Journal of Refractive Surgery

Original Article Supplemental Data

Five-Year Follow-up of Correction of Myopia: Posterior Chamber Phakic Intraocular Lens With a Central Port Design

José F. Alfonso, MD, PhD; Luis Fernández-Vega-Cueto, MD, PhD; Belén Alfonso-Bartolozzi, MD; Robert Montés-Micó, PhD; Luis Fernández-Vega, MD, PhD

Abstract

PURPOSE:

To assess the long-term correction of moderate to high myopia using a posterior chamber phakic intraocular lens with a central port design.

METHODS:

Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, intraocular pressure (IOP), endothelial cell density (ECD), vault, and adverse events over a 5-year period were evaluated retrospectively.

RESULTS:

A total of 147 eyes (83 patients) were evaluated. Mean postoperative UDVA and CDVA were 0.05 ± 0.11 and 0.02 ± 0.08 logMAR at 1 year and 0.13 ± 0.18 and 0.02 ± 0.09 logMAR at 5 years, respectively. More than 95% of eyes achieved CDVA of 20/25 or better at both follow-up periods. CDVA was unchanged or improved from one to three or more lines in all eyes. Preoperatively, mean spherical equivalent (SE) was −9.20 ± 3.02 diopters (D). At 1 year, the mean SE was −0.17 ± 0.26 D, with 91.53% of eyes within ±0.50 D and 100% of eyes within ±1.00 D of the target. At 5 years, the mean SE was −0.44 ± 0.47 D, with 67.4% of eyes within ±0.50 D and 90.1% of eyes within ±1.00 D of the target. Mean IOP was 12.74 ± 1.65 and 13.0 ± 2.03 mm Hg, at 1 and 5 years, respectively. No significant rise in IOP (> 20 mm Hg) occurred during the follow-up period. Mean ECD was 2,696 ± 358 and 2,645 ± 359 cells/mm2 at 1 and 5 years, respectively, representing a non-significant loss of 0.43% from preoperative values (P = .304). Mean vault changed significantly from 398 ± 187 µm at 1 year to 340 ± 163 µm at 5 years (P < .001). No intraoperative or postoperative complications or adverse events occurred during the follow-up period.

CONCLUSIONS:

The good long-term outcomes found in this study support the use of this lens with a central port design for the correction of moderate to high myopia.

[J Refract Surg. 2019;35(3):169–176.]

Abstract

PURPOSE:

To assess the long-term correction of moderate to high myopia using a posterior chamber phakic intraocular lens with a central port design.

METHODS:

Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, intraocular pressure (IOP), endothelial cell density (ECD), vault, and adverse events over a 5-year period were evaluated retrospectively.

RESULTS:

A total of 147 eyes (83 patients) were evaluated. Mean postoperative UDVA and CDVA were 0.05 ± 0.11 and 0.02 ± 0.08 logMAR at 1 year and 0.13 ± 0.18 and 0.02 ± 0.09 logMAR at 5 years, respectively. More than 95% of eyes achieved CDVA of 20/25 or better at both follow-up periods. CDVA was unchanged or improved from one to three or more lines in all eyes. Preoperatively, mean spherical equivalent (SE) was −9.20 ± 3.02 diopters (D). At 1 year, the mean SE was −0.17 ± 0.26 D, with 91.53% of eyes within ±0.50 D and 100% of eyes within ±1.00 D of the target. At 5 years, the mean SE was −0.44 ± 0.47 D, with 67.4% of eyes within ±0.50 D and 90.1% of eyes within ±1.00 D of the target. Mean IOP was 12.74 ± 1.65 and 13.0 ± 2.03 mm Hg, at 1 and 5 years, respectively. No significant rise in IOP (> 20 mm Hg) occurred during the follow-up period. Mean ECD was 2,696 ± 358 and 2,645 ± 359 cells/mm2 at 1 and 5 years, respectively, representing a non-significant loss of 0.43% from preoperative values (P = .304). Mean vault changed significantly from 398 ± 187 µm at 1 year to 340 ± 163 µm at 5 years (P < .001). No intraoperative or postoperative complications or adverse events occurred during the follow-up period.

CONCLUSIONS:

The good long-term outcomes found in this study support the use of this lens with a central port design for the correction of moderate to high myopia.

[J Refract Surg. 2019;35(3):169–176.]

Phakic intraocular lenses have been used widely to correct moderate to high ametropia. They have several advantages, such as fast visual recovery, excellent refractive accuracy and stability, improved visual acuity, and reversibility.

The Visian Implantable Collamer Lens (ICL) (STAAR Surgical AG, Nidau, Switzerland) is a posterior chamber phakic lens that allows correction of myopia, hyperopia, and astigmatism. The most recent model of this lens (V4c) incorporates a central port or hole of 0.36 mm (KS-Aquaport). The port allows physiologic flow of aqueous without the need for Nd:YAG peripheral iridotomies or intraoperative iridectomies. Short-term (6-month) studies published in 2012 by Shimizu et al.1 with 20 eyes and in 2013 by Alfonso et al.2 with 138 eyes have shown good outcomes in moderate to severe myopia based on uncorrected and corrected visual acuities, refractive predictability and stability, and safety. Authors of studies with follow-up from 9 months to 5 years and sample sizes from 10 to 294 eyes3–19 have uniformly concluded that implantation of the V4c ICL with a central port is a safe and effective surgical option for the treatment of moderate to high myopia.

