Toric phakic implantable collamer lens for correction of astigmatism: 1-year outcomes
Clinical Ophthalmology
Toric phakic implantable collamer lens for correction of astigmatism: 1-year outcomes
erik L Mertens 0
0 Medipolis eye Centre , Antwerp , Belgium
PowerdbyTCPDF(ww.tcpdf.org) Purpose: The purpose of this study was to assess predictability, efficacy, safety and stability in patients who received a toric implantable collamer lens to correct moderate to high myopic astigmatism. Methods: Forty-three eyes of 23 patients underwent implantation of a toric implantable collamer lens (STAAR Surgical Inc) for astigmatism correction. Mean spherical refraction was −4.98 ± 3.49 diopters (D) (range: 0 to −13 D), and mean cylinder was −2.62 ± 0.97 D (range: −1.00 to −5.00 D). Main outcomes measures evaluated during a 12-month follow-up included uncorrected visual acuity (UCVA), refraction, best-corrected visual acuity (BCVA), vault, and adverse events. Results: At 12 months the mean Snellen decimal UCVA was 0.87 ± 0.27 and mean BCVA was 0.94 ± 0.21, with an efficacy index of 1.05. More than 60% of the eyes gained $1 line of BCVA (17 eyes, safety index of 1.14). The treatment was highly predictable for spherical equivalent (r2 = 0.99) and astigmatic components: J0 (r2 = 0.99) and J45 (r2 = 0.90). The mean spherical equivalent dropped from −7.29 ± 3.4 D to −0.17 ± 0.40 D at 12 months. Of the attempted spherical equivalent, 76.7% of the eyes were within ±0.50 D and 97.7% eyes were within ±1.00 D, respectively. For J0 and J45, 97.7% and 83.7% were within ±0.50 D, respectively. Conclusion: The results of the present study support the safety, efficacy, and predictability of toric implantable collamer lens implantation to treat moderate to high myopic astigmatism.
Introduction
Clinical results of posterior phakic intraocular lenses (pIOLs) have confirmed this
procedure as a promising treatment option for patients who cannot undergo
keratorefractive procedures.1 The main advantages are the correction of higher levels
of myopia, hyperopia, and astigmatism and the reversibility of the procedure.2–12
Presently, one of the most successful pIOL, known as implantable collamer lens
(ICL), is the Visian ICLV4 manufactured by STAAR Surgical (Monrovia, CA;
Figure 1). The Visian ICL is the only posterior pIOL currently under revision for
approval by the United States Food and Drug Administration (FDA) for the
treatment of astigmatism.10
Several studies have been published on an anterior chamber iris-fixated toric
pIOL13–17 demonstrating a significant reduction in spherical and astigmatic refractive
errors. However concerns still exist regarding potentially induced progressive
endothelial cell loss.18 The recently published outcomes of the toric ICL8–12 showed good efficacy
and predictability. Additionally, in cases in which keratorefractive or other alternative
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refractive procedures were not a good or feasible option, toric
ICL implantation showed promising results.19–22
The purpose of this study was to assess safety, efficacy,
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with follow-up visits up to 12 months.
Patients
We prospectively studied 43 eyes of 23 patients, 17 (73.9%)
females and 6 (26.1%) males, who underwent implantation
of a toric ICL to correct myopic astigmatism at the Medipolis
Eye Centre (Antwerp, Belgium). Mean patient age was
34.41 ± 9.42 years (range: 22 to 49 years). Table 1 shows
the demographic data prior to surgery and parameters of
implanted lenses.
The inclusion criteria were best-corrected distance visual
acuity (BCVA) of 20/40 or better, stable refraction and clear
central cornea. The exclusion criteria included age ,22 years,
anterior chamber depth ,2.8 mm from endothelium,
endothelial cell density ,2000 cell/mm2, cataract, history of
glaucoma or retinal detachment, macular degeneration or
retinopathy, neuro-ophthalmic diseases, and history of ocular
inflammation. Before the TICL implantation, patients had a
complete ophthalmologic examination, including refraction,
keratometry, corneal topography, endothelial cell count,
pachymetry, slit-lamp microscopy, Goldmann applanation
tonometry, and binocular indirect ophthalmoscopy. The
targeted refraction was emmetropia in all cases.
Toric ICL is a pIOL manufactured with an haptic design
identical to the spherical ICL2 in terms of size, thickness, and
shape, with central convex/concave optical zone, and cylinder
as necessary to address each patient’s astigmatic condition.8
Toric ICL power calculation was performed using the software
provided by the manufacturer. Toric ICL is manufactured to
minimize rotation and required the surgeon to rotate the toric
ICL no more than 22.5° from the horizontal meridian. Each
toric ICL comes with a guide demonstrating the amount and
direction of rotation from the (...truncated)