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Phakic IOLs: An Overview
These lenses are fundamental tools in a successful refractive surgery practice.
By António Marinho, MD, P h D
T
he aim of refractive surgery is to modify the refractive power of the eye in a permanent and stable
way. There are two main refractive structures in
the eye: the cornea and the natural lens. Changing
the shape and thickness of the cornealaser corneal surgery,
or exchanging the natural lens for an IOL, as in refractive
lens exchange or cataract surgery, allows us to achieve the
aim of refractive surgery. However, there is another possibility: introduction of a new refractive surface in the eye
without touching the cornea or the natural lens.
This is the concept behind phakic IOLs. This article addresses
four questions: (1) Why implant phakic IOLs? (2) When should
phakic IOLs be implanted? (3) Which phakic IOL should be
implanted? and (4) How should a phakic IOL be implanted?
Question No. 1: WHY IMPLANT?
Laser corneal surgery changes the shape and thickness of the
cornea to achieve a refractive correction. If this change is limited
(up to -6.00 D in myopia and 3.50 D in hyperopia), there will be
a stable result. But if we correct more significant ametropias, factors associated with corneal biomechanics and wound healing
can lead to regression and corneal instability. Additionally, the
abnormal corneal shape created by laser ablation can result in
poor quality of vision, as demonstrated by ray-tracing studies.1,2
On the other hand, lens surgery is not associated with
problems of regression or limited by the amount of ametropia correction. However, loss of accommodation in
younger patients is an important issue that even modern
accommodating or multifocal IOLs cannot solve, as they
are unable to match the quality of vision of young eyes.
Phakic IOLs are important tools in refractive surgery; they
can be used to accurately and stably correct high ametropias
because they are not associated with wound healing and
they preserve the natural accommodation of the eye.
Question No. 2: WHEN TO IMPLANT?
The general indications for phakic IOL implantation are
myopia greater than -6.00 D, hyperopia greater than 3.50 D,
stable refraction (for at least 18 months), age between 18 and
45 years, and a healthy eye. In special circumstances, these criteria can be slightly adapted. In patients with myopia, phakic
IOLs may be the procedure of choice for lower degrees if the
cornea is too thin (less than 480 μm) or if some form of ectac60 Cataract & Refractive Surgery Today Europe May 2013
tic disorder, even subclinical, is present. Also, very steep corneas are not suitable for hyperopic laser treatment and may
be more appropriately addressed with intraocular surgery.
Concerning patient age, phakic IOLs are being used with
good results in children with anisometropia.3 Above the
age of 45 years, when accommodation is waning, the use of
phakic IOLs is generally discontinued. Intraocular pathology
such as diabetic retinopathy, uncontrolled glaucoma, and
any form of uveitis are considered contraindications to the
implantation of phakic IOLs. On the other hand, corneal
ectactic disorders (if stable) may be a good indication.
In addition to these general indications, safe and successful
phakic IOL implantation requires the surgeon to extensively
study the anatomy of the eye. The following parameters must
be determined before surgery: anterior chamber depth and
size, iris configuration, pupil size, and endothelial profile.
Anterior chamber depth is an important factor for safe
implantation of all types of phakic IOLs. It must be measured
from the endothelium to the anterior surface of the natural
lens, and the minimum depth is 2.8 mm. Recent studies show
that a 3.0-mm depth improves the safety of IOL implantation.4 Some papers and textbooks report that 3.2 mm from
the epithelium to the anterior surface of the lens is a suitable
measurement for phakic IOL implantation; however, this
concept is inaccurate and should be disregarded, as a thick
cornea can coexist with a shallow anterior chamber.
Anterior chamber depth can be determined using several devices, the most common of which are the Orbscan
(Bausch + Lomb Technolas), the Pentacam (Oculus
Optikgeräte GmbH), the IOLMaster (Carl Zeiss Meditec),
the Spectralis (Heidelberg Engineering) anterior segment
optical coherence tomography (OCT) device, and the
Visante OCT (Carl Zeiss Meditec). Ultrasonic biometers are
not suitable, as they include corneal thickness in the measurement. If phakic IOL implantation is performed in a shallow anterior chamber, the risk of endothelial cell loss and
eventually corneal decompensation is too high.
