Today’s Practice refractive Fundamentals eyetube.net

Phakic IOLs: An Overview These lenses are fundamental tools in a successful practice.

By António Marinho, MD, PhD

he aim of refractive surgery is to modify the refrac- tic disorder, even subclinical, is present. Also, very steep cor- tive power of the eye in a permanent and stable neas are not suitable for hyperopic laser treatment and may way. There are two main refractive structures in be more appropriately addressed with intraocular surgery. the eye: the cornea and the natural lens. Changing Concerning patient age, phakic IOLs are being used with theT shape and thickness of the cornealaser corneal surgery, good results in children with anisometropia.3 Above the or exchanging the natural lens for an IOL, as in refractive age of 45 years, when accommodation is waning, the use of lens exchange or surgery, allows us to achieve the phakic IOLs is generally discontinued. Intraocular pathology aim of refractive surgery. However, there is another pos- such as diabetic retinopathy, uncontrolled glaucoma, and sibility: introduction of a new refractive surface in the eye any form of uveitis are considered contraindications to the without touching the cornea or the natural lens. implantation of phakic IOLs. On the other hand, corneal This is the concept behind phakic IOLs. This article addresses ectactic disorders (if stable) may be a good indication. four questions: (1) Why implant phakic IOLs? (2) When should In addition to these general indications, safe and successful phakic IOLs be implanted? (3) Which phakic IOL should be phakic IOL implantation requires the surgeon to extensively implanted? and (4) How should a phakic IOL be implanted? study the anatomy of the eye. The following parameters must be determined before surgery: anterior chamber depth and Question No. 1: WHY IMPLANT? size, iris configuration, pupil size, and endothelial profile. Laser corneal surgery changes the shape and thickness of the Anterior chamber depth is an important factor for safe cornea to achieve a refractive correction. If this change is limited implantation of all types of phakic IOLs. It must be measured (up to -6.00 D in and 3.50 D in hyperopia), there will be from the endothelium to the anterior surface of the natural a stable result. But if we correct more significant ametropias, fac- lens, and the minimum depth is 2.8 mm. Recent studies show tors associated with corneal biomechanics and wound healing that a 3.0-mm depth improves the safety of IOL implanta- can lead to regression and corneal instability. Additionally, the tion.4 Some papers and textbooks report that 3.2 mm from abnormal corneal shape created by laser ablation can result in the epithelium to the anterior surface of the lens is a suitable poor quality of vision, as demonstrated by ray-tracing studies.1,2 measurement for phakic IOL implantation; however, this On the other hand, lens surgery is not associated with concept is inaccurate and should be disregarded, as a thick problems of regression or limited by the amount of ame- cornea can coexist with a shallow anterior chamber. tropia correction. However, loss of accommodation in Anterior chamber depth can be determined using sev- younger patients is an important issue that even modern eral devices, the most common of which are the Orbscan accommodating or multifocal IOLs cannot solve, as they (Bausch + Lomb Technolas), the Pentacam (Oculus are unable to match the quality of vision of young eyes. Optikgeräte GmbH), the IOLMaster (Carl Zeiss Meditec), Phakic IOLs are important tools in refractive surgery; they the Spectralis (Heidelberg Engineering) anterior segment can be used to accurately and stably correct high ametropias optical coherence tomography (OCT) device, and the because they are not associated with wound healing and Visante OCT (Carl Zeiss Meditec). Ultrasonic biometers are they preserve the natural accommodation of the eye. not suitable, as they include corneal thickness in the mea- surement. If phakic IOL implantation is performed in a shal- Question No. 2: WHEN TO IMPLANT? low anterior chamber, the risk of endothelial cell loss and The general indications for phakic IOL implantation are eventually corneal decompensation is too high. myopia greater than -6.00 D, hyperopia greater than 3.50 D, The sizes of the anterior and posterior chambers are stable refraction (for at least 18 months), age between 18 and important for the implantation of some phakic IOLs. 45 years, and a healthy eye. In special circumstances, these cri- Angle-supported anterior chamber phakic IOLs must teria can be slightly adapted. In patients with myopia, phakic match the anterior chamber dimensions exactly. If they IOLs may be the procedure of choice for lower degrees if the do not, significant complications such as rotation and cornea is too thin (less than 480 μm) or if some form of ectac- decentration of the IOL, caused by a too-small IOL, or

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Once all the aforementioned criteria are met, it is neces- sary to determine the appropriate lens power of the phakic IOL. To do that, the most commonly used formula is one developed by Van der Hejde,6 which takes into account the spherical equivalent (cycloplegic for hyperopia), anterior chamber depth, and keratometry.

