White-to-white Research Articles

Assessment of measurement variability across automated biometry devices

Purpose: To evaluate measurement variability between different readily available automated biometric devices for the purposes of improving surgeon decision making for phakic intraocular lens (IOL) sizing. Setting: Private practice (Houston, TX, USA) Design: Prospective, single center, bilateral, non-randomized, open-label, observational study. Methods: This study included healthy eyes, with no prior eye surgery, and with a spherical equivalent of at least -1.00D. Orbscan II was compared to Argos, Atlas 9000, caliper, IOLMaster 500, IOLMaster 700, iTrace, Lenstar LS900, Pentacam HR, and Pentacam AXL Wave. Preoperative measurements included white to white (WTW), anterior chamber depth (ACD), and central corneal thickness (CCT). Linear mixed effect models were created to determine adjustment factor between the Orbscan II and other devices for WTW, ACD, and CCT measurements. Results: A total of 204 subjects (408 eyes) completed the study. All mean WTW measurements were significantly different compared to the Orbscan II (p < 0.01), except for Pentacam AXL Wave. All mean ACD and CCT measurements were significantly different compared to the Orbscan II (p < 0.01). Adjustment factors for WTW ranged from -0.65 mm to 0.24 mm. Adjustment factors for ACD ranged from -0.21 mm to -0.16 mm. Adjustment factors for CCT ranged from 19.9 µm to -36.0 µm. Conclusions: The biometers tested were not interchangeable with the Orbscan II. Adjustment factors for WTW and ACD may compensate for differences between devices and adapt ICL sizing recommendations.

Peripheral Iridectomy in Intrascleral Intraocular Lens Fixation: Preventing Reverse Pupillary Block

To compare clinical outcomes, reverse pupillary block (RPB) findings and anterior segment parameters in patients with and without intraoperative peripheral iridectomy during sutureless flattened flange intrascleral intraocular lens (IOL) fixation. Retrospective comparative case series. This study included 94 eyes of 82 patients who underwent IOL explantation due to vitreous-dislocated IOL at our clinic between March 2020 and September 2023, followed by flattened haptic-tipped IOL intrascleral fixation combined with pars plana vitrectomy (PPV). The patients were divided into two groups: Group 1 (n=54) underwent peripheral iridectomy during surgery, while Group 2 (n=40) did not undergo surgical peripheral iridectomy. Anterior chamber depth (ACD), anterior chamber angle (ACA) and white-to-white (WTW) distance were measured with Scheimpflug imaging. Visual outcomes, ACD, ACA, spherical equivalence (SE), intraocular pressure (IOP), complications, and secondary interventions were evaluated. There was no significant difference between the two groups preoperatively in terms of IOP, ACD, ACA, WTW distance, and axial length (p > 0.05). Postoperatively, the mean ACD was significantly less in Group 1 (3.79 ± 0.67 mm) than in Group 2 (4.11 ± 0.75 mm) (p = 0.03). Postoperative IOP was 15.51 ± 2.48 mmHg in group 1 and 18.20 ± 4.51 mmHg in group 2 (p < 0.001). The postoperative ACA was statistically significantly shallower in Group 1 (41.72 ± 3.47 degrees) than in Group 2 (52.45 ± 17.93 degrees) (p < 0.001). Postoperatively, RPB developed in 10 eyes (25.0%) in Group 2, while it was not observed in any patient in Group 1 (p < 0.001). In Group 2, pupillary capture developed in 4 cases (10%) in addition to RPB. Laser peripheral iridotomy was performed in cases with RPB. After laser peripheral iridotomy, mean IOP, mean ACA and ACD also decreased significantly (p < 0.001). Intraoperative peripheral iridectomy during scleral fixation surgery combined with PPV leads to significantly less RPB, a more stable anterior chamber, and fewer complications. Laser peripheral iridotomy was very useful in managing RPB that developed in the postoperative period.

