Clinical Ophthalmology Dovepress

open access to scientific and medical research

Open Access Full Text Article Review

The Implantable Collamer Lens with a central

port: review of the literature
This article was published in the following Dove Press journal:
Clinical Ophthalmology

Mark Packer Abstract: The purpose of this review is to summarize preclinical and clinical data from
Mark Packer MD Consulting, Inc., publications appearing in the peer-reviewed scientific literature relevant to the safety and
Boulder, CO, USA effectiveness of the EVO Implantable Collamer Lens (ICL) posterior chamber phakic refractive
lens with a central port (V4c Visian ICL with KS Aquaport, STAAR Surgical, Inc.). A litera-
ture search was conducted using PubMed.gov to identify all articles relating to the EVO ICL.
Articles were examined for their relevance, and the references cited in each article were also
searched for additional relevant publications. On the basis of a total of 67 preclinical studies and
clinical reports, including effectiveness data on 1,905 eyes with average weighted follow-up of
12.5 months and safety data on 4,196 eyes with weighted average follow up of 14.0 months,
the EVO ICL is safe and effective for the correction of a broad range of refractive errors.
High levels of postoperative uncorrected visual acuity, refractive predictability, and stability
demonstrate the effectiveness of the EVO ICL. Safety data suggest reduced rates of anterior
subcapsular cataract and pupillary block compared with earlier models. Improved safety and
proven effectiveness make EVO an attractive option for surgeons and patients.
Keywords: myopia, astigmatism, hyperopia, phakic refractive lens

Introduction
The EVO Implantable Collamer Lens (ICL Model V4c; STAAR Surgical, Monrovia,
CA, USA), which has been commercially available since 2011, is a single piece poste-
rior chamber phakic refractive intraocular lens designed with a central port to eliminate
the need for iridotomy or iridectomy that was required by earlier implantable collamer
lens (ICL) models. The central port functions by allowing sufficient aqueous flow from
the posterior chamber to the anterior chamber to maintain the normal physiology of
the anterior segment of the eye.

Sizing, vault, and safety

Historically, concerns related to ICL safety have included sizing methodology because
of the relationship of excessive or insufficient vault to adverse events such as lens
exchange or explantation, pupillary block, endothelial cell loss, pigment dispersion,
elevated intraocular pressure (IOP), and cataract. Sizing represents the methodology
by which the appropriate overall lens diameter is selected for implantation in order to
achieve a safe level of vault, which is the axial distance between the ICL and the crystal-
Correspondence: Mark Packer
Mark Packer MD Consulting Inc., 1400
line lens. Sizing applies equally to older lens designs without the central port and to the
Bluebell Ave., Boulder, CO 80302, USA EVO ICL. Authors have suggested alternatives to the most commonly used method of
Tel +1 541 915 0291
Fax +1 888 840 9392
sizing, which is based on the horizontal corneal white-to-white (WTW) distance and the
Email mark@markpackerconsulting.com anterior chamber depth (ACD). These alternative methods include the use of ultrasound

submit your manuscript | www.dovepress.com Clinical Ophthalmology 2018:12 2427–2438 2427

Dovepress © 2018 Packer. This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https://www.dovepress.com/terms.php
http://dx.doi.org/10.2147/OPTH.S188785
and incorporate the Creative Commons Attribution – Non Commercial (unported, v3.0) License (http://creativecommons.org/licenses/by-nc/3.0/). By accessing the work you
hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission
for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms (https://www.dovepress.com/terms.php).
Packer Dovepress

biomicroscopy to measure the sulcus-to-sulcus (STS) distance. followed for up to 7.5 years, including 334 eyes available for
However, a meta-analysis of published results has demon- analysis at 5 or more years. Over that period of time, a total of
strated that “sulcus-to-sulcus and white-to-white measurement- 31 eyes developed ASC opacities; however, only 5 of these
based sizing methods result neither in clinically meaningful eyes developed visually significant ASC cataracts. Per eye
nor statistically significant differences in vault (two-sample at 5 years, the risk of developing any ASC opacity was 6.1%
two-sided t-test using pooled mean and SDs; t (2,594)=1.33; and the risk of developing a visually significant ASC cataract
P=0.18).”1 Therefore, the clinical outcomes achieved by the was 1.2%. In regard to the incidence of cataract, evidence
different sizing methodologies appear to be the same. shows that older age and higher levels of myopia represent
The degree of variation in vault is independent of sizing risk factors; thus, patient selection can reduce this risk.2
methodology and is related to the interaction of the lens The risk of cataract may also be reduced by the new central
implant with the anatomy and physiology of the posterior port design of the EVO ICL. No visually significant cataracts
chamber. As noted, “In summary, neither clinically meaning- have been reported to date following EVO implantation with
ful nor statistically significant difference in achieved vault up to 5 years of follow-up, and the incidence of nonvisually
differentiates WTW- and STS-based sizing methodologies. significant ASC opacities has remained low.1 Preclinical
No methodology has proven superior to WTW-based sizing studies described below suggest that the central port helps
in terms of the predictability of vault, and sizing based on to maintain the health of the crystalline lens by allowing
WTW and ACD remains the most popular and best-studied physiologic flow of aqueous humor across the anterior
technique. While the quest for improved predictability of lens capsule.
vault based on different imaging technologies may appear
to represent an appealing endeavor, it has resulted neither in IOP
a demonstrable reduction in the variability of achieved vault The incidence of elevated IOP requiring treatment, especially
nor in the already low rate of vault-related adverse events in the immediate postoperative period when pupillary block
that occur following ICL implantation.”1 has been reported, is another important safety concern. In
the MICL PAS clinical trial, there were 17 cases of pupillary
Postapproval study of the visian MICL: block out of 526 eyes implanted (3.2%). All cases were
implications for safety of the EVO ICL treated successfully with neodymium: yttrium aluminum
Long-term data now available from a Post Approval Study garnet laser iridotomy.2 There were also three eyes with
(PAS) of the Implantable Collamer Lens for Myopia (MICL) elevated IOP due to retained ophthalmic viscosurgical device
conducted under the U.S. Food and Drug Administration (viscoelastic, OVD), all of which resolved after irrigation and
have provided additional information on safety in regard aspiration. The risk of elevated IOP in the early postoperative
to the incidence of cataract, elevated IOP, and endothelial period can be mitigated by proper surgical technique because
cell loss.2 The MICL is an earlier version of the ICL, which it depends on construction of iridotomies of adequate size
does not feature a central port and therefore requires the and thorough removal of OVD.
construction of laser iridotomies or a surgical iridectomy The risk of elevated IOP may also be reduced by the
to preserve the flow of aqueous from the posterior to the central port design: only one case of pupillary block has
anterior chamber. Nevertheless, the findings of this study been reported in the literature we have reviewed, which
regarding vault-related adverse events may be applicable to includes safety data from 4,196 eyes with a weighted average
the EVO ICL, because a meta-analysis has demonstrated that postoperative follow-up of over 1 year.
the achieved vault of the EVO ICL and the achieved vault of
earlier models without the central port such as the MICL “are Endothelial cell loss
not statistically significantly different (two-sample two-sided Corneal endothelial health was also addressed in the MICL
t-test using pooled means and SDs; t (2,594)=-1.70; P=0.09). PAS. Based on clinical data collected through 5–7 years
The 95% confidence interval for the difference (V4c minus postoperative, the calculated chronic rate of loss of endothe-
others) was found to be -3 to 42 µm.”1 lial cell density (ECD) was ~1.8% per year. Additional data
have been provided in the published literature on the MICL.
Cataract For example, Moya et al have provided a 12-year retrospec-
In the MICL PAS, the incidence of anterior subcapsular tive study on 144 eyes implanted with the ICL from 1998 to
(ASC) cataract was studied in 526 eyes of 294 patients, 2001,3 noting an initial 6.46% decrease in ECD the first year,

