Association between anterior chamber biometry and posterior capsular defects.

PURPOSE: To analyze the association between anterior chamber biometric factors and posterior capsular defects (PCDs) that occur during extracapsular cataract extraction. SETTING: University Eye Hospital, Goethe University Frankfurt, Germany. DESIGN: Population-based study. PATIENTS AND METHODS: Extracapsular cataract extractions for inpatient cases within 4 years were retrospectively analyzed. The data on the occurrence of PCDs, age, sex, surgeon, and biometry were obtained. For cases with PCDs, the secondary ocular diseases, number of procedures, lens implant, visual acuity, and course were also recorded. Swept-source optical coherence tomography measurements allowed the measurement of lens thickness (LT) in addition to the usual biometry values. RESULTS: A total of 1967 cataract surgeries (patients age: 70.56 ± 8.42, 1005 women; 962 men) were included, and PCDs were documented for 59 (2.54%; 31 women, 28 men) cases (patient age: 70.95 ± 8.52 years). There were no differences ( P = .76) related to the surgeons (n = 9) with minimal effect sizes. The mean LT, axial length, corneal curvature, and anterior chamber depth were 4950.36 ± 466.63 µm, 23.73 ± 1.77 mm, 43.89 ± 1.36 diopters, and 3.02 ± 0.71 mm, respectively. The Wilcoxon-Mann-Whitney test showed significant associations between LT ( P = .01) and PCDs with moderate relevance for the Rosenthal effect size (LT R = 0.34; ACD R = 0.29). CONCLUSIONS: In addition to ACD, a tendency for the occurrence of PCD could be proven, especially for LT. Therefore, special attention should be paid to LT preoperatively for comprehensive risk stratification.

Anterior Segment Biometry in a Caucasian Population with Cataracts.

PURPOSE: To investigate biometric factors of the anterior segment of phakic eyes with cataracts. METHODS: This population-based study included Caucasian patients with cataracts in the University Eye Hospital, Goethe University Frankfurt, Germany. Biometric parameters were measured using the swept-source optical coherence tomography method. Patients were grouped into intermediate stages based on decades of life. RESULTS: In total, 6289 eyes of 3615 patients (age: 70.67 ± 8.42 years) were included. Age-related reductions in the anterior chamber depth (mean ± standard deviation) decreased from 3.26 ± 0.42 mm (group A: 55-59 years) to 2.94 ± 0.4 mm (group G: 85-89 years), and those in the axial length decreased from 24.37 ± 1.87 mm (group A) to 23.39 ± 1.07 mm (group G). Likewise, the white-to-white distance decreased from 12.12 ± 0.48 mm (group A) to 11.96 ± 0.47 mm (group G). Lens thickness tended to increase accordingly from 4.39 ± 0.36 µm (group A) to 4.9 ± 0.40 µm (group G). A comparison of the eyes showed no detectable lateral difference regarding the biometric parameters between the groups (axial length: p = 0.26, Rosenthal effect size = 0.03; lens thickness: p = 0.12, R = 0.03; anterior chamber depth: p = 0.63, Rosenthal effect size = 0.01). The axial length and anterior chamber depth differed significantly between sexes (r = 0.22, p < 0.0001 and r = 0.16, p < 0.0001, respectively). Multiple regression analysis of the anterior chamber depth as a function of biometry parameters as well as age and sex additionally indicated a positive correlation of anterior chamber depth with white-to-white distance (b = 0.32, p = 10-5), axial length (b = 0.10, p = 10-5), keratometry (b = 0.07, p = 10-5), and lens thickness (b=-0.05, p = 10-5) with a high effect size (Cohen f2=1.866, p = 10-5) and strong multiple correlation coefficient (Rosenthal effect size = 0.80, p = 10-5). CONCLUSIONS: In the anterior segment, there are age- and sex-dependent changes in biometric parameters. In addition, changes in anterior chamber depth were noted in relation to white-to-white distance, axial length, keratometry, and lens thickness. These data should be considered in lens calculation formulas.