Behavior of biometric parameters during clinical hours

Purpose: To evaluate and quantify variation of biometric parameters - axial length (AL), anterior chamber depth (ACD), central corneal thickness (CCT) and white-to-white (WTW).Methods: A population-based retrospective cohort study was performed on patients who underwent a biometry test prior to cataract surgery using the IOL Master 700 (Carl Zeiss Meditec, Jena, Germany) between the years 2017-2021. Differences in these parameters were evaluated between scans executed at different times of the day.Results: 21,975 examinations of 8,611 patients were included. Mean age was 70.50±12.56 years. The mean time of the biometry exams was 10:52±1:23 AM. Measurements of AL, ACD, CCT and WTW were tested hourly and grouped between 7:00-9:00 AM and 12:00-03:00 PM.All the parameters showed a diurnal increase with a significance of p<0.001 (AL from 23.64±1.5 to 24.01±1.76mm; ACD from 3.29±0.67 to 3.35± 0.64mm; CCT from 0.52±0.04 to 0.53±0.04 µm and WTW from11.83±0.46 to 11.90±0.51mm). The most significant change was seen in AL.The difference between time groups remained significant in a generalized linear mixed model (P<0.001).Conclusions: There are fluctuations in AL, ACD, CCT, WTW measurements during office hours. These results raise questions about the significance of timing of the biometry exam and the effect on the ELP calculation.

Axial length acquisition success rates and agreement of two swept-source optical biometers in eyes with dense cataracts.

Swept-source optical coherence tomography-based (SS-OCT) biometers have been used in different clinical studies with the aim of assessing the accuracy of the technique, specifically in eyes with dense cataracts. Our objective is to evaluate the axial length acquisition success rates and agreement of two SS-OCT biometers when measuring axial length and biometric parameters in eyes with dense cataracts. 46 eyes (46 patients) with dense cataracts (LOCS III grade ≥ 4) were measured 3 consecutive times using the Eyestar 900 and Argos SS-OCT biometers. Keratometry (K1, flat and K2, steep), central corneal thickness (CCT), white-to-white (WTW), anterior-chamber-depth (ACD), lens-thickness (LT), and axial length were measured using both biometers. The percentage acquisition success rate and a Bland-Altman analysis to determine the agreement between the biometers were calculated. Corrected and uncorrected distance visual acuity, subjective refraction, and axial length (to assess preoperative axial length accuracy) were measured 1-month post-cataract surgery. The mean LOCS III score was 4.37 ± 0.68. The acquisition success rates for both biometers was 100%. There were statistically significant differences between the two SS-OCT biometers for all parameters evaluated (p < 0.05). The mean differences for K1, K2, CCT, WTW, ACD, LT and axial length were 0.106 D, 0.128 D, -6.347 μm, -0.054 mm, 0.095 mm, 0.110 mm, and -0.036 mm, respectively. The mean pre- and post-surgery axial length difference was -0.036 mm for the Eyestar 900 and -0.020 mm for the Argos. This difference was ≤ 0.1 mm in 97.82% of eyes with the Eyestar 900 and in 100% of eyes with the Argos. SS-OCT biometry successfully measures axial length in dense cataracts. The differences between biometers in some parameters may have a clinically significant impact but should be judged individually. The pre- and post-surgery axial length differences for each biometer can be considered clinically negligible and should not affect the IOL power calculation.

Comparison of scansys and pentacam HR in healthy eyes

ABSTRACT Background To determine the interchangeability of Scansys (MediWorks, Shanghai, China) and entacam HR (Oculus, Wetzlar, Germany) in anterior segment measurements. Research designs and methods 42Forty-two healthy individuals’ right eye (mean age 31.5 ± 7.3 years) were assessed for keratometry (K), central corneal thickness (CCT), thinnest corneal thickness (TCT), pupil center pachymetry, corneal volume, anterior chamber volume (ACV), anterior chamber depth (ACD), terior chamber angle (ACA), intraocular pressure (IOP) sum, Q-value (asphericity), and horizontal white-to-white (WTW). Intraclass correlation coefficient (ICC), linear regression analysis, difference of mean, and Bland-Altman plots [bias line and 95% limits of agreement (LoA)] were analyzed. Results Scansys repeated excellently the Pentacam HR for keratometry (except for anterior steep K), ACD, pupil center pachymetry, CCT, TCT, IOP sum, and corneal volume (all ICC > 0.9, r2 > 0.8, and narrow LoAs). There was strong correlations in measuring WTW and ACV (r2 = 0.631 and r2 = 0.623, respectively) and weak correlations in measuring ACA and Q values (all r2 < 0.5). Conclusion The interchangeability of devices were confirmed in measuring ACD, pupil center achymetry, CCT and TCT, IOP sum, corneal volume, and keratometry except for the anterior steep K. However, in measuring WTW, ACV, asphericity, and ACA, Scansys should not be used instead of Pentacam HR.

