Phakic Intraocular Lens Implantation Research Articles

Refractive Surgery in Myopic Children

In this paper, we summarize the current knowledge on refractive surgery performed in the myopic pediatric population. We describe the main concerns about refractive surgery in myopic children and the indications for refractive surgery in this age group. We present a range of surgical procedures that are being used for the management of unilateral/bilateral myopia in children: corneal refractive surgery (PRK, LASEK, LASIK, FS-LASIK and SMILE) and intraocular refractive surgery (phakic intraocular lens implantation, refractive lens exchange or clear lens extraction), with both their advantages and drawbacks. We also describe the various complications and measures to prevent them.

Implantation of phakic intraocular lenses in patients with stabilized keratoconus

To date, extensive experience has been accumulated in the correction of high myopia and myopic astigmatism through the implantation of additional negative lenses (phakic intraocular lenses). However, the use of this method in patients with anatomically altered corneas due to keratoconus remains unresolved.Purpose: to assess the effectiveness and safety of correcting high myopia combined with myopic astigmatism by implanting phakic intraocular lenses in patients with stabilized keratoconus at stages 1–2.Materials and methods. The study encompassed results from 27 surgeries involving the implantation of phakic intraocular lenses in patients with high myopia and myopic astigmatism (12.63 ± 4.25 D). These patients had thin corneas and were diagnosed with stage 1–2 keratoconus after undergoing corneal collagen crosslinking treatment – this constituted the main group. The control group comprised 35 surgeries performed on patients with subclinical non-progressive keratoconus (Forme Fruste). All participants underwent evaluations for visual acuity dynamics and refractive stability of spherical and cylindrical components before surgery, immediately post-surgery, and then at 1, 6, and 12 months after implantation. Additional assessments included intraocular pressure measurements, gonioscopy, ultrasonic echobiometry, ultrasonic ophthalmoscopy, biomicroscopy, ophthalmoscopy, endothelial microscopy, vision character and stereopsis determination, ultrasound biomicroscopy, anterior segment optical coherence tomography, electrophysiological studies, and statistical analysis. An IPCL (a type of phakic intraocular lenses made from hydrophilic acrylic) was implanted, capable of correcting myopia up to 30 D and astigmatism up to 10 D.Results. All patients achieved high uncorrected visual acuity 0.86 ± 0.11. Astigmatism correction was successful in 96% of cases. The average postoperative vault – the distance from the back surface of the phakic intraocular lenses to the anterior lens capsule – was 527.5 ± 40.27 μm (range 460–600 μm), and the intraocular pressure was 11.7 ± 2.08 mm Hg. There was a minor decrease in corneal endothelial cell count from 2599 ± 157.3 to 2375 ± 125.3 cells/mm² in the first group and from 2614 ± 104.8 to 2375 ± 43.3 cells/mm² in the second group respectively (p > 0.05), which falls within the acceptable loss range of 4–7% from preoperative values for both groups. Throughout the observation period, there were no cases of cataract development, pigmentary glaucoma, pupillary block, or other vision-threatening complications.Conclusions. Implantation of phakic intraocular lenses in patients with early-stage stabilized keratoconus and subclinical non-progressive keratoconus provides an effective and practically safe means of correcting high myopia and astigmatism.

Implantation of phakic intraocular lenses in patients with stabilized keratoconus

Implantation of phakic intraocular lenses in patients with stabilized keratoconus

Paying attention to safety of posterior chamber phakic intraocular lens implantation

Posterior chamber phakic intraocular lens implantation is a type of intraocular surgery. With advancements in implant materials and design, this procedure has seen rapid adoption and widespread use in ophthalmology clinics in recent years. However, the changes in surgical techniques and the occurrence of postoperative complications have raised safety concerns that require significant attention in clinical practice. This paper aims to address the key factors influencing the safety of posterior chamber phakic intraocular lens implantation, exploring relevant characteristics, mechanisms, and current challenges. By emphasizing the importance of this surgery and proposing effective measures, it aims to provide guidance for clinical practice, enhance the safety of posterior chamber phakic intraocular lens implantation, and foster the healthy advancement of this surgical technique.

