Chamber Phakic Intraocular Lens Implantation Research Articles

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.

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.

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.

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.

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.

Clinical outcomes of implantation of posterior chamber phakic intraocular lens for pathologic and non-pathologic myopia

BackgroundTo compare the clinical outcomes of posterior chamber phakic intraocular lens (pIOL) implantation for non-pathological myopia and pathological myopia.MethodsThis retrospective case series study which were conducted in Beijing Tongren Eye Center between July 2017 and Oct 2021 comprised 192 eyes of 100 consecutive patients undergoing pIOL implantation. Eyes were divided into two groups based on having pathological myopia or not. Predictability, efficacy, safety, and adverse events were compared at 6 months after pIOL implantation.ResultsOur study included 86 non-pathological myopes (171 eyes, group1) and 14 pathological myopes (21eyes, group2) to analysis. The average ages were 25.5 and 33.0, respectively, and the spherical equivalent (SE) were -9.31D and -17.50D pre-operation. Six months after pIOL implantation, the SE were 0.00 and -0.50, respectively, and the refraction changes were statistically significant (P ≤ 0.05). Six months after surgery, 76.92% and 80.41% were within ± 0.50 D of the target and 92.31% and 95.88% were within ± 1.00 D. All eyes had unchanged BCVA or gained 1 or more lines in both groups and mean BCVA both improved a line 6m after operation. The efficacy index in the two groups were 0.95 and 0.88 and the safety index were 1.20, 1.33, respectively which was significantly different (P ≤ 0.05). Over the 6-month follow-up, no cataract, pigment dispersion glaucoma, pupillary block, or other vision-threatening complications happened, either.ConclusionsThe pIOL performed well for the correction of both non-pathological and pathological myopia throughout the 6-month observation period. The clinical outcomes of pIOL implantation for non-pathological myopia are essentially equivalent to those for pathological myopia.

Association between the site of clear corneal Phakic intraocular lens implantation incisions and the inflow of ocular surface fluid into the anterior chamber.

Posterior chamber phakic intraocular implantable collamer lens (ICL) implantation is an effective surgical option for the management of myopia. Over the past few years, the number of ICL surgeries has significantly increased. Postoperative inflammation and endophthalmitis are among the most serious complications after successful ICL surgery. Sometimes, when the blepharospasm is removed at the end of surgery, a small amount of the ocular surface fluid will flow into the anterior chamber, which can lead to an increased risk of infection and inflammation. However, little attention has been paid to this phenomenon. We conducted a retrospective study to compare the incidence of extraocular fluid inflow into the eye through the clear corneal incision (CCI) at two different positions (superior and temporal sides). A total of 116 patients with myopia underwent superior CCI ICL implantation (n = 58) or temporal CCI ICL implantation (n = 58) at our hospital from October to December 2021. The incidence of conjunctival sac fluid entering the anterior chamber after eyelid fixative was removed was compared in both groups. Both groups were well matched in all parameters. Ocular surface fluid inflow into the anterior chamber was significantly higher in the superior CCI group (25/58, 47.1%) than in the temporal CCI group (1/58, 1.7%) (p < 0.05). In the patients with ICL implantation, the temporal CCI was better than the superior CCI in avoiding the ocular surface fluid inflow into the anterior chamber, and the potential risk of infection and inflammation was lower.

Predicting Postoperative Anterior Chamber Angle for Phakic Intraocular Lens Implantation Using Preoperative Anterior Segment Metrics.

The anterior chamber angle (ACA) is a critical factor in posterior chamber phakic intraocular lens (EVO Implantable Collamer Lens [ICL]) implantation. Herein, we predicted postoperative ACAs to select the optimal ICL size to reduce narrow ACA-related complications. Regression models were constructed using pre-operative anterior segment optical coherence tomography metrics to predict postoperative ACAs, including trabecular-iris angles (TIAs) and scleral-spur angles (SSAs) at 500 µm and 750 µm from the scleral spur (TIA500, TIA750, SSA500, and SSA750). Data from three expert surgeons were assigned to the development (N = 430 eyes) and internal validation (N = 108 eyes) datasets. Additionally, data from a novice surgeon (N = 42 eyes) were used for external validation. Postoperative ACAs were highly predictable using the machine-learning (ML) technique (extreme gradient boosting regression [XGBoost]), with mean absolute errors (MAEs) of 4.42 degrees, 3.77 degrees, 5.25 degrees, and 4.30 degrees for TIA500, TIA750, SSA500, and SSA750, respectively, in internal validation. External validation also showed MAEs of 3.93 degrees, 3.86 degrees, 5.02 degrees, and 4.74 degrees for TIA500, TIA750, SSA500, and SSA750, respectively. Linear regression using the pre-operative anterior chamber depth, anterior chamber width, crystalline lens rise, TIA, and ICL size also exhibited good performance, with no significant difference compared with XGBoost in the validation sets. We developed linear regression and ML models to predict postoperative ACAs for ICL surgery anterior segment metrics. These will prevent surgeons from overlooking the risks associated with the narrowing of the ACA. Using the proposed algorithms, surgeons can consider the postoperative ACAs to increase surgical accuracy and safety.