Ray tracing intraocular lens calculation performance improved by AI-powered postoperative lens position prediction.

AIMS: To assess whether incorporating a machine learning (ML) method for accurate prediction of postoperative anterior chamber depth (ACD) improves cataract surgery refraction prediction performance of a commonly used ray tracing power calculation suite (OKULIX). METHODS AND ANALYSIS: A dataset of 4357 eyes of 4357 patients with cataract was gathered at the Kellogg Eye Center, University of Michigan. A previously developed machine learning (ML)-based method was used to predict the postoperative ACD based on preoperative biometry measured with the Lenstar LS900 optical biometer. Refraction predictions were computed with standard OKULIX postoperative ACD predictions and ML-based predictions of postoperative ACD. The performance of the ray tracing approach with and without ML-based ACD prediction was evaluated using mean absolute error (MAE) and median absolute error (MedAE) in refraction prediction as metrics. RESULTS: Replacing the standard OKULIX postoperative ACD with the ML-predicted ACD resulted in statistically significant reductions in both MAE (1.7% after zeroing mean error) and MedAE (2.1% after zeroing mean error). ML-predicted ACD substantially improved performance in eyes with short and long axial lengths (p<0.01). CONCLUSIONS: Using an ML-powered postoperative ACD prediction method improves the prediction accuracy of the OKULIX ray tracing suite by a clinically small but statistically significant amount, with the greatest effect seen in long eyes.

Repeatability of new optical biometer and agreement with 2 validated optical biometers, all based on SS-OCT.

PURPOSE: To evaluate the repeatability of the measurements provided by a new optical biometer (EyeStar 900) based on swept-source optical coherence tomography (SS-OCT) and their agreement with the measurements given by 2 validated biometers based on the same technology, the IOLMaster 700 and Argos. SETTING: IRCCS G.B. Bietti Foundation, Rome, Italy. DESIGN: Prospective evaluation of diagnostic test. METHODS: In a series of unoperated eyes, 3 consecutive scans were acquired with the EyeStar 900, and 1 with the IOLMaster 700 and the Argos. The following biometry parameters were analyzed: axial length (AL), keratometry (K), corneal astigmatism, central corneal thickness, corneal diameter (CD), anterior chamber depth (ACD), lens thickness (LT), and lens tilting. Repeatability was assessed using test-retest variability, the coefficient of variation (CoV), and the intraclass correlation coefficient (ICC); agreement was based on the 95% limits of agreement. RESULTS: 56 eyes of 56 patients were analyzed. High repeatability was achieved for all measured parameters, as the CoV was <1% in most cases and ICC was >0.95 for all parameters. Good to high agreement was found among the measurements of the 3 optical biometers, although some statistically significant differences were detected between the EyeStar 900 and Argos (mean K, ACD, LT, and CD were higher with the Argos). The Argos measured a shorter AL in eyes >25 mm. CONCLUSIONS: The new generation SS-OCT EyeStar 900 optical biometer produces highly repeatable measurements that are in good agreement with those provided by 2 previously validated instruments.

Axial length measurement failure rates using optical biometry based on swept-source OCT in cataractous eyes.

INTRODUCTION: Ocular dimensions measurement is extremely important in cataract procedures and refractive surgery. The use of optical techniques for axial measurements has been developed in recent years. AREAS COVERED: The purpose was to summarize the outcomes reported when swept-source optical coherence tomography (SS-OCT) optical biometry failed during axial length measurement. A peer-reviewed literature search was carried out to identify publications reporting clinical outcomes for cataractous eyes measured with SS-OCT optical biometers available on the market. A comprehensive analysis of the available data was performed, focusing on parameters such as the sample of eyes evaluated, failure rates, and specifically, the cataract type when the measurement was not possible. 27 studies were included in this review. In general, SS-OCT biometers lead to only small failure rates when measuring axial length (but in some cases up to 38.49%). In the few cases where the measurement was not possible, the cataract type of the eyes was mainly mature white or grade ≥ IV. SS-OCT optical biometers show good outcomes when measuring axial length in eyes with advanced cataracts. EXPERT OPINION: We believe that the use of SS-OCT technology may be considered the gold standard for measuring axial length in any type of cataract.