2428 submit your manuscript | www.dovepress.com Clinical Ophthalmology 2018:12

Dovepress
Dovepress EVO review

followed by an annual decrease of 1.20%. These rates should Fluid dynamics

be viewed in the context of the expected age-related loss of A preclinical study performed by Fujisawa et al demonstrated
ECD, which is 0.6% per year.4 Of note, no cases of corneal that introduction of a central 3.0 mm hole in ICLs implanted
decompensation in the absence of trauma have been reported in 20 eyes of ten 3-month-old miniature pigs eliminated the
following ICL implantation.5 As shown in the literature dis- development of ASC opacities.7 Shiratani et al noted that
cussed below, reported rates of endothelial cell loss with EVO “unperforated ICLs cause cataracts, but placing a hole in the
are in a range similar to those observed with the MICL. center of the optic appears to prevent the development of a
secondary cataract. In addition, it was found that, even if the
The EVO ICL hole diameter is only 1.0 mm, cataracts can be prevented.
The EVO ICL Model V4c is a single piece posterior chamber The mechanism of cataract prevention is considered to be
phakic refractive intraocular lens designed with a central related to the aqueous humor circulation.”8
convex/concave optical zone diameter of 4.9–5.8 mm and Kawamorita et al performed a computer simulation of
a 360 µm central port. The EVO ICL Model V5 includes a aqueous flow utilizing thermal–hydraulic analysis software.
larger optical zone diameter of 5.0–6.1 mm. The central port Their results demonstrated increased circulation of aqueous
eliminates the need for iridotomy or iridectomy, which was humor to the anterior surface of the crystalline lens when
required by earlier models, because it allows sufficient aque- a 0.36 mm central hole was placed in the ICL, supporting
ous flow to maintain the normal physiology of the anterior the hypothesis that the central hole “may improve aqueous
segment of the eye. The EVO lens is produced from collamer, humor circulation, preventing secondary cataracts” as well
a proprietary hydroxyethyl methacrylate/porcine-collagen as eliminating the requirement for laser iridotomy.9 In a
based biocompatible polymer material and an ultraviolet second study, these authors determined that the flow around
absorbing chromophore. the crystalline lens reached a maximum with a hole size
of ~0.4 mm, indicating that “the current model, based on a
Literature review central hole size of 0.36 mm, was close to ideal.”10 Recently,
In order to assess preclinical testing and relevant clinical these authors also reported that “laser iridotomy is unneces-
experience with the EVO ICL when used as described in the sary from the viewpoint of theoretical aqueous circulation” in
Directions for Use,6 we performed a literature search with the presence of a central hole.11 Fernández-Vigo et al reported
the term “implantable collamer lens” utilizing PubMed.gov. a full three-dimensional study based on computational fluid
A total of 287 publications were returned and reviewed dynamics and concluded that “the circulation of aqueous
individually for relevance. Publications were excluded humor is influenced by the type of lens implanted, being
from further review for the following reasons: studies of more physiological in the central hole model than in the one
older ICL models without the central port (128), individual that requires an iridotomy.”12 These authors more recently
case reports (25), treatment of keratoconus (19), studies of provided an interesting theoretical paper describing a model
concomitant diagnostic or refractive procedures (13), pub- of the circulation of aqueous humor in eyes with and without
lications not in English (10), review articles (8), treatment phakic refractive lenses.13
of amblyopia (7), treatment of ametropia following corneal In summary, preclinical studies demonstrate that the
surgery or refractive surgery (5), correspondence (4), treat- 0.36 mm central port incorporated in the design of EVO
ment of pseudophakic ametropia (4), cataract surgery with provides sufficient aqueous flow to maintain normal fluid
ICL explantation (3), and treatment of presbyopia (1). The 60 dynamics in the eye and improves the circulation of aqueous
remaining publications were then selected for examination in around the crystalline lens, which may reduce the incidence
detail. References cited in these publications were reviewed of cataract formation in comparison to earlier ICL models
for potential relevance and seven publications were addition- without the central port.
ally reviewed on this basis for a total of 67 peer-reviewed
papers examined for this literature review. Optical effects
Uozato et al investigated the optical performance of the Hole
Preclinical studies ICL for various ICL powers and effective pupil diameters
Laboratory evaluations of the EVO ICL have focused on using a model eye composed of a wet cell filled with bal-
aqueous humor fluid dynamics and optical effects of the anced salt solution.14 Either the conventional ICL or the Hole
central port. ICL was placed in the posterior chamber of the model eye.