Long-term efficacy and safety profiles of iris-fixated foldable anterior chamber phakic intraocular lens implantation in eyes with more than 10 years of follow-up.

To evaluate the long-term efficacy, safety, predictability, and stability of a foldable anterior chamber phakic intraocular lens (pIOL) (Artiflex) implantation in eyes with more than 10 years of follow-up. Instituto de Microcirugía Ocular, Barcelona, Spain. Retrospective study. Patients who underwent Artiflex pIOL implantation during 2008 to 2011 and with more than 10 years of follow-up were included. Variables analyzed were as follows: uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, spherical equivalent (SE), endothelial cell count (ECC), and intraocular pressure (IOP) preoperatively and at 1 month, 1 year, 5 years, and the final follow-up. Descriptive statistics were performed and results reported following the Standard for Reporting Refractive Surgery Outcomes. 76 eyes (40 patients) were analyzed, and the mean follow-up was 10.67 ± 0.64 years. The mean preoperative SE was -8.26 ± 2.47 diopters (D), and the mean preoperative cylinder was -0.95 ± 0.86 D. At the final follow-up, efficacy and safety indices were 0.82 and 1.11, respectively. In total, 58 eyes (76%) achieved a UDVA of ≥20/40. 30 eyes (39%) gained ≥1 line of CDVA, and no eye lost ≥2 lines of CDVA. At the final follow-up, 46 (61%) and 58 (76%) eyes were within ±0.50 D and ±1.00 D of attempted SE correction, respectively. 72 eyes (95%) had ≤1.00 D of postoperative astigmatism, and 46 eyes (61%) were within ±15 degrees from the intended correction axis. At the last visit, a statistically significant myopic progression of -0.56 ± 0.83 D was observed ( P = .01). The mean ECC loss at the final follow-up was 12.2 ± 12.5%. IOP remained stable. Two eyes (2.63%) developed cataract after 10.3 years. Long-term results demonstrated that Artiflex pIOL implantation was effective, predictable, stable, and safe.

Mechanical analysis of the impact of the morphology of the iris and ciliary body on the central vault after posterior chamber phakic intraocular lens implantation

