Mariano Royo1,2, Ángel Jiménez1,2, Irene Martínez-Alberquilla3 y José F Alfonso4
Abstract
Purpose: To analyse long-term efficacy, safety, visual and refractive stability and physiological changes of Artiflex Myopia
and Toric phakic intraocular lenses (pIOL) separately throughout an 8-year follow-up.
Design: Retrospective cohort study.
Methods: A total of 67 eyes of 37 patients underwent Artiflex Myopia (47 eyes) or Artiflex Toric (20 eyes) implantation
for correcting myopia and/or astigmatism. Follow-up evaluations were performed 1, 3, 5 and 8 years after surgery.
Preoperative and postoperative data included corrected (CDVA) and uncorrected distance visual acuity (UDVA),
manifest refraction, endothelial cell density (ECD) and intraocular pressure (IOP) assessments. Efficacy and safety
indexes were analysed. The vectorial analysis was performed using the Thibos method.
Results: Mean CDVA and UDVA of both pIOLs significantly improved from preoperative to 1 year after implantation,
and then it remained stable over the 8-year follow-up. The efficacy and safety indexes after 8 years were 0.94 ± 0.16 and
1.07 ± 0.18 for Artiflex Myopia and 1.00 ± 0.11 and 1.10 ± 0.15 for Artiflex Toric, respectively. The spherical equivalent
(SE) significantly improved after surgery. J0, J45 and SE refractive components showed no changes between postoperative
visits. A total ECD loss of 4.8% (p < 0.001) and 10.4% (p = 0.005) was found after 8 years for Artiflex Myopia and Toric,
respectively.
Conclusions: Artiflex Myopia and Toric pIOLs are a safe, efficient and predictable option for the correction of myopia
and/or astigmatism. The vectorial analysis showed excellent rotation stability for the toric version.
Keywords
Refractive surgery, phakic intraocular lens, refraction
Introduction
There are currently different surgical approaches for the correction of refractive errors: corneal refractive surgery, refractive lens exchange and phakic intraocular lenses (pIOLs), including anterior and posterior chamber lenses.1,2
Despite the consolidation of corneal refractive surgery as a treatment of moderate to high myopia for those wanting to preserve accommodation, pIOLs have become a popular method to treat refractive errors as an alternative for cases not suitable for corneal surgery.3-5
The main benefits of pIOLs include preservation of the corneal tissue and topography without inducing high order aberrations, refractive stability, no removal of ocular tissue and exchangeability.6
Artiflex lens (Ophtec B.V., Groningen, The Netherlands) is an iris-fixated foldable pIOL that has demonstrated to be effective, safe and highly predictable for the correction of myopia and astigmatism.7-9 However, as an anterior chamber IOL, potential endothelial damage due to surgical implantation and proximity to the endothelial layer makes it important to evaluate long-term endothelial cell loos.10-12
The toric version of Artiflex offers the advantage of correcting myopic refractions with astigmatism, and its iris-claw fixation provides excellent stability.13 However, unfavourable visual results due to residual astigmatism and misalignments should be considered. Therefore, it is of great importance to analyse toric pIOLs separately to evaluate possible lens rotation over time and analyse longterm refractive and visual stability
Several studie7,9,14-19 have evaluated safety, efficacy, predictability, stability and endothelial cell loss of the spheric and/or the toric version as a group. However, there is still a lack of long-term visual data for both lenses separately. Jonker et al.20 individually assessed Artiflex Myopia and Toric over a 5-year follow-up but was only focused on endothelial cell loss. To the best of the author’s knowledge, this is the first report which analyse, separately, the outcomes of Artiflex Myopia and Toric over 8 years of follow-up.
Therefore, this study aimed to analyse efficacy, safety, long-term visual and refractive stability and physiological changes of Artiflex Myopia and Artiflex Toric pIOL separately throughout an 8-year follow-up.