Clinical Ophthalmology 2018:12 submit your manuscript | www.dovepress.com

2429
Dovepress
Packer Dovepress

The authors concluded that differences in modulation transfer compromise the optical quality of the image as measured by
function (MTF) between the Hole ICL and the conventional MTF, wavefront aberrometry, or adaptive optics simulation.
ICL for various ICL powers and effective pupil diameters One study has shown that reflected stray light from eccentric
were small and clinically negligible. An investigation into the sources may result in positive dysphotopsia.
wavefront aberrations of the ICL with and without the central
port was conducted by Perez-Vives et al.15 No statistically Clinical studies: effectiveness
significant differences were found between conventional Measures of clinical effectiveness include postoperative
and Hole ICLs at any refractive power and pupil diameter. uncorrected distance visual acuity (UDVA), manifest
The authors concluded that “our study shows good and refractive spherical equivalent (MRSE), refractive predict-
comparable optical quality of conventional and Hole ICLs ability, and refractive stability. As of October 2018, a total
for all ICL powers evaluated. ICL decentering affects both of 27 peer-reviewed papers have provided effectiveness data
ICL models evaluated in the same manner. Although coma for the EVO ICL from prospective or retrospective case
aberration increased with ICL decentering, these values series, including data from a total of 1,905 eyes with average
were clinically negligible and have no significant effect on weighted follow-up of 12.5 months (Table 1).
the visual performance.” Perez-Vives et al used an adaptive Considering available data from the literature, includ-
optics simulator to study ICL models with and without the ing information from 16 publications on 1,023 eyes with
central port.16 They found no differences (P.0.05) in visual weighted average mean preoperative manifest refraction
acuity and contrast sensitivity, regardless of decentration. spherical equivalent of -9.81 D and weighted average follow
In an interesting attempt to study the optical effects of a up of 13.7 months, the reported efficacy index, which is the
central port design, Ferrer-Blasco et al performed a single- ratio of uncorrected postoperative visual acuity to preopera-
blind cross-over study comparing a standard contact lens to tive best-corrected acuity, ranges from 0.90 to 1.35, with a
a perforated contact lens designed to mimic the EVO ICL.17 weighted average of 1.04.
The authors concluded that “a contact lens having a central The weighted average uncorrected postoperative
hole provides good visual and optical quality outcomes visual acuity is 20/19 (logMAR -0.02), with a range from
comparable to those yielded by the same lens without a hole. 20/12 to 20/27 (logMAR -0.20 to 0.14). The reported
The results suggest that the impact of a central hole may be percentage of eyes within a half diopter of target averages
clinically negligible.” 90.8% and ranges from 72% to 100%, while the percentage
More recently, Dominguez-Vicent et al investigated the of eyes within 1 D of target averages 98.7% and ranges from
optical properties of the EVO V4c ICL and the EVO V5 ICL, 91.8% to 100%. Selected representative studies are discussed
which features an optic diameter up to 6.10 mm depending further below.
on the dioptric power. The authors concluded that “patients In a prospective study of 61 eyes of 32 patients implanted
with larger pupil diameters could benefit from implanta- with EVO, Yan et al reported, “At 2 years, the spherical equiv-
tion of the V5 model because this pIOL showed excellent alent refraction decreased from preoperative −14.62±4.29 D
in vitro optical quality with a larger optical diameter than to −0.90±0.95 D, with 79% of the eyes within ±0.50 D and
its previous design.”18 98% within ±1.00 D of the intended correction”.20
Noting that previous investigations had examined only In a multicenter retrospective case series including
on-axis optical quality, Eppig et al performed an optical 351 eyes of 351 subjects, representing the largest single
simulation to determine whether an ICL model with a central series, eyes were divided into groups based on the preopera-
hole would induce more photic phenomena compared to one tive degree of myopia: group 1 included 57 eyes with mani-
without a hole in response to off-axis light.19 The authors fest spherical equivalent less than -6 D, and group 2 included
concluded that the central hole may engender stray light and 294 eyes −6 D or more. In this study, Kamiya et al reported,
ghost images with off-axis illumination, although on-axis “Uncorrected and corrected visual acuities were −0.17±0.14
visual quality is unaffected. The authors also noted that “our and −0.21±0.10 logMAR in group 1, and −0.16±0.09
simulations showed that reflections with negative power ICLs and −0.21±0.08 logMAR in group 2, 1 year postopera-
are reduced compared to positive-power ICLs, and that the tively. In groups 1 and 2, 98% and 99% of eyes were within
effect decreases with increasing myopia correction.”19 1.0 D of the targeted correction. Manifest refraction changes
In summary, optical studies of the EVO ICL have of −0.12±0.34 D (group 1) and −0.18±0.43 D (group 2)
demonstrated that the presence of the central port does not occurred from 1 day to 1 year.”21 The full range of MRSE

2430 submit your manuscript | www.dovepress.com Clinical Ophthalmology 2018:12

Dovepress
Dovepress EVO review

Table 1 Measures of effectiveness include the efficacy index, uncorrected visual acuity (expressed as logMAR), and the accuracy of
refractive correction expressed as percentages within 0.5 and 1.0 D of target
References n eyes N patients Follow-up Efficacy Mean logMAR ±0.50 D ±1.0 D
months index UDVA
Shimizu et al 201248 20 20 6 1.03±0.30 -0.20±0.12 95.0% 100.0%
Alfonso et al 201325 138 70 6 1.00 0.009±0.062 98.5% 100.0%
Higueras-Esteban et al 2013 29
18 10 3 NR -0.07±0.11 100.0% 100.0%
Huseynova et al 201423 44 44 3 1.03 0.13±0.08 (0.10–0.30) NR NR
Lisa et al 2015 24
147 80 12 1.00 0.028±0.055 93.9% 100.0%
Fernández-Vigo et al 201649 50 25 3 NR 0.05±0.11 NR NR
Liu et al 201643
82 42 5 1.27 -0.03±0.08 NR NR
Shimizu et al 201622 32 32 60 NR -0.17±0.14 (0.15–0.30) 88.0% 96.0%
Cao et al 2016 50
63 32 6 1.11±0.19 0.118±0.096 NR NR
Cao et al 201651 78 39 6 NR 0.136±0.104 (0.000–0.301) NR NR
Iijima et al 2016 45
29 29 3 NR 0.04±0.21 (0.52–0.30) NR NR
Park et al 2017 (central port
52
46 NR 3 NR -0.01±0.06 NR NR
within 1, 2, or 3 port diameters 42 NR 3 NR -0.04±0.07 NR NR
of pupil center)
6 NR 3 NR -0.03±0.08 NR NR
Tian et al 201744 18 18 1 NR -0.02 NR NR
Kamiya et al 2017 21
57 57 12 NR -0.17±0.14 (-0.30–0.30) 93.0% 98.0%
(myopia ,6, $6 D) 294 294 12 NR -0.16±0.09 (-0.30–0.15) 94.0% 99.0%
Garcia-de La Rosa et al 2018 53
76 42 12 NR 0.12±0.12 NR NR
Hyun et al 201754 24 24 8 1.09 0.01±0.07 (-0.10–0.15) NR NR
Fernández-Vigo et al 2017 31
54 27 24 NR 0.02±0.10 (0.1–0.2) NR NR
Ganesh et al 2017 35
30 30 12 1.12 -0.022±0.021 NR NR
Pjano et al 201734 28 16 12 1.20 0.13 NR NR
Liu et al 201855 40 22 3 NR -0.04±0.05 NR NR
Zhao et al 2018 56
37 19 18 0.95 0.03±0.05 NR NR
Lee et al 2018 26
52 52 6 1.35±0.19 NR 88.0% 100.0%
Miao et al 201857 67 38 3 1.14±0.23 -0.01±0.09 72.0% 95.0%
Takahashi et al 2018 58
42 21 6 NR -0.03±0.20 100.0% 100.0%
Yan et al 201820 61 32 24 1.03±0.23 0.08 79.0% 98.0%
Kojima et al 2018 (V4c, V5) 67
23 23 6 1.16±0.22 -0.23±0.09 94.7% 100.0%
23 23 6 1.03±0.23 -0.19±0.12 84.2% 100.0%
Fernández-Vega-Cueto et al 184 92 36 0.90 NR 74.5% 91.8%
201836
Total number of eyes reported Weighted averages
1,905 12.5 1.04 -0.02 90.8% 98.7%
Abbreviations: NR, not reported; UDVA, uncorrected distance visual acuity.

corrected in this study extended from -0.5 to -18.63 D. 100%, 100%, and 85% of eyes, respectively …”22 Overall,
The authors concluded that “… we believe that the surgical these reports demonstrate excellent postoperative uncorrected
indication for ICL implantation can be expanded to include visual acuity, accuracy, refractive predictability, and stability
the correction of low-to-moderate myopia.”21 up to 5 years postoperatively.
In the study with the longest available follow-up,
Shimizu et al reported that “the postoperative UDVAs of Safety
the Hole ICL group were 20/20 or better 1, 3, and 6 months Reported safety outcomes include preservation of corrected
and 1, 3, and 5 years postoperatively, in 97%, 100%, 100%, distance visual acuity (CDVA), changes in IOP, changes