Objective: To investigate the impact of the iris and ciliary body morphology on the central vault after phakic posterior chamber intraocular lens (pIOL) implantation. Methods: This research was based on the retrospective analysis of 123 patients (123 eyes) who underwent pIOL implantation in the Department of Ophthalmology, Affiliated Hospital of Qingdao University between June 2018 and June 2020. The anterior segment structure was observed with an ultrasound biomicroscope before surgery, and all morphological parameters of the iris and ciliary body were measured manually using the ImageJ software, including iris span (IS), iris convexity (IC), iris-ciliary body contact distance (ICCD) and iris-lens contact distance (ILCD). The ICCD was divided into Q1, Q2 and Q3 groups according to the equidistant distance of 0.36 mm. The lens thickness was measured with the IOLMaster. The horizontal corneal diameter and anterior chamber depth were measured using the Pentacam. The central vaults were measured by optical coherence tomography at 1 week, 3 months and 1 year after surgery. The relationships between vault values and preoperative parameters of the anterior segment were evaluated using the Pearson correlation analysis, Spearman correlation analysis, and multiple linear regression. The repeated measures ANOVA was applied to identify changes of vault values over time. Results: The mean values of the vaults at 1 week, 3 months and 1 year after surgery were (723±265) μm, (642±255) μm and (613±280) μm, respectively. The difference among them was statistically significant (F=50.143, P<0.001). The vaults continued to decline within 1 year after pIOL implantation, and the total decline was (122±86) μm. The vaults declined by (69±98) μm from postoperative 1 week to 3 months and by (52±54) μm from postoperative 3 months to 1 year. The regression formula showed that the pIOL size and ILCD were positively related with the vault, while the LT, IS and IC were negatively related with the vault at 1 week postoperatively (adjusted R²=0.404, P<0.001). The pIOL size and ILCD were positively related with the vault, while the IS and IC were negatively related with the vault at 3 months postoperatively (adjusted R²=0.342, P<0.001). The pIOL size was positively related with the vault, while the IS and IC were negatively related with the vault at 1 year postoperatively (adjusted R²=0.661, P<0.001). The vault values were higher in group Q3 compared to group Q1 at every timepoint, and the vault value was higher in group Q2 compared to Q1 at 1 year postoperatively. Conclusions: In the early postoperative period, eyes with a larger pIOL, shorter iris span, longer contact distance between the iris and ciliary body, and longer contact distance between the iris and lens were associated with a higher rate of excessive vaults. Meanwhile, eyes with a thicker lens and larger iris reverse convexity were more likely to obtain insufficient vaults. Within one year after surgery, the pIOL size, IS, IC and ICCD continued to impact on the vault. The ICCD, ILCD and IC can reflect the posterior chamber volume and change the haptic location and force, thus affecting the vault.

Long-term efficacy and safety profiles after posterior chamber phakic intraocular lens implantation in eyes with more than 10 years of follow-up.

To evaluate long-term efficacy, safety, predictability, and stability of a posterior chamber phakic intraocular lens (Visian implantable collamer lens [ICL]) in eyes with ≥10 years of follow-up. Instituto de Microcirugía Ocular, Barcelona, Spain. Retrospective study. Eyes undergoing ICL implantation from 2008 to 2011 with ≥10 years of follow-up were included. Variables analyzed were preoperative, 1-month, 1-year, 5-year, and last follow-up uncorrected distance (UDVA) and corrected distance visual acuity (CDVA), manifest refraction, spherical equivalent (SE), endothelial cell count (ECC), and intraocular pressure (IOP). Descriptive statistics were performed and results reported following the Standard for Reporting Refractive Surgery Outcomes. 45 eyes (26 patients) were analyzed; the mean follow-up 11.35 ± 1.30 years. The mean preoperative SE was -10.06 ± 3.40 diopters (D) and the mean preoperative cylinder -1.55 ± 1.45 D. At the last follow-up, efficacy and safety indices were 0.79 and 1.12, respectively. In total, 32 eyes (71%) achieved an UDVA of ≥20/40. 22 eyes (49%) gained ≥1 line of CDVA, and 2 eyes (4%) lost ≥2 lines of CDVA. At the final follow-up, 19 eyes (42%) and 29 eyes (64%) were within ±0.50 D and ±1.00 D of attempted SE correction, respectively. 31 eyes (69%) had ≤1.00 D of postoperative astigmatism, and 29 eyes (74%) were within ±15 degrees from the intended correction axis. At the last visit, a statistically significant myopic progression of -0.75 ± 1.20 D was observed ( P = .01). ECC loss at the last follow-up was 9.85 ± 11.35%. IOP remained stable. There were no intraoperative complications. 3 eyes (7%) developed cataract after 10 years. The long-term results demonstrated that ICL was effective, predictable, stable, and safe.

A Nationwide Multicenter Study on 1-Year Outcomes of Posterior Chamber Phakic Intraocular Lens Implantation for Low Myopia.

PurposeTo assess the nationwide multicenter outcomes of posterior chamber phakic intraocular lens implantation with a central hole (EVO-ICL, STAAR Surgical) for patients with low myopia.MethodsThis multicenter study comprised 172 eyes of 111 consecutive patients undergoing hole ICL implantation to correct low myopia and myopic astigmatism [manifest spherical equivalent (MSE);−3 diopters (D) or less] at seven nationwide major surgical facilities. We retrospectively determined safety, efficacy, predictability, stability, and adverse events at 1 week, 1, 3, 6, and 12 months postoperatively, and at the final visit.ResultsThe mean follow-up period was 1.4 ± 1.0 years. Uncorrected and corrected visual acuities at 1 year postoperatively were −0.17 ± 0.12 and −0.24 ± 0.07 logarithm of the minimal angle of resolution (logMAR), respectively. At 1 year postoperatively, 91% and 100% of eyes were within 0.5 and 1.0 D of the target correction, respectively. No significant manifest refraction changes of −0.07 ± 0.26 D occurred from 1 week to 1 year. No vision-threatening complications occurred at any time in this series.ConclusionsAccording to our experience, the EVO-ICL performed well without significant complications throughout the 1-year observation period, even for the correction of low myopia. It is suggested that current ICL implantation is one of the viable surgical options for correcting low myopia.

