The influence of age and gender on ocular biometrics and corneal astigmatism in adults undergoing cataract surgery.

Objectives: To assess the influence of age and gender on ocular biometric values and corneal astigmatism features in individuals undergoing phacoemulsification surgery and intraocular lens implantation. Methodology: This retrospective study measured ocular biometrics and corneal keratometric astigmatism using the IOLMaster 700 instrument prior to phacoemulsification surgery and intraocular lens implantation. Results: Analysis included ocular biometric and keratometric values from 3385 eyes of 3385 patients. Lens thickness (p < 0.001, r = 0.387), mean keratometry (p < 0.001, r = 0.156), and corneal astigmatism (p < 0.001, r = 0.082) were positively correlated with age. Conversely, axial length (p < 0.001, r = -0.133), anterior chamber depth (p < 0.001, r = -0.244), and horizontal white-to-white corneal diameter (p < 0.001, r = -0.226) exhibited negative correlations with age. Increasing age led to a significant shift towards against-the-rule astigmatism (p < 0.001, r = 0.248). Mean keratometry was significantly lower in males than females (p < 0.001). Axial length, anterior chamber depth, lens thickness, and white-to-white corneal diameter were higher in males compared to females (all ps ⩽ 0.001). Corneal astigmatism types differed significantly between genders (p < 0.001), with against-the-rule being more prevalent among males (52.9%) and with-the-rule astigmatism having the highest prevalence among females (40.3%). Conclusions: Mean keratometry and lens thickness increased, while axial length and anterior chamber depth decreased with age. Males exhibited higher values for axial length, anterior chamber depth, and lens thickness, whereas females had steeper corneas.

Five-year changes in retinal nerve fibre layer thickness in the adult population: a population-based cohort study.

CLINICAL RELEVANCE: Distinguishing between the pathological thinning of the retinal nerve fibre layer (RNFL) and age-related reduction requires a comprehensive understanding of the longitudinal changes in RNFL thickness within a healthy population. BACKGROUND: To determine five-year changes in RNFL thickness and associated factors in people aged 45-69 years. METHODS: This report pertains to the second and third phases of the Shahroud Eye Cohort Study. Participants were recruited by a multi-stage cluster sampling in Shahroud, Iran. Data on demographic details, visual acuity, non-cycloplegic refraction, and slit-lamp biomicroscopy were collected. High-definition optical coherence tomography was employed for retinal imaging. RESULTS: A total of 1,524 eyes from 908 participants were examined. The average RNFL thickness was 92.2 ± 8.5 (95% CI: 91.6 to 92.8) and 93.1 ± 8.7 µm (95% CI: 92.5 to 93.7) in the first and second phases with a five-year mean change of 0.95 ± 4.15 µm (95% CI: 0.70 to 1.20). The RNFL thickness mean changes in the superior, inferior, nasal, and temporal quadrants were 2.51 ± 7.86 (95% CI: 2.01 to 3.02), 2.93 ± 7.39 (95% CI: 2.56 to 3.29), -0.53 ± 6.15 (95% CI: -0.84 to -0.21), and -1.01 ± 4.67 µm (95% CI: -1.27 to -0.75), respectively. The five-year changes in average RNFL thickness were inversely correlated with axial length (ß = -0.69, p < 0.001), mean keratometry (ß = -0.37, p = 0.017), and baseline RNFL thickness (ß = -0.617, p < 0.001). In hyperopic individuals, the increase in average RNFL thickness (ß = 0.65, p = 0.012) was significantly greater than in those with emmetropia. Macular volume (ß = 1.65, p < 0.001) showed a direct association with five-year changes in average RNFL thickness. CONCLUSION: Over 5 years, RNFL thickness changes were clinically insignificant in the normal population. The mean RNFL thickness seems to remain stable unless there is ocular disease. However, increased axial length and steeper keratometric readings were linked to RNFL thinning. Those with thicker RNFL measurements were at higher risk of thinning over time.

Intraoperative Aberrometry versus Preoperative Biometry for Intraocular Lens Power Calculations: A Report by the American Academy of Ophthalmology.