A comparative study of two phakic posterior chamber implantable lenses.

This study aimed to compare the postimplantation clinical outcomes of 2 types of posterior chamber phakic intraocular lenses (IOLs): Visian™ implantable collamer lenses (ICL; EVO+ V5; Staar Surgical, Monrovia, CA) and an implantable phakic contact lens (IPCL) (IPCL V2.0, Care Group Sight Solution, India) to correct high myopia and myopic astigmatism. This retrospective study included patients who had undergone phakic IOL implantation performed by a single surgeon between March 2021 and March 2022. Preoperative assessments included slit-lamp examination, fundus examination, spherical equivalent, uncorrected distant visual acuity (UDVA), corrected distant visual acuity (CDVA), specular microscope parameters, and optical quality analysis system parameters. Postoperative assessments after 1 year included slit-lamp examination to detect adverse effects and spherical equivalent, UDVA, CDVA, specular microscope, optical quality analysis system, and anterior-segment optical coherence tomography. Eighty eyes from 42 patients (47 eyes from 24 patients in the ICL group and 33 eyes from 18 patients in the IPCL group) were included. No statistically significant differences were observed between the 2 groups regarding preoperative parameters. At 1-year postoperatively, the mean UDVA in the ICL and IPCL groups was 0.019 ± 0.040 logMAR and 0.019 ± 0.041 logMAR, respectively. The mean CDVA was 0.001 ± 0.008 logMAR and 0.001 ± 0.007 logMAR in the ICL and IPCL groups, respectively, showing no statistically significant differences. The postoperative parameters did not differ significantly between the 2 groups. The visual acuity and refractive results of both groups were excellent, and both groups exhibited similar efficacy and safety profiles.

Analysis after posterior chamber phakic intraocular lens implantation: 17- to 19-year follow-up study.

To evaluate the clinical outcomes of the Visian implantable collamer lens (ICL) in eyes with ≥17 years of follow-up. Single-center. Retrospective observational study. 70 eyes from 38 patients who underwent surgery between 2002 and 2006 with V4 ICL implantation were analyzed. Preintervention data included corrected distance visual acuity (CDVA), refraction, and intraocular pressure (IOP). At the 19-year mark, CDVA, refraction, IOP, endothelial count, and vault were measured using Tomey Casia 2 anterior pole tomography, along with recording long-term events. The operated patients had a spherical correction between -4 diopters (D) and -21 D and a cylinder up to 7.5 D. The mean CDVA (decimal) at the 17-year check-up was 0.89 ± 0.18, with a spherical equivalent of -1.05 ± 1.36 D. IOP has remained stable because mean measurements before surgery and currently were 15.16 ± 2.54 mm Hg and 16.19 ± 3.29 mm Hg, respectively. The endothelial cell count showed values of 2191 ± 386 cells/mm2, with a maximum of 2804 cells and a minimum of 1125 cells. Finally, the vault obtained was 348.53 ± 234.58 mm. Over the years, 2 eyes developed angle-closure glaucoma and 9 eyes were operated on for the development of anterior subcapsular cataracts. Visian ICL implantation demonstrated long-term visual and refractive stability, indicating it as a low-risk procedure. The ICL V4 model yielded satisfactory results for myopia and astigmatism correction after 17 years.

Implantable Collamer Lens Procedure Planning: A Review of Global Approaches.