RETRACTED ARTICLE: Posterior chamber phakic intraocular lens implantation after laser in situ keratomileusis

BackgroundTo assess the multicenter outcomes of posterior chamber phakic intraocular lens implantation with a central hole (EVO-ICL, STAAR Surgical) for patients undergoing previous laser in situ keratomileusis (LASIK).MethodsThis case series enrolled 31 eyes of 21 consecutive patients undergoing EVO-ICL implantation to correct residual refractive errors after LASIK at 7 nationwide major surgical sites. We investigated safety, efficacy, predictability, stability, and adverse events at 1 week, 1, 3, and 6 months postoperatively, and at the final visit.ResultsThe mean observation period was 1.6 ± 1.8 years. Uncorrected and corrected visual acuities were − 0.14 ± 0.11 and − 0.22 ± 0.09 logMAR at 6 months postoperatively. At 6 months postoperatively, 81% and 100% of eyes were within ± 0.5 D and ± 1.0 D, respectively, of the targeted correction. We found neither significant manifest refraction changes of 0.05 ± 0.38 D from 1 week to 6 months nor apparent intraoperative or postoperative complications in any case.ConclusionsOur multicenter study confirmed that the EVO-ICL provided good outcomes in safety, efficacy, predictability, and stability, even in post-LASIK eyes. Therefore, EVO-ICL implantation may be a viable surgical option, even for correcting residual refractive errors after LASIK.Trial registration University Hospital Medical Information Network Clinical Trial Registry (000045295).

Vertically Fixated Posterior Chamber Phakic Intraocular Lens Implantation Through a Superior Corneal Incision.

IntroductionTo assess the 1-year outcomes of vertically fixated posterior chamber phakic intraocular lens implantation through a superior corneal incision.MethodsThis pilot study comprised 78 eyes of 53 consecutive patients undergoing vertically fixated implantable collamer lens (ICL) implantation through a superior corneal incision to correct moderate to high myopia and myopic astigmatism. We prospectively determined the safety, efficacy, predictability, stability, and adverse events preoperatively, and at 1 week and 1, 3, and 12 months postoperatively.ResultsThe mean follow-up period was 10.4 ± 5.4 months. Uncorrected and corrected visual acuity were −0.20 ± 0.10 and −0.25 ± 0.07 logMAR, respectively, at 1 year postoperatively. At 1 year postoperatively, 98% and 100% of eyes were within 0.5 and 1.0 D, respectively, of the targeted correction. A nonsignificant change in manifest refraction of −0.01 ± 0.08 D occurred from 1 week to 1 year. The manifest astigmatism decreased significantly, from 0.69 ± 0.73 D preoperatively to 0.21 ± 0.27 D at 1 year postoperatively (Mann–Whitney U test, p < 0.001). No vision-threatening complications occurred at any time in this series.ConclusionsAccording to our experience, the vertically fixated ICL through a superior incision achieved good results, without significant complications. Considering that younger patients requiring ICL surgery tend to have with-the-rule astigmatism, this surgical technique may be a viable option for reducing astigmatism without using toric ICLs.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40123-022-00470-6.