In any refractive procedure, long-term postoperative follow-up examinations are needed to prevent and monitor complications, and to establish long-term safety and effectiveness. The purpose of this study was to assess the long-term clinical and refractive outcomes of the V4c Visian ICL for the correction of moderate to high myopia.

Patients and Methods

This retrospective chart review study included 83 patients (147 eyes) who underwent implantation of the Visian ICL for the correction of myopia at Fernández-Vega Ophthalmological Institute, Oviedo, Spain, from November 2011 to January 2013. The study followed the tenets of the Declaration of Helsinki. Written informed consent was obtained from all patients after receiving a full explanation of the nature and possible consequences of the surgery. The inclusion and exclusion criteria were those adopted for all patients undergoing ICL implantation during this time period. Inclusion criteria were stable refraction with a myopic refractive error in the range correctable with the V4c ICL (from −18.00 to −0.50 diopters [D]) and a clear central cornea. Exclusion criteria were age younger than 20 years, anterior chamber depth from the corneal endothelium of less than 2.8 mm, endothelial cell density (ECD) of less than 2,000 cell/mm2, mesopic pupil larger than 7 mm, cataract, history of glaucoma or retinal detachment, macular degeneration or retinopathy, neuro-ophthalmic disease, or any history of ocular inflammation.

Preoperative Assessment

Before ICL implantation, patients had a complete ophthalmologic examination, including uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest and cycloplegic refractions, slit-lamp examination, keratometry, corneal topography, pachymetry and anterior chamber depth measurement (Sirius; CSO Ophthalmic, Florence, Italy), ECD measurement (SP 3000P; Topcon Europe Medical BV, Capelle aan den Ijssel, The Netherlands), intraocular pressure (IOP) measurement by Goldmann applanation tonometry, and anterior segment optical coherence tomography (Visante; Carl Zeiss Meditec AG, Jena, Germany).

ICL and Surgical Technique

All included eyes underwent implantation of the Visian V4c ICL model for myopia. This posterior chamber lens is composed of Collamer, a flexible, hydrophilic, biocompatible material composed of collagen and hydroxyethylmethacrylate with an ultraviolet-absorbing chromophore. The lens has a plate-haptic design with a central convex/concave optical zone and incorporates anterior vault to avoid contact with the crystalline lens. The model V4c ICL includes a central port 0.36 mm in diameter in the center of the optic (the KS-Aquaport), which maintains physiologic aqueous humor circulation and obviates the need for laser or surgical peripheral iridotomy or iridectomy. The V4c ICL is available in four overall lengths (12.1, 12.6, 13.2, and 13.7 mm) and is designed to correct myopia in a power range of −0.50 to −18.00 D.

Emmetropia was selected as the postoperative target refraction for all eyes. ICL power calculation was performed using a modified vertex formula provided by the manufacturer (STAAR Surgical AG). ICL size was individually determined based on the horizontal white-to-white distance and anterior chamber depth measured by Scheimpflug photography, following the manufacturer's recommendations. Angle-to-angle distance was measured with OCT.

All surgeries were performed by the same experienced surgeon (JFA) on the steep meridian through a clear corneal tunnel incision as a function of the refractive astigmatism, as follows: one single incision of 3 mm for 0.75 to 1.00 D; two opposite clear corneal incisions of 3 mm for 1.25 to 1.50 D; two opposite clear corneal incisions of 3.2 mm for 1.75 to 2.00 D; and two opposite clear corneal incisions of 3.4 mm for 2.25 to 2.50 D. Anesthesia was obtained with a peribulbar block. Mydriatic eye drops and povidone-iodine 5% were applied 30 and 5 minutes before surgery, respectively. The anterior chamber was filled with sodium hyaluronate 1%, which was completely removed at the end of the surgery. Tobramycin and dexamethasone 0.1% eye drops were used four times a day for 7 days, after which diclofenac sodium eye drops were started four times a day for 2 weeks. The second eye had surgery within 1 week of the first eye.

Postoperative Assessment

Postoperative follow-up visits were scheduled at 1 day, 1 week, and 1, 3, 12, and 60 months. Outcomes from the preoperative and 12- and 60-month visits are provided in this report. The examinations included measurement of UDVA and CDVA, manifest refraction, slit-lamp examination, IOP, ECD, and funduscopy. The central distance between the ICL and the crystalline lens (vault) was assessed using OCT. The vault between the crystalline lens and the ICL was measured perpendicular to the lens apex.

Assessment was based on a comparison of preoperative and postoperative visual acuities, both UDVA (efficacy) and CDVA (safety), and the attempted versus achieved refractive outcome (predictability). The efficacy index (defined as the ratio between the postoperative UDVA and the preoperative CDVA) and the safety index (defined as the ratio between the postoperative CDVA and the preoperative CDVA) were calculated based on Snellen decimal visual acuity values. All recorded visual acuity data were converted to logMAR values for statistical analyses.