More than 2 million implantable collamer lenses (ICLs) have been implanted worldwide. With a central port to improve aqueous flow through the ICL, the latest iteration of this phakic intraocular lens (pIOL) has been shown to have stable outcomes with very low rates of adverse events. However, correct planning and ICL size selection continue to be important to achieve an optimal vault. Shallow or excessive vaults are not complications in and of themselves but may increase the risk of complications. Historically, surgeons have relied on measurements of anterior chamber depth (ACD) and manual, caliper-measured white-to-white (WTW) distance to select the ICL size. New diagnostic and imaging technologies such as optical coherence tomography (OCT) and ultrasound biomicroscopy (UBM) provide additional opportunities for visualization and measurement of the intraocular dimensions involved in phakic intraocular lens implantation, including sulcus-to-sulcus (STS) and angle-to-angle (ATA) diameters. This paper reviews various approaches to ICL planning and sizing that have been published in the peer-reviewed literature, all of which produce acceptable results for predicting vault and size selection. Surgeons may also want to identify a methodology for patient evaluation and ICL size selection that best aligns with their personal preferences, diagnostic technology, and familiarity with analytical optimization tools.

Retinal complications post posterior chamber phakic intraocular lens implantation at a tertiary eye hospital in the Eastern Province of Saudi Arabia.

Phakic intraocular lenses treat higher degrees of myopia not possible previously with conventional refractive surgery. The aim of this study is to report the incidence and risk factors of retinal complications after posterior chamber PIOL implantation and assess the differences in biometric parameters between patients who developed such complications versus those who did not. This retrospective study recruited 514 patients who underwent ICL implantation to correct myopia at a tertiary eye hospital center in the Eastern province of Saudi Arabia. Follow up period was at least one year. Medical records of the patients were reviewed to obtain the required data. Associations between respondents' characteristics and retinal complications were evaluated using the Chi-squared test. The mean (SD) age was 27.7 (± 6.5) years ranging from 18 to 47. Laser treatment was performed in 14 cases (2.7%). Retinal complications occurred in six cases (1.2%). The risk of retinal complication was significantly higher among patients with high axial length (OR = 1.3, 95% CI 1.2, 1.4) and patients with high pre-spherical equivalent before ICL (OR = 1.09, 95% CI 1.03, 1.4). Patients with higher axial length and higher pre-spherical equivalent before ICL implantation are at high risk of retinal complications.

Comparison of the Biometric Characteristics After Long-term Implantation of Iris-fixated Phakic Intraocular Lens in Explanted and Nonexplanted Groups of Eyes

PurposeTo evaluate and compare the biometric characteristics of the anterior chamber of a group of patients with significant endothelial cell loss (ECL) that required phakic IOL (pIOL) explantation and a group of patients who did not fulfill the explantation criteria related to corneal decompensation. DesignRetrospective consecutive interventional case series MethodsThe study included all consecutive patients implanted with pIOL at Oftalmosalud Instituto de Ojos, Lima, Peru, between 2001 and 2012. The explanted group (E-group) consisted of eyes in which the pIOLs were explanted due to ECL and the non-explanted group (NE-group) consisted of eyes randomly selected in which the pIOL was not explanted with a minimum follow-up time of eight years. Slit-lamp biomicroscopy, visual acuity, refraction, endothelial cells count, and anterior segment OCT were assessed at the preoperative evaluation for both groups and before explantation in the E-group and eight years post implantation in the NE-group. Results265 eyes were implanted with pIOL. The annual percentage of ECL was 1.47% and 5.55% in the NE-group and the E-group, respectively (p < .001). The mean minimum endothelial lens distance (min-ELD) was 1.44 ± 0.22 mm and 1.05 ± 0.23 mm in the NE-group and the E-group, respectively (p < 0.001). The mean time for explantation was 12.58 ± 3.79 years for the NE-group. Annual ECL could accurately discriminate between NE-group and E-group, a cutoff point of 3.5 (%/year) or 86.5 (cells/years) had a 100% sensitivity and specificity. A cutoff of 1.21 mm in the min-ELD, has a 91% sensitivity and 79% specificity to discriminate between E-group and NE-group. ConclusionpIOL explantation due to ECL occurs in eyes with a significantly postoperative lower min-ELD. Annual ECL and min-ELC can effectively discriminate between explanted and non-explanted groups.