Трехлетний опыт имплантации заднекамерной акриловой факичной интраокулярной линзы в коррекции миопии высокой степени

Aim: to evaluate the efficacy and safety of posterior chamber phakic intraocular lens (pIOL) implantation for the high myopia correction. Patients and Methods: 37 patients (55 eyes) aged 20 to 43 years were included in the study. All patients underwent the following ophthalmic examinations before surgery: visometry, autorefractometry, biometry, tonometry, optical coherence tomography, evaluation of corneal endothelial cell density, peripheral retinal exam using a Goldmann lens. pIOL power calculation was conducted using a modified vergence formula. All surgeries were performed by one surgeon according to the standard procedure. Patients were examined after surgery after 1 day, 1 month, 3 months, then every 6 months for 3 years. Visometry was performed 1 day and 1 month after the surgery. During subsequent visits, all of the listed examinations were performed, except for peripheral retinal exam using a Goldmann lens. Results: all patients completed the study. There were no intraoperative complications. No cases of cataracts or other postoperative complications were observed during 3-year follow-up. Uncorrected visual acuity 3 years after surgery was 18.4% higher than the maximum corrected visual acuity before surgery, and target refraction was observed in 86% of the eyes. Intraocular pressure during 3-year follow-up was within the normal range and averaged 17.04 mmHg. Fluctuations in the lens vault from the pIOL posterior surface to the anterior surface of the lens (VAULT) were within the normal range. Corneal endothelial cell density decreased by an average of 0.09% 3 years after surger During 3-year follow-up, there were no clinically significant changes in the anterior chamber depth of the eye. The average change in the axis orientation was also &lt;6° for all visit intervals. At the same time, the patients did not notice a change in the pIOL orientation up to 10°. Conclusion: pIOL implantation is a safe and effective method for high myopia surgical correction. Keywords: myopia, myopia correction, implantation, phakic intraocular lens, VAULT, endothelial cell density, anterior chamber of the eye. For citation: Saliev I.F., Yusupov A.F., Mukhamedova N.I. Three-year experience of posterior chamber phakic intraocular lens implantation in the high myopia correction. Russian Journal of Clinical Ophthalmology. 2022;22(3):156–160 (in Russ.). DOI: 10.32364/2311-7729- 2022-22-3-156-160.

Correction of ametropia with posterior chamber phakic intraocular lens

Posterior chamber phakic intraocular lens (PIOL) implantation is a widely accepted and performed refractive surgery for correction of moderate and high myopia used when corneal laser ablation procedures are not suitable. This paper analyzes literature data to reveal the advantages and limitations of the technology.

Posterior Chamber Phakic Intraocular Lenses for the Correction of Myopia: Factors Influencing the Postoperative Refraction

Posterior chamber phakic intraocular lens implantation is a refractive technique for the correction of myopia. This study aimed to identify those factors contributing to variability in postoperative refraction. Methods: This retrospective study evaluated 73 eyes (one eye per patient) implanted with myopic implantable collamer lenses (ICL). Eyes were divided into two groups, the low myopic group (LMG) (ICL &gt; −9.5 DS) and the high myopic group (HMG) (ICL ≤ −9.5 DS), to compare the predictability, efficacy index, and postoperative refraction between groups. The association of postoperative refraction with anatomical, demographic, and optical features was assessed through correlation analysis and investigated using ray-tracing. Results: Postoperative refraction at 3 months for the whole group was close to emmetropia at −0.02 ± 0.37 DS, the LMG tended toward myopia and the HMG, toward hyperopia. The results showed that 65% and 54% of the eyes had postoperative refraction of within ±0.25 DS, respectively, in the LMG and HMG, and in both groups, 100% were within ±1.00 DS. ICL implantation had a higher efficacy index in the HMG (1.13 ± 0.15) than in the LMG (1.04 ± 0.15). Postoperative refraction was positively associated with the vault (R = 0.408) and negatively correlated with ICL power (R = −0.382). Conclusion: The predictability and effectiveness of ICL implantation is high in a wide range of myopias. Considering the expected vault and including accurate vertex measurements would contribute to improving the predictability of the results.

Accuracy of Intraocular Lens Calculation Formulas in Patients Undergoing Combined Phakic Intraocular Lens Removal and Cataract Surgery