To place the outcomes found in the current study in perspective, we undertook a review of the literature by searching PubMed (U.S. National Library of Medicine). We limited our search to English language publications and peer-reviewed scientific studies in which the V4c ICL model was used. No date restriction was used in the electronic search. The date of the last search was August 15, 2018. After searching the literature using these criteria, 66 articles were found and analyzed. These publications included clinical prospective and retrospective studies, case reports, experimental/laboratory/theoretical studies, letters to the editor, and reviews/meta-analyses. Because the current study aimed to assess the long-term outcomes of the V4c ICL model, we considered only those clinical studies with a minimum follow-up of 6 months. A total of 20 studies was reviewed. Table A (available in the online version of this article) lists the studies, including author, year of publication, sample size, patient age, and preoperative SE.

Studies Reporting Data for the V4c ICL With a Minimum of 6 Months of Follow-upa

Table A:

Studies Reporting Data for the V4c ICL With a Minimum of 6 Months of Follow-up

Statistical Analysis

Data analysis was performed using Excel software (version 2016; Microsoft Corporation, Redmond, WA) and statistical analysis was performed using Sigma-plot software (version 14.0; Systat Software Inc., London, United Kingdom). Repeated measures analysis of variance (rANOVA) or Friedman rANOVA on rank tests with a post-hoc Tukey test or Wilcoxon signed-rank test were performed to reveal significant differences for the different variables through the follow-up period. The normality of all data sets was evaluated by the Shapiro–Wilk test. The statistical significance limit was set to a P value of less than .05 in all cases.

Results

Surgery was carried out from November 2011 to January 2013. This study enrolled 141 eyes of 83 patients, of which 60 (72.3%) were women and 23 (27.7%) were men. The mean age at the time of surgery was 31.24 ± 5.43 years (range: 22 to 51 years). The mean preoperative spherical equivalent refractive error was −9.20 ± 3.02 D (range: −18.25 to −3.13 D). Preoperative demographic data of the patients and ICL characteristics are summarized in Table 1.

Preoperative Patient Demographics and ICL Characteristics

Table 1:

Preoperative Patient Demographics and ICL Characteristics

To fully analyze the outcomes of the study, we have reported the main indices related to efficacy, safety, predictability, stability, IOP, vault, and ECD. Standard graphs for reporting refractive and visual acuity outcomes were constructed. Any adverse events and secondary surgeries were reported.

Efficacy and Safety

The mean postoperative UDVA was 0.05 ± 0.11 and 0.13 ± 0.18 logMAR at 1 and 5 years, respectively (P < .001). Figure 1A shows the cumulative UDVA at 1 and 5 years postoperatively. The reduction in UDVA at 5 years was related to progressive myopia: the mean SE changed from −0.17 ± 0.26 D at 1 year postoperatively (P < .001) to −0.44 ± 0.47 D at 5 years postoperatively (P < .001). The efficacy index was 1.01 ± 0.21 and 0.87 ± 0.26 at 1 and 5 years postoperatively, respectively. Preoperatively, the mean CDVA was 0.04 ± 0.01 logMAR. After ICL implantation, the mean CDVA was 0.02 ± 0.08 and 0.02 ± 0.09 logMAR at 1 and 5 years postoperatively, respectively. There was a statistically significant improvement in logMAR CDVA 1 year after the surgery (P < .001) and it was maintained without significant difference between 1 and 5 years (P > .10). Figure 1B shows the cumulative CDVA before and at 1 and 5 years postoperatively. More than 95% of eyes achieved CDVA of 20/25 or better at both follow-up periods. Figure 1C shows the changes in CDVA outcomes. At 1 year, no eye lost one or more lines, 106 eyes (75.18%) did not change from preoperative values, 20 eyes (14.18%) gained one line, 10 eyes (7.09%) gained two lines, and 5 eyes (3.55%) gained more than two lines of CDVA. At 5 years, no eye lost one or more lines, 105 eyes (74.47%) did not change from preoperative values, 24 eyes (17.02%) gained one line, 6 eyes (4.26%) gained two lines, and 6 eyes (3.55%) gained more than two lines of CDVA. The safety index was 1.07 ± 0.21 and 1.09 ± 0.36 at 1 and 5 years postoperatively, respectively.

(A) Cumulative uncorrected distance visual acuity (UDVA) at 1 and 5 years postoperatively. (B) Cumulative corrected distance visual acuity (CDVA) before and at 1 and 5 years postoperatively. (C) Postoperative changes in CDVA at 1 and 5 years postoperatively. (D) Attempted versus achieved spherical equivalent (SE) at 1 and 5 years postoperatively. Black dots refer to data for 1 year postoperatively (y = 0.9x – 018, R2 = 0.99) and open dots for 5 years postoperatively (y = 0.99x – 0.48, R2 = 0.97). (E) SE refractive accuracy at 1 and 5 years postoperatively. D = diopters

Figure 1.