The sizes of the anterior and posterior chambers are
important for the implantation of some phakic IOLs.
Angle-supported anterior chamber phakic IOLs must
match the anterior chamber dimensions exactly. If they
do not, significant complications such as rotation and
decentration of the IOL, caused by a too-small IOL, or
Today’s Practice refractive Fundamentals
Once all the aforementioned criteria are met, it is necessary 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.
Figure 1. The AcrySof Cachet.
Figure 2. The Artisan.
pupil distortion and iris atrophy, caused by a too-large
IOL, may result. Likewise, sulcus-fixated posterior
chamber phakic IOLs must be appropriately sized to
avoid touching the natural lens, leading to cataract development, caused by a too-small IOL, or pushing the iris
forward and closing the angle, caused by a too-large IOL.
Concerning this problem, iris-fixated phakic IOLs offer the
advantage of being one-size-fits-all.
Classically, to determine the angle-to-angle and sulcusto-sulcus distances, the white-to-white measurement was
calculated with calipers or with instruments such as the
Orbscan, Pentacam, or IOLMaster. However, this measurement does not always correlate with intraocular distances,5 leading to errors in IOL sizing. Nowadays, at least
for angle-supported anterior chamber phakic IOLs, OCT
provides an accurate in vivo measurement of the angleto-angle distance. High-frequency ultrasound is the procedure of choice to measure the sulcus-to-sulcus distance.
Although in most eyes the iris is flat, in some (mostly
hyperopic) eyes the iris is somewhat convex. These eyes
are not suitable for implantation of iris-fixated phakic IOLs.
OCT is the most reliable method to assess iris configuration.
Pupil size is another important factor for phakic IOL implantation. The rule is that the mesopic pupil size should not be
more than 1.00 mm larger than the optic of the phakic IOL.
A healthy endothelium, with a low index of pleomorphism and polymegathism and a cell density of at least 2,200
cells/mm2, is also a prerequisite for phakic IOL implantation.
TABLE 1. PHAKIC IOL MODELS
AcrySof
Cachet
Artisan
Artiflex
ICL
Myopia
Yes
Yes
Yes
Yes
(-6.00 D / (-2.00 D / (-2.00 D / (-0.25 D /
-16.50 D) -23.00 D) -14.50 D) -18.00 D)
Hyperopia
No
Yes
(2.00 D /
12.00 D)
No
Yes
(0.50 D /
10.00 D)
Astigmatism No
(Toric)
Yes (+/-)
Yes (-)
Yes (+/-)
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),
(2) anterior chamber iris-supported phakic IOLs (eg, Artisan
and Artiflex [both by Ophtec BV]; also marketed as the
Verisyse and Veriflex by Abbott Medical Optics Inc.), and
(3) posterior chamber phakic IOLs (eg, Visian ICL; STAAR
Surgical).
A variety of phakic IOLs in each of these categories
has been available over the past 20 years. Four currently
available phakic IOLs are detailed below and in Table 1.
AcrySof Cachet. The hydrophobic acrylic AcrySof
Cachet (Figure 1) has a 6.00-mm optic and four haptics to
ensure angle fixation. It is available only for myopia correction (-6.00 to -16.50 D) and comes in four sizes (12.5 mm,
13.0 mm, 13.5 mm, and 14.0 mm).7
Artisan/Verisyse. The Artisan lens (Figure 2) is made of
PMMA. The optic is 5.00 or 6 mm, and the two haptics are
shaped like claws to grasp the midperipheral iris tissue. The
5.00-mm Artisan is available for correction of myopia (-2.00
to -23.00 D), hyperopia (2.00 to 12.00 D), and astigmatism
(both myopic and hyperopic up to 7.50 D). The 6.00-mm lens
is available only for myopia correction (-2.00 to -14.50 D).