Repeatability and comparability of a new swept-source optical coherence tomographer in optical biometry.

PURPOSE: To evaluate the reproducibility in the measurement of ocular biometric parameters using a new swept-source optical coherence tomographer and its comparability with an optical low coherence reflectometry biometer. DESIGN: An observational, descriptive, cross-sectional study. METHODS: 45 right eyes of 45 patients diagnosed with cataract were included. Three successive biometric measurements with Anterion and one with Lenstar LS900 were performed on each patient. The following variables were collected: axial length (AXL), anterior chamber depth (ACD), flat K (K1), steep K (K2), central corneal thickness (CCT), lens thickness (LT) and white-to-white distance (WTW). The intrasubject standard deviation (Sw) and the coefficient of Pearson "R" were calculated in order to assess the repeatability. The intraclass correlation coefficient (ICC) and the concordance correlation coefficient (CCC) were obtained to evaluate the comparability between devices. A Bland-Altman plot was performed for each variable. RESULTS: The coefficient of Pearson was excellent and statistically significant in the evaluation of the repeatability in all the variables. The highest values were 0.987 (AXL), 0.983 (CCT) and 0.942 (ACD). There were no statically significant differences between repeated measurements with Anterion in all the parameters. The ICC and CCC were excellent in the evaluation of AXL, CCT and ACD, and were also good in regard to K1, K2, LT and WTW. CONCLUSIONS: Performing biometry with the SS-OCT Anterion is a reliable and reproducible procedure, and it is comparable with the Lenstar LS900.

Comparison of axial length measurements in silicone oil-filled eyes using SS-OCT and partial coherence interferometry.

PURPOSE: To compare axial length (AL) measurements in silicone oil (SO)-filled eyes using swept-source optical coherence tomography (SS-OCT) (the IOLMaster 700 and OA2000) and partial coherence interferometry (the IOLMaster 500). SETTING: Zhongshan Ophthalmic Center, Guangzhou, China. DESIGN: Cross-sectional study. METHODS: We enrolled phakic patients who underwent SO removal surgery. The AL measurements by the IOLMaster 500, IOLMaster 700, and OA2000, both before and after SO removal, were compared. Multiple regression analysis was performed to identify risk factors for the differences between preoperative and postoperative AL measurements. RESULTS: 68 patients (68 eyes) with a mean age of 46.43 ± 13.24 years were included. No statistically significant difference was observed in the preoperative AL measurements between the IOLMaster 500 and IOLMaster 700 (25.48 ± 2.51 mm vs 25.49 ± 2.46 mm; P = .63), whereas the OA2000 yielded shorter AL (25.34 ± 2.36 mm) (both P < .001). After SO removal, the AL measurements showed no statistically significant differences among the 3 devices. In reference to the postoperative AL, the IOLMaster 500 and IOLMaster 700 tended to overestimate the AL in SO-filled eyes (both P < .001), and this measurement error increased with longer AL (ß = 0.08 and 0.05, respectively; both P < .001). No statistically significant difference was observed between preoperative and postoperative AL measurements by the OA2000 ( P = .18). CONCLUSIONS: The OA2000 is the preferred biometer for AL measurement in SO-filled eyes, whereas the IOLMaster 500 and IOLMaster 700 overestimate the AL especially for long eyes, which needs adjustment in clinical use.

Advantageous effect of pupil dilation on the quality of optical biometry axial length measurement in individuals with dense cataract.