(A) Cumulative uncorrected distance visual acuity (UDVA) at 1 and 5 years postoperatively. (B) Cumulative corrected distance visual acuity (CDVA) before and at 1 and 5 years postoperatively. (C) Postoperative changes in CDVA at 1 and 5 years postoperatively. (D) Attempted versus achieved spherical equivalent (SE) at 1 and 5 years postoperatively. Black dots refer to data for 1 year postoperatively (y = 0.9x – 018, R2 = 0.99) and open dots for 5 years postoperatively (y = 0.99x – 0.48, R2 = 0.97). (E) SE refractive accuracy at 1 and 5 years postoperatively. D = diopters

Predictability and Stability

Figure 1D shows a scatterplot of the attempted versus achieved spherical equivalent (SE) refraction at 1 and 5 years postoperatively. At 1 year after surgery, 129 eyes (91.53%) were within ±0.50 D of the desired SE refraction and all eyes (100%) were within ±1.00 D. At 5 years, these values changed to 95 eyes (67.4%) and 127 eyes (90.1%), respectively. Figure 1E shows the SE accuracy at the two times postoperatively. In relation to stability, the mean SE was reduced from −9.20 ± 3.02 D preoperatively to −0.17 ± 0.26 D at 1 year postoperatively (P < .001) and to −0.44 ± 0.47 D at 5 years postoperatively (P < .001).

IOP, ECD, and Vault

Figure 2A shows the IOP variation over time. The mean IOP was 13.26 ± 1.91 mm Hg (range: 8 to 19 mm Hg) before surgery. Postoperatively, the mean IOP was 12.74 ± 1.65 mm Hg (range: 8 to 19 mm Hg) and 13.0 ± 2.03 mm Hg (range: 8 to 19 mm Hg) at 1 and 5 years, respectively. A statistically significant reduction was found between preoperatively and 1 year postoperatively (P < .05). However, no significant differences were found between preoperatively and 5 years postoperatively or between 1 and 5 years postoperatively (P > .05). Figure 2B shows the postoperative change in IOP at 1 and 5 years. At 1 year after ICL implantation, 37 eyes (26.2%) experienced no change, 31 eyes (21.9%) increased 1 to 2 mm Hg, and 8 eyes (5.6%) increased 3 to 4 mm Hg from the preoperative IOP; however, no eyes experienced an increase of 5 mm Hg or more. At 5 years, 32 eyes (22.7%) experienced no change from the preoperative IOP, 35 eyes (24.8%) increased 1 to 2 mm Hg, 13 eyes (9.2%) increased 3 to 4 mm Hg, and 1 eye (0.7%) increased 5 mm Hg; again, no eyes experienced an increase of more than 5 mm Hg. For both follow-up periods, the largest proportion of eyes reported reduction of IOP by 1 to 2 mm Hg. No significant increase in IOP (> 20 mm Hg) occurred in any case during the follow-up periods.

(A) Evolution of the mean intraocular pressure (IOP) (mm Hg) for the whole follow-up period. Errors bars represent the standard deviation. (B) Postoperative changes in IOP (mm Hg) at 1 and 5 years postoperatively.

Figure 2.

(A) Evolution of the mean intraocular pressure (IOP) (mm Hg) for the whole follow-up period. Errors bars represent the standard deviation. (B) Postoperative changes in IOP (mm Hg) at 1 and 5 years postoperatively.

Postoperative mean ECD was 2,696 ± 358 and 2,645 ± 359 cells/mm2 at 1 and 5 years, respectively. The loss of ECD from the preoperative baseline at the last follow-up visit was 0.43%. The rANOVA test revealed that there were no statistically significant differences between preoperative and postoperative ECD (P = .304). Figure 3A shows the mean values for the three visits.

(A) Evolution of the mean endothelial cell density (ECD) (cells/mm2), for the whole follow-up period. Errors bars represent the standard deviation. (B) Distribution of eyes according to the vault (µm), at 1 and 5 years postoperatively.

Figure 3.

(A) Evolution of the mean endothelial cell density (ECD) (cells/mm2), for the whole follow-up period. Errors bars represent the standard deviation. (B) Distribution of eyes according to the vault (µm), at 1 and 5 years postoperatively.

The mean postoperative vault was 398 ± 187 µm at 1 year and 340 ± 163 µm at 5 years. A statistically significant difference in the mean vault between the follow-up visits was found (P < .001), with a mean reduction of 58.30 µm from 1 to 5 years. Figure 3B shows the postoperative distribution of vault. The most prevalent range of vault was from 301 to 400 µm (26 eyes, 18.44%) at 1 year and 201 to 300 µm (31 eyes, 21.99%) at 5 years.

Adverse Events and Secondary Surgeries

There were no intraoperative complications, and no eye required ICL explantation or repositioning. During the 5-year follow-up, no cases of anterior subcapsular opacity, cataract, pigment dispersion glaucoma, pupillary block, or other vision-threatening complications were reported.

Discussion

The visual acuity outcomes found in our study were good. The efficacy index was 1.01 ± 0.21 and 0.87 ± 0.26 at 1 and 5 years postoperatively, respectively. These results were similar to those reported by other authors at various postoperative intervals. Table B (available in the online version of this article) shows UDVA, CDVA, and efficacy index. At 1 year, the current outcomes were similar to those in one of our previous studies3 (efficacy index of 1.00) and comparable to others (efficacy index from 1.12 to 1.6).4,11,13,18,19 Only one study by Shimizu et al.6 reported 5-year results: UDVA and CDVA were −0.17 and −0.24 logMAR, respectively. In all reports, the efficacy index was 1.00 or greater in those studies where this information was reported (Table B).