PURPOSE: To evaluate the published literature to compare intraoperative aberrometry (IA) with preoperative biometry-based formulas with respect to intraocular lens (IOL) power calculation accuracy for various clinical scenarios. METHODS: Literature searches in the PubMed database conducted in August 2022, July 2023, and February 2024 identified 157, 18, and 6 citations, respectively. These were reviewed in abstract form, and 61 articles were selected for full-text review. Of these, 29 met the criteria for inclusion in this assessment. The panel methodologists assigned a level of evidence rating to each of the articles; 4 were rated level I, 19 were rated level II, and 6 were rated level III. RESULTS: Intraoperative aberrometry performed better than traditional vergence formulas, including the Haigis, HofferQ, Holladay, and SRK/T, and similarly to the Barrett Universal II and Hill-RBF with respect to minimization of spherical equivalent (SE) refractive error. For toric IOLs, IA outperformed formulas that only considered anterior corneal astigmatism and was similar to formulas like the Barrett Toric Calculator (BTC), which empirically account for the contribution from the posterior cornea. In eyes with a history of corneal refractive surgery, IA performed similarly to the Barrett True-K and slightly better than other tested methods, including the Haigis-L, Shammas, and Wang-Koch-Maloney formulas. CONCLUSIONS: Intraoperative aberrometry corresponds well with modern vergence formulas, including the Barrett Universal II, Hill-RBF, BTC, and Barrett True-K. It has greater accuracy than traditional vergence-based IOL power calculation formulas in eyes with and without a history of corneal refractive surgery. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Comparative Analysis of Refractive Outcomes Following Cataract Surgery Using IOL Master 500 and IOL Master 700 Biometry Devices: A Retrospective Analysis.

Background: This study aims to compare the refractive outcomes of cataract surgery using two different biometry devices, the IOL Master 500 and IOL Master 700, and to investigate the influence of patient-related factors on these outcomes. Methods: In this retrospective study, we analyzed data from 2994 eyes that underwent cataract surgery. Multiple linear regression analyses were performed to examine the impact of the biometry device (IOL Master 500 or IOL Master 700), patient age, time elapsed between biometry and surgery, gender, and insurance status, as well as biometric parameters (anterior chamber depth, axial length, and corneal curvature), on postoperative refractive outcomes, specifically the deviation from target refraction. Results: The choice of the IOL Master device did not result in a statistically significant difference between the two devices (p = 0.205). Age (p = 0.006) and gender (p = 0.001) were identified as significant predictors of refractive outcomes, with older patients and males experiencing slightly more hyperopic outcomes compared to younger patients and females, respectively. The time elapsed between biometry and surgery and insurance status did not significantly influence the refractive outcomes. Conclusions: Our study, supported by a large cohort and a diverse group of patients representing typical anatomical variants seen in cataract surgery, supports the thesis that the IOL Master 500 and IOL Master 700 can be regarded as equivalent and effective for biometry in cataract surgery. The differences between the devices were negligible. Therefore, switching between the devices is safe for bilateral patients.

Estimating the astigmatic power of the crystalline lens and eye from ocular biometry.

PURPOSE: To estimate the astigmatic power of the crystalline lens and the whole eye without phakometry using a set of linear equations and to provide estimates for the astigmatic powers of the crystalline lens surfaces. METHODS: Linear optics expresses astigmatic powers in the form of matrices and uses paraxial optics and a 4 × 4 ray transfer matrix to generalise Bennett's method comprehensively to include astigmatic elements. Once this is established, the method is expanded to estimate the contributions of the front and back lens surfaces. The method is illustrated using two examples. The first example is of an astigmatic model eye and compares the calculated results to the original powers. In the second example, the method is applied to the biometry of a real eye with large lenticular astigmatism. RESULTS: When the calculated powers for the astigmatic model eye were compared to the actual powers, the difference in the power of the eye was 0.03 0.13 0.04 T D $$ {\left(0.03\kern0.5em 0.13\kern0.5em 0.04\right)}^{\mathrm{T}}\ \mathrm{D} $$ (where T represents the matrix transpose) and for the crystalline lens, the difference was 0.08 0.29 0.08 T D $$ {\left(0.08\kern0.5em 0.29\kern0.5em 0.08\right)}^{\mathrm{T}}\ \mathrm{D} $$ (power vector format). A second example applies the method to a real eye, obtaining lenticular astigmatism of -5.84 × 175. CONCLUSIONS: The method provides an easy-to-code way of estimating the astigmatic powers of the crystalline lens and the eye.

Refractive Predictability of Two Intraocular Lens Power Formulas in Long, Medium, and Short Eyes Using a Swept Source Optical Coherence Tomography Biometer.