question no. 3: WHICH TO IMPLANT? According to their location inside the eye, phakic IOLs can be divided into three groups: (1) anterior chamber angle-supported phakic IOLs (eg, AcrySof Cachet; Alcon), Figure 1. The AcrySof Cachet. Figure 2. The Artisan. (2) anterior chamber iris-supported phakic IOLs (eg, Artisan pupil distortion and iris atrophy, caused by a too-large and Artiflex [both by Ophtec BV]; also marketed as the IOL, may result. Likewise, sulcus-fixated posterior Verisyse and Veriflex by Abbott Medical Optics Inc.), and chamber phakic IOLs must be appropriately sized to (3) posterior chamber phakic IOLs (eg, Visian ICL; STAAR avoid touching the natural lens, leading to cataract devel- Surgical). opment, caused by a too-small IOL, or pushing the iris A variety of phakic IOLs in each of these categories forward and closing the angle, caused by a too-large IOL. has been available over the past 20 years. Four currently Concerning this problem, iris-fixated phakic IOLs offer the available phakic IOLs are detailed below and in Table 1. advantage of being one-size-fits-all. AcrySof Cachet. The hydrophobic acrylic AcrySof Classically, to determine the angle-to-angle and sulcus- Cachet (Figure 1) has a 6.00-mm optic and four haptics to to-sulcus distances, the white-to-white measurement was ensure angle fixation. It is available only for myopia correc- calculated with calipers or with instruments such as the tion (-6.00 to -16.50 D) and comes in four sizes (12.5 mm, Orbscan, Pentacam, or IOLMaster. However, this mea- 13.0 mm, 13.5 mm, and 14.0 mm).7 surement does not always correlate with intraocular dis- Artisan/Verisyse. The Artisan lens (Figure 2) is made of tances,5 leading to errors in IOL sizing. Nowadays, at least PMMA. The optic is 5.00 or 6 mm, and the two haptics are for angle-supported anterior chamber phakic IOLs, OCT shaped like claws to grasp the midperipheral iris tissue. The provides an accurate in vivo measurement of the angle- 5.00-mm Artisan is available for correction of myopia (-2.00 to-angle distance. High-frequency ultrasound is the proce- to -23.00 D), hyperopia (2.00 to 12.00 D), and astigmatism dure of choice to measure the sulcus-to-sulcus distance. (both myopic and hyperopic up to 7.50 D). The 6.00-mm lens Although in most eyes the iris is flat, in some (mostly is available only for myopia correction (-2.00 to -14.50 D). hyperopic) eyes the iris is somewhat convex. These eyes The overall length of the Artisan is 8.5 mm; because the lens is are not suitable for implantation of iris-fixated phakic IOLs. iris-fixated, there is no need for different sizes.8 OCT is the most reliable method to assess iris configuration. Artiflex/Veriflex. The Artiflex is a foldable lens (Figure 3) Pupil size is another important factor for phakic IOL implan- with a design similar to the Artisan. It is has a 6.00-mm tation. The rule is that the mesopic pupil size should not be silicone optic and two PMMA haptics. The overall length more than 1.00 mm larger than the optic of the phakic IOL. is 8.5 mm. The Artiflex is available for the correction of A healthy endothelium, with a low index of pleomor- myopia (-2.00 to -14.50 D) and astigmatism (myopic up phism and polymegathism and a cell density of at least 2,200 -5.00 D, provided that the sphere plus cylinder does not cells/mm2, is also a prerequisite for phakic IOL implantation. exceed -14.50 D).8 Visian ICL. The Visian ICL is designed to fit in the cili- TABLE 1. PHAKIC IOL MODELS ary sulcus. It features a plate-haptic design made of the AcrySof Artisan Artiflex ICL proprietary material Collamer, with an optic diameter of Cachet 4.65 to 5.50 mm (myopia, according to power) or 5.50 mm Myopia Yes Yes Yes Yes (hyperopia). The Visian ICL is available for correction of (-6.00 D / (-2.00 D / (-2.00 D / (-0.25 D / myopia (-0.25 to -18.00 D), hyperopia (0.50 to 10.00 D), -16.50 D) -23.00 D) -14.50 D) -18.00 D) and, with the brand name Toric ICL, astigmatism (-6.00 Hyperopia No Yes No Yes to 6.00 D). The ICL comes in four sizes for myopia and (2.00 D / (0.50 D / 12.00 D) 10.00 D) astigmatism (12.1, 12.6, 13.2, and 13.7 mm) and four for hyperopia (11.6, 12.1, 12.6, and 13.2 mm). The most recent Astigmatism No Yes (+/-) Yes (-) Yes (+/-) (Toric) version, the V4c, has a hole in the middle of the optic for improved aqueous humor flow (Figure 4).9

