Computational Study of Aqueous Humor Dynamics Assessing the Vault and the Pupil Diameter in Two Posterior-Chamber Phakic Lenses

Fernández‐Vigo, José Ignacio; Macarro-Merino, Ana; Francos, Joaquín Fernández; De‐Pablo‐Gómez‐de‐Liaño, Lucía; Martínez-de-la-Casa, J.M.; García‐Feijoó, Julián; Fernández‐Vigo, José Ángel

doi:10.1167/iovs.16-19900

Cited by 24 publications

(19 citation statements)

References 30 publications

(46 reference statements)

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“…In a second study, these authors determined that the flow around the crystalline lens reached a maximum with a hole size of ~0.4 mm, indicating that “the current model, based on a central hole size of 0.36 mm, was close to ideal.”10 Recently, these authors also reported that “laser iridotomy is unnecessary from the viewpoint of theoretical aqueous circulation” in the presence of a central hole 11. Fernández-Vigo et al reported a full three-dimensional study based on computational fluid dynamics and concluded that “the circulation of aqueous humor is influenced by the type of lens implanted, being more physiological in the central hole model than in the one that requires an iridotomy.”12 These authors more recently provided an interesting theoretical paper describing a model of the circulation of aqueous humor in eyes with and without phakic refractive lenses 13…”

Section: Introductionmentioning

confidence: 99%

The Implantable Collamer Lens with a central port: review of the literature

Packer¹

2018

OPTH

137

110

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The purpose of this review is to summarize preclinical and clinical data from publications appearing in the peer-reviewed scientific literature relevant to the safety and 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 literature 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.

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Section: Introductionmentioning

confidence: 99%

The Implantable Collamer Lens with a central port: review of the literature

Packer¹

2018

OPTH

137

110

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“…These phenomena might represent a potential mechanical impact between the anterior side of the ICL and the posterior iris surface, thus influencing the function of the pupillae sphincter and dilator pupillae. Another explanation might relate to the aqueous humor; a study on aqueous humor dynamics using a computational simulation showed that the flow velocity of the aqueous humor was much greater if the pupil size was smaller after ICL V4c implantation [22]. Thus, aqueous humor resistance might also play a role.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Disk Halo Size after Implantation of a Collamer Lens with a Central Hole (ICL V4c)

Chen

Han

Zhao

et al. 2019

Journal of Ophthalmology

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Purpose. To investigate disk halo size changes produced by a glare source after surgical insertion of an implantable collamer lens with a central hole (ICL V4c) for myopia correction. Methods. In this prospective study, disk halo size and pupillary light response with a vision monitor were measured preoperatively and at 1 week, 1 month, and 3 months postoperatively. Pupillary light response parameters included contraction amplitude, latency, duration, and velocity; dilation latency, duration, and velocity; and initial, maximum, minimum, and average pupil diameters. Results. Forty-two right eyes of 42 patients were enrolled. Postoperative uncorrected distance visual acuity was better than or equal to 20/20 in all eyes. Compared to preoperative values, disk halo size showed no significant difference at 1 week postoperatively (P>0.05) and then decreased significantly at 1 and 3 months postoperatively (both P<0.001). Contraction amplitude and velocity, as well as dilation velocity, decreased significantly at all postoperative time points (all P<0.001). Disk halo size at 3 months postoperatively was significantly correlated with initial (r = 0.446, P=0.003), maximum (r = 0.483, P=0.001), minimum (r = 0.425, P=0.005), and average pupil diameters (r = 0.474, P=0.002). Conclusions. After ICL V4c implantation, disk halo size was reduced in the short term. Patients with smaller pupil sizes during pupillary response to light experienced smaller halos after ICL V4c implantation.

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“…In agreement with our results ( Fig 4 ), Dvoriashyna et al[ 29 ] described that most of AH flows through the PI, with almost all of it going through the PI for diameters larger than 150 μm. They described that the ideal size and location of a PI are influenced by various geometrical and fluid mechanical factors, the most relevant of which are the size of the hole, also analyzed by our group in a previous paper [ 19 ], and the length and height of the iris–lens channel. On the contrary, the location of the iridotomy only changes the total flow by 2% from an iridotomy placed in the middle of the PC to one placed peripherally, which is because the pressure is approximately uniform across the PC.…”

Section: Discussionmentioning

confidence: 99%

“…A three-dimensional full study simulation based on computational fluid dynamics (CFD) was performed with Ansys Fluent software (v16.2, ANSYS Inc. Pennsylvania, USA) enhancing our previous geometry model [ 19 ]. Simulations were conducted in steady laminar flow mode, setting a constant AH inflow rate of 2 μL/min (3.34 x 10–8 kg/s) and outflow boundary condition at the outlet section [ 19 ]. No-slip boundary conditions were prescribed on the solid surfaces.…”

Section: Methodsmentioning

confidence: 99%

Computational simulation of aqueous humour dynamics in the presence of a posterior-chamber versus iris-fixed phakic intraocular lens

et al. 2018

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PurposeTo compare aqueous humour (AH) dynamics in the presence of a precrystalline (Implantable Collamer Lens®; ICL) or iris-fixed (Artiflex®) phakic intraocular lens (PIOL).MethodsBy computational fluid dynamics simulation, AH flow was modelled through a peripheral iridotomy (PI) or central lens hole (both 360 μm) in the presence of an Artiflex or ICL lens, respectively. The impacts of AH flow were then determined in terms of wall shear stress (WSS) produced on the endothelium or crystalline lens. Effects were also modelled for different scenarios of pupil diameter (PD 3.5 or 5.5 mm), ICL vault (100, 350, 800 μm) and number of Artiflex iridotomies (1 or 2) and location (12 or 6 o’clock).ResultsFor a PD of 3.5 mm, AH volumes flowing from the posterior to the anterior chamber were 37.6% of total flow through the lens hole (ICL) and 84.2% through PI (Artiflex). For an enlarged PD (5.5 mm), corresponding values were 10.3% and 81.9% respectively, so PI constitutes a very efficient way of evacuating AH. Central endothelial WSS in Pa was lower for the large vault ICL and the Artiflex (1−03 and 1.1−03 respectively) compared to the PIOL-free eye (1.6−03). Crystalline lens WSS was highest for the lowest vault ICL (1−04).ConclusionsAH flow varied according to the presence of a precrystalline or iris-fixed intraocular lens. Endothelial WSS was lower for an implanted ICL with large vault and Artiflex than in the PIOL-free eye, while highest crystalline WSS was recorded for the lowest vault ICL.

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Computational Study of Aqueous Humor Dynamics Assessing the Vault and the Pupil Diameter in Two Posterior-Chamber Phakic Lenses

Abstract: AH flow varies depending on the type of ICL implanted, whether it is implanted with an iridotomy or a central hole on the lens, the PD, and the vault.

Cited by 24 publications

References 30 publications

The Implantable Collamer Lens with a central port: review of the literature

The Implantable Collamer Lens with a central port: review of the literature

Evaluation of Disk Halo Size after Implantation of a Collamer Lens with a Central Hole (ICL V4c)

Computational simulation of aqueous humour dynamics in the presence of a posterior-chamber versus iris-fixed phakic intraocular lens

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