - Pl\IMA 5.5 up to -25 DI 12.0-14.0 (0.5) Phakic 6112 Oil Biconca\'e 6.0 up to -10 D; - -4.0 to -20.0 D, Phase 11 (FDA) - PMl\·IA 5.5 up to -25 DI +2.0 to+ I 0.0 ------12-.0-14.0 (0.5) GBR/Vivartc C IBA/ Biconcave acrylic 5.5/12.0. - -7.0to 3·point angle, foldablc, - IOLTECH optic, PMlVIA 12.5, 13.0 -25.0 (0.5) 3.2 nun wound haptics, soft acrylic footplates ------GBR/Vivarte CIBA/ Acrylic 5.5 - -5.0 to +5.0 - - for presbyopia IOLTECH f- Kelman Duet Tckia PMMA haptic 5.5/1 2.0, 12 .5, - -8.0 to -20.0 Few clinical results - phakic AC with silicone optic 13.0. 13.5 I-CARE lens Come al Hydrophilic 5.75/12.0, 12.5, - - Has 4 independent haptics - (France) acrylic 13.0, 13.5 ------Thinlens ThinOptX Acrylic - - - - - Abbre\'ia1ions: AC = <11irc1im· c/1a111bN; Oil = Oplttlwlmi<: /111wmtio11s lnrt'n1t1tiu11a/; l'M.llA = poly111e1/Jyl 111et/Jacry/11tt•; ms = 111illi«•<·u11ds; FD1\ = foot! a11d Drug Ad111i11istmtiu11.
HKJOphthalmol ® Vol.10 No.1 33 REVIEW dislocation, and severe endothelial cell loss may occur as a Bioptics late complication of PC PIOL implantation.8 1 Although PTOL implantation shows good predictability Halos and glare can be present after lens implantation. The clinically , ~9 -5 1 LASIK or photorefractive keratectomy are incidence is more common with PC PIOL than for AS PIOL sometimes used to treat residual refractive error;8H 6 the term 16 87 or IF PIOL implantation. In general, lenses with a larger 'bioptics' is used to describe thi s kind of surgery. • Some optical zone result in a lower incidence of halos.5u 2 authors have suggested using ' adjustable refractive surgery' by creating a LASIK flap before PIOL implantation,8s.s9 but CNV has also been found with this type of lens; this this technique has become less popular due to the develop occurred in l patient 5 weeks after lens implantati on and ment of higher power PIOLs and the improved technique was subsequently treated by photodynamic therapy.71 Rheg for surface ablation. The complications of this procedure matogcnous retinal detachment (2%) has also been reported inc lude pain, halos, endothe lial cell loss, recurrent in 2% of patients after the implantation of PC PIOL.83 The iridocyclitis, transient ocular hypertension, anterior subcap designs and specifications of certain lenses as well as the sular opacities, and macular hemorrhage, but these occur complications are summarized in Tables 1 to 3. with acceptable incidcnces.8u 6
'I'nble 2. Summary of lrls-lixntcd phakic lntraocular lenses.
i\lodcl i\lanufaclurer i\la lerial Oplir/Ol'Cntll Ha nge (step) [Dl Hem arks diameter (111111 ) ------Artisan/Verisyse Ophtech I AMO Concave-convex PMMA 5.0-6.017.5. 8.5 -5 !O -20 0. 78% 10 17.41 'fti endothelial cell loss
· ~ Artisan 206 Ophtech Concave-convex P1'. t1'.IA 5.0·6.017 .5. 8.5 -3.0 10 -23.0 (0.5) - Artisan 203 Ophtech PMMA 5.0 + 1.010 +12.0 (0.5) - Artisan for Ophtech Biconcave PMMA 5.0/8.5 - A: cylinder on axis, Astigmatism B: cylinder perpe ndicular 10 axis Worst-Fechner - Biconcave PMMA 4.0-5.0/8.5 -5.0 10 -20.0 ( 1.0) 17 .6% endothelial cell loss, 3 1.03 to 28.8 pigment photons/ms at 24 moll!hs
Abbr~'· iaii ons: AMO =Ar frm1ccd ,\/edim l Op1ic.<. /11 c: PMMA =p uly111<'1/1yl 111e1hacry/ate: ms =111illi .«"<'U11
Table 3. Sun1111111·y of posterior chamber phakic intraocular lenses.