VISUAL AND REFRACTIVE OUTCOME OF NEW GENERATION SMALL INCISION LENTICULE EXTRACTION (SMILE) IN MYOPIA AND MYOPIC ASTIGMATISM

Introduction: Two main options for the surgical correction of high myopia and myopic astigmatism are corneal refractive surgery and implantation of phakic intraocular lens (IOL). Small Incision Lenticule Extraction (SMILE) is becoming more popular technique which includes a minimally invasive flap-free procedure. The aim of this study is to evaluate the visual and refractive outcome of New Generation SMILE in myopia and myopic astigmatism. Methods: This is an observational retrospective study in patients who underwent SMILE using Visumax 800 Femtosecond laser procedure at Undaan Eye Hospital in period December 2022 to February 2023. Pre and post operative uncorrected visual acuity (UCVA), spherical equivalent (SE), astigmatism value, keratometry and intra ocular pressure (IOP) were evaluated at 1 day, 1 week and 1 month follow-up. Results: The study comprised 30 eyes of 15 patients age from 18 to 32 years old. The mean post operative UCVA was significantly improved to 0.03 ± 0.06 logMAR at 1-day, 0.02 ± 0.04 logMAR at 1-week and -0.01 ± 0.02 logMAR at 1-month follow-up compared to preoperative UCVA 1.35 ± 0.23 logMAR (p&lt;0.001). The mean refractive spherical equivalent was significantly changed from -4.60 ± 1.47 D preoperatively to -0.57 ± 0.38 D at 1-month follow up (p &lt; 0.001). The mean refractive astigmatism decreased from -1.02 ± 0.66 D preoperatively to -0.34 ± 0.25 D at 1- month follow up (p&lt;0.001). Conclusion: New Generation of SMILE has shown good visual and refractive outcome for the correction of myopia and myopic astigmatic eyes since the early phase after surgery.

Analysis of pre-operative factors affecting vault after posterior chamber phakic intraocular lens implantation

Objective: To analyze the early changes in vault height and its influencing factors after implantation of posterior chamber phakic intraocular lenses (pIOL). Methods: A retrospective case series study was conducted, including patients who underwent pIOL implantation at Zhongshan Ophthalmic Center, Sun Yat-sen University, from September 2020 to August 2021, and completed a 3-month follow-up. Data were collected from myopic or myopic astigmatism patients. Preoperative ocular examinations, including Pentacam anterior segment analysis system, Sirius anterior segment analysis system, ultrasound biomicroscopy (UBM), and IOLMaster optical biometry, were performed to measure parameters such as refractive power, corneal curvature, corneal horizontal diameter, anterior chamber volume, anterior chamber depth, pupil diameter, sulcus-to-sulcus diameter (STS), and lens thickness. The degree and position of implanted pIOL, as well as vault height measured by anterior segment optical coherence tomography (AS-OCT) at 1 day, 1 week, 1 month, and 3 months postoperatively, were recorded. Statistical analyses were conducted using repeated measures analysis of variance, Pearson correlation analysis, and multiple linear regression analysis. Results: A total of 314 patients (314 eyes) were included, with 52 male (16.56%) and 262 female (83.44%) patients, and an average age of (26.44±4.60) years. The preoperative equivalent spherical power was (-8.09±2.41) D. Postoperative vault heights at 1 day, 1 week, 1 month, and 3 months were (671.88±273.02) μm, (652.26±272.21) μm, (615.08±259.69) μm, and (591.14±250.71) μm, respectively, with statistically significant differences among groups (P<0.001). Eyes with vault height>750 μm showed a greater decrease in early postoperative vault height (P<0.001). The eyes implanted with 12.1 mm pIOL had the lowest postoperative vault height, while those with 13.2 mm had the highest (P>0.05). Factors correlated with vault height at 1 day postoperatively included corneal horizontal diameter, anterior chamber depth, preoperative cylinder power, angle degree, lens thickness, and pIOL cylinder power. Factors correlated with vault height at 3 months postoperatively included corneal horizontal diameter, anterior chamber depth, preoperative cylinder power, anterior chamber volume, angle degree, lens thickness, axial length, pIOL spherical and cylinder power. Factors associated with changes in early postoperative vault height included corneal curvature K2, anterior chamber depth, anterior chamber volume, pupil diameter, horizontal STS, vertical STS, axial length, and preoperative spherical power (all P<0.05). Multiple linear regression analysis revealed that lens thickness significantly influenced vault height at 1 day postoperatively, anterior chamber volume significantly influenced vault height at 3 months postoperatively, and pupil diameter significantly influenced changes in early postoperative vault height (all P<0.05). Conclusions: Vault height after pIOL implantation is unstable in the early postoperative period and gradually decreases within 3 months. A higher baseline vault height is associated with a greater decrease. Anterior chamber volume, pupil diameter, and lens thickness are influencing factors on vault height during the first 3 months postoperatively.