Visual and Refractive Outcomes of the Different Studies Considereda

Table B:

Visual and Refractive Outcomes of the Different Studies Considered

From Figure 1B, we may observe the cumulative CDVA where more than 95% of eyes achieved CDVA of 20/25 or better at both follow-up visits. This was similar to results reported by Lisa et al.3 and Karandikar et al.4 (1.04 and 1.15, respectively) and slightly worse than those reported by Ganesh et al.11 and Pjano et al.13 (1.14 and 1.15, respectively). At 5 years, the safety index in the current study was 1.09 ± 0.36, but no prior studies have reported this information.

Our results also confirmed satisfactory predictability after V4c ICL implantation. A good correlation between the attempted and achieved SE refraction was obtained at both postoperative visits. These values confirm the good predictability of the procedure and point out that mild changes in refraction may still occur due to the expected progression of myopia over time). The change in SE refraction from 1 to 5 years postoperatively was −0.27 D.

Other authors have reported 86% to 100% of eyes within ±1.00 D at 1 year postoperatively3,4,11,18,19 and 85% to 94% of eyes within ±0.50 D.3,11,18,19 At 5 years, Shimizu et al.6 found values of 88% and 96% within ±0.50 and ±1.00 D, respectively. At 1 year, postoperative SE refraction reported by other authors was always within ±0.25 D of target (from −0.0613 to −0.21 D19); the same holds true for 5 years (−0.15 D).6 Taking into account our results and those found in other studies, the high percentage of eyes achieving SE values within ±0.50 or ±1.00 D and the limited variability during the postoperative period supports excellent predictability and stability for the procedure.

In relation to the IOP evaluation, in the current study the mean value had a significant but small reduction from preoperatively to 1 year postoperatively and remained stable during the rest of the follow-up period. No acute postoperative hypertension and no increase of more than 5 mm Hg was reported during the entire follow-up period.

Our results agree with those found by other authors at 1 year postoperatively such as Lisa et al.3 (12.4 mm Hg, 0 eyes > 20 mm Hg) and Kamiya et al.18 (13.1 to 13.6 mm Hg, 0 eyes > 21 mm Hg). At 5 years postoperatively, Shimizu et al.6 reported a mean value of 13.6 mm Hg with no eyes greater than 21 mm Hg. In our study, when we calculated the change between preoperative and postoperative values, we found that most eyes had no IOP change or showed a change within ±2 mm Hg: 83.7% and 80.1% at 1 and 5 years, respectively.

The central port of the ICL offers surgical advantages over the earlier models because no preoperative Nd:YAG iridotomy or intraoperative iridectomy is needed to prevent an IOP increase that may be associated with pupillary block or chronic pigment dispersion.21 The central port of the V4c model allows more physiologic aqueous humor flow. This and previous studies with short-, medium- and long-term follow-up demonstrate that there are no significant variations in IOP over time. The central port simplifies surgery and reduces possible postoperative complications.

In relation to ECD, we found no statistically significant changes between preoperative and postoperative visits. Our results agree with those found previously at 1 year, where mean values ranged from 2,51213 to 2,80811 cells/mm2. The percentage of loss varied significantly among studies from 0.118 reported by Kamiya et al.18 to 9% reported by Ganesh et al.11 At 5 years, our results (mean of 2,645 cells/mm2 and loss of 0.43%) agree with those Shimizu et al.,6 who reported a mean value of 2,799 cells/mm2 and a percentage of loss of 0.5%. If we analyze the results shown in Table C (available in the online version of this article), the greatest loss occurs during the early postoperative period and ECD tends to remain stable or have lower rates of loss after that period. The surgical procedure is likely the cause of the early ECD loss, whereas further decreases in the late postoperative period may reflect the expected physiologic cell loss of approximately 0.6% per year.22,23 A comparative study performed by Goukon et al.10 between ICL models with and without the central port concluded that neither lens induces a significant change in ECD 2 years postoperatively (0.3% and 1.1% for with and without the port, respectively). An isolated but significant decrease in ECD was reported in the superior quadrants in patients who had undergone peripheral iridotomy.

IOP, ECD, and Vault Outcomes With Adverse Events and Complications of the Different Studies Considereda

Table C:

IOP, ECD, and Vault Outcomes With Adverse Events and Complications of the Different Studies Considered

The mean postoperative vault at 1 year in the current study was 398 ± 187 µm, which agrees with that reported by Lisa et al.3 and García-de la Rosa et al.19 At 5 years, it was significantly reduced to 340 ± 163 µm (P < .001); however, no comparison with previous studies with the same model was possible. Alfonso et al.24 found a significant reduction during early follow-up after implantation of the ICL without a central port (approximately 70 µm at 6 months) that slowed over time (approximately 2 µm/month after 36 months). We found a change of 58.30 µm from 1 to 5 years (48 months, approximately 1.2 µm/month). It appears that the presence of the central port does not significantly affect the degree of vault over time. Kamiya et al.25 reported on 46 eyes with 1 year of follow-up and concluded that the vault of the ICL with the central port appeared to be essentially equivalent to the vault of the ICL without the central port, suggesting that the presence of the central port did not significantly affect the vault or the refractive accuracy. Chen et al.,9 who directly compared ICL models in fellow eyes of the same patient during 6 months of follow-up, reached a similar conclusion. In contrast, Eissa et al.8 reported an increase of vault with time in 54 eyes with 18 months of follow-up, indicating a “fountain effect” to explain the mild increase in vault. Our understanding is that aqueous humor initially flows through the central port and lifts the ICL away from the crystalline lens, but over time its vault becomes more similar to that of the ICL without the central port.