A comparison of white-to-white measurements obtained by Anterion AS-OCT versus three optical devices in refractive surgery candidates.

To assess the agreement between Anterion AS-OCT and three optical devices in measuring the white-to-white (WTW) diameter in candidates for refractive surgery. In this cross-sectional prospective study, 129 right eyes of 129 normal individuals underwent consecutive scans with the Anterion, the Pentacam AXL, the IOLMaster 700, and the Orbscan IIz. Mean difference (MD), 95% limits of agreement (LoA), and concordance correlation coefficient (CCC) were calculated to assess agreement and interchangeability. The mean age of participants was 30.4 ± 5.9 (range: 21-47) years. The mean WTW distance measured by the different instruments was as follows: 12.00 ± 0.42 mm (range, 10.57 to 13.05) using the Anterion, 11.87 ± 0.34 (11.10 to 12.80) using the Pentacam, 12.12 ± 0.44 (11.00 to 13.30) using the IOLMaster, and 11.73 ± 0.37 (11.00 to 13.10) using the Orbscan. The MD and 95% LoA for Anterion vs. Pentacam, IOLMaster, or Orbscan were [0.11; -0.31 to 0.54 mm], [-0.13; -0.93 to 0.66], and [0.25; -0.28 to 0.78], respectively. The corresponding CCCs were 0.803, 0.514, and 0.631. This study found weak agreement between Anterion and Pentacam AXL, IOLMaster 700, and Orbscan IIz devices regarding WTW distance measurements in refractive surgery candidates. Therefore, it is not recommended to use Anterion's WTW measurements interchangeably with the other three devices, particularly for phakic intraocular lens sizing.

Effect of lighting conditions on implantable collamer lens vault: Influence of anterior chamber and lens parameters

PurposeTo investigate the change in the vault of the implantable collamer lens (ICL) under dark-to-light conditions and its association with anterior chamber and lens parameters in patients undergoing ICL surgery. MethodsIn 76 eyes from 40 patients, preoperative anterior chamber volume (ACV), pupil diameter (PD), anterior chamber angle, central corneal thickness (CCT), white-to-white (WTW), lens thickness (LT), axial length (AL), spherical equivalent (SE) and patient's age were collected. Postoperative vault, PD and LT were measured under dark and light conditions using anterior segment optical coherence tomography (CASIA2; TOMEY, Japan), and changes and lens displacement under dark-to-light conditions were calculated. Mixed-effects models were used to analyze the correlation between the vault change and the anterior chamber and lens parameters of all subjects and the high-vault subgroup. ResultsThe vault under light condition (648.36 ± 304.47 μm) was significantly smaller compared to the vault under dark condition (708.89 ± 316.15 μm). In all patients, vault change increased with the increase of age, lens displacement and PD change; and increased with the decrease of ACV, LT change and baseline vault (under dark condition). In the high-vault subgroup, vault change increased with the increase of CCT, lens displacement and PD change; and increased with the decrease of ACV. ConclusionsICL vault changes significantly from dark to light, influenced by age, ACV, PD change, LT change, lens displacement, and baseline vault. A higher baseline vault is correlated with a larger LT change, affecting the levels of accommodation under dark-to-light transition.

The Postoperative Visual and Refractive Outcomes of Trifocal and Extended Depth-of-Focus Intraocular Lenses in Patients with Different Biometric Characteristics.