Purpose: To compare the refractive predictability of Argos measurements with Barrett Universal II (BUII) and Barrett True Axial Length (BTAL) formulas in a large sample of long, medium, and short axial length (AL) eyes. Methods: A retrospective chart review identified 445 eyes of 247 patients for inclusion. The Argos was used for preoperative biometry, and BUII formula for intraocular lens (IOL) power calculations. Back calculations were performed using data from the Argos for the BTAL formula. Data were collected for postoperative absolute prediction error (APE), refractive outcomes, and monocular uncorrected and distance corrected visual acuities at distance (UDVA, CDVA). Results: Overall, mean APE was 0.36 ± 0.33 D for BUII and for 0.34 ± 0.32 D BTAL (p = 0.04). In short AL eyes, mean APE was 0.45 ± 0.37 D for BUII and for 0.37 ± 0.31 D BTAL (p < 0.001). No significant differences between BUII and BTAL were identified for long AL or medium AL eyes. The percentages of eyes with APE of 0.5 D or less in long, medium, and short eyes were 79%, 79% and 51%, respectively, for BUII and 82%, 78% and 69%, respectively, for BTAL. Conclusion: The prediction accuracies were high with both the BUII and BTAL formulas in long, medium, and short eyes, leading to excellent refractive outcomes. The BTAL formula may have lower absolute prediction error in short eyes compared to BUII.

When the natural lens inside the eye becomes opaque, it can be replaced during cataract surgery with a clear artificial intraocular lens (IOL). It is critical for good postoperative outcomes that the optimal power for the IOL is implanted. Biometers are devices used to measure the eye and typically have built-in formulas to calculate the most appropriate IOL power for implantation. However, it is challenging to select the optimal power in eyes that are longer or shorter than average. The purpose of this study was to compare the refractive predictability of a novel biometer using two IOL power calculation formulas in a large sample of long, medium, and short eyes. The results of this study suggest that predictability was high with both formulas in long, medium, and short eyes, leading to excellent refractive outcomes.

Comparison of measurements and calculated lens power using three biometers: a Scheimpflug tomographer with partial coherence interferometry and two swept source optical coherence tomographers.

PURPOSE: To compare the biometric measurements obtained from the Pentacam AXL Wave, IOLMaster 700, and ANTERION and calculate the recommended intraocular lens power using the Barrett Formulae. METHODS: This was a retrospective cross-sectional study of patients who underwent biometry using the Pentacam AXL Wave, IOLMaster 700, and ANTERION. Flat keratometry (K1), steep keratometry (K2), anterior chamber depth (ACD), and axial length (AL) from each device were measured and compared. These parameters were used to calculate the recommended IOL powers using the Barrett formula. RESULTS: The study included 252 eyes of 153 patients. The IOLMaster had the highest acquisition rate among the two biometers. The Pentacam obtained the shortest mean AL, the IOLMaster measured the highest mean keratometry values, and the ANTERION measured the highest mean ACD. In terms of pairwise comparisons, keratometry and axial length were not significantly different between the Pentacam-IOLMaster and ANTERION-IOLMaster groups, while the rest of the pairwise comparisons were statistically significant. In nontoric and toric eyes, 35-45% of patients recommended the same sphere of IOL power. In another 30-40%, the Pentacam and ANTERION recommended an IOL power one step greater than that of the IOLMaster-derived data. 50% of the study population recommended the same toric-cylinder IOL power. CONCLUSIONS: The Pentacam AXL Wave, IOLMaster 700, and ANTERION can reliably provide data for IOL power calculations; however, these data are not interchangeable. In nontoric and toric eyes, 35-45% of cases recommended the same sphere IOL power, and in another 30-40%, the Pentacam and ANTERION recommended one-step higher IOL power than the IOLMaster-derived data. In targeting emmetropia, selecting the first plus IOL power is advisable when using the Pentacam and ANTERION to approximate the IOL power calculations recommended by the IOLMaster 700.

PSFHS challenge report: Pubic symphysis and fetal head segmentation from intrapartum ultrasound images.