1'.loclcl i\lanufncturer i\laterial Optic/overall Range (step) Remarks Formula diameter (mm) IDJ - - -- - Adatomed Chiron Biconcave 5.5/ 11 .5-13.0 x 6.5 -8.0 10 -2 1.0 44.06% anterior subcapsular Van der Hcijde/ (094M-I ) Polydimethylsiloxane cataract, 1.46% nucleosclcrosis: Holladay 54.23% pig111ent deposits ------Staar S!aar Foldable concave-convex 4.5-5.5/12.0-13.0 x 6 -3.0 10 -20.0 Sizing: white-to-white minus Van der I lcijde/ (ICM series) collamer, (collage n- 0.5 m111: 9.5'k- I 3.~% cataract; Holladay polymer, 2-hydroxyethyl 38. I 0% pig111elll deposits 111c1hacrylatc) ,....__ --- - ICLV4 Staar Colla 111er 4.5-5.5/11 .5 to 13.0 -3.0 to -20.0 For myopia Van der Hcijde/ (ICM) Holladay
~ ICLV4 Staar Colla111er 5.5 +3.0to +17.0 For hyperopia: sizing according Van der Hcijde/ OCH) 10 anterior chamber depth: Holladay
2.8-2.9 111 m: -0.6 111111, 3.0-3.1: -0.4. 3.2: -0.2. ~3 .2: 0 Torie ICL Staar Collamer - 10+6.0 - Van der Heijde/ l lolladay - - - -- RPL CIBA Biconcave silicon 4.5-5.0110.8 for -3.0 !O ·20.00 'Floats' due to hydrophobic; Ve rtex for11111l a: l'lledennium PRL-100. 11.3 ( 1.0 for PRL- 100, available for white· P=ref/ (PRL-100, for PRL- 101 0.5 forPRL-1 0 1) lo-white distance
34 HKJOphthalmol $ Vol.10 No.1 REVIEW
The future of phakic intraocular lenses use of LASIK has been suggested to treat myopia up to - 12 D, PC PIOL to treat myopia of -12 to -18 D, and bioptics Now that there is sufficient experience of PIOL implantation, (PIOL implantation plus corneal surgery) to treat myopia of the designs of the lenses are evolving to fit a smaller wound greater than - I 8D, with the LASIK procedure performed at 31 87 91 size and give better outcomes. With the recent acceptance least a month after PC PIOL implantatio n. · However, of PIOL implantation in the USA7 0 and the development of longer postoperative evaluation of the complications of these 26 66 toric PIOLs, · PTOL implantation may provide an alterna procedures are needed despite the fact that the lenses have tive treatment for patients with high refractive errors.90 The been in use for more than a decade.
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36 HKJOphthalmol $ Vol.10 No.1 REVIEW
40:237-44. impla11tatio11for severe myopia. Ophthalmology. 2005; 112: 76. Jimenez-A/faro I, Benitez de/ Castillo JM, Garcia-Feijoo J, 580-5. Gil de Bema be JG, Serrano de w Iglesia JM. Safety ofpos 84. Sanchez-Galea11a CA, Smith RJ, Rodriguez X, Mo11tes M, terior chamber plwkic i11traoc11lar lenses for the correction Clwyet AS. wser in situ keratomileusis and plwtorefractive of high myopia: anterior segment changes after posterior keratectomy for residual refractil•e error after plwkic chamberphakic i111moc11lar lens implantation. Ophthalmology. intraocular lens implantation. J Refract Surg. 2001; 17: 2001; 108:90-9. 299-304. 77. Fink AM, Gore C, Rosen E. Cataract development after im 85. Munoz G, Alio JL, Mo11tes-Mico R, Belda JI. Angle-supported plantation ofth e Staar co/lamer posterior chamber phakic phakic i11tmocular lenses followed by laser-assisted in situ lens. J Cataract Refract Surg. 1999;25:278-82. keratomileusis for the correction of high myopia. Am J 78. Garcia-Feijoo J, Hernandez-Matamoros JL, Castillo-Gomez Ophthalmol. 2003; 136:490-9. A, et al. High-frequency ultrasound bio111icroscopy of 86. Leccisolli A. Bioptics by angle-supported plwkic lenses mu/ silicone posterior chamber phakic intraocular lens for photorefractive keratectomy. Eur J Ophtlwlmol. 2005; 15: hyperopia. J Cmaract Refract Surg. 2003;29: 1940-6. 1-7. 79. Menezo JL, Peris-Martinez C, Cisneros AL, Martinez-Costa 87. Zaldivar R, Davido1f JM, Oscherow S, Ricur G, Piezzi \~ R. Phakic intraocular lenses to correct high myopia: Combined posterior chamber phakic intraocular lens and Adatomed, Stam; and Artisan. J Cataract Refract Surg. 2004; laser in situ kemtomileusis: bioptics for extreme myopia. J 30:33-44. Refract S111g. 1999; 15:299-308. 80. Menezo JL, Peris-Martinez C, Cisneros-Lanuza 1\L, 88. Guell J. Th e adjustable refmctive s111ge1)' concept (ARS). J Martinez- Costa R. Rate ofcataract formation in 343 highly Refract S111g. 1998; /4:271. myopic eyes after implantation of three types of plwkic 89. Guell JL, Vazquez M, Cris 0. Adjustable refractive s11rge1y: intraocular lenses. J Refract Surg. 2004;20:317-24. 6 -111111 Artism1 lens plus laser in silll keratomileusis for 81. Mastropasqua L, Toto L, Nubile M, Falconio G, Ciancaglini the correction ofhi gh myopia. Ophthalmology. 2001;108: Iv/. Long-term complicatio11s ofbilateral posterior chamber 945-52. phakic intraocular lens implantation. J Cataract Refract 90. Guell JL, Vazquez M, Cris 0, De Muller A, Manero F. Com Surg. 2004;30:901 -4. bined surgery to correct high myopia: iris claw phakic 82. Maroccos R, \!az F, Marinlw A, Guell J, Lohmm111 CP. Glare intraocu/ar lens and laser in situ keratomileusis. J Refract and halos after "phakic !OL". S11rge1y for the correction of S111g. 1999; 15:529-37. high myopia. Ophthalmologe. 2001;98: 1055-9. [Germa11/ 91. Arne JL, Lesueur LC, Huli11 HH. Photorefractive keratec 83. Martinez-Castillo V, Boi.mdera A, \!erdugo A, £lies D, Core/ tomy or laser in situ keratomileusis for residua/ refmctive A, Garcia-An1111i J. Rhegmmoge11 ous retinal detachment i11 error after phakic intraocular lens implantmion. J Cata met phakic eyes after posterior chamber phakic intraocular lens Refm ct Surg. 2003;29: 1167-73.
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