We aimed to survey the potential correlation between biometric parameters and postoperative outcomes after implanting extended depth-of-focus (EDOF) intraocular lenses (IOLs) and trifocal IOLs. A retrospective cohort study was conducted, and patients receiving EDOF or trifocal IOL implantations were included. In total, 36 and 26 eyes were enrolled in the EDOF and trifocal groups, respectively. The primary outcomes of this study were the postoperative uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), and spherical equivalent (SE). The generalized linear model was applied to evaluate the adjusted odds ratio (aOR) and 95% confidence intervals (CIs) of primary outcomes in patients with different biometric characters. The final UDVA of the EDOF group was significantly better than that of the trifocal group (p = 0.020), and the UNVA and SE did not show significant differences between the two groups throughout the postoperative period (all p > 0.05). In a multivariable analysis, the UDVA was significantly better in the EDOF group than in the trifocal group (p = 0.038). For the subgroup analysis, the high axial length (AXL) value correlated to a lower postoperative UDVA in the EDOF group (both p < 0.05). Additionally, a large white-to-white (WTW) diameter was related to worse postoperative UNVA in the trifocal group (p = 0.042), and a high AXL was associated with higher SE in both the EDOF and trifocal groups (both p < 0.05). In conclusion, a high AXL correlates to worse postoperative outcomes in both the EDOF and trifocal IOLs, and trifocal IOL outcomes could be affected by large WTW diameters.

Tilt and decentration of the crystalline lens in ultra-high myopia with cataract and its influencing factors: A study based on CASIA2'.

This study aims to examine the characteristics and influencing factors of crystalline lens tilt and decentration in ultra-high myopic cataract patients, as measured by the CASIA2. 60 eyes scheduled for cataract surgery with an axial length (AL) ≥ 28 mm were included. The IOLMaster700 was utilized to measure AL and the white-to-white (WTW) distance. The CASIA2 was employed to measure front curvature radius (FCR), crystalline lens tilt, and crystalline lens decentration. The relationships between lens tilt, decentration, and related factors were evaluated. The degree of lens tilt was 4.62 ± 2.44°, and the decentration was 0.20 (Q1 0.13, Q3 0.28) mm. Among the 60 eyes, 11 (18.3%) had a tilt ≥7°, and 6 (10%) had a decentratiolens tilt ≥7° (P = 0.038, P = 0.018). Eyes with AL >30.00 mm and FCR <8.45 mm had a higher degree of lens tilt. Additionally, a tilt ≥7° was associated with a greater decentration (P = 0.032), n. Preoperative crystalline lenses in eyes with ultra-high myopia and cataract exhibit certain degrees of tilt and decentration. An AL >30 mm is a risk factor for a lens tilt ≥7° and an decentration ≥0.4 mm. An FCR <8.45 mm is a risk factor for increased lens tilt, and a tilt ≥7° is a risk factor for increased lens decentrati ≥ 0.4 mm. An increase in AL and FCR <8.45 mm were risk factors for a and eyes with AL >30.00 mm had a higher degree of decentration (P = 0.005).

Risk Factors for Postoperative Refractive Error in New-Generation Intraocular Lens Calculation Formulas.

We examined differences in the accuracy of three intraocular lens (IOL) calculation formulas: the traditional Sanders-Retzlaff-Kraff/Theoretical (SRK/T) formula; the Barrett Universal II (BU II) formula, which is a new-generation IOL calculation formula; and the postoperative spherical equivalent prediction using artificial intelligence and linear algorithms developed by Debellemanière, Gatinel, and Saad formula (PEARL-DGS [PEARL]) formula, and evaluated factors that cause postoperative refractive error (PE). The study included 205 patients (205 eyes) with a mean age of 75.2 ± 8.7 years who underwent cataract surgery at our institution from December 2018 to October 2023. The PE of the three IOL calculation formulas was calculated and compared. Multivariate logistic regression analysis was performed with a PE higher than ±0.50 D as the dependent variable, and age, sex, axial length (AL), mean keratometry (mean K), anterior chamber depth (ACD), lens thickness (LT), and white-to-white (WTW) as independent variables. The mean PE (ME)±standard deviation of the SRK/T, BU II, and PEARL formulas was 0.11 ± 0.52, 0.11 ± 0.50, and 0.21 ± 0.50 D, respectively. MEs of the three IOL calculation formulas were significantly different from 0 (p < 0.01). The median absolute error (MedAE) was not significantly different among the three IOL calculation formulas (p = 0.83). The percentage of PE within ±0.50 D was not significantly different among the three IOL calculation formulas (p = 0.13). Multivariate logistic regression analysis showed that the significantly associated factors with PE higher than ±0.50 D were AL, ACD, and LT for the SRK/T formula, sex and LT for the BU II formula, and LT for the PEARL formula (all p < 0.05). In the BU II and PEARL formulas, AL was excluded as a factor affecting PE, indicating that LT was a risk factor.