Segmentation of the fetal and maternal structures, particularly intrapartum ultrasound imaging as advocated by the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) for monitoring labor progression, is a crucial first step for quantitative diagnosis and clinical decision-making. This requires specialized analysis by obstetrics professionals, in a task that i) is highly time- and cost-consuming and ii) often yields inconsistent results. The utility of automatic segmentation algorithms for biometry has been proven, though existing results remain suboptimal. To push forward advancements in this area, the Grand Challenge on Pubic Symphysis-Fetal Head Segmentation (PSFHS) was held alongside the 26th International Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI 2023). This challenge aimed to enhance the development of automatic segmentation algorithms at an international scale, providing the largest dataset to date with 5,101 intrapartum ultrasound images collected from two ultrasound machines across three hospitals from two institutions. The scientific community's enthusiastic participation led to the selection of the top 8 out of 179 entries from 193 registrants in the initial phase to proceed to the competition's second stage. These algorithms have elevated the state-of-the-art in automatic PSFHS from intrapartum ultrasound images. A thorough analysis of the results pinpointed ongoing challenges in the field and outlined recommendations for future work. The top solutions and the complete dataset remain publicly available, fostering further advancements in automatic segmentation and biometry for intrapartum ultrasound imaging.

Evaluation of the effect of SARS-COV-2 infection on Doppler ultrasound and placental findings of pregnant women: a systematic review and meta-analysis.

PURPOSE: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can infect the human placenta and has been shown to have an adverse effect on Doppler ultrasound parameters and placental features. However, the specific effects of the SAS-CoV-2 infection on the fetal-placental unit in pregnant women remain unclear. The aim of this systematic review and meta-analysis was to evaluate the impact of SARS-CoV-2 infection on Doppler ultrasound and placental findings in pregnant women. METHODS: A systematic search was conducted using four electronic databases (PubMed, Embase, Scopus, and Cochrane Library) to select publications published in peer-reviewed journals written in English. Odds ratios (ORs) were calculated, along with their 95% confidence intervals (CIs). Heterogeneity was assessed using Cochrane Q and I² statistics and the appropriate P-value. The analysis used RevMan 5.3. RESULTS: This meta-analysis included 1,210 pregnant women from 10 case-control studies. SARS-CoV-2-infected pregnant women exhibited higher likelihoods of placental abnormalities (OR, 2.62; 95% CI, 1.66 to 4.13), aberrant Doppler values (OR, 1.95; 95% CI, 1.16 to 3.27), an abnormal cerebroplacental ratio (OR, 2.68; 95% CI, 1.52 to 4.75), altered fetoplacental circulation (OR, 1.56; 95% CI, 1.07 to 2.28), and increased placental thickness and placental venous lakes (OR, 1.85; 95% CI, 1.25 to 2.72). CONCLUSION: According to this meta-analysis, pregnant women infected with SARS-CoV-2 are more likely to experience altered Doppler ultrasonography parameters and placental abnormalities, including increased placental thickness, placental venous lakes, altered fetoplacental circulation, and cerebroplacental ratio. However, the limited number of case-control studies requires larger sample sizes to validate and enhance the evidence.

A Retrospective Study of Visual Outcomes When Using a Cloud-Based Surgical Planning Platform and the Barrett Universal II Formula.

Purpose: To evaluate the efficacy of a cloud-based surgical planning platform with regards to refractive target accuracy. Methods: This was a retrospective chart review of consecutive cases from January 2022 through December 2023. Surgical planning was performed using the SMARTCataract platform, eyes were implanted with Clareon monofocal IOLs, and power calculations were done using the Barrett Universal II formula. Data were collected for the percentage of eyes within ±0.5 D of target refraction, mean absolute error (MAE), and postoperative visual acuity. Results: A total of 148 eyes were identified that met the inclusion/exclusion criteria. The percentage of eyes within ±0.5 D of the planned target was 94%. The MAE was 0.25 ± 0.17 D. In addition, 57%, 93%, 98%, and 100% of eyes had MAE ≤ 0.25 D, ≤ 0.5 D, ≤ 0.75 D, and ≤ 1.0 D, respectively. Conclusion: The results of this study suggest high refractive accuracy when using the SMARTCataract planning platform with the Barrett Universal II formula and excellent distance visual acuity.

When the natural lens inside the eye develops a cataract (becomes opaque) it can be replaced with a clear artificial intraocular lens (IOL). Good visual outcomes after surgery are heavily reliant on implanting the optimal lens power. A new cloud-based surgical planning tool (SMARTCataract) aims to automatically use patient data, surgeon preferences, favored IOL power calculation formulas, and desired IOL type to guide surgical planning. However, to date there are no data on the refractive outcomes when using the SMARTCataract platform. The purpose of this study was to evaluate the efficacy of the SMARTCataract platform with regards to refractive target accuracy. The results of this study suggest high refractive accuracy when using the SMARTCataract platform with the Barrett Universal II formula and excellent distance visual acuity.

Digital Biometry as an Obesity Diagnosis Tool: A Review of Current Applications and Future Directions.