The overall length of the Artisan is 8.5 mm; because the lens is
iris-fixated, there is no need for different sizes.8
Artiflex/Veriflex. The Artiflex is a foldable lens (Figure 3)
with a design similar to the Artisan. It is has a 6.00-mm
silicone optic and two PMMA haptics. The overall length
is 8.5 mm. The Artiflex is available for the correction of
myopia (-2.00 to -14.50 D) and astigmatism (myopic up
-5.00 D, provided that the sphere plus cylinder does not
exceed -14.50 D).8
Visian ICL. The Visian ICL is designed to fit in the ciliary sulcus. It features a plate-haptic design made of the
proprietary material Collamer, with an optic diameter of
4.65 to 5.50 mm (myopia, according to power) or 5.50 mm
(hyperopia). The Visian ICL is available for correction of
myopia (-0.25 to -18.00 D), hyperopia (0.50 to 10.00 D),
and, with the brand name Toric ICL, astigmatism (-6.00
to 6.00 D). The ICL comes in four sizes for myopia and
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
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
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question no. 4: HOW TO
IMPLANT?
After carefully selecting the patient
and the appropriate size and power
of the phakic IOL, perfect implantation must be performed to avoid
intra- or postoperative complications. The main points of the surgical
Figure 3. The Artiflex.
Figure 4. The Visian ICL.
techniques used with the same four
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 Artisan
Artiflex
ICL
AcrySof Cachet. Preoperatively,
Pupil
Miosis
Miosis
Miosis
Mydriasis
miosis can be achieved using topical
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
Viscoelastic
Cohesive
Cohesive
Cohesive Cohesive
general anesthesia can be used, depending 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 incivideo demonstration of AcrySof Cachet implantation, visit
sion at the 9-o’clock position (optional);
• Create the main incision (2.6 mm in clear cornea) at the eyetube.net/?v=gaviz.
Artisan/Verisyse. For implantation of the this lens, topical
12-o’clock position;
pilocarpine 2% applied 15 minutes before surgery or intraoper• Fill the anterior chamber with a cohesive ophthalmic
ative acetylcholine can be used for pupil constriction. Topical,
viscosurgical device (OVD);
peribulbar, or general anesthesia can be used, depending on
• Introduce the IOL into the cartridge (cartridge P);
patient and surgeon preference; however, if possible, general
• Introduce the cartridge into the eye and past the iris;
anesthesia is recommended in the surgeon’s first cases.
• Inject the IOL slowly, watching it unfold in the right
The main surgical steps of implantation are:
way; note that the small mark on the leading haptic
• Create two 1.0-mm sideport incisions at the 10- and
must be on the right, and the one on the trailing haptic
2-o’clock positions;
on the left;
• Create the main incision (5.2 or 6.2 mm) at the
• Remove the cartridge and introduce the trailing haptics;
12-o’clock position; the incision may be corneal or
• Wash out all of the OVD using I/A or passive irrigascleral, but, because it is large, a scleral location is better
tion; and
to avoid inducing astigmatism;
• Close the wound with hydration of the cornea.
• Fill the anterior chamber with a cohesive OVD;
There is no need for iridotomy or iridectomy.
• Introduce the IOL into the eye and rotate it to the
Postoperative medication includes topical antibiotic
horizontal position;
(levofloxacin) plus steroid (prednisolone acetate) four
• Fixate the IOL to the midperiphery of the iris. To pertimes daily for 2 weeks.
form this step, introduce the blunt needle provided
With the AcrySof Cachet, most intraoperative complicaby Ophtec through a sideport incision and forceps
tions can be avoided with a carefully performed surgery.
through the main incision to hold the optic of the IOL.
Cases of the IOL being implanted upside-down have been
Then, using a bimanual technique, introduce a sufficient
described, but this is easily avoided if one pays attenamount of iris tissue through the claw haptics of the
tion to the position of the haptic marks during unfoldIOL. This step is done in each haptic. The amount of tising. Although this IOL is relatively new to the market, in
sue grasped by the haptic must be at least 1.00 mm;
clinical study over a 10-year period
• Wash out all of the OVD using I/A or passive irrigation;
investigators did not observe the
• Perform iridectomy or iridotomy; these can alternatively
complications that were commonly
be performed preoperatively with Nd:YAG laser; and
reported with previous designs of
• Suture the wound.
angle-supported phakic IOLs such as
eyetube.net/?v=gaviz
Postoperative medications include subconjuntival dexairis atrophy or pupil distortion.7 For a
62 Cataract & Refractive Surgery Today Europe May 2013
Today’s Practice refractive Fundamentals
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steroids (prednisolone acetate) four times daily for 4 weeks.