The comparison of white-to-white via triple person-times caliper measuring and machine-measuring in V4c implantable collamer lens implantation

This study aimed to compare the differences and characteristics of white-to-white (WTW) values obtained before V4c implantation using triple person-times caliper, IOL-Master 700, Pentacam HR, and UBM, and to assess their correlation with vaulting. A total of 930 myopia patients (1842 eyes) who were interested in undergoing ICL surgery were assessed before the procedure using various instruments. The WTW measurements were obtained using a triple person-times caliper, Pentacam HR, and IOL-Master 700, whereas the angle-to-angle (ATA) measurements were obtained using UBM. The size of the ICL was subsequently calculated using triple person-times caliper measurements. The vault of the ICL was assessed using Pentacam HR three months after the surgery. The WTW was determined to be 11.30 ± 0.29 mm, 11.43 ± 0.29 mm, and11.86 ± 0.38 mm, respectively, using the triple person-times caliper, Pentacam HR, and IOL-Master 700. The measurement of ATA was 11.57 ± 0.51 mm, as done by UBM. The ICL vault was measured to be 400.97 ± 198.46 µm when examined with Pentacam HR three monthsafter the procedure. The linear regression analyses of ICL size and WTW of triple person-times caliper, ICL vault and WTW were (R = 0.703, p < 0.001; R = 0.0969, p < 0.001) respectively. The highest correlation was found between IOL-Master and Pentacam HR (r = 0.766, p = 0.000). The lowest correlation was found between UBM and Pentacam HR (r = 0.358, p = 0.002). Bland–Altman analysis showed that the 95% limits of agreement (LoA) were the triple person-times caliper and Pentacam HR (– 0.573, 0.298) and the triple person-times caliper and UBM (– 1.15, – 0.605). This indicated a strong agreement between the triple person-times caliper and Pentacam HR and a lack of agreement between the triple person-times caliper and UBM. Triple person-times caliper measurements offer excellent maneuverability, practicality, and reliable outcomes for determining ICL vaults. Measurements obtained using the triple-person caliper were less differece than those obtained using the Pentacam HR.

Correlations of Corneal Endothelial Morphology and Corneal Thickness With Anterior Segment Parameters in Healthy Individuals.

The purpose of this study was to investigate the associations between central corneal endothelial cell density (ECD), endothelial morphology, and corneal thickness (central corneal thickness) with the anterior chamber depth, corneal volume (CV), white-to-white (WTW) distance, mean anterior chamber angle (CAmean), and gender in healthy individuals. This observational study included 136 healthy volunteers. The ECD, coefficient of variation of cell area, and hexagonal cell appearance ratio (%Hex) were measured by means of specular microscopy. The central corneal thickness, anterior chamber depth, CV, WTW distance, and the angle width of 12 points were taken by the Pentacam HR Scheimpflug anterior segment imaging. The arithmetical mean of the 12 points was considered as the CAmean. We used mixed effect linear regression model for the statistical analysis of the data. ECD was positively correlated with CV ( P = 0.028), while after adjusting for age, it was negatively correlated with age ( P < 0.001). Coefficient of variation of cell area was positively correlated with CAmean ( P = 0.036), while after adjusting for age, it was positively correlated with age ( P < 0.001) and CAmean ( P = 0.005). Hex was negatively correlated with WTW ( P = 0.023) and CAmean ( P = 0.025), and after adjusting for age, this correlation remained the same ( P = 0.029 when correlated with WTW and P = 0.035 with CAmean). There were significant changes in the morphology of the corneal endothelial cells in eyes with wider anterior chamber angle. Greater pleomorphism and polymegethism of the corneal endothelium was observed in healthy patients with wider CAmean. Deepening of the anterior chamber as myopia progresses could render the corneal endothelium more fragile and susceptible to mechanical stress, which is an area worthy of further study.