May 2013 Cataract & Refractive Surgery Today Europe 61 Today’s Practice refractive Fundamentals

question no. 4: HOW TO IMPLANT? After carefully selecting the patient and the appropriate size and power of the phakic IOL, perfect implanta- tion must be performed to avoid intra- or postoperative complica- tions. The main points of the surgical techniques used with the same four Figure 3. The Artiflex. Figure 4. The Visian ICL. phakic IOLs and the complications most frequently associated with each TABLE 2. OVERVIEW OF PHAKIC IOL SURGERY are detailed below and in Table 2. AcrySof Cachet. Preoperatively, AcrySof Cachet Artisan Artiflex ICL miosis can be achieved using topical Pupil Miosis Miosis Miosis Mydriasis pilocarpine 2% applied 15 minutes Sideport 1 2 2 2 before surgery or acetylcholine injected Incision 2.6 mm 5.2/6.2 mm 3.2 mm 3.2 mm intraoperatively. Topical, peribulbar, or general anesthesia can be used, depend- Viscoelastic Cohesive Cohesive Cohesive Cohesive ing on patient and surgeon preference. Iridectomy/Iridotomy No Yes Yes Yes/No The main surgical steps are as follows: Suture No Yes No No • Create a 1.0-mm sideport inci- sion at the 9-o’clock position (optional); video demonstration of AcrySof Cachet implantation, visit • Create the main incision (2.6 mm in clear cornea) at the eyetube.net/?v=gaviz. 12-o’clock position; Artisan/Verisyse. For implantation of the this lens, topical • Fill the anterior chamber with a cohesive ophthalmic pilocarpine 2% applied 15 minutes before surgery or intraoper- viscosurgical device (OVD); ative acetylcholine can be used for pupil constriction. Topical, • Introduce the IOL into the cartridge (cartridge P); peribulbar, or general anesthesia can be used, depending on • Introduce the cartridge into the eye and past the iris; patient and surgeon preference; however, if possible, general • Inject the IOL slowly, watching it unfold in the right anesthesia is recommended in the surgeon’s first cases. way; note that the small mark on the leading haptic The main surgical steps of implantation are: must be on the right, and the one on the trailing haptic • Create two 1.0-mm sideport incisions at the 10- and on the left; 2-o’clock positions; • Remove the cartridge and introduce the trailing haptics; • Create the main incision (5.2 or 6.2 mm) at the • Wash out all of the OVD using I/A or passive irriga- 12-o’clock position; the incision may be corneal or tion; and scleral, but, because it is large, a scleral location is better • Close the wound with hydration of the cornea. to avoid inducing astigmatism; There is no need for iridotomy or iridectomy. • Fill the anterior chamber with a cohesive OVD; Postoperative medication includes topical antibiotic • Introduce the IOL into the eye and rotate it to the (levofloxacin) plus steroid (prednisolone acetate) four horizontal position; times daily for 2 weeks. • Fixate the IOL to the midperiphery of the iris. To per- With the AcrySof Cachet, most intraoperative complica- form this step, introduce the blunt needle provided tions can be avoided with a carefully performed surgery. by Ophtec through a sideport incision and forceps Cases of the IOL being implanted upside-down have been through the main incision to hold the optic of the IOL. described, but this is easily avoided if one pays atten- Then, using a bimanual technique, introduce a sufficient tion to the position of the haptic marks during unfold- amount of iris tissue through the claw haptics of the ing. Although this IOL is relatively new to the market, in IOL. This step is done in each haptic. The amount of tis-

clinical study over a 10-year period et sue grasped by the haptic must be at least 1.00 mm; investigators did not observe the • Wash out all of the OVD using I/A or passive irrigation; be .n tu

complications that were commonly e • Perform iridectomy or iridotomy; these can alternatively

reported with previous designs of ey be performed preoperatively with Nd:YAG laser; and angle-supported phakic IOLs such as • Suture the wound. iris atrophy or pupil distortion.7 For a eyetube.net/?v=gaviz Postoperative medications include subconjuntival dexa-