Seven-Year clinical outcomes after implantation of Eyecryl posterior chamber phakic intraocular lenses for high myopia.

To evaluate the long-term clinical outcomes, safety and efficacy of Eyecryl posterior-chamber phakic intraocular lens implantation (pIOL) implantation in patients with high myopia. Patients with myopia between -6.00 and -20.00 dioptres and with endothelial cell density (ECD) was ≥2300 cells/mm2 were included. Preoperative and postoperative first, fourth, and seventh years of refraction, uncorrected/corrected distance visual acuity (UDVA/CDVA), ECD, central vault were detected. Thirty-six eyes were analyzed. The mean UDVA and CDVA in postoperative seventh years were 0.25 ± 0.31 and 0.13 ± 0.24 logMAR, respectively. The safety and efficacy indices were 1.55 ± 0.54 and 1.24 ± 0.53, respectively. The mean cumulative ECD loss was 6.96% (p < 0.001). The central vault at the 1st and the 7th year were 0.52 ± 0.14 and 0.49 ± 0.14 mm, respectively (p = 0.25). These findings supported the long-term stability, efficacy, safety of the Eyecryl pIOL for high myopia. Eyecryl posterior chamber pIOL is one of the effective refractive options in correcting high myopia.

The Influence of Lens Position, Vault Prediction, and Posterior Cornea on Phakic Posterior Chamber Intraocular Lens Power

BackgroundAchieving precise refractive outcomes in phakic posterior chamber intraocular lens (pIOL) implantation is crucial for patient satisfaction. This study investigates factors affecting pIOL power calculations, focusing on myopic eyes, and evaluates the potential benefits of advanced predictive models. DesignRetrospective, single-center, algorithm improvement study MethodsVarious variations with different effective lens position (ELP) algorithms were analyzed. The algorithms included a fixed constant model, and a multiple linear regression model and were tested with and without incorporation of the posterior corneal curvature (Rcp). Furthermore, the impact of inserting the postoperative vault, the space between the pIOL and the crystalline lens, into the ELP algorithm was examined, and a simple vault prediction model was assessed. ResultsIntegrating Rcp and the measured vault into pIOL calculations did not significantly improve accuracy. Transitioning from constant model approaches to ELP concepts based on linear regression models significantly improved pIOL power calculations. Linear regression models outperformed constant models, enhancing refractive outcomes for both ICL and IPCL pIOL platforms. ConclusionsThis study underscores the utility of implementing ELP concepts based on linear regression models into pIOL power calculation. Linear regression based ELP models offered substantial advantages for achieving desired refractive outcomes, especially in lower to medium power pIOL models. For pIOL power calculations in both pIOL platforms we tested with preoperative measurements from a Scheimpflug device, we found improved results with the LION 1ICL formula and LION 1IPCL formula. Further research is needed to explore the applicability of these findings to a broader range of pIOL designs and measurement devices.