Obesity is a chronic relapsing disease and a major public health concern due to its high prevalence and associated complications. Paradoxically, several studies have found that obesity might positively impact the prognosis of patients with certain existing chronic diseases, while some individuals with normal BMI may develop obesity-related complications. This phenomenon might be explained by differences in body composition, such as visceral adipose tissue (VAT), total body fat (TBF), and fat-free mass (FFM). Indirect measures of body composition such as body circumferences, skinfold thicknesses, and bioelectrical impedance analysis (BIA) devices are useful clinically and in epidemiological studies but are often difficult to perform, time-consuming, or inaccurate. Biomedical imaging methods, i.e., computerized tomography scanners (CT scan), dual-energy X-ray absorptiometry (DEXA), and magnetic resonance imaging (MRI), provide accurate assessments but are expensive and not readily available. Recent advancements in 3D optical image technology offer an innovative way to assess body circumferences and body composition, though most machines are costly and not widely available. Two-dimensional optical image technology might offer an interesting alternative, but its accuracy needs validation. This review aims to evaluate the efficacy of 2D and 3D automated body scan devices in assessing body circumferences and body composition.

Effect of Burned Multi-Crop Ashes on Faba Bean-Development Parameters.

The use of burned plant biomass ashes could help not only with respect to utilizing combustion residues, but also with respect to optimizing the nutrition of cultivated agricultural plants without harming the environment. With this aim, a pot experiment of the effects of multi-crop biomass ash on faba bean seedlings was carried out in the Academy of Agriculture of the Vytautas Magnus University (VMU). Four ash fertilization rates were tested: 1. unfertilized (N0, comparative-control treatment); 2. fertilized at a low rate (N1, 200 kg ha-1); 3. fertilized at an average rate (N2, 1000 kg ha-1); 4. fertilized at a high rate (N3, 2000 kg ha-1). Final observations showed that ash fertilization significantly increases the height of faba bean sprouts by 21-38%, the length of the roots by 10-20% and the chlorophyll concentration in the leaves by 17%. The average green biomass of faba bean sprouts consistently increased with increasing fertilization rate, from 56% to 209%. Dried biomass increased by 160-220%. With increasing ash fertilization rate, the percentage of dry matter in the roots decreased by 10-50%. We recommend fertilizing faba bean with medium (1000 kg ha-1) and high (2000 kg ha-1) ash rates, as these rates led to the largest plants with the highest productivity potential.

Accuracy Validation of the New Barrett True Axial Length Formula and the Optimized Lens Factor Using Sum-of-Segment Biometry.

Objectives: This study aims to verify the accuracy of a new calculation formula, Barrett true axial length formula (T-AL), and the optimized lens factor (LF) for predicting postoperative refraction after cataract surgery. Methods: We included 156 Japanese patients who underwent cataract surgery using Clareon monofocal intraocular lenses at our clinic between January 2022 and June 2023. Postoperative spherical equivalent was calculated using subjective refraction values obtained 1 month post-surgery. The LFs were optimized so that the mean prediction error (PE) of each calculation formula was zero (zero optimization). We calculated the mean absolute PE (MAE) to assess accuracy and used a Friedman test for statistical comparisons. The accuracy of T-AL and the optimized LFs was compared with that of the conventional Barrett Universal II formula for ARGOS (AR-B) and OA-2000 (OA-B) with equivalent refractive index. Results: For T-AL, AR-B, and OA-B, the MAEs ± standard deviations were 0.225 ± 0.179, 0.219 ± 0.168, and 0.242 ± 0.206 D, respectively. The Friedman test showed no statistically significant differences among the three groups. The device-optimized LFs were 2.248-2.289 (T-AL), 2.236-2.246 (AR-B), and 2.07-2.08 (OA-B); the corresponding zero-optimized LFs were 2.262-2.287 (T-AL), 2.287-2.303 (AR-B), and 2.160-2.170 (OA-B). Conclusion: There were no significant differences in prediction accuracy among the formulas. However, the accuracy of LF optimization varied by device, with T-AL being closest to the value under zero optimization. This suggests that T-AL is clinically useful for predicting an accurate postoperative refraction without zero optimization.

An Analysis of Ocular Biometrics: A Comprehensive Retrospective Study in a Large Cohort of Pediatric Cataract Patients.