No intraoperative or postoperative complications or adverse events occurred during the follow-up period in the current study. Our safety results are similar to those of Shimizu et al.,6 who also reported no adverse events or complications during their 5-year study. Other studies, with shorter follow-up periods, have reported complications such as anterior subcapsular opacities, ICL exchange due to rotation, iritis, and retinal detachment (Table A). The reported rates of complications are low and most studies reported no events. The most frequently reported complication after implantation of the ICL without the central port is cataract formation.21 In a recent meta-analysis by Packer,26 previous studies of the V4c model (including data on 1,291 eyes) described a zero incidence of asymptomatic anterior subcapsular cataract formation. We believe that improvements in lens design, anterior segment imaging systems, accurate nomograms for appropriate ICL size selection, and the surgeon's learning curve are essential factors in the decreased occurrence of postoperative complications.

Our study supports the use of the V4c ICL model for correction of moderate to high myopia. The lens performed well in providing patients with good uncorrected visual acuity. Safety, efficacy, predictability, and stability parameters were all satisfactory and suggest that this lens is safe and effective for the correction of myopia. Future studies should focus on longer follow-up periods and larger cohorts of patients.

References

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  14. Kamiya K, Takahashi M, Takahashi N, Shoji N, Shimizu K. Monovision by implantation of posterior chamber phakic intraocular lens with a central hole (hole ICL) for early presbyopia. Sci Rep. 2017;7:11302. doi:10.1038/s41598-017-11539-9 [CrossRef]
  15. Takahashi M, Kamiya K, Shoji N, Kato S, Igarashi A, Shimizu K. Intentional undercorrection by implantation of posterior chamber phakic intraocular lens with a central hole (Hole ICL) for early presbyopia. Biomed Res Int. 2018;10:6158520.
  16. Totsuka K, Ishikawa H, Kamiya K, Shoji N, Shimizu K. Pupil dynamics induced by light reflex after posterior chamber phakic intraocular lens implantation. J Refract Surg. 2017;33:704–707. doi:10.3928/1081597X-20170721-06 [CrossRef]
  17. Fernández-Vigo JI, Macarro-Merino A, Fernández-Vigo C, et al. Impacts of implantable collamer lens V4c placement on angle measurements made by optical coherence tomography: two-year follow-up. Am J Ophthalmol. 2017;181:37–45. doi:10.1016/j.ajo.2017.06.018 [CrossRef]
  18. Kamiya K, Shimizu K, Igarashi A, et al. Posterior chamber phakic intraocular lens implantation: comparative, multicentre study in 351 eyes with low-to-moderate or high myopia. Br J Ophthalmol. 2018;102:177–181. doi:10.1136/bjophthalmol-2017-310164 [CrossRef]
  19. Garcia-de la Rosa G, Olivo-Payne A, Serna-Ojeda JC, et al. Anterior segment optical coherence tomography angle and vault analysis after toric and non-toric implantable collamer lens V4c implantation in patients with high myopia. Br J Ophthalmol. 2018;102:544–548.
  20. Fernández-Vega-Cueto L, Lisa C, Esteve-Taboada JJ, Montés-Micó R, Alfonso JF. Implantable collamer lens with central hole: three-years follow-up. Clin Ophthalmol. 2018;12:2015–2029. doi:10.2147/OPTH.S171576 [CrossRef]
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  22. Edelhauser HF, Sanders DR, Azar R, Lamielle HICL in Treatment of Myopia Study Group. Corneal endothelial assessment after ICL implantation. J Cataract Refract Surg. 2004;30:576–583. doi:10.1016/j.jcrs.2003.09.047 [CrossRef]
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  24. Alfonso JF, Fernández-Vega L, Lisa C, Fernandes P, González-Meijome J, Montés-Micó R. Long-term evaluation of the central vault after phakic Collamer® lens (ICL) implantation using OCT. Graefes Arch Clin Exp Ophthalmol. 2012;250:1807–1812. doi:10.1007/s00417-012-1957-0 [CrossRef]
  25. Kamiya K, Shimizu K, Ando W, Igarashi A, Iijima K, Koh A. Comparison of vault after implantation of posterior chamber phakic intraocular lens with and without a central hole. J Cataract Refract Surg. 2015;41:67–72. doi:10.1016/j.jcrs.2014.11.011 [CrossRef]
  26. Packer M. Meta-analysis and review: effectiveness, safety, and central port design of the intraocular collamer lens. Clin Ophthalmol. 2016;9;10:1059–1077. doi:10.2147/OPTH.S111620 [CrossRef]