To investigate the prediction accuracy of intraocular lens (IOL) calculation formulas, and the impact of anterior chamber depth (ACD) and lens thickness (LT) measurement errors on IOL power calculation in patients undergoing combined phakic IOL (PIOL) removal and cataract surgery. Retrospective, consecutive case series study. Thirty-six PIOL implanted eyes (12 anterior chamber PIOLs and 24 posterior chamber PIOLs [PC-PIOL]) undergoing cataract surgery were included. The prediction accuracy of new formulas (Barrett universal II, Emmetropia verifying optical, Kane, and Ladas super formula) and traditional formulas (Haigis, Hoffer Q, Holladay 1 and SRK/T) with or without Wang-Koch (WK) axial length (AL) adjustment was evaluated. The influence of ACD and LT measurement errors of IOLMaster 700 on refractive outcomes was also investigated. The Kane and traditional formulas with WK AL adjustment had no significant systematic prediction error and displayed a smaller median absolute error, whereas the other formulas showed significant hyperopia shift (P < .05) and relatively lower prediction accuracy. The accuracy rate of IOLMaster 700 in measuring the ACD and LT was 100% in eyes with anterior chamber PIOL implantation, and 37.50% in the PC-PIOL subgroup. No significant difference was observed in refractive outcomes of formulas using correct and wrong parameters in the PC-PIOL subgroup (P > .05). The Kane and traditional formulas with WK AL adjustment exhibited relatively higher prediction accuracy in patients who underwent combined PIOL removal and cataract surgery. The IOLMaster 700 displayed low accuracy in ACD and LT measurements for PC-PIOL implanted eyes, but showed negligible impact on IOL prediction accuracy.

Diode laser transscleral cyclophotocoagulation causes intraocular collamer lens displacement in pseudophakic eye: a case report

BackgroundWith the rapid development of intraocular collamer lens (ICL) operation, it is foreseeable that we will encounter a large number of glaucoma patients with ICL implantation history. However, our current understanding of the treatment of glaucoma patients with ICL is limited. Hence we report a rare case of refractory glaucoma after intraocular collamer lens and intraocular lens implantation in a patient who underwent unsuccessful transscleral cyclophotocoagulation, which led to intraocular collamer lens displacement, angle closure and uncontrolled intraocular pressure.Case presentationA 39-year-old woman presented with intractably elevated intraocular pressure in the right eye. Since her intraocular collamer lens implantation surgery in 2017, her intraocular pressure had remained over 40 mmHg while using 3 types of anti-glaucoma medications. The patient had a history of phacoemulsification and posterior chamber phakic intraocular lens implantation for complicated cataracts secondary to uveitis in 2006. On gonioscope examination, there were signs of pigment dispersion, and the anterior chamber angle was open. Ultrasound biomicroscopy examination showed contact and rubbing between the intraocular collamer lens and posterior surface of the iris. And typical advanced glaucomatous optic neuropathy and visual field defects were observed. Transscleral cyclophotocoagulation was performed to control the intraocular pressure and prevent further visual field loss. However, the intraocular collamer lens was displaced after transscleral cyclophotocoagulation, which resulted in formation of a shallow anterior chamber 1 week later, angle closure and loss of intraocular pressure control 1 month later, even though the maximum dose of anti-glaucoma medication was used. Finally, an Ahmed glaucoma valve was successfully implanted in her anterior chamber, and the glaucoma was controlled, as observed at the 10-month follow-up.ConclusionsPigment dispersion is a common phenomenon after intraocular collamer lens implantation and may accelerate the progression of glaucoma. Transscleral cyclophotocoagulation should be carefully considered in glaucoma patients with elevated intraocular pressure after intraocular collamer lens implantation, given that transscleral cyclophotocoagulation may cause intraocular collamer lens displacement.

Posterior Chamber Phakic Intraocular Lens Implantation for Refractive Correction in Corneal Ectatic Disorders: A Review.

To summarize the indications and outcomes of posterior chamber phakic intraocular lens (PIOL) implantation in corneal ectasias including keratoconus, pellucid marginal degeneration (PMD), post-refractive surgery, and post-keratoplasty ectasias. A review of the literature was conducted using the relevant keywords from various databases up to August 15, 2020. All pertinent studies were reviewed, and the relevant articles were studied in detail for efficacy, stability, predictability, and safety outcomes. In addition, visual quality, corneal biomechanical outcomes, complications, the role of posterior chamber PIOL in combination treatment, and comparison of posterior chamber PIOL with other PIOLs for ectasias were also evaluated. A total of 30 relevant studies (13 prospective, 13 retrospective, 4 case reports) on the subject were studied and summarized. All studies showed a favorable refractive outcome. Quality of vision remained unaffected and no significant complications were reported in any of the studies. Posterior chamber PIOLs represent a viable option in the treatment of mild to moderate and stable corneal ectasia in patients with contact lens intolerance who have low irregular astigmatism, a clear central cornea, and good preoperative corrected distance visual acuity. [J Refract Surg. 2021;37(5):351-359.].