Anterior chamber phakic lens implantation after deep anterior lamellar keratoplasty. Retrospective cohort with 24‐month follow‐up

Aims/Purpose: To report the outcome of correction of high myopia with anterior chamber phakic intraocular lenses (IOLs) implantation after deep anterior lamellar keratoplasty (DALK).Methods: Retrospective study with 7 eyes of patients who underwent DALK. The main variables measured were corrected visual acuity (CVA) and uncorrected visual acuity (UCVA), spherical equivalent, and endothelial cell density (ECD). Follow‐up was performed up to 24 months after the lens implant.Results: The spherical equivalent (SE) recorded a mean of −14.16 (± 3.50) before the lens implant and −0.30 (±0.93) after the implant, with a mean difference of 13.85 (10.25 to 13.85) and a p‐value of &lt;0.001. The mean of uncorrected visual acuity (UCVA) before the lens was 1.82 (±0.63), 6 months after lens implant was 0.22 (±0.07), and after 24 months, 0.30 (±0.14) with a p‐value of 0.001. Among patients, 85.71% had a UCVA equal to or better than 0.3 logMAR and 42.85% had a UCVA of 0.2 logMAR vs. 0% preoperatively. 71.42% of the patients had residual ametropia within ±1.00 D. The mean corrected visual acuity (CVA) was 0.31 (±0.06) before lens implantation, 0.12 (±0.04) 6 months post‐ implantation and 0.14 (±0.05) 24 months post‐implantation. All patients had improvement of UCVA of at least 10 lines of vision (range 10 to 14); at 6 months, 71.42% of patients had a gain of at least 2 lines of vision in CVA and at 24 months only one patient had a decrease in UCVA. The mean difference in ECD was 68.71 (95% CI 11.97 to 125.44), corresponding to a loss of 1.26% of cells per year.Conclusions: Phakic IOLs are an effective and stable procedure for management of high myopia after DALK, demonstrating stable safety and efficacy rates up to 24 months. The known risk of endothelial loss should be closely monitored, as such loss is higher compared to eyes with phakic IOL implants without DALK.

Artificial intelligence, anterior segment and refractive surgery: Which relationship and association?

Aims/Purpose: The goal of our work is to synthesize the different fields identified by AI in refractive surgery.Methods: Research in the literature of the different manifestations of artificial intelligence related to refractive surgery.Results: Several articles including reviews reported several studies done in this direction. Lops and al introduced the PRFI (Pentacam Random Forest Index) using data from 3 different countries. The PRFI has a sensitivity of 85.2% and specificity of 96.6%. Xie and Co developed PIRSS (Pentacam InceptionResNetV2 Screening) for refractive surgery with a little number of false positive in identifying normal cornea, suspected irregular and keratoconic cornea. AI has also been used in recommending the appropriate refractive surgery and nomograms used, Kamiya and al developed an ML‐based algorithm to predict the postoperative posterior chamber phakic intraocular lens (IOL) vault using preoperative AS‐OCT images of patients undergoing phakic IOL implantation to predict the achieved vault. These examples of studies and discoveries open new horizons in refractive surgery using AI.Conclusions: AI has been successfully used in the prediction of diagnosis of various corneal disorders, including IK, keratoconus, pterygium, endothelial diseases, and corneal graft‐related complications but also in refractive surgery; certainly it has limits but next to telemedicine, 5G/6G networks, Quantum Communication Networks and Internet of Medical Things, AI is likely to form part of the new health care revolution.

ILM Insertion for the Treatment of Macular Hole Associated with Phakic Intraocular Lens Implantation

Purpose: To report a case of macular hole closure using an internal limiting membrane (ILM) flap following implantation of a posterior chamber phakic implantable contact lens (ICL).Case summary: An 18-year-old female patient presented with visual loss of the left eye after ICL implantation. She had high myopia of -12.5 diopter (spherical equivalent) and a corrected visual acuity of 2/100. The fundus photograph and optical coherence tomography showed a full-thickness macular hole measuring 688 µm in width and 976 µm in length. The ILM around the hole was detached from the retinal surface, which was greater in size than the macular hole. The initial surgical intervention involved vitrectomy, inverted ILM flap placement, and gas tamponade. The decrease in gas volume was associated with a loss of the ILM flap. For hole closure, the remaining ILM flap in the peripheral macula was harvested and inserted in the hole during the second surgery. The silicone oil was used for tamponade. One month after ILM insertion, complete closure of the hole was observed. The visual acuity improved to 20/40 after silicone oil removal.Conclusions: A large full-thickness macular hole developed after ICL implantation in a patient with high myopia. Macular hole surgery using ILM insertion and prolonged tamponade closed the hole and effectively improved the visual acuity.