PURPOSE: To evaluate the effect of pharmacologic pupil dilation on the quality of axial length (AL) measurement in patients with dense cataracts and previous low-quality AL measurements performed without dilation. SETTING: Shaare-Zedek Medical Center, Jerusalem, Israel. DESIGN: Retrospective case series. METHODS: All participants underwent swept-source optical coherence tomographic (SS-OCT) biometry. Those with low-quality AL measurements due to dense cataract underwent an additional SS-OCT biometric evaluation after pupil dilation, and the AL measurement of the same eye was recorded. RESULTS: 2076 patients underwent SS-OCT during the study period, and 177 (8.52%) had low-quality AL measurements because of dense cataract. 79 (44.63%, mean age 72.53 ± 13.27 years, 43 females) of those 177 patients underwent repeat SS-OCT biometric imaging after pharmacologic pupil dilation, and formed the study group. After pupil dilation, high-quality AL measurements were successfully obtained in 60 (75.95%) of the 79 eyes. The mean SD of the AL measurements decreased significantly ( P &lt; .001), and the number of successful OCT scans per measurement increased significantly ( P &lt; .001) after pupil dilation. The mean difference of the AL before and after pupil dilation was 0.03 ± 0.07 mm ( P &lt; .001). CONCLUSIONS: Pharmacologic pupil dilation improved the quality of SS-OCT biometrically measured AL in patients with low-quality AL measurement due to dense cataract. These results could potentially improve postoperative refractive outcomes after cataract surgery and reduce the need of additional AL measurements by more complicated alternative means in this group.

Agreement between 2 SS-OCT biometry devices.

PURPOSE: To assess the agreement between 2 swept-source optical coherence tomography biometry devices, Anterion and IOLMaster 700. SETTING: Tertiary referral center, Brisbane, Australia. DESIGN: Prospective comparative study. METHODS: Bland-Altman analysis was used to assess agreement between devices for flat (K1), steep (K2), and mean (Km) keratometry for anterior, posterior, and total cornea, lens thickness (LT), anterior chamber depth (ACD), central corneal thickness (CCT), white to white (WTW), and axial length (AL). Generalized estimating equations were used to control for within-patient between-eye correlations. Interdevice differences were considered clinically significant if they were likely to alter the spherical refractive outcome by 0.25 diopter (D) or more. RESULTS: 159 eyes of 91 patients (41 male, 50 female) were included. Statistically significant differences were found for K1, K2, and Km for anterior, posterior, and total cornea. When the Anterion was compared with the IOLMaster 700, the mean differences were as follows: anterior K1: -0.17 D, anterior K2: -0.18 D, anterior Km: -0.17 D, posterior K1: -0.38 D, posterior K2: -0.36 D, posterior Km: -0.37 D, total K1: -0.65 D, total K2: -0.82 D, and total Km: -0.74 D. The difference in posterior and total K metrics was clinically significant. Statistically significant differences were noted for LT: 0.159 mm, CCT: -0.004 mm, ACD: 0.054 mm, and WTW: -0.152 mm, although these were not found to be clinically significant. There was no significant difference between devices for AL. CONCLUSIONS: This study found statistically and clinically significant differences for both posterior and total keratometry between the Anterion and the IOLMaster 700. Posterior and total corneal parameters cannot be considered interchangeable between devices.

Predicted Refraction Variability Due to Reliability of Nine Optical Biometers for Intraocular Lens Power Calculation.

PURPOSE: To assess the influence of reliability (repeatability and reproducibility) of eye parameter measurements on the prediction refraction by using the outcomes of nine optical biometers reported in the literature. METHODS: A search was conducted in PubMed focused on the outcomes from original studies regarding reliability. The mean population of within-subject standard deviation (Sw) was estimated from the mean samples reported in the included studies. Repeatability coefficients (R) for the mean population were computed as 2.77 × Sw. The influence of reliability on the prediction refraction for eye biometric parameters, such as mean corneal power in diopters (D) (Km), anterior chamber depth (ACD), and axial length (AXL), were evaluated using a thick lens formula. The lens thickness (LT), central corneal thickness (CCT), and white-to-white (WTW) distance were also evaluated. RESULTS: The repeatability of optical biometers ranged from 0.19 to 0.42 D for Km, from 0.04 to 0.13 mm for ACD, from 0.03 to 0.22 mm for AXL, from 0.06 to 0.13 mm for LT, from 5.5 to 17.7 µm for CCT, and from 0.18 to 0.48 mm for WTW distance. Total prediction refraction due to repeatability ranged from 0.21 to 0.61 D, with Km the variable that caused the major part of total prediction refraction variability, followed by AXL and ACD. Reproducibility for the evaluated variables was generally inside the repeatability ranges. CONCLUSIONS: New optical biometers are equally reliable as earlier technologies. Special attention should be focused on Km and AXL, which explain the major part of prediction refraction variability. [J Refract Surg. 2022;38(2):120-127.].

