Insights into the rotational stability of toric intraocular lens implantation: diagnostic approaches, influencing factors and intervention strategies.

Toric intraocular lenses (IOLs) have been developed to enhance visual acuity impaired by cataracts and correct corneal astigmatism. However, residual astigmatism caused by postoperative rotation of the toric IOL is an important factor affecting visual quality after implantation. To decrease the rotation of the toric IOL, significant advancements have been made in understanding the characteristics of toric IOL rotation, the factors influencing its postoperative rotation, as well as the development of various measurement techniques and interventions to address this issue. It has been established that factors such as the patient's preoperative refractive status, biological parameters, surgical techniques, postoperative care, and long-term management significantly impact the rotational stability of the toric IOL. Clinicians should adopt a personalized approach that considers these factors to minimize the risk of toric IOL rotation and ensure optimal outcomes for each patient. This article reviews the influence of various factors on toric IOL rotational stability. It discusses new challenges that may be encountered to reduce and intervene with rotation after toric IOL implantation in the foreseeable future.

Exploring anterion capsular contraction syndrome in cataract surgery: insights into pathogenesis, clinical course, influencing factors, and intervention approaches.

Anterior capsular contraction syndrome (ACCS) is a challenging complication that can occur following phacoemulsification cataract surgery. Characterized by capsular bag wrinkling, intraocular lens (IOL) decentration and tilt, ACCS can have negative effects on visual outcomes and patient satisfaction. This review aims to investigate the pathogenesis, clinical course, influencing factors, and intervention approaches for ACCS after cataract surgery. By understanding the underlying mechanisms and identifying factors that contribute to ACCS, surgeons can enhance their ability to predict and manage this complication. Various intervention strategies are discussed, highlighting their importance in reducing complications and improving surgical outcomes. However, further research is needed to determine optimal prevention and management strategies through long-term follow-up and comparative analyses. Advancements in this field will ultimately lead to improved visual outcomes and optimized cataract surgery for patients.

Evaluation of a new dynamic real-time visualization 25 kHz swept-source optical coherence tomography based biometer.

BACKGROUND: To evaluate the intraobserver repeatability and interobserver reproducibility of a newly developed dynamic real-time visualization 25 kHz swept-source optical coherence tomography (SS-OCT) based biometer (ZW-30, TowardPi Medical Technology Ltd, China) and compare its agreement with another SS-OCT based biometer (IOLMaster 700, Carl Zeiss Meditec AG, Jena, Germany). METHODS: Eighty-two healthy right eyes were enrolled in this prospective observational study. Measurements were repeated for three times using the ZW-30 and IOLMaster 700 in a random order. Obtained parameters included axial length (AL), central corneal thickness (CCT), aqueous depth (AQD), anterior chamber depth (ACD), lens thickness (LT), mean keratometry (Km), astigmatism magnitude (AST), vector J0, vector J45, and corneal diameter (CD). The within-subject standard deviation (Sw), test-retest (TRT) variability, coefficient of variation (CoV), and intraclass correlation coefficient (ICC) were adopted to assess the intraobserver repeatability and interobserver reproducibility. The double-angle plot was also used to display the distribution of AST. To estimate agreement, Bland-Altman plots were used. RESULTS: For the intraobserver repeatability and interobserver reproducibility, the Sw, TRT and CoV for all parameters were low. Meanwhile, the ICC values were all close to 1.000, except for the J45 (ICC = 0.887 for the intraobserver repeatability). The double-angle plot showed that the distribution of AST measured by these two devices was similar. For agreement, the Bland-Altman plots showed narrow 95% limits of agreements (LoAs) for AL, CCT, AQD, ACD, LT, Km AST, J0, J45, and CD (- 0.02 mm to 0.02 mm, - 7.49 µm to 8.08 µm, - 0.07 mm to 0.04 mm, - 0.07 mm to 0.04 mm, - 0.07 mm to 0.08 mm, - 0.16 D to 0.30 D, - 0.30 D to 0.29 D, - 0.16 D to 0.16 D, - 0.23 D to 0.13 D, and - 0.39 mm to 0.10 mm, respectively). CONCLUSIONS: The newly dynamic real-time visualization biometer exhibited excellent intraobserver repeatability and interobserver reproducibility. The two devices both based on the SS-OCT principle had similar ocular parameters measurement values and can be interchanged in clinical practice.

Repeatability and Interobserver Reproducibility of a Swept-Source Optical Coherence Tomography for Measurements of Anterior, Posterior, and Total Corneal Power.