62 Cataract & Refractive Surgery Today Europe May 2013 Today’s Practice refractive Fundamentals

methasone plus a topical antibiotic (levofloxacin) and ste- steroids (prednisolone acetate) four times daily for 4 weeks. roid (prednisolone acetate) four times daily for 2 weeks. A carefully performed implantation reduces the risk of With careful implantation of the Artisan/Verisyse lens, complications. Some bleeding from the iridectomy may occur most complications can be avoided. Because a large incision with Artiflex/Veriflex IOL implantation, but it is usually resolved is used, iris prolapse is sometimes observed, although rarely with the OVD. The same long-term complications described under general anesthesia. If prolapse is encountered, perform for the Artisan lens apply to the Artiflex, but they are mainly iridectomy immediately. Some bleeding from the iridectomy related to the surgery and patient selection. In about 5% of eyes may occur, but it is usually resolved with OVD material. implanted with the Artiflex, pigment and giant cell deposits, The Artisan is the phakic IOL with the longest user experi- peaking at 1 month, are seen on the IOL. In the vast majority ence,10 and, therefore, important long-term complications of cases, these deposits are not clinically have been published. Complications such as decentration or significant and disappear by 3 months, et luxation of the IOL are not due to the lens itself but rather and no treatment is needed. If the be .n tu to surgical technical problems, such as poor centration patient complains of blurred vision, e ey or insufficient tissue grasped by the haptics. Additionally, steroid therapy solves the problem.8,11 some reports of endothelial cell loss For a video demonstration of Artiflex eyetube.net/?v=hopil are invariably associated with shal- et implantation, visit eyetube.net/?v=hopil. low anterior chambers. However, if be .n Visian ICL. For Visian ICL implantation, mydriasis can be tu patient selection and surgery are opti- e achieved with topical phenylephrine 1% and tropicamide mal, this IOL should not be associated ey 1%. Depending on patient and surgeon preference, topical, with significant complications.8,11 For peribulbar, or general anesthesia can be used. eyetube.net/?v=pozul a video demonstration of Artisan The main surgical steps of implantation are: implantation, visit eyetube.net/?v=pozul. • Create two 1.0-mm sideport incisions at the 6- and Artiflex/Veriflex. For Artiflex/Veriflex phakic IOL implan- 12-o’clock positions; tation, miosis can be achieved with topical pilocarpine 2% • Create the main incision (3.2 mm clear cornea) on the applied for 15 minutes before surgery or with intraopera- temporal side; tive acetylcholine. Topical, peribulbar, or general anesthesia • Fill the anterior chamber with cohesive OVD; can be used, depending on patient and surgeon choice. • Introduce the IOL into the cartridge; The main surgical steps of implantation are: • Introduce the cartridge into the eye; • Create two 1.0-mm sideport incisions at the 10- and • Inject the IOL slowly into the anterior chamber, watch- 2-o’clock positions; ing it unfold in the correct direction (note that the • Create the main incision (3.2 mm in clear cornea) at small mark on the leading haptic must be on the right the 12-o’clock position; and the mark on the trailing haptic on the left); • Fill the anterior chamber with cohesive OVD; • Introduce a soft-tip manipulator through the sideport inci- • Place the IOL in the spatula provided by Ophtec; sions and press down the tip of the haptics to move the • Introduce the spatula with the IOL into the eye and, ICL into the posterior chamber; never press on the optic; once the IOL is in the anterior chamber, press down on • Wash out all OVD using I/A or passive irrigation; and remove the spatula; • Constrict the pupil with acetylcholine; • Rotate the Artiflex to the horizontal position; • Perform iridectomy only if central hole is not present • Fixate the IOL to the midperipheral iris. To perform this (hyperopia); and step, introduce the blunt needle provided by Ophtec • Close the wound with corneal hydration. through a sideport incision and use forceps through Postoperatively, topical antibiotic (levofloxacin) and the main incision to hold the haptic of the IOL. Then, steroid (prednisolone acetate) should be administered with a bimanual technique, introduce a sufficient four times daily for 2 weeks. A carefully performed sur- amount of iris tissue through the IOL haptics. This gery should avoid most complications. Cases of the Visian step is done in each haptic, and the amount of tissue ICL being implanted upside-down have been described, grasped by the haptic must be at least 1.0 mm; Take-Home Message • Wash out all of the OVD using I/A or passive irrigation; • Perform iridectomy or iridotomy; this can alternatively • Phakic IOLs can be used to correct high ametropias. be performed preoperatively with Nd:YAG laser; and • These IOLs are not associated with wound healing and • Close the wound with corneal hydration. preserve the natural accommodation of the eye. Postoperative medications include subconjunctival • Anterior chamber depth is an important factor for dexamethasone plus topical antibiotic (levofloxacin) and safe implantation of all types of phakic IOLs.