Agreement of intraocular lens power calculation between 2 SS-OCT-based biometers.

PURPOSE: To assess agreement of measurements by 2 swept-source optical coherence tomography biometers and to evaluate the prediction error (PE) in intraocular lens power calculation with 7 formulas. SETTING: Tertiary public eye hospital. DESIGN: Consecutive observational. METHODS: Axial length (AL), keratometry (K), anterior chamber depth (ACD), lens thickness (LT), and corneal diameter (CD) were measured with the IOLMaster 700 (Biometer A) and Anterion (Biometer B). Agreement was quantified by the limits of agreement and concordance correlation coefficient (CCC). The PE, the median absolute error, and the mean absolute error of the Barrett Universal II, EVO 2.0, Haigis, Hoffer Q, Holladay 1, Kane, and SRK/T formulas were investigated after constant optimization. RESULTS: In 78 eyes from 78 patients, excellent agreement was obtained for AL (CCC >0.99), very good agreement for K, ACD, and LT (CCC >0.95), and strong agreement for CD (CCC >0.72). An additive offset of 0.07 mm was measured for ACD and LT whose mean values were higher with Biometer B (P < .001). No statistically significant difference was found between the PEs and their absolute values when comparing the results of each formula between the 2 biometers. CONCLUSIONS: Agreement of biometric measurements by the 2 biometers was high, although Biometer B provided higher mean values of ACD and LT by 0.07 mm. In cataract patients with normal eye length, measurements by the 2 biometers did not lead to different refractive outcomes with the 7 formulas investigated.

Comparative analysis of 2 biometers using swept-source OCT technology.

PURPOSE: To report the repeatability, level of agreement, and correlation of 2 swept-source optical coherence tomography (SS-OCT) biometers, the IOLMaster 700 (biometer A) and the ANTERION (biometer B). SETTING: Rothschild Foundation Hospital, Paris, France. DESIGN: Prospective comparative case series. METHODS: Consecutive patients who attended for cataract assessment had SS-OCT biometry performed with the reference, biometer A, and biometer B. Axial length, mean keratometry, central corneal thickness, anterior chamber depth, lens thickness, and corneal diameter measurements (white-to-white [WTW] distance) were measured. The intraoperator repeatability was calculated using analysis of variance and repeatability limits. Correlations were assessed, and the level of agreement between the biometers was represented with the Bland-Altman method. RESULTS: The study comprised 63 patients (125 eyes). There was a statistically significant difference between the 2 biometers in all measurements (P < .05). All repeatability measurements were very high, as were the level of correlation and level of agreement between biometer A and biometer B for all parameters. CONCLUSIONS: Biometer B provided good agreement and repeatability compared with biometer A; however, all parameters were not interchangeable, particularly, the WTW measurement and the high keratometric values.

Agreement between the Swept-Source Optical Coherence Tomography and the Image-Guided System for Biometry Assessment in Cataract Surgery.

PURPOSE: To assess the agreement on biometric data obtained using the Verion image-guided surgery system and the swept-source-OCT biometer IOL Master 700. MATERIALS AND METHODS: All patients underwent biometry using the SS-OCT and the Image-Guide System. The comparison between instruments was assessed using the Intraclass correlation coefficient (ICC). Level of Agreement (LoA) employing the Bland-Altman analysis. RESULTS: The image-based system produced significantly higher keratometry values, evidencing a low LoA between the SS-OCT and the image-based system, ranging from -1.30 D to 0.65 D (1.95 D), -1.04 D to 0.72 D (1.76 D), and -1.31 D to 0.65 D (1.96 D), respectively. The LoA for the Cylinder ranged from -0.46 D to 0.74 D (1.2 D) and from 0.82 to 0.94 mm for WTW. CONCLUSIONS: In our study, the SS-OCT biometer and the Image-based System evidenced statistically significant differences in measuring the main biometric parameters except for the WTW.