Patients and methods
Study design and population
This was a retrospective and observational study of patients who underwent Artiflex pIOL implantation for the correction of myopia and astigmatism at the Madrid Ophthalmological Institute. A total of 67 eyes of 37 patients were enrolled in the study. Signed informed consent was obtained from all participants prior to study procedures. The study conformed to the principles of the declaration of Helsinki and was approved by the hospital ethics committee. All participants had at least 1 year of stable refraction and a 1-week contact lens washout period was required for the preoperative visit. If there was any sign of contact lens warpage in the preoperative visit, documentation of corneal stability by repeating examinations was performed until stable results
Inclusion criteria included: central anterior chamber depth (ACD) ⩾2.7 mm (measured from the endothelium), endothelial cell count according to age and a minimum of 2200 cells/mm2 and mesopic pupil size <5.0-6.0 mm.10
Exclusion criteria included pregnancy, diabetes, systemic autoimmune diseases, age younger than 18 years, history of intraocular or corneal surgery, intraocular pressure (IOP) higher than 21 mmHg or glaucoma, cataract, posterior or anterior segment pathology, pupil abnormalities, recurrent or chronic uveitis or corneal anomalies such as keratoconus.1
The preoperative examination included: uncorrected distance visual acuity (UDVA) and best-corrected distance visual acuity (CDVA) (transformed into a logarithmic scale) under photopic conditions; spherical and cylindrical refraction; keratometry (IOLMaster, Carl Zeiss Meditec AG); slit-lamp biomicroscopic examination; endothelial cell counting using a noncontact specular microscope (Tomey EM 300); anterior segment analysis (Oculus Sheimpflug Pentacam); and pachymetry-corrected IOP data collection.
Routine long-term follow-up was scheduled for 1, 3, 5 and 8 years, and the same test battery was performed for each visit. Efficacy and safety indexes were calculated and defined as the quotient between UDVA postoperative and CDVA preoperative and the quotient between CDVA postop and CDVA preop, respectively. The vectorial analysis was performed using J0 and J45 power vectors for toric lenses, according to Thibos and Horner.21 No refractive surgery to correct residual refractive error was performed during follow-up.
Lens and surgical procedure
The study was carried out using the Artiflex Myopia and Artiflex Toric pIOLs (Ophtec B.V., Groningen, The Netherlands). Both designs are formed by a 6-mm diameter flexible optical part made of silicone and the PMMA rigid haptics, with a total diameter of 8.5 mm. Artiflex Myopia power ranges from −2.0 to −14.5 diopters (D) and Artiflex Toric power ranges from −1.0 to −13.5 D with a cylinder correction from −1.0 to −5.0 D
PIOL power was calculated by the manufacturer with the refractive power, axial length, ACD and keratometry data using the van der Heijde formula.2
The surgical procedure was previously described in the literature.14 Patients were prepared with miotic drops before surgery, and ocular anaesthesia was instilled, either peribulbar or retrobulbar depending on surgeon’s preference
The corneal incision for the implantation of the lens was 3.2 mm at the 12 O’clock position, smaller in comparison to the 5.2- or 6.2-mm incision of the rigid Artisan model. Two stab incisions were located at 10 and 2 O’clock. Viscoelastic was injected in the anterior chamber before lens insertion, and the lens was rotated to its correct position. Afterwards, the lens was fixated in the iris by the haptics claws. An iridotomy was made in order to facilitate aqueous humour flow. Viscoelastic material was removed and replaced for a balanced saline solution. The corneal incision was hydrated for its sealing. IOL implantations were performed by the same surgeon (M.R.).
Statistical analysis
Statistical analysis was performed using SPSS (version 17.0, SPSS Inc.). The Kolmogorov-Smirnov test was applied for all variables to analyse normality. The repeated-measures analysis of variance (ANOVA) was applied for parametric data, whereas the Kruskal-Wallis’s test was used for non-parametric data. Comparisons were made between preoperative and postoperative data and between visits. The level of statistical significance was set at p < 0.05. At each follow-up stage, only the patients that attended that visit were included in the statistical analysis.
ORCID iDs
Irene Mart.nez-Alberquilla https://orcid.org/0000-0003-4870-5862
Jos. F Alfonso https://orcid.org/0000-0002-0373-8209
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