May 2013 Cataract & Refractive Surgery Today Europe 63 Today’s Practice refractive Fundamentals

but this is easily avoidable if one pays attention to the plication rate, particularly the long-term complications, as position of the haptic marks during unfolding. the refractive accuracy is similar across all models. The Visian ICL has been associated with different rates of ante- Phakic IOLs are fundamental tools in a successful refrac- rior subcapsular cataract formation.12 These are of met- tive surgery practice. If the selection of patients is strict, abolic nature and are caused by a lack of space (vault) between the surgeon adheres to the described guidelines, and the ICL and the natural lens. This occurs when the IOL is too surgery is performed perfectly, phakic IOL implantation short for the eye, as a result of difficulty accurately measuring the should be almost devoid of complications. n sulcus-to-sulcus distance. Other factors such as high myopia and patient age also increase the rate of cataract development. To António Marinho, MD, PhD, is the Chairman of the avoid cataract, if insufficient vault is seen after implantation, the Department of Ophthalmology, Hospital Arrábida, Porto, ICL should be exchanged for a longer version.9,13 Portugal. Dr. Marinho states that he has no financial interest in the products or companies mentioned. He may be reached TORIC PHAKIC IOLs at tel: +35 1936093345; e-mail: [email protected]. The Artisan, Artiflex, and ICL are also available in toric ver- 1. Waring G. Comparison of refractive corneal surgery and phakic IOLs. J Refract Surg. 1998;14:277-279. sions. The implantation of these IOLs is similar to that of the 2. Marinho A. The Limits of Lasik: comparative analysis between corneal and phakic IOL refractive surgery. In: Alio J, Perez-Santonja J, eds. Refractive Surgery with Phakic IOLs. Clayton, Panama: Jaypee Highlights; 2013:12-21. spherical models, except that the axis of the IOL must be 3. Lesueur LC, Arne JL. Phakic to correct high myopic amblyopia in children. J Refract Surg. 2002;18(5):519-523. placed in the axis of astigmatism. The first step is to mark the 4. Doors M, Cals D, Berendshot T, et al. Influence of anterior chamber morphometrics on endothelial cell changes after axis of implantation in the patient’s eye. This is commonly phakic intraocular lens implantation. J Cataract Refract Surg. 2008;34:2110-2118. 5. Werner L, Izak A, Pandey S, et al. Correlation between different measurements within the eye relative to phakic done at the slit lamp—to avoid cyclotorsion—marking the intraocular lens implantation. J Cataract Refract Surg. 2004;30:1982-1988. 6. Heijde GL. Some optical aspects of implantation of an IOL in a myopic eye. Eur J Implant Refract Surg. 1989;1:245-248. limbus with a surgical pen. After implantation, the IOL should 7. Knorz M. The AcrySof Cachet angle-supported phakic IOL. In: Alio J, Perez-Santonja J, eds. Refractive Surgery with be aligned along the marked axis. With the Artisan and Artiflex Phakic IOLs. Clayton, Panama: Jaypee Highlights; 2013:86-95. 8. Budo C. Iris-fixated phakic IOLs. In: Alio J, Perez-Santonja J, eds. Refractive Surgery with Phakic IOLs. Clayton, Panama: lenses, the axis of the claws must be aligned with the limbus Jaypee Highlights; 2013:64-75. 9. Lovisolo C, Mazzolani F. ICL posterior chamber phakic IOL. In: Alio J, Perez-Santonja J, eds. Refractive Surgery with marks. The ICL is always implanted in the same axis (0° to 180°), Phakic IOLs. Clayton, Panama: Jaypee Highlights; 2013:96-122. 14 10. Budo C, Hessloehl JC, Izak M, et al. Multicenter study of the Artisan phakic intraocular lens. J Cataract Refract Surg. as the cylinder is included in the lens design. 2000; 26:1163-1171. 11. Marinho A. Complications of iris-supported phakic IOLs. In: Alio J, Azar D, eds. Management of Complications of Refractive Surgery. Heidelberg: Springer; 2008:238-244. conclusion 12. Sanders D. Anterior subcapsular opacities and cataracts 5 years after surgery in the Visian implantable collamer lens FDA trial. J Refract Surg. 2008;24:566-570. All phakic IOLs have shown outstanding refractive 13. Lovisolo C, Mazzolani F. Complications of posterior chamber phakic IOLs. In: Alio J, Azar D, eds. Management of results concerning accuracy and stability.7-9 The key to Complications of Refractive Surgery. Heidelberg: Springer; 2008;245-264. 14. Dick B, Elies D. Phakic intraocular lenses for correction of astigmatism. In: Alio J, Perez-Santonja J, eds. Refractive choosing among the available types is the associated com- Surgery with Phakic IOLs. Clayton, Panama: Jaypee Highlights; 2013:141-167.

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