Ocular Biometric Characteristics Measured by Swept-Source Optical Coherence Tomography in Individuals Undergoing Cataract Surgery.

PURPOSE: To study the distribution of ocular biometric parameters using a swept-source optical coherence tomography (SS-OCT) biometer in adult candidates for cataract surgery. DESIGN: A retrospective cross-sectional study. METHODS: This is a single-center analysis of consecutive eyes measured with the IOLMaster 700 SS-OCT biometer at a large tertiary medical center between February 2018 and June 2020. RESULTS: Three thousand eight hundred thirty-six eyes of 3836 patients were included in the study. The mean ± SD age was 72.3 ± 12.8 years and 53% were female. The mean biometric values were as follows: total corneal power (44.17 ± 1.70 diopters [D]), total corneal astigmatism (TCA; 1.11 ± 0.87 D), mean posterior keratometry (-5.87 ± 0.26 D), posterior corneal astigmatism (-0.26 ± 0.15 D), axial length (AL; 23.95 ± 1.66 mm), anterior chamber depth (ACD; 3.18 ± 0.42 mm), lens thickness (LT; 4.49 ± 0.47 mm), white-to-white distance (WTW; 11.92 ± 0.44 mm), central corneal thickness (CCT; 0.54 ± 0.04 mm), angle alpha (0.49 ± 0.17 mm), and angle kappa (0.34 ± 0.17 mm). There were sex-related differences in all biometric parameters save for LT (P = .440), angle kappa (P = .216), and corneal astigmatism (P = .103). Biometric parameters demonstrated correlations between AL, WTW distance, ACD, and LT (P < .001). Age correlated with all parameters (P < .001) except CCT and posterior keratometry. Angle alpha and angle kappa magnitudes also correlated (P < .001). The prevalence of patients with TCA ≥0.75 D, 1.0 D, and 1.5 D were 59.1%, 43.4%, and 22.6%, respectively. CONCLUSIONS: Age significantly correlated with most of the biometric parameters and significant differences between sexes were noted. In addition, the high prevalence of TCA and relatively large angle alpha and angle kappa magnitudes were noted among subjects. These data can be relevant in planning local and national health economics.

Evaluation of 6 biometers based on different optical technologies.

PURPOSE: To evaluate repeatability and agreement between various biometric parameters using 6 biometers based on different optical technologies. SETTING: University of Valencia, Spain. DESIGN: Prospective, comparative case series. METHODS: 150 eyes were measured using the Aladdin, AL-Scan, Argos, IOLMaster700, Lenstar LS900, and OA-2000 biometers. Keratometry (K1 and K2), J0 and J45, central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), axial length (AL), white to white (WTW), and pupil size (PS) were measured 5 times with each device. Intrasubject SD, coefficient of variability (CoV), coefficient of repeatability, intraclass correlation coefficient, and Bland -Altman graphs were analyzed. RESULTS: CoV values were <0.30% for K1, K2, and AL and up to 1.61% for CCT, ACD, LT, and WTW. PS values were higher (from 4.2% to 7.68%). There was statistically significant differences between biometers for all parameters evaluated (P < .001), and these differences varied as a function of the parameter analyzed. The limit of agreement (LoA) width of some comparisons for K1 and the majority for K2 were >0.50 diopter. A similar pattern was found for J0/J45. For CCT, many comparisons showed LoA width values of >25 µm. The LoA width for ACD ranged from 0.366 mm to 0.175 mm and for LT was about 0.2 mm. AL showed a highest LoA width of 0.225 mm. The LoA width for WTW was, in most cases, about ≥0.50 mm. The LoA width for PS ranged from 1.578 mm to 3.541 mm. CONCLUSIONS: The 6 biometers provided repeatable measurements for the different parameters analyzed. The LoA obtained for each comparison should be analyzed carefully to consider the interchangeability of these devices.