Corneal densitometry in Chinese adults with healthy corneas: associations with sex, age, ocular metrics, and optical characteristics

BackgroundStandardized corneal densitometry (CD) values in large samples of healthy Chinese individuals are scarce. Therefore, we aimed to determine the standard CD values using a Scheimpflug camera in healthy corneas, investigate the correlations of sex, age, and ocular parameters with corneal density, and explore the impact of corneal density on the forward scattering and optical quality of the eye.MethodsThis retrospective observational study involved 990 healthy Chinese individuals, including 494 males and 496 females (mean age: 23.88 ± 6.90 years). The CD values at various depths and radial areas of 0–12 mm were measured using a Scheimpflug camera. Densitometric measurements were expressed in standardized grayscale units (GSU). The optical scatter index (OSI), modulation transfer function cutoff values (MTFcutoff), and Strehl’s ratio (SR) were also determined using an optical quality analysis system.ResultsThe average CD within a 12 mm diameter area was 16.26 ± 1.35 GSU. The highest and lowest optical densities at different depths were observed in the anterior (21.41 ± 2.16 GSU) and posterior (12.00 ± 1.01 GSU) layers, respectively (P < 0.001). Similarly, the maximum and minimum optical densities at different radial areas were observed in the 10–12 mm (14.09 ± 0.93 GSU) and 2–6 mm (25.93 ± 4.77 GSU) circles, respectively (P < 0.001). There was no significant difference in the average CD within a 12 mm diameter area between males and females (P > 0.05). However, upon adjusting for age, central corneal thickness (CCT), corneal curvature, white-to-white (WTW) corneal diameter, and axial length, females exhibited a greater average CD within the 12 mm diameter and in the 6–10 mm and 10–12 mm circles than males. Age-related changes in CD were evident, except in the 2–6 mm circle. CCT, corneal curvature, WTW corneal diameter, and partial depth correlated with CD in the radial area, and CD in different areas correlated with the OSI, MTFcutoff, and SR (P < 0.05).ConclusionsThis study provides the normative CD measurement data of Chinese adults with healthy corneas, emphasizing the significance of sex, age, CCT, corneal curvature, and WTW corneal diameter in CD evaluation. Notably, elevated CD can lead to increased forward scattering within the eye, thereby affecting the optical quality.

Changes in corneal endothelial cells after scleral-fixated intraocular lens surgery in children with congenital ectopia lentis: 2-year follow-up.

To investigate the changing patterns of corneal endothelial cells and the associated factors in children with congenital ectopia lentis (CEL) after scleral-fixated intraocular lens (SF IOL) surgery. Zhongshan Ophthalmic Center, Guangzhou, China. Retrospective study. Patients were divided into the surgery group and the control group. Central endothelial cell density (ECD), coefficient of variation in cell size, the percentage of hexagonal cells (hexagonality), average cell size (AVG), and central corneal thickness were analyzed for both groups at baseline and each follow-up visit. Clinic characteristic, ocular parameters, IOL decentration, and IOL tilt of patients in the surgery group were collected. Multiple linear regression was performed to assess the potential associated factors for the postoperative changes in corneal endothelial cells in the surgery group. After 2-year follow-up, the decline of ECD was 17.8% (95% CI, -21.8 to -13.9) in the surgery group and -3.1% (95% CI, -5.2 to -1.0) in the control group ( P < .001), while the increase of AVG was 24.3% (17.1-31.6) in the surgery group and 2.7% (1.0 to 4.5) in the control group ( P < .001). Multivariate analysis showed that axial length (AL) ≥24 mm and white-to-white (WTW) <12.2 mm were significantly associated with greater loss of ECD (β = -241.41, 95% CI, -457.91 to -24.91, P = .030 and β = 251.63, 95% CI, 42.10-461.17, P = .020, respectively) and AL ≥24 mm was significantly positively associated with the increase of AVG (β = 34.81, 95% CI, 0.90-68.71, P = .044). The SF IOL had a significant impact on corneal endothelium in children with CEL. More attention should be paid to monitor postoperative corneal endothelium change during long-term follow-up in CEL children, especially for those with longer AL and smaller WTW.