A carefully performed implantation reduces the risk of
complications. Some bleeding from the iridectomy may occur
with Artiflex/Veriflex IOL implantation, but it is usually resolved
with the OVD. The same long-term complications described
for the Artisan lens apply to the Artiflex, but they are mainly
related to the surgery and patient selection. In about 5% of eyes
implanted with the Artiflex, pigment and giant cell deposits,
peaking at 1 month, are seen on the IOL. In the vast majority
of cases, these deposits are not clinically
significant and disappear by 3 months,
and no treatment is needed. If the
patient complains of blurred vision,
steroid therapy solves the problem.8,11
For a video demonstration of Artiflex
eyetube.net/?v=hopil
implantation, visit eyetube.net/?v=hopil.
Visian ICL. For Visian ICL implantation, mydriasis can be
achieved with topical phenylephrine 1% and tropicamide
1%. Depending on patient and surgeon preference, topical,
peribulbar, or general anesthesia can be used.
The main surgical steps of implantation are:
• Create two 1.0-mm sideport incisions at the 6- and
12-o’clock positions;
• Create the main incision (3.2 mm clear cornea) on the
temporal side;
• Fill the anterior chamber with cohesive OVD;
• Introduce the IOL into the cartridge;
• Introduce the cartridge into the eye;
• Inject the IOL slowly into the anterior chamber, watching it unfold in the correct direction (note that the
small mark on the leading haptic must be on the right
and the mark on the trailing haptic on the left);
• Introduce a soft-tip manipulator through the sideport incisions and press down the tip of the haptics to move the
ICL into the posterior chamber; never press on the optic;
• Wash out all OVD using I/A or passive irrigation;
• Constrict the pupil with acetylcholine;
• Perform iridectomy only if central hole is not present
(hyperopia); and
• Close the wound with corneal hydration.
Postoperatively, topical antibiotic (levofloxacin) and
steroid (prednisolone acetate) should be administered
four times daily for 2 weeks. A carefully performed surgery should avoid most complications. Cases of the Visian
ICL being implanted upside-down have been described,
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methasone plus a topical antibiotic (levofloxacin) and steroid (prednisolone acetate) four times daily for 2 weeks.
With careful implantation of the Artisan/Verisyse lens,
most complications can be avoided. Because a large incision
is used, iris prolapse is sometimes observed, although rarely
under general anesthesia. If prolapse is encountered, perform
iridectomy immediately. Some bleeding from the iridectomy
may occur, but it is usually resolved with OVD material.
The Artisan is the phakic IOL with the longest user experience,10 and, therefore, important long-term complications
have been published. Complications such as decentration or
luxation of the IOL are not due to the lens itself but rather
to surgical technical problems, such as poor centration
or insufficient tissue grasped by the haptics. Additionally,
some reports of endothelial cell loss
are invariably associated with shallow anterior chambers. However, if
patient selection and surgery are optimal, this IOL should not be associated
with significant complications.8,11 For
eyetube.net/?v=pozul
a video demonstration of Artisan
implantation, visit eyetube.net/?v=pozul.
Artiflex/Veriflex. For Artiflex/Veriflex phakic IOL implantation, miosis can be achieved with topical pilocarpine 2%
applied for 15 minutes before surgery or with intraoperative acetylcholine. Topical, peribulbar, or general anesthesia
can be used, depending on patient and surgeon choice.