Clinical Ophthalmology 2018:12 submit your manuscript | www.dovepress.com

2431
Dovepress
 Table 2 Measures of safety include the safety index, the percentage of central corneal endothelial cell loss, and the rates of incidence for asymptomatic anterior subcapsular (ASC)
opacity, visual significant cataract, pupillary block, pigment dispersion, and secondary surgical intervention
Packer

2432
References n eyes N patients Follow-up Safety Endothelial ASC opacity Cataract Pupillary Pigment Secondary
months index cell loss block dispersion surgical
intervention

Dovepress
Shimizu et al 201248 20 20 6 1.13±0.24 -2.8% NR 0.0% 0.0% 0.0% 0.0%
38
Shimizu et al 2012 29 29 3 NR NR NR 0.0% 0.0% 0.0% 0.0%
Alfonso et al 201325 138 70 6 1.01 -8.5% NR 0.0% 0.0% 0.0% 0.0%
28
Gonzalez-Lopez et al 2013 100 56 1 1.16±0.24 NR NR NR 0.0% NR 0.0%
Higueras-Esteban et al 201329 18 10 3 NR NR NR NR 0.0% NR NR
23

submit your manuscript | www.dovepress.com

Huseynova et al 2014 44 44 3 1.14 +1.1% NR NR 0.0% NR NR
Kamiya et al 201559 23 23 12 NR NR NR 0.0% 0.0% 0.0% NR
60
Alfonso et al 2015 781 NR 6 NR NR NR 0.0% NR NR NR
Lisa et al 201524 147 80 12 1.04 -1.7% NR 0.0% 0.0% 0.0% 0.0%
30
Karandikar et al 2015 34 NR 12 1.15 -7.1% 2.9% 0.0% 0.0% 0.0% 5.9%
Brar et al 201532 342 NR 60 NR NR NR 0.0% NR NR 0.0%
Fernández-Vigo et al 201649 50 25 3 NR -6.8% 0.0% 0.0% 0.0% NR NR
43
Liu et al 2016 82 42 5 1.28 -4.83% NR NR NR NR NR
22
Shimizu et al 2016 32 32 60 NR -0.5%±5.4% 0.0% 0.0% 0.0% 0.0% 0.0%
Eissa et al 201661 54 27 18 NR NR NR NR 0.0% NR NR
35
Ganesh et al 2016 40 20 0.07 NR NR NR NR 0.0% NR NR
Bhandari et al 201533 10 5 9 1.14 -6.1% 3.1% 0.0% 0.0% NR 16.7%a
Cao et al 201650 63 32 6 1.42±0.34 -2.0% 0.0% 0.0% 0.0% 0.0% 0.0%
51
Cao et al 2016 78 39 6 NR -2.0% NR 0.0% 0.0% 0.0% 0.0%
45
Iijima et al 2016 29 29 3 NR NR NR 0.0% 0.0% 0.0% 0.0%
Senthil et al 201627 195 107 8 NR NR 0.5% 0.0% 0.5% 0.0% 0.5%
Chen et al 201662 22 22 6 NR NR NR 0.0% 0.0% 0.0% 0.0%
63
Rodríguez-Una et al 2017 763 384 7 NR NR NR NR 0.0% 0.0% 0.0%
Kamiya et al 201721 (myopia ,6, $6 D) 57 57 12 NR -0.1%±9.7% NR NR NR NR 0.9%
294 294 12 -0.1%±10.0%
Garcia-de La Rosa et al 201853 76 42 12 NR NR NR NR NR NR 0.0%
54
Hyun et al 2017 24 24 8 1.2 -3.7% 0.0% 0.0% 0.0% 0.0% 0.0%
Fernández-Vigo et al 201731 54 27 24 NR -5.9% 1.9% 0.0% NR NR NR
35
Ganesh et al 2017 30 30 12 1.24 -9.0% NR 0.0% 0.0% 0.0% 10.0%
Goukon et al 201764 34 34 24 NR -0.3% NR 0.0% 0.0% 0.0% 0.0%

Clinical Ophthalmology 2018:12

Dovepress
Dovepress EVO review

in ECD, ASC opacity or visually significant cataract, and

secondary surgical intervention. Table 2 provides a listing
of 38 peer-reviewed publications reporting safety data from

0.47%
7.2%
0.0%

0.0%
0.0%
0.0%
0.0%
0.0%
2.2%
NR

NR
retrospective or prospective series and includes information on
4,196 eyes with weighted average follow-up of 14.0 months.

CDVA
0.0%
0.0%
0.0%

0.0%
0.0%
0.0%
0.0%
0.0%

0.0%
NR

NR
The safety index is the ratio of postoperative CDVA to pre-

Overall incidence
operative CDVA. Seventeen publications, including data on
1,100 eyes with a weighted average preoperative manifest
refraction spherical equivalent of -9.60 D and a weighted

0.04%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
NR
average follow-up of 13.2 months, demonstrated a weighted
average safety index of 1.15, with a range from 1.01 to 1.42.
For example, Huseynova et al noted that “the safety index at
3 months was 1.07 (for group I [V4b]) and 1.14 (for group II
0.00%
0.0%
0.0%
0.0%

0.0%
0.0%
0.0%
0.0%
0.0%
NR

NR

[EVO]).”23 Lisa et al,24 Alfonso et al,25 and Lee et al26 reported

safety indices of 1.04, 1.01, and 1.38±0.22, respectively.
Seventeen studies including a total of 1,410 eyes reported
on lines of CDVA lost or gained with a weighted average
0.49%
0.0%
0.0%
0.0%
NR
NR
NR
NR

NR
NR
NR

follow-up of 14.0 months. Only 0.2% of eyes lost two or

more lines of CDVA, while 95.5% maintained or gained
lines of CDVA (Table 3).
-5.5%

-0.7%

-2.9%

-2.6%
6.6%

NR

NR
NR
NR
NR
NR

IOP
Weighted averages

Note: aBhandari et al expressed the incidence of secondary surgical intervention as a percentage of toric implants only.

A single case of pupillary block was reported by Senthil et al,

1.38±0.22

1.24±0.26
1.21±0.20

who noted that “the central aquaport of the ICL was blocked
1.19±0.2

with viscoelastic and inflammatory debris.”27 One month after

1.25

1.11

1.03

1.15
NR

NR

NR

surgery CDVA was 20/30 and IOP was 10 mmHg without ocular
hypotensive medication. Visual acuity and IOP were maintained
at 1 year; however, the pupil remained fixed and dilated. No
14.0

cases of pigment dispersion glaucoma have been reported.

15
12

18

24

36
1

6
6

6
6

Additional information on IOP may be gleaned from

individual publications. Gonzalez-Lopez et al reported that no
eye in their series of 100 eyes had an IOP greater than 30 mmHg
43
16
22
19
52
21
32
23
23
92

at any postoperative measurement.28 Higueras-Esteban et al noted

“a mild and transient increase in IOP during the first month; how-
184

ever, no chronically elevated IOP levels or pupillary block were

43
28
40
37
52
42
61
23
23

observed in either group.”29 Lisa et al stated that “in the present

study, we found no significant rise in IOP (.20 mmHg) in any
case, with stable IOP values during the 12-month follow-up ….
Fernández-Vega-Cueto et al 201836

when we evaluated variations in IOP over time and calculated

Total number of eyes reported

Abbreviation: NR, not reported.