INTRODUCTION: The aim of this work is to evaluate the intraobserver repeatability and interobserver reproducibility of corneal power measurements obtained with a swept-source optical coherence tomographer (CASIA 2, Tomey, Japan) in healthy subjects. METHODS: A total of 67 right eyes from 67 healthy subjects were enrolled. Two experienced observers measured each eye three times consecutively with the CASIA 2. Corneal power values were recorded as simulated keratometry, anterior, posterior, and total corneal power. Parameters were flattest keratometry (Kf), steepest keratometry (Ks), mean keratometry (Km), astigmatism magnitude, astigmatism power vectors J0 and J45. Intraobserver repeatability and interobserver reproducibility of the CASIA 2 were assessed by the within-subject standard deviation (Sw), test-retest repeatability (TRT), coefficients of variation (CoV), and intraclass correlation coefficients (ICCs). Double-angle plots were used for astigmatism vector analysis. RESULTS: The CASIA 2 had high repeatability for all corneal power values, with Sw values ≤ 0.17 diopters (D), TRT ≤ 0.46 D, and ICCs ranging from 0.866 to 0.998. Interobserver reproducibility was also high, showing all Sw values ≤ 0.10 D, TRT ≤ 0.27 D, and ICCs ≥ 0.944. The reproducibility of the average of three consecutive measurements (Sw 0.01-0.10 D, TRT 0.03-0.27 D, ICC 0.944-0.998) was higher than the reproducibility of single measurements (Sw 0.01-0.17 D, TRT 0.03-0.47 D, ICC 0.867-0.996). CONCLUSIONS: The CASIA 2 showed high intraobserver repeatability and interobserver reproducibility for anterior, posterior, and total corneal power measurements in 6.0-mm diameter area. In addition, we suggest that using the average of three consecutive measurements can improve reproducibility between observers, compared to single measurements only.

Comparison of a New Scheimpflug Camera and Swept-Source Optical Coherence Tomographer for Measurements of Anterior Segment Parameters.

INTRODUCTION: This study evaluated the differences and agreement between a new Scheimpflug camera (Scansys) and a swept-source anterior segment optical coherence tomographer (CASIA 2) for measurements of the anterior segment of the eye in normal subjects. METHODS: This prospective study included 84 eyes from 84 normal adult subjects who underwent three consecutive measurements with the Scansys and the CASIA 2 in random order. The mean keratometry (Km), astigmatism magnitude (AST), J0, and J45 vectors for both anterior and posterior corneal surfaces, central corneal thickness (CCT), thinnest corneal thickness (TCT), and anterior chamber depth (ACD) were obtained by both devices. The difference between these two devices was assessed using paired t test and violin plots. Bland-Altman plots and 95% limits of agreement (LoAs) were used to evaluate agreement. RESULTS: No statistically significant differences between the two devices were found for the anterior AST, anterior J45, and posterior J45 (P > 0.05). The remaining parameters were statistically significant (P ≤ 0.05), but the differences not clinically significant. The violin plots showed that the distribution and probability density of the measured parameters were similar for both devices. Bland-Altman plots revealed high agreement for the measured parameters between the Scansys and CASIA 2, with narrow 95% LoAs. CONCLUSIONS: In terms of assessing parameters for the anterior segment, our study indicated that Scansys and CASIA 2 generally showed significant agreement. The two devices used in this study's assessment of all the parameters can be used interchangeably in refractive analysis.

Assessment of corneal biomechanics in anisometropia using Scheimpflug technology.

Purpose: To investigate the relationship between corneal biomechanical and ocular biometric parameters, and to explore biomechanical asymmetry between anisometropic eyes using the corneal visualization Scheimpflug technology device (Corvis ST). Methods: 180 anisometropic participants were included. Participants were divided into low (1.00≤△Spherical equivalent (SE) < 2.00D), moderate (2.00D≤△SE < 3.00D) and high (△SE ≥ 3.00D) anisometropic groups. Axial length (AL), keratometry, anterior chamber depth (ACD) and corneal biomechanical parameters were assessed using the OA-2000 biometer, Pentacam HR and Corvis ST, respectively. Results: The mean age of participants was 16.09 ± 5.64 years. Stress-Strain Index (SSI) was positively correlated with SE (r = 0.501, p < 0.001) and negatively correlated with AL (r = -0.436, p < 0.001). Some other Corvis ST parameters had weak correlation with SE or AL. Corneal biomechanical parameters except for time of first applanation (A1T), length of second applanation (A2L), deformation amplitude (DA), first applanation stiffness parameter (SPA1) and ambrosia relational thickness-horizontal (ARTh) were correlated with ametropic parameters (SE or AL) in multiple regression analyses. A1T, velocity of first applanation (A1V), time of second applanation (A2T), A2L, velocity of second applanation (A2V), corneal curvature radius at highest concavity (HCR), peak distance (PD), DA, deformation amplitude ratio max (2 mm) (DAR), SPA1, integrated radius (IR), and SSI showed significant differences between fellow eyes (p < 0.05). There was no significant difference in asymmetry of corneal biomechanics among the three groups (p > 0.05). Asymmetry of some biomechanical parameters had weak correlation with asymmetry of mean corneal curvatures and ACD. However, asymmetry of corneal biomechanical parameters was not correlated with asymmetry of SE or AL (p > 0.05). Conclusion: More myopic eyes had weaker biomechanical properties than the contralateral eye in anisometropia. However, a certain linear relationship between anisometropia and biomechanical asymmetry was not found.