The main surgical steps of implantation are:
• Create two 1.0-mm sideport incisions at the 10- and
2-o’clock positions;
• Create the main incision (3.2 mm in clear cornea) at
the 12-o’clock position;
• Fill the anterior chamber with cohesive OVD;
• Place the IOL in the spatula provided by Ophtec;
• Introduce the spatula with the IOL into the eye and,
once the IOL is in the anterior chamber, press down on
and remove the spatula;
• Rotate the Artiflex to the horizontal position;
• Fixate the IOL to the midperipheral iris. To perform this
step, introduce the blunt needle provided by Ophtec
through a sideport incision and use forceps through
the main incision to hold the haptic of the IOL. Then,
with a bimanual technique, introduce a sufficient
amount of iris tissue through the IOL haptics. This
step is done in each haptic, and the amount of tissue
grasped by the haptic must be at least 1.0 mm;
• Wash out all of the OVD using I/A or passive irrigation;
• Perform iridectomy or iridotomy; this can alternatively
be performed preoperatively with Nd:YAG laser; and
• Close the wound with corneal hydration.
Postoperative medications include subconjunctival
dexamethasone plus topical antibiotic (levofloxacin) and
Take-Home Message
• Phakic IOLs can be used to correct high ametropias.
• These IOLs are not associated with wound healing and
preserve the natural accommodation of the eye.
• Anterior chamber depth is an important factor for
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
position of the haptic marks during unfolding.
The Visian ICL has been associated with different rates of anterior subcapsular cataract formation.12 These cataracts are of metabolic nature and are caused by a lack of space (vault) between
the ICL and the natural lens. This occurs when the IOL is too
short for the eye, as a result of difficulty accurately measuring the
sulcus-to-sulcus distance. Other factors such as high myopia and
patient age also increase the rate of cataract development. To
avoid cataract, if insufficient vault is seen after implantation, the
ICL should be exchanged for a longer version.9,13
TORIC PHAKIC IOLs
The Artisan, Artiflex, and ICL are also available in toric versions. The implantation of these IOLs is similar to that of the
spherical models, except that the axis of the IOL must be
placed in the axis of astigmatism. The first step is to mark the
axis of implantation in the patient’s eye. This is commonly
done at the slit lamp—to avoid cyclotorsion—marking the
limbus with a surgical pen. After implantation, the IOL should
be aligned along the marked axis. With the Artisan and Artiflex
lenses, the axis of the claws must be aligned with the limbus
marks. The ICL is always implanted in the same axis (0° to 180°),
as the cylinder is included in the lens design.14
conclusion
All phakic IOLs have shown outstanding refractive
results concerning accuracy and stability.7-9 The key to
choosing among the available types is the associated com-
64 Cataract & Refractive Surgery Today Europe May 2013
plication rate, particularly the long-term complications, as
the refractive accuracy is similar across all models.
Phakic IOLs are fundamental tools in a successful refractive surgery practice. If the selection of patients is strict,
the surgeon adheres to the described guidelines, and
surgery is performed perfectly, phakic IOL implantation
should be almost devoid of complications. n
António Marinho, MD, PhD, is the Chairman of the
Department of Ophthalmology, Hospital Arrábida, Porto,
Portugal. Dr. Marinho states that he has no financial interest
in the products or companies mentioned. He may be reached
at tel: +35 1936093345; e-mail: [email protected].
1. Waring G. Comparison of refractive corneal surgery and phakic IOLs. J Refract Surg. 1998;14:277-279.
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.
3. Lesueur LC, Arne JL. Phakic intraocular lens to correct high myopic amblyopia in children. J Refract Surg.
2002;18(5):519-523.
4. Doors M, Cals D, Berendshot T, et al. Influence of anterior chamber morphometrics on endothelial cell changes after
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
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.
7. Knorz M. The AcrySof Cachet angle-supported phakic IOL. In: Alio J, Perez-Santonja J, eds. Refractive Surgery with
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:
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
Phakic IOLs. Clayton, Panama: Jaypee Highlights; 2013:96-122.
10. Budo C, Hessloehl JC, Izak M, et al. Multicenter study of the Artisan phakic intraocular lens. J Cataract Refract Surg.
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.
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.
13. Lovisolo C, Mazzolani F. Complications of posterior chamber phakic IOLs. In: Alio J, Azar D, eds. Management of
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
Surgery with Phakic IOLs. Clayton, Panama: Jaypee Highlights; 2013:141-167.