67
Kojima et al 2018 (V4c, V5)

the change between preoperative and postoperative values, we

found that most eyes (74.1%) had no IOP variations or showed
Takahashi et al 201858

a reduction of 1–2 mmHg from the preoperative IOP.”24

66
Pjano et al 201734

Zhao et al 201856
Nam et al 201765

Titiyal et al 2017

Yan et al 201820
26
Lee et al 2018

ECD
A total of 21 studies including data on 1,476 eyes with
4,196

weighted average follow-up of 14.7 months demonstrated

Clinical Ophthalmology 2018:12 submit your manuscript | www.dovepress.com

2433
Dovepress
Packer Dovepress

Table 3 An important measure of safety is the lines of best-corrected visual acuity lost or gained at the study endpoint compared
to baseline
References -3 or more -2 -1 -0.5 No change +1 +2 +3 or more
Shimizu et al 2012 48
0 0 1 NR 12 5 2 0
Alfonso et al 201325 0 0 0 NR 113 21 4 0
Gonzalez-Lopez et al 2013 28
0 0 0 3 97
Lisa et al 201524 0 0 0 NR 116 21 5 5
Liu et al 201643 0 0 0 NR 30 26 18 8
Shimizu et al 2016 22
0 0 4 NR 9 11 2 0
Bhandari et al 201533 0 10
Cao et al 201650 0 63
Chen et al 201662 0 NR
Kamiya et al 201721 (myopia ,6, $6 D) 0 0 8 NR 36 13 0 0
0 1 26 NR 142 112 13 0
Garcia-de La Rosa et al 201853 0 1 4 NR 37 19 12 3
Ganesh et al 2017 35
0 30
Pjano et al 201734 0 1 0 NR 11 8 5 3
Lee et al 201826 0 7 45
Takahashi et al 201858 0 0 5 NR 23 12 2 0
Yan et al 201820 0 0 1 NR 14 33 10 3
Fernández-Vega-Cueto et al 201836 0 0 11 NR 145 16 9 3
Total number of eyes reported Numbers of eyes that lost or gained lines
1,410 0 3 57 3 834 343 145 25
Percentage of eyes that lost or gained lines 0.0% 0.2% 4.0% 0.2% 59.1% 24.3% 10.3% 1.8%
Abbreviation: NR, not reported.

mean endothelial cell loss of 2.6%. It is important to note Brar et al have reported on the incidence of cataract over
that this percentage reduction includes both the acute effect 5 years in 342 eyes implanted with EVO.32 The authors noted
of surgery as well as any chronic loss during the follow-up that “no V4c ICL was explanted due to cataract in this series.
period. A prospective study by Lisa et al of 147 eyes of 80 This may suggest the benefit of central hole in recent V4c ICL
subjects reported a 1.7% decline in ECD at 1 year.24 In the model in providing better nutrition to the natural lens, thus
study with the largest case series, Kamiya et al reported a preventing cataract genesis, although V4c model is launched
mean decrease of 0.1% in 351 eyes of 351 subjects followed recently so they have smaller follow-up as compared to the
for 1 year.21 Five-year data from Shimizu et al demonstrate older models.”32
that “the mean percentage of endothelial cell loss 5 years Five years following implantation, Shimizu reported a
postoperatively was 0.5%±5.4%.”22 zero incidence of ASC opacity and cataract.22

ASC opacity and cataract Secondary surgical intervention

Visually significant cataract related to insufficient vault has not Data from 28 publications of prospective or retrospective case
been reported in patients implanted with EVO. Overall, 11 pub- series demonstrated a 0.47% incidence of secondary surgical
lications including data on a total of 617 eyes with a weighted intervention in 2,970 eyes with weighted average follow-up of
average follow-up of 13 months reported a 0.49% incidence 16.7 months. Of the 14 total secondary surgical interventions
of asymptomatic ASC opacities. Karandikar et al reported one reported, 10 were related to rotation of a toric lens. Karandikar
visually insignificant ASC opacity at 1 year.30 Fernández-Vigo et al described two eyes,30 Bhandari et al reported one eye,33
et al reported that “we also recorded mild anterior subcapsular Pjano et al reported one eye,34 Kamiya et al reported one eye,21
cataract in one eye, but CDVA remained stable (0.1 logMAR) Ganesh et al reported three eyes,35 and Fernández-Vega-Cueto
at 2 years, so the lens was not explanted.”31 Senthil et al reported et al reported two eyes36 that required rotation of a toric lens.
one eye that developed localized ASC cataract following pupil- In their multicenter study of 351 eyes of 351 subjects
lary block treated with anterior chamber lavage.27 followed for 12 months, Kamiya et al noted that “an ICL