Influencing factors of effective lens position in patients with Marfan syndrome and ectopia lentis

AimsThe aim of this study was to analyse the effective lens position (ELP) in patients with Marfan syndrome (MFS) and ectopia lentis (EL).MethodsPatients with MFS undergoing lens removal and primary...

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.

The Repeatability and Agreement of Ocular Parameters Measured with the MYAH and Myopia Master Devices between Expert and Non-Expert Practitioners.

In myopia control, it is essential to measure the axial length (AL) and corneal parameters, and to monitor whether changes in these parameters have occurred over time. The aim of this study was to analyse the repeatability and agreement between expert and non-expert practitioners in ocular parameters measured by the MYAH and Myopia Master. Three repeated measurements (n = 42) were recorded with the MYAH and Myopia Master by two (an expert and a non-expert) observers in a randomized order. The AL, K1, K2, and white-to-white (WTW) distance were collected. The intraobserver repeatability was excellent in all parameters measured with both devices in both observers. The AL outcome presented the best repeatability with the MYAH and Myopia Master (intraclass correlation coefficient, ICC = 1.0; coefficient of variation, CV ≤ 0.06% for both observers), while the WTW presented poorer results (ICC ≤ 0.991; CV ≤ 0.52%). The Myopia Master provides a significantly (p ≤ 0.01) flatter K1 and K2 as well as a lower WTW (p ≤ 0.01) than the MYAH. No statistically significant difference in AL measurements was found with either device (p ≥ 0.10; ICC = 1.0). None of the parameters showed differences (p ≥ 0.12) between the expert and non-expert observer. The MYAH and Myopia Master provide consistent measurements in a healthy adult population regardless of the previous clinical experience of the observer. AL measurements should be used interchangeably but K1, K2, and WTW should be used interchangeably with caution.

Distribution and associations of anterior lens zonules lengths in patients with cataract.

To investigate the characteristics and associations of anterior lens zonules lengths in cataract patients via ultrasound biomicroscope (UBM) measurement. Patients with age-related cataracts and high myopic cataracts who planned to undergo cataract surgery were included in the study. After routine ophthalmic examinations, the UBM was performed on both eyes to get images of the anterior lens zonules, and Image J software was used to measure the lengths of the lens zonules. Axial length (AL), anterior chamber depth (ACD), lens thickness (LT), and white-to-white (WTW) diameter of both eyes were obtained by IOL Master 700. Univariate and multivariate regression analyses were used to assess associated factors of anterior lens zonules lengths. Forty-nine patients with age-related cataracts and 33 patients with high myopic cataracts were enrolled. High myopic cataract patients were younger and had longer anterior lens zonules. Multivariate regression analysis showed that anterior lens zonules lengths were associated with axial lengths (temporal location: β = 0.036, P = 0.029; nasal location: β = 0.034, P = 0.011; superior location: β = 0.046, P = 0.002) and ACD (inferior location: β = 0.305, P = 0.016) in right eyes. In left eyes, anterior lens zonules lengths were associated with axial lengths (temporal location: β = 0.028, P = 0.017; inferior location: β = 0.026, P = 0.016; nasal location: β = 0.033, P < 0.001) and ACD (inferior location: β = 0.215, P = 0.030; superior location: β = 0.290, P = 0.011). High myopic cataract patients have longer anterior lens zonules. AL and ACD contributed to the lengths of anterior lens zonules. Thus, for patients with long AL and deeper ACD, lens zonules measurement was crucial. www.chictr.org.cn identifier is ChiCTR2300071397.