Comprehensive comparisons of ocular biometry: A network-based big data analysis.

PURPOSE: To systematically compare and rank ocular measurements with optical and ultrasound biometers based on big data. METHODS: PubMed, Embase, the Cochrane Library and the US trial registry ( www. CLINICALTRIAL: gov ) were used to systematically search trials published up to October 22nd, 2020. We included comparative studies reporting the following parameters measured by at least two devices: axial length (AL), flattest meridian keratometry (Kf), steepest meridian keratometry (Ks), mean keratometry (Km), astigmatism (AST), astigmatism vectors J0 and J45, anterior chamber depth (ACD), aqueous depth (AQD), central corneal thickness (CCT), corneal diameter (CD) and lens thickness (LT). A network-based big data analysis was conducted using STATA version 13.1. RESULTS: Across 129 studies involving 17,181 eyes, 12 optical biometers and two ultrasound biometers (with both contact and immersion techniques) were identified. A network meta-analysis for AL and ACD measurements found that statistically significant differences existed when contact ultrasound biometry was compared with the optical biometers. There were no statistically significant differences among the four swept-source optical coherence tomography (SS-OCT) based devices (IOLMaster 700, OA-2000, Argos and ANTERION). As for Ks, Km and CD, statistically significant differences were found when the Pentacam AXL was compared with the IOLMaster and IOLMaster 500. There were statistically significant differences for CCT when the OA-2000 was compared to Pentacam AXL, IOLMaster 700, Lenstar, AL-Scan and Galilei G6. CONCLUSION: For AL and ACD, contact ultrasound biometry obtains the lower values compared with optical biometers. The Pentacam AXL achieves the lowest values for keratometry and CD. The smallest value for CCT measurement is found with the OA-2000.

The Precision of a New Anterior Segment Optical Coherence Tomographer and Its Comparison With a Swept-Source OCT-Based Optical Biometer in Patients With Cataract.

PURPOSE: To assess the precision of a new spectral-domain optical coherence tomographer (SD-OCT)/Placido topographer (MS-39; CSO) and its comparison with a swept-source OCT (SS-OCT) biometer (Argos; Movu, Inc) in patients with cataract. METHODS: Fifty-three right eyes from 53 patients were examined by two experienced operators three times using both devices randomly. Employing the within-subject standard deviation (Sw), test-retest variability, coefficient of variation, and intraclass correlation coefficient to evaluate intraoperator repeatability and interoperator reproducibility; the double-angle plots to analyze astigmatism; and Bland-Altman plots and 95% limits of agreement to verify the agreement between devices. RESULTS: The SD-OCT/Placido tomographer showed high precision, with coefficient of variation of 0.44% or less, intraclass correlation coefficient of 0.945 or greater for all parameters, test-retest variability of 4.21 µm or less for central corneal thickness (CCT), 0.03 mm or less for anterior chamber depth (ACD) and aqueous depth (AQD), and 0.25 diopters (D) or less for mean keratometry (Km), J0, and J45. The inter-device differences in Km, J0, and J45 were statistically insignificant, whereas the remaining were statistically but not clinically significant. The 95% limits of agreement of CCT, ACD, AQD, Km, J0, and J45 were -3.70 to 15.25 µm, -0.06 to 0.04 mm, -0.06 to 0.04 mm, -0.28 to 0.35 D, -0.27 to 0.26 D, and -0.27 to 0.21 D, respectively. The double-angle plot confirmed the high agreement in astigmatism. CONCLUSIONS: For CCT, ACD, AQD, Km, and astigmatism measurements in patients with cataract, the new SD-OCT/Placido tomographer has excellent precision and high agreement with the Argos SS-OCT biometer, and can be used interchangeably. [J Refract Surg. 2021;37(9):616-622.].