2434 submit your manuscript | www.dovepress.com Clinical Ophthalmology 2018:12

Dovepress
Dovepress EVO review

exchange occurred in two eyes (0.7%) in group 2 (high validated questionnaire,42 noting that “during the early
myopia .–6 D), due to incorrect initial sizing or power.”21 postoperative follow-up period, halos occurred in 23 patients
Pjano et al reported one eye that developed a retinal detach- (54.8%). With time, halos gradually disappeared at 3 months
ment 3 months after implantation: “The patient had high degen- after operation without any treatments.”43
erative myopia and preoperatively underwent prophylactic In their prospective comparative study of lenses with
laser photocoagulation on both eyes. Pars plana vitrectomy was and without the central port, Tian et al reported that “visual
successfully performed, with no further complications on this fatigue and halo occurred in both groups, visual fatigue
eye.”34 Senthil et al performed anterior chamber lavage to resolve occurred in the case of near vision, the incidence of visual
pupillary block related to retained viscoelastic in one eye.27 fatigue was 25% in the ICL V4 group and 22.2% in the ICL
Steinwender et al reported cataract in eleven eyes of eight V4c group; the incidence of halo was 65% in the ICL V4
patients in the immediate postoperative period as a result of an group and 55.6% in the ICL V4c group. These incidences
irrigation technique, “… producing an enforced stream through showed no significant difference between two groups.”44
the pIOL hole onto the lens capsule …” The authors noted that Overall, patient-reported outcomes reflect the presence of
“after changing surgical technique to very gentle irrigation and some visual disturbances in the early postoperative period
keeping the cannula near the main incision, more than 90 pIOL that decrease with time.
implantations were performed in the clinic during a follow-up of Authors have reported high levels of patient satisfaction
14 months, with no further case of anterior subcapsular cataract with EVO implantation. For example, Iijima et al administered
occurring.”37 We have therefore attributed these events to the the National Eye Institute Refractive Error Quality of Life
surgical technique and not to the EVO ICL and have not included Instrument-42 to 29 patients at 3 months postoperative and
these events in the overall rates reported in this review. This reported a mean satisfaction score of 79.3.45 In their 2-year
report highlights the importance of avoiding operative trauma study of 32 patients, Yan et al reported an overall satisfaction
to the crystalline lens during implantation. score ranging from 0 = very unsatisfied to 10 = the most
satisfied and noted “All patients were satisfied with their
Quality of vision visual performance, and 71% were more than satisfied
Shimizu et al have provided data on higher-order aberrations (very satisfied). The mean score of overall satisfaction
and contrast sensitivity and found that the central port had no was 9.27±0.87 (range, 8–10). And all the patients chose
significant impact (P.0.05).38 Kamiya et al reproduced these ‘yes’, when asked ‘Would you consider recommending this
findings that EVO “implantation appears to be essentially operation to patients like you?’”20
equivalent in the optical quality variables to conventional To date, over 500,000 EVO ICLs with the central port
ICL implantation, suggesting that the presence of the central design out of a historic total of 900,000 total ICLs have been
artificial hole does not significantly affect the optical quality distributed globally in countries including Canada, Japan, and
and the intraocular scattering after surgery.”39 Huseynova those in the European Union, Asia, Latin America, and Africa.
et al similarly reported no significant differences in wavefront Patient satisfaction reported in the manufacturer’s registry has
aberrations between EVO and conventional ICL subjects.23 remained very high, with 99.4% of 1,542 patients surveyed
stating that they would elect to have the surgery again.46
Patient-reported outcomes
Eom et al utilized a modification of a validated questionnaire40 Conclusion
and reported that “of 29 total eyes, 18 (62.1%) experienced As McLeod has pointed out, “Phakic intraocular lenses
glare with the mean duration of 3.0±3.4 months (range, can provide optically superb correction of relatively high
1–12 months), 16 (55.2%) experienced halos with the degrees of ametropia that lie well beyond the recommended
mean duration of 3.1±3.6 months (range, 1–12 months), range for keratorefractive procedures, such as laser in situ
10 (34.5%) experienced starbursts with the mean duration keratomileusis and photorefractive keratectomy.”47 High
of 1.8±0.8 months (range, 1–3 months) and 15 (51.7%) levels of postoperative uncorrected visual acuity, refractive
experienced ring-shaped dysphotopsia with the mean dura- predictability, and stability demonstrate the effectiveness
tion of 2.9±3.8 months (range, 1–12 months) after hole ICL of the EVO ICL. Safety data suggest reduced rates of ASC
implantation.”41 These findings suggest that undesirable cataract and pupillary block. Improved safety and effective-
visual effects tend to disappear over time. Liu et al offered ness across a broad range of refractive errors make EVO an
confirmation in their retrospective study utilizing a different attractive option for surgeons and patients.

Clinical Ophthalmology 2018:12 submit your manuscript | www.dovepress.com

2435
Dovepress
Packer Dovepress

Disclosure 15. Pérez-Vives C, Ferrer-Blasco T, Madrid-Costa D, García-Lázaro S,

Montés-Micó R. Optical quality comparison of conventional and hole-
The author is a consultant to STAAR Surgical Company, visian implantable collamer lens at different degrees of decentering.
Advanced Vision Science (Santen Pharmaceutical Co., Am J Ophthalmol. 2013;156(1):69–76.
Ltd.), Alcon Laboratories (Novartis AG), Bausch & Lomb 16. Pérez-Vives C, Ferrer-Blasco T, Madrid-Costa D, García-Lázaro S,
Montés-Micó R. Visual quality comparison of conventional and Hole-
(Bausch Health Companies Inc.), and Rayner Intraocular Visian implantable collamer lens at different degrees of decentering.
Lenses Ltd. The author reports no other conflicts of interest Br J Ophthalmol. 2014;98(1):59–64.
17. Ferrer-Blasco T, García-Lázaro S, Belda-Salmerón L, Albarrán-