Preoperative Patient Demographics and ICL Characteristics

ParameterMean ± SDRange [Min, Max]
Age (years)31.24 ± 5.4[22, 51]
Refraction sphere (D)−8.74 ± 2.91[−17.50, −2.50]
Refraction cylinder (D)−0.91 ± 0.84[−2.50, 0.00]
Spherical equivalent (D)−9.20 ± 3.02[−18.25, −3.13]
Flat keratometry (D)43.43 ± 1.54[40.00, 46.50]
Steep keratometry (D)44.51 ± 1.67[40.75, 48.00]
Corneal thickness (µm)534.05 ± 38.38[448, 630]
ACD (mm)3.16 ± 0.26[2.80, 3.90]
WTW (mm)11.72 ± 0.36[11.00, 13.20]
ATA (mm)11.93 ± 0.43[11.00, 13.45]
ECD (cells/mm2)2,657.12 ± 361.77[2,000, 3903]
IOP (mm Hg)13.26 ± 1.9[8, 19]
ICL optical power (D)−9.98 ± 2.8[−18.00, −3.00]
ICL size (mm)13.11 ± 0.32[12.6, 13.7]

Studies Reporting Data for the V4c ICL With a Minimum of 6 Months of Follow-upa

AuthorYearFollow-upEyes (Patients)Age (y)SE (D)
Shimizu et al.120126 mo20 (20)31.7 ± 8.0 (23 to 49)−7.36 ± 2.13 (−3.50 to −11.75)
Alfonso et al.220136 mo138 (70)30.5 ± 4.8 (20 to 41)−8.73 ± 2.54 (−3.00 to −17.50 sph; −0.25 to −3.00 cyl)
Lisa et al.320151 yr147 (80)30.4 ± 4.8 (20 to 40)−8.80 ± 2.60 (−2.75 to −17.50 sph; 0.00 to −3.00 cyl)
Karandikar et al.420151 yr34 (34)26.13 ± 3.8 (NR)−9.24 ± 2.4 (NR)
Cao et al.520166 mo63 (32)30.6 ± 7.9 (21 to 43)−12.81 ± 3.11 (−5.75 to −17.50)
Shimizu et al.620165 yrs32 (32)31.9 ± 7.5 (23 to 49)−7.54 ± 2.40 (−2.00 to −13.25)
Bhandari et al.720169 mo10 (5)26.13 ± 3.8 (NR)−9.14 ± 2.40 (NR)
Eissa et al.8201618 mo54 (27)29 ± 2.3 (NR)NR (NR)
Chen et al.920166 mo22 (22)26.5 ± 5.8 (20 to 35)−9.43 ± 5.01 (−4.75 to −15.75)
Goukon et al.1020172 yrs34 (34)32.1 ± 6.6 (23 to 49)−7.99 ± 2.57 (−3.25 to −11.75)
Ganesh et al.1120171 yrNR (NR)26.4 ± 2.4 (NR)−5.98 ± 1.15 (NR)
Rodríguez-Una et al.1220172 yrs78 (NR)NR (NR)NR (NR)
Pjano et al.1320171 yr28 (16)28.21 ± 4.06 (21 to 35)−9.52 ± 3.69 (NR)
Kamiya et al.1420176 mo17 (17)46.1 ± 4.2 (40 to 53)−8.67 ± 4.35 (−2.25 to −18.25)
Takahashi et al.1520176 mo42 (21)45.0 ± 3.8 (40 to 53)−7.37 ± 3.18 (−2.25 to −14.75)
Totsuka et al.1620176 mo28 (28)31.1 ± 6.8 (25 to 42)−7.38 ± 2.26 (−3.25 to −11.80)
Fernández-Vigo et al.1720172 yrs54 (27)31.2 ± 5.1 (22 to 44)−8.48 ± 4.03 (sph) (−2.25 to −21.00); −1.56 ± 1.13 (cyl) (0.00 to −5.00)
Kamiya et al.1820181 yr
  Low-to-moderate myopia57 (57)34.8 ± 7.4 (20 to 57)−4.29 ± 1.31 (−0.50 to −5.88)
  High myopia294 (294)33.6 ± 7.3 (18 to 54)−10.13 ± 2.64 (−6.00 to −18.63)
García-de la Rosa et al.1920181 yr76 (42)27.4 ± 5.14 (20 to 39)−11.94 ± 3.51 (−7.50 to −22.88)
Fernádez-Vega-Cueto et al.2020183 yrs184 (92)30.4 ± 5.4 (20 to 45)−8.30 ± 2.98 (−2.88 to −18.25)