Phakic intraocular Lens implantation in keratoconus patients.

Both the anterior chamber and posterior chamber phakic intraocular lenses (pIOLs) implantation are acceptable refractive surgical approaches in keratoconus patients with high anisometropia, contact lens intolerance, or who prefer spectacle and contact lens independent. They are beneficial for correcting anisometropia in stable keratoconus cases or following corneal procedures such as intrastromal corneal ring segments (ICRS), collagen cross-linking (CXL), and keratoplasty. They are suitable for eyes without advanced keratoconus with acceptable best-corrected distance visual acuity (BCDVA) or without highly irregular astigmatism, high comma, and higher-order aberrations (HOAs). Combined procedures for irregular astigmatism reduction and corneal regularization with either ICRS or topography/wavefront-guided transepithelial PRK (with or without CXL) can be associated in advance with pIOLs implantation to improve BCDVA in these cases. To study and report the evidence regarding the safety and efficacy of pIOLs for KC patients' visual and refractive rehabilitation, we have analyzed the scientific evidence published within the last 10 years (from 2012 onwards). No randomized controlled trials but only eleven retrospective case series and two prospective case series were identified. Satisfactory visual rehabilitation was achieved regarding uncorrected and corrected distance visual acuity (CDVA) and predictability of the refractive correction. Both types of pIOL (iris claw and posterior chamber pIOLs) offer very good results in terms of safety and efficacy with indexes close to or even exceeding 1. pIOLs implantation is a valid refractive therapeutic approach for correcting stable keratoconus with moderate-to-high refractive errors, especially anisometropia associated with regular or mildly irregular astigmatism, and good CDVA.

Comparison of Dynamic Vault Changes Following Implantation of Two Different Models of Phakic Intraocular Lenses.

To compare the dynamic vault range (the difference in the central vault height from scotopic to photopic light condition) after implantation of the ICL/TICL (STAAR Surgical) and Eyecryl phakic/Eyecryl phakic toric intraocular lens (IOL) (Biotech Healthcare). This retrospective study included patients with myopia or myopic astigmatism eligible for phakic IOL implantation with either the ICL/TICL or Eyecryl phakic/Eyecryl phakic toric IOL. Vault changes in varying light conditions (scotopic, mesopic, and photopic) were assessed using an anterior segment optical coherence tomography-based tomographer and dynamic vault range (DVR) was compared between the two groups. A total of 60 eyes from 36 patients (30 eyes in each group) with a mean age of 28.63 ± 6.36 years were included. The mean postoperative follow-up at the time of assessment was 9.4 ± 5.3 and 8.9 ± 5.28 months (P = .75) in the ICL and Eyecryl groups, respectively. The mean values of scotopic, mesopic, and photopic vault were 490.56 ± 238.64, 453.56 ± 224.30, and 373.96 ± 200.24 μm in the ICL group and 515.46 ± 174.34, 490.26 ± 184.04, 450.43 ± 173.92 μm in the Eyecryl group (P = .32, .24, and .05, respectively). The DVR was 116.6 ± 59.29 μm in the ICL group versus 65.03 ± 31.78 μm in the Eyecryl group (P < .001). The Eyecryl phakic IOL showed significantly fewer light-induced changes in the central vault height (DVR) compared to the ICL, which may be attributed to the difference in the material of the two phakic IOL models. This may be clinically significant in eyes with low postoperative vaults with respect to their follow-up and risk assessment of cataractogenesis in the long term. [J Refract Surg. 2023;39(8):546-554.].