Objectives: This study aims to provide a comprehensive analysis of ocular biometric parameters in pediatric patients with cataracts to optimize surgical outcomes. By evaluating various biometric data, we seek to enhance the decision-making process for intraocular lens (IOL) placement, particularly with advanced technologies like femtosecond lasers. Methods: This retrospective comparative study included pediatric patients with cataracts who underwent ocular biometric measurements and cataract extraction with anterior vitrectomy at the Medical University of Vienna between January 2019 and December 2021. Parameters measured included corneal diameter (CD), axial length (AL), corneal thickness (CT) and flat and steep keratometry (Kf and Ks). The study explored the correlations between these parameters and IOL placement. Results: A total of 136 eyes from 68 pediatric patients were included in the study. Significant positive correlations were found between corneal diameter, age and AL. The mean CD was 11.4 mm, mean AL was 19.5 mm, CT was 581.2 ± 51.8 µm, Kf was 7.76 ± 0.55 mm and Ks 7.41 ± 0.59 mm, respectively. Older pediatric patients with larger corneal diameters and longer ALs were more likely to receive in-the-bag IOL implantation. Conversely, younger patients often required alternative IOL placements or remained aphakic. Our data indicated that over 95% of the study population and all patients aged one year and older had a corneal diameter of 10 mm or larger. Conclusions: Detailed ocular biometric analysis is crucial for optimizing both surgical outcomes and postoperative care in pediatric cataract patients. The positive correlations between CD, age and AL underline the importance of individualized surgical planning tailored to each patient's unique anatomical features. Additionally, our findings suggest that the use of a femtosecond laser is both feasible and safe for pediatric patients aged one year and older, potentially offering enhanced surgical precision and improved outcomes.

Does blepharospasm effect biometric parameters and intraocular lens power calculations?

PURPOSE: To investigate the effect of botulinum toxin-A (BTX-A) treatment on corneal topography, ocular biometry and keratometry in patients with benign essential blepharospasm (BEB) and hemifacial spasm (HFS). METHODS: This study comprised 66 eyes of 33 patients with BEB and 5 eyes of 5 patients with HFS who underwent BTX-A injections consecutively. Refractive error values, tear break-up time (TBUT), corneal topography [corneal power of flat axis (K1) and steep axis (K2), mean corneal power (Km), corneal astigmatism (K2-K1)] and ocular optical biometry [axial length (AL), anterior chamber depth (ACD)] were recorded before BTX-A treatment and 1 month after BTX-A treatment. The researchers calculated the expected emmetropic intraocular lens power (emm-IOL) using the SRK-T, Holladay, Hoffer-Q and Haigis formulas at each examination. RESULTS: K1 (43.48 ± 2.02 vs. 43.57 ± 2.08, p = 0.036), Km (43.91 ± 1.99 vs. 43.99 ± 2.06, p = 0.024) and ACD (3.22 (2.77-3.76) vs. 3.41 (2.99-4.02), p < 0.001) values were found to be significantly higher. The expected emm-IOL according to the SRK-T (21.04 ± 1.6 vs. 20.93 ± 1.6, p = 0.048), Holladay (21.05 ± 1.6 vs. 20.91 ± 1.62, p = 0.037) and Hoffer-Q (21.08 ± 1.65 vs. 20.94 ± 1.68, p = 0.038) decreased significantly. The expected emm-IOL according to the Haigis formula slightly decreased, but it was not significant (p = 0.386). Additionally, TBUT was found to be significantly lower (p < 0.001) after BTX-A injection. Other parameters were not statistically significant (p > 0.05). CONCLUSIONS: Our study is the first in the literature to compare optic biometry data and intraocular lens power calculation formulas before and after BTX-A injection in eyes with BEB and HFS. BTX-A injection could play an important role in changing the keratometric and ACD values. It should be considered that IOL power calculations that might be unpredictable due to blepharospasm, so repeated measurements and especially measurements after releasing the spasm with BTX-A injections, are necessary in BEB and HFS.

External validation of models to estimate gestational age in the second and third trimester using ultrasound: A prospective multicentre observational study.

OBJECTIVES: Accurate assessment of gestational age (GA) is important at both individual and population levels. The most accurate way to estimate GA in women who book late in pregnancy is unknown. The aim of this study was to externally validate the accuracy of equations for GA estimation in late pregnancy and to identify the best equation for estimating GA in women who do not receive an ultrasound scan until the second or third trimester. DESIGN: This was a prospective, observational cross-sectional study. SETTING: 57 prenatal care centres, France. PARTICIPANTS: Women with a singleton pregnancy and a previous 11-14-week dating scan that gave the observed GA were recruited over an 8-