Comparison of keratometric values and anterior segment parameters measured using Scheimpflug Sirius topography and Lenstar biometry.

This study aimed to evaluate the consistency of preoperative keratometric values, anterior segment, and intraocular lens (IOL) power measurements in patients with cataract and no comorbidities using the Sirius topography device (CSO, Italy) and Lenstar LS 900 (Haag-Streit AG, Köeniz, Switzerland). Patients with grade 2 and 3 cataracts who applied to Ophthalmology Clinic of Dışkapı Yıldırım Beyazıt Education and Research Hospital, University of Health Sciences and planned for cataract surgery were included the study. Forty eyes with cataract from 40 patients were taken in the study. All patients underwent preoperative assessment using a combined Scheimpflug-Placido disc-based tomography device (Sirius) and Lenstar before cataract surgery. Keratometric measurements, such as flat keratometry (K1), steep keratometry (K2), and maximum keratometry (Kmax), and anterior segment parameters, white-to-white (WTW) distance, IOL power, astigmatism (AST), anterior chamber depth (ACD), aqueous depth (AD), and central cornea thickness (CCT), were recorded. There were significant differences between K1Lenstar and K1Sirius, K2Lenstar and K2Sirius, KmaxLenstar and KmaxSirius, WTWLenstar and WTWSirius, and IOL powerLenstar versus IOL powerSirius. However, there were insignificant differences between ASTLenstar and ASTSirius, ACDLenstar versus ACDSirius, ADLenstar and ADSirius, and CCTLenstar and CCTSirius variables. Furthermore, it was found that Sirius measured significantly higher than Lenstar, especially in terms of IOL power. Significant differences were observed between Lenstar and Sirius in terms of keratometric values, WTW distance, and IOL power. The IOL power value measured with Sirius was found to be higher than the IOL power value measured with Lenstar.

Comparison of Optical Biometry and Scheimpflug Device Keratometric Readings Accuracy in Predicting Intraocular Lens Power in Cataract Surgery

Abstract Background: A correct preoperative intraocular lens (IOL) power measurement in cataract surgery depends on accurate assessment of axial length (AL), anterior segment parameters, and using the suitable formula for the calculation of the power. Objectives: To determine the accuracy of IOL power calculations using keratometric measurements of the IOL Master compared to the Pentacam and to determine whether the results obtained can be used interchangeably in clinical practice in calculating IOL power in routine cataract surgery. Patients and Methods: In this prospective study, the biometric data including AL, keratometric readings, and anterior chamber depth (ACD) were obtained by both the IOL Master 500 and Pentacam Scheimpflug devices added to these measures the white-to-white (WTW) distance by IOL Master and central corneal thickness by Pentacam and calculation of the IOL power using SRK/T formula for the enrolled patients who undergone uneventful cataract surgery with IOL implantation. Postoperatively, spherical equivalent refraction was measured and the mean arithmetic error and the mean absolute error (MAE) for both keratometric readings were calculated to compare the accuracy between them in calculating the IOL power. Results: The study evaluated 57 eyes of 57 patient, the mean K value for the IOL Master was 43.92 (D) ± 1.5 (standard deviation [SD]) and the mean K value for the Pentacam was 43.77 (D) ± 1.7 (SD) (P = 0.62), ACD values between the two groups, was 3.19 ± 0.44 mm measure by IOL Master compared to 3.22 ± 0.48 mm in Pentacam (P = 0.769), with a very strong positive correlation between the two values (r = 0.995, P &lt; 0.001). MAE for the IOL Master was 0.230 (D) ± 0.187 (SD), while for the Pentacam was 0.255 (D) ± 0.204 (SD), with no statistically significant differences between two devices’ values (P = 0.54). Conclusions: Pentacam Scheimpflug measured keratometric and ACD data had good correlation with IOL Master data with good interchangeability between two devices readings in measuring the IOL power in routine cases of cataract surgeries.