Dynamic Stimulation Aberrometry: Objectively Measured Accommodation and Pupil Dynamics after Phakic Iris-Fixated Intraocular Lens Implantation

Anterior iris-claw phakic intraocular lens (pIOL) implantation is a treatment option for refractive, ametropic patients. However, the postoperative accommodative ability has not been systematically researched. Dynamic stimulation aberrometry allows the objective and dynamical measurement of accommodation by observing ocular aberrations during the accommodation process. We investigated the dynamic accommodative ability after pIOL implantation compared with a healthy age- and gender-matched control group. Clinical, comparative case-control study. We included patients aged 18-50 years that either underwent pIOL implantation > 1 month ago or served as a healthy, phakic control group. The accommodative ability and pupil dynamics of both groups were investigated using dynamic stimulation aberrometry. The method allows the analysis of dynamic parameters during accommodation, such as the accommodation speed. A 1:1 propensity score matching was conducted based on the patients' age and gender. Parameters of objective accommodation, such as accommodative amplitude and pupil dynamic during accommodation. Fifty-eight healthy, phakic eyes < 50 years of age and 21 eyes after pIOL implantation to correct myopia (pIOL, Verisyse, AMO, Inc) were enrolled. Patients that underwent anterior pIOL implantation were examined on average 24 ± 18 months after surgery. After matching, the mean age of both groups was not significantly different (35 ± 8 vs. 34 ± 8 years). No significant difference in dynamic parameters of accommodation or the accommodative amplitude (2.8 ± 1.4 and 2.9 ± 1.4 diopters [D] for pIOL and control group, P= 0.82) were seen. Maximum and minimum pupil sizes were not significantly different. The change in pupil size during deaccommodation was significantly faster in patients after pIOL implantation (P < 0.001). Dynamic stimulation aberrometry allowed the objective, dynamic, measurement of wavefronts in subjects with accommodative amplitudes up to 7 D. Phakic intraocular lens implantation does not impair the accommodative ability. It alters pupil dynamics during deaccommodation. Proprietary or commercial disclosure may be found after the references.

Predicting Vault and Size of Posterior Chamber Phakic Intraocular Lens Using Sulcus to Sulcus-Optimized Artificial Intelligence Technology

To investigate the accuracy of posterior chamber phakic intraocular lens (PIOL) vault and size prediction models based on sulcus to sulcus (STS) optimized artificial intelligence and big data analysis technology. Big data and artificial intelligence prediction model. We included 5873 eyes with posterior chamber PIOL implantation, and the postoperative vault was measured using an anterior segment analyzer (Pentacam AXL) 1 month postoperatively. A random forest regression model and classification model were used to predict the postoperative vault and PIOL size. The postoperative vault and PIOL size were set as output features; other vault-related eye parameters were set as input features. The influence of white to white (WTW), horizontal sulcus to sulcus (STS), and vertical STS on predicting postoperative vault and PIOL size was analyzed and compared. The mean preoperative WTW diameter was 11.64 ± 0.37 mm, the mean horizontal STS diameter was 11.85 ± 0.47 mm, and the mean vertical STS diameter was 12.39 ± 0.52 mm. In the regression model for numerical prediction of the vault, the combination of WTW, horizontal STS, and vertical STS was the most optimal for vault prediction (R2=0.3091, root mean square error [RMSE]=0.1705); solely relying on WTW was the least optimal (R2=0.2849, RMSE=0.1735). Among the models for classification prediction of the vault, the combination of WTW, horizontal STS, and vertical STS was the most accurate (accuracy, 0.6302; mean area under the curve, 0.8008; and mean precision recall rate, 0.6940). Moreover, the combination of WTW, horizontal STS, and vertical STS exhibited the highest accuracy for classification prediction of PIOL size (accuracy, 0.8170; mean area under the curve, 0.9540; and mean precision recall rate, 0.8864). Whether in the regression prediction models of vault values or in the classification prediction models of vault and PIOL size, the accuracy of STS optimized model was significantly improved compared with the traditional WTW model (P < .001). Artificial intelligence combined with STS optimization contributes to the accuracy of PIOL size and vault prediction models. The random forest machine-learning model optimized by STS is superior to the traditional WTW model.