Visual and Refractive Outcomes of the Different Studies Considereda

AuthorUDVA (logMAR)CDVA (logMAR)SafetyEfficacy% ±0.50 D% ±1.00 DRefraction SE (D)
Shimizu et al.1−0.20 ± 0.12−0.25 ± 0.061.13 ± 0.241.03 ± 0.30951000.01 ± 0.29
Alfonso et al.20.009 ± 0.062−0.015 ± 0.0321.011.0098.55100−0.03 ± 0.19
Lisa et al.30.028 ± 0.0550.003 ± 0.0131.041.0093.9100−0.14 ± 0.26
Karandikar et al.4NRNR1.151.657.1298.12−0.19 ± 1.18
Cao et al.50.118 ± 0.0960.018 ± 0.0351.42 ± 0.341.11 ± 0.1996.8100−0.05 ± 0.27
Shimizu et al.6−0.17 ± 0.14−0.24 ± 0.08NRNR8896−0.15
Bhandari et al.7NRNR1.141.5NRNR−0.2 ± 1.18
Eissa et al.8NRNRNRNRNRNRNR
Chen et al.9NRNRNRNRNRNRNR
Goukon et al.10NRNRNRNRNRNRNR
Ganesh et al.11−0.022 ± 0.021−0.071 ± 0.0791.241.1290100−0.164 ± 0.20
Rodríguez-Una et al.12NRNRNRNRNRNRNR
Pjano et al.130.76 ± 0.16 (decimal)0.79 ± 0.14 (decimal)1.251.2NRNR−0.21 ± 0.27
Kamiya et al.14−0.04 ± 0.18−0.19 ± 0.09NRNR100100−0.08 ± 0.17b
Takahashi et al.15c−0.03 ± 0.20−0.19 ± 0.08NRNR100100NR
Totsuka et al.16NRNRNRNRNRNRNR
Fernández-Vigo et al.170.02 ± 0.100.01 ± 0.09NRNRNRNR−0.02 ± 0.44 (sph); −0.11 ± 0.37 (cyl)
Kamiya et al.18
  Low-to-moderate myopia−0.17 ± 0.14−0.21 ± 0.10NRNR9398−0.12
  High myopia−0.16 ± 0.09−0.21 ± 0.08NRNR94990.02
García-de la Rosa et al.190.12 ± 0.120.05 ± 0.08NRNR8586−0.06 ± 0.77
Fernández-Vega-Cueto et al.200.08 ± 0.120.01 ± 0.041.030.9074.591.8−0.37± 0.47

IOP, ECD, and Vault Outcomes With Adverse Events and Complications of the Different Studies Considereda

AuthorIOP (mm Hg) (Eyes > 21)ECD (cells/m2) (% Loss)Vault (μm)Adverse Events/Complications
Shimizu et al.113.0 ± 3.0 (0)2,720 ± 268 (2.8)NRNo
Alfonso et al.212.4 ± 1.5 (0 > 20)2,533 (8.5)482.7 ± 210.5 (90 to 970)No
Lisa et al.312.4 ± 1.4 (0 > 20)2,650 ± 438 (1.7)405.5 ± 184.7 (100 to 980)No
Karandikar et al.419.1 ± 1.3 (NR)NR (7.1)628.2 ± 300.1 (NR)Anterior subcapsular opacity present in 2.94% of eyes; glare/halos 27%
Cao et al.515.3 ± 2.0 (0)2,648 ± 317 (2)505.2 ± 258.9 (120 to 990)No
Shimizu et al.613.6 (0)2,799 (0.5 ± 5.4)NRNo
Bhandari et al.719.9 (NR)NR (6.1)612 ± 251.14 (NR)Anterior subcapsular opacity present in 3.14% of eyes; 1 eye had axis rotation >30 degrees and required realignment
Eissa et al.816.07 ± 4.13 (0)NR637 ± 125 (NR)No
Chen et al.916.0 ± 2.2 (0)NR542.8 ± 45.3 (NR)No
Goukon et al.10NR2,806 ± 248 (0.3)NRNo
Ganesh et al.11NR2,808 ± 315 (9.0)NR3 eyes required ICL exchange due to rotation (>30 degrees) and high vault
Rodríguez-Una et al.1212.7 ± 1.1 (0)NR369.9 ± 191.0 (0 to 980)No
Pjano et al.1314.96 ± 1.7 (NR)2,512 ± 127 (5.5)NR1 eye had retinal detachment (high degenerative myopia); 1 eye required ICL exchange due to rotation
Kamiya et al.14NR (0 > 22)NRNRNo
Takahashi et al.15NR (0)NRNRNo
Totsuka et al.16NRNR382.1 ± 176.5 (NR)No
Fernández-Vigo et al.1715.5 ± 2.11 (0)2,480.8 ± 214.3 (5.9%)458.3 ± 258.4 (NR)1 eye with crystalline opacity
Kamiya et al.18
  Low-to-moderate myopia13.1 (0)NR (0.1)NRNo
  High myopia13.6 (0)NRNR2 eyes had ICL exchange, 1 eye had significant axis rotation and 1 eye developed iritis
García-de la Rosa et al.19NRNR449 ± 180 (NR)No
Fernández-Vega-Cueto et al.2012.8 ± 1.7 (0)2,663 ± 366 (NR)349 ± 165 (NR)No
Authors

From Fernández-Vega Ophthalmological Institute, Oviedo, Spain (JFA, LF-V-C, BA-B, LF-V); the Surgery Department, School of Medicine, University of Oviedo, Oviedo, Spain (JFA, LF-V); and the Optics Department, Faculty of Physics, University of Valencia, Valencia, Spain (RM-M).

Supported in part by an unrestricted grant from STAAR Surgical to the Fernández-Vega Ophthalmological Institute and the University of Valencia.

The authors have no financial or proprietary interest in the materials presented herein.

AUTHOR CONTRIBUTIONS

Study concept and design (JFA, LF-V-C, BA-B, LFV); analysis and interpretation of data (JFA, LF-V-C, BA-B, RM-M, LF-V); writing the manuscript (RM-M); critical revision of the manuscript (JFA, LF-V-C, BA-B, RM-M, LF-V)

Correspondence: José F. Alfonso MD, PhD, Instituto Oftalmológico Fernández-Vega, Avda. Dres. Fernández-Vega 114, Oviedo 33012, Spain. E-mail: j.alfonso@fernandez-vega.com

Received: August 18, 2018
Accepted: January 14, 2019

10.3928/1081597X-20190118-01

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