in this work. Diego C, Montés-Micó R. Intra-eye visual function comparison with and
without a central hole contact lens-based system: potential applications
to ICL design. J Refract Surg. 2013;29(10):702–707.
References 18. Domínguez-Vicent A, Ferrer-Blasco T, Pérez-Vives C, Esteve-
1. Packer M. Meta-analysis and review: effectiveness, safety, and central Taboada JJ, Montés-Micó R. Optical quality comparison between
port design of the intraocular collamer lens. Clin Ophthalmol. 2016;10: 2 collagen copolymer posterior chamber phakic intraocular lens designs.
1059–1077. J Cataract Refract Surg. 2015;41(6):1268–1278.
2. Visian ICL (Implantable Collamer Lens) for Myopia: Directions 19. Eppig T, Spira C, Tsintarakis T, et al. Ghost-image analysis in phakic
for Use. STAAR Surgical. Available from: http://staar.com/file/ intraocular lenses with central hole as a potential cause of dysphotopsia.
PKG-02012_Rev_2_DFU-for-MICL-Visian-ICL.pdf. Accessed J Cataract Refract Surg. 2015;41(11):2552–2559.
April 3, 2018. 20. Yan Z, Miao H, Zhao F, et al. Two-year outcomes of visian implant-
3. Moya T, Javaloy J, Montés-Micó R, Beltrán J, Muñoz G, Montalbán R. able collamer lens with a central hole for correcting high myopia.
Implantable collamer lens for myopia: assessment 12 years after implan- J Ophthalmol. 2018;2018:1–9.
tation. J Refract Surg. 2015;31(8):548–556. 21. Kamiya K, Shimizu K, Igarashi A. Posterior chamber phakic
4. Bourne WM, Nelson LR, Hodge DO. Central corneal endothelial cell intraocular lens implantation: comparative, multicentre study in
changes over a ten-year period. Invest Ophthalmol Vis Sci. 1997;38(3): 351 eyes with low-to-moderate or high myopia. Br J Ophthalmol.
779–782. 2018;102(2):177–181.
5. US Department of Health and Human Services; Food and Drug 22. Shimizu K, Kamiya K, Igarashi A, Kobashi H. Long-term comparison
Administration; Center for Devices and Radiological Health; Medical of posterior chamber phakic intraocular lens with and without a central
Devices Advisory Committee. Proceedings of the Opthalmic Devices hole (Hole ICL and Conventional ICL) implantation for moderate
Panel Meeting, March 14, 2014. Available from: https://wayback. to high myopia and myopic astigmatism: consort-compliant article.
archive-it.org/7993/20170114045353/http://www.fda.gov/downloads/ Medicine. 2016;95(14):e3270.
AdvisoryCommittees/CommitteesMeetingMaterials/MedicalDevices/ 23. Huseynova T, Ozaki S, Ishizuka T, Mita M, Tomita M. Compara-
MedicalDevicesAdvisoryCommittee/OphthalmicDevicesPanel/ tive study of 2 types of implantable collamer lenses, 1 with and 1
UCM392476.pdf. Accessed November 19, 2018. without a central artificial hole. Am J Ophthalmol. 2014;157(6):
6. Staar Surgical. SURGICALEVO Visian ICL; Life with EVO; Life with 1136–1143.
Visian ICL. Available from: https://uk.discovericl.com/life-with-evo. 24. Lisa C, Naveiras M, Alfonso-Bartolozzi B, Belda-Salmerón L,
Accessed May 21, 2018. Montés-Micó R, Alfonso JF. Posterior chamber collagen copolymer
7. Fujisawa K, Shimizu K, Uga S, et al. Changes in the crystalline lens phakic intraocular lens with a central hole to correct myopia: one-year
resulting from insertion of a phakic IOL (ICL) into the porcine eye. follow-up. J Cataract Refract Surg. 2015;41(6):1153–1159.
Graefes Arch Clin Exp Ophthalmol. 2007;245(1):114–122. 25. Alfonso JF, Lisa C, Fernández-Vega Cueto L, Belda-Salmerón L,
8. Shiratani T, Shimizu K, Fujisawa K, Uga S, Nagano K, Murakami Y. Madrid-Costa D, Montés-Micó R. Clinical outcomes after implantation
Crystalline lens changes in porcine eyes with implanted phakic IOL of a posterior chamber collagen copolymer phakic intraocular lens with a
(ICL) with a central hole. Graefes Arch Clin Exp Ophthalmol. 2008; central hole for myopic correction. J Cataract Refract Surg. 2013;39(6):
246(5):719–728. 915–921.
9. Kawamorita T, Uozato H, Shimizu K. Fluid dynamics simulation of 26. Lee H, Kang DSY, Choi JY, et al. Rotational stability and visual
aqueous humour in a posterior-chamber phakic intraocular lens with a outcomes of V4c toric phakic intraocular lenses. J Refract Surg. 2018;
central perforation. Graefes Arch Clin Exp Ophthalmol. 2012;250(6): 34(7):489–496.
935–939. 27. Senthil S, Choudhari NS, Vaddavalli PK, Murthy S, Reddy JC,
10. Kawamorita T, Shimizu K, Shoji N. Effect of hole size on fluid Garudadri CS. Etiology and management of raised intraocular pressure
dynamics of a posterior-chamber phakic intraocular lens with a central following posterior chamber phakic intraocular lens implantation in
perforation by using computational fluid dynamics. Graefes Arch Clin myopic eyes. PLoS One. 2016;11(11):e0165469.
Exp Ophthalmol. 2016;254(4):739–744. 28. Gonzalez-Lopez F, Bilbao-Calabuig R, Mompean B, et al. Intraocular
11. Kawamorita T, Shimizu K, Shoji N. Theoretical study on the need pressure during the early postoperative period after 100 consecutive
for laser iridotomy in an implantable collamer lens with a hole using implantations of posterior chamber phakic intraocular lenses with a
computational fluid dynamics. Eye. 2017;31(5):795–801. central hole. J Cataract Refract Surg. 2013;39(12):1859–1863.
12. Fernández-Vigo JI, Macarro-Merino A, Fernández-Francos J, et al. 29. Higueras-Esteban A, Ortiz-Gomariz A, Gutiérrez-Ortega R, et al.
Computational study of aqueous humor dynamics assessing the vault Intraocular pressure after implantation of the Visian Implantable Col-
and the pupil diameter in two posterior-chamber phakic lenses. Invest lamer Lens with CentraFLOW without iridotomy. Am J Ophthalmol.
Ophthalmol Vis Sci. 2016;57(11):4625–4631. 2013;156(4):800–805.
13. Fernández-Vigo JI, Marcos AC, Agujetas R, et al. Computational 30. Karandikar S, Bhandari V, Reddy J. Outcomes of implantable collamer
simulation of aqueous humour dynamics in the presence of a posterior- lens V4 and V4c for correction of high myopia – a case series. Nepal
chamber versus iris-fixed phakic intraocular lens. PLoS One. 2018; J Ophthalmol. 2015;7(14):164–172.
13(8):e0202128. 31. Fernández-Vigo JI, Macarro-Merino A, Fernández-Vigo C, et al.
14. Uozato H, Shimizu K, Kawamorita T, Ohmoto F. Modulation transfer Impacts of implantable collamer lens V4c placement on angle measure-
function of intraocular collamer lens with a central artificial hole. ments made by optical coherence tomography: two-year follow-up.
Graefes Arch Clin Exp Ophthalmol. 2011;249(7):1081–1085. Am J Ophthalmol. 2017;181:37–45.

2436 submit your manuscript | www.dovepress.com Clinical Ophthalmology 2018:12

Dovepress
Dovepress EVO review

32. Brar S, Ganeresh S, Pandey R. Incidence & factors responsible for 50. Cao X, Wu W, Wang Y, Xie C, Tong J, Shen Y. Posterior chamber collagen
Implantable Collamer Lens (ICL) explantation & outcomes of further copolymer phakic intraocular lens with a central hole for moderate-
management – 5 year retrospective study. EC Ophthalmology. 2015; to-high myopia: first experience in China. Medicine. 2016;95(36):
3(1):231–239. e4641.
33. Bhandari V, Karandikar S, Reddy JK, Relekar K. Implantable collamer 51. Cao X, Wu W, Wang Y, Xie C, Shen Y. Comparison over time of vault
lens V4b and V4c for correction of high myopia. J Curr Ophthalmol. in Chinese eyes receiving implantable contact lenses with or without a
2015;27(3–4):76–81. central hole. Am J Ophthalmol. 2016;172:111–117.
34. Pjano MA, Pidro A, Biscevic A, Grisevic S, Pandzic B, Cerovic V. 52. Park MJ, Jeon HM, Lee KH, Han SY. Comparison of postoperative
Refractive outcomes of posterior chamber phakic intraocular lens optical quality according to the degree of decentering of V4c implant-
implantation for correction of myopia and myopic astigmatism. able collamer lens. Int J Ophthalmol. 2017;10(4):619–623.
Med Arch. 2017;71(2):93–96. 53. Garcia-de La Rosa G, Olivo-Payne A, Serna-Ojeda JC, et al. Anterior
35. Ganesh S, Brar S, Pawar A. Matched population comparison of visual segment optical coherence tomography angle and vault analysis after
outcomes and patient satisfaction between 3 modalities for the correction toric and non-toric implantable collamer lens V4c implantation in
of low to moderate myopic astigmatism. Clin Ophthalmol. 2017;11: patients with high myopia. Br J Ophthalmol. 2018;102(4):544–548.
1253–1263. 54. Hyun J, Lim DH, Eo DR, Hwang S, Chung ES, Chung TY, Dr E.
36. Fernández-Vega-Cueto L, Lisa C, Esteve-Taboada JJ, Montés-Micó R, A comparison of visual outcome and rotational stability of two types
Alfonso JF. Implantable collamer lens with central hole: 3-year of toric implantable collamer lenses (TICL): V4 versus V4c. PLoS One.
follow-up. Clin Ophthalmol. 2018;12:2015–2029. 2017;12(8):e0183335.
37. Steinwender G, Varna-Tigka K, Shajari M, Kohnen T. Anterior sub- 55. Liu HT, Zhou Z, Luo WQ, et al. Comparison of optical quality after
capsular cataract caused by forceful irrigation during implantation of a implantable collamer lens implantation and wavefront-guided laser in
posterior chamber phakic intraocular lens with a central hole. J Cataract situ keratomileusis. Int J Ophthalmol. 2018;11(4):656–661.
Refract Surg. 2017;43(7):969–974. 56. Zhao J, Luo D, Sun Y, et al. Implanting a posterior chamber phakic
38. Shimizu K, Kamiya K, Igarashi A, Shiratani T. Intraindividual compari- intraocular lens in highly myopic eyes with peripheral primary iris and
son of visual performance after posterior chamber phakic intraocular ciliary body cysts. Eur J Ophthalmol. 2018;1:112067211876644.
lens with and without a central hole implantation for moderate to high 57. Miao H, Chen X, Tian M, Chen Y, Wang X, Zhou X. Refractive
myopia. Am J Ophthalmol. 2012;154(3):486–494. outcomes and optical quality after implantation of posterior chamber
39. Kamiya K, Shimizu K, Saito A, Igarashi A, Kobashi H. Comparison phakic implantable collamer lens with a central hole (ICL V4c). BMC
of optical quality and intraocular scattering after posterior chamber Ophthalmol. 2018;18(1):141.
phakic intraocular lens with and without a central hole (Hole ICL and 58. Takahashi M, Kamiya K, Shoji N, Kato S, Igarashi A, Shimizu K.
Conventional ICL) implantation using the double-pass instrument. Intentional undercorrection by implantation of posterior chamber phakic
PLoS One. 2013;8(6):e66846. intraocular lens with a central hole (Hole ICL) for early presbyopia.
40. Mcalinden C, Pesudovs K, Moore JE. The development of an instrument Biomed Res Int. 2018;2018:1–5.
to measure quality of vision: the Quality of Vision (QoV) questionnaire. 59. Kamiya K, Shimizu K, Ando W, Igarashi A, Iijima K, Koh A.
Invest Ophthalmol Vis Sci. 2010;51(11):5537–5545. Comparison of vault after implantation of posterior chamber phakic
41. Eom Y, Kim DW, Ryu D, et al. Ring-shaped dysphotopsia associated intraocular lens with and without a central hole. J Cataract Refract
with posterior chamber phakic implantable collamer lenses with a Surg. 2015;41(1):67–72.
central hole. Acta Ophthalmol. 2017;95(3):e170–e178. 60. Alfonso JF, Lisa C, Fernández-Vega L, Almanzar D, Pérez-Vives C,
42. Mcghee CN, Craig JP, Sachdev N, Weed KH, Brown AD. Functional, Montés-Micó R. Prevalence of cataract after collagen copolymer phakic
psychological, and satisfaction outcomes of laser in situ keratomileusis intraocular lens implantation for myopia, hyperopia, and astigmatism.
for high myopia. J Cataract Refract Surg. 2000;26(4):497–509. J Cataract Refract Surg. 2015;41(4):800–805.
43. Liu T, Linghu S, Pan L, Shi R. Effects of V4c-ICL implantation on 61. Eissa SA, Sadek SH, El-Deeb MW. Anterior chamber angle evaluation
myopic patients’ vision-related daily activities. J Ophthalmol. 2016; following phakic posterior chamber collamer lens with centraFLOW and
2016:5717932. its correlation with ICL vault and intraocular pressure. J Ophthalmol.
44. Tian Y, Jiang HB, Jiang J, Wen D, Xia XB, Song WT. Comparison of 2016;2016:1383289.
implantable collamer lens visian ICL V4 and ICL V4c for high myopia: 62. Chen H, Niu G, Fan Y, Ma J. Comparison of intraocular pressure and-
a cohort study. Medicine. 2017;96(25):e7294. vault after implantation of implantable collamer lens with and without
45. Iijima A, Shimizu K, Yamagishi M, Kobashi H, Igarashi A, Kamiya K. a central hole. BMC Ophthalmol. 2016;16(1):203.
Assessment of subjective intraocular forward scattering and quality of 63. Rodríguez-Una I, Rodríguez-Calvo PP, Fernández-Vega Cueto L,
vision after posterior chamber phakic intraocular lens with a central hole Lisa C, Fernández-Vega Cueto A, Alfonso JF. Intraocular pressure
(Hole ICL) implantation. Acta Ophthalmol. 2016;94(8):e716–e720. after implantation of a phakic collamer intraocular lens with a central
46. Staar Surgical. Patient Survey; Visian ICL™ (Implantable Collamer hole. J Refract Surg. 2017;33(4):244–249.
Lens) For Nearsightedness; Facts You Need To Know About STAAR 64. Goukon H, Kamiya K, Shimizu K, Igarashi A. Comparison of corneal
Surgical’s Visian ICL; Surgery; Patient Information Booklet. Available endothelial cell density and morphology after posterior chamber pha-
from: https://www.staar.com/our-resources. Accessed November 19, kic intraocular lens implantation with and without a central hole. Br J
2018. Ophthalmol. 2017;101(11):1461–1465.
47. Mcleod SD. Long-term clinical outcomes and cataract formation rates 65. Nam SW, Lim DH, Hyun J, Chung ES, Chung TY. Buffering zone
after posterior phakic lens implantation for myopia. JAMA Ophthalmol. of implantable collamer lens sizing in V4c. BMC Ophthalmol. 2017;
2016;134(5):494–495. 17(1):260.
48. Shimizu K, Kamiya K, Igarashi A, Shiratani T. Early clinical outcomes 66. Titiyal JS, Kaur M, Sahu S, Sharma N, Sinha R. Real-time assess-
of implantation of posterior chamber phakic intraocular lens with a ment of intraoperative vaulting in implantable collamer lens and cor-
central hole (Hole ICL) for moderate to high myopia. Br J Ophthalmol. relation with postoperative vaulting. Eur J Ophthalmol. 2017;27(1):
2012;96(3):409–412. 21–25.
49. Fernández-Vigo JI, Macarro-Merino A, Fernández-Vigo C, et al. 67. Kojima T, Kitazawa Y, Nakamura T, et al. Prospective randomized
Effects of implantable collamer lens V4c placement on iridocorneal multicenter comparison of the clinical outcomes of V4c and V5
angle measurements by Fourier-domain optical coherence tomography. implantable collamer lenses: a contralateral eye study. J Ophthalmol.
Am J Ophthalmol. 2016;162:43–52. 2018;2018:7623829.

Clinical Ophthalmology 2018:12 submit your manuscript | www.dovepress.com

2437
Dovepress
Packer Dovepress

Clinical Ophthalmology Dovepress

Publish your work in this journal
Clinical Ophthalmology is an international, peer-reviewed journal PubMed Central and CAS, and is the official journal of The Society of
covering all subspecialties within ophthalmology. Key topics include: Clinical Ophthalmology (SCO). The manuscript management system
Optometry; Visual science; Pharmacology and drug therapy in eye is completely online and includes a very quick and fair peer-review
diseases; Basic Sciences; Primary and Secondary eye care; Patient system, which is all easy to use. Visit http://www.dovepress.com/
Safety and Quality of Care Improvements. This journal is indexed on testimonials.php to read real quotes from published authors.
Submit your manuscript here: http://www.dovepress.com/clinical-ophthalmology-journal

2438 submit your manuscript | www.dovepress.com Clinical Ophthalmology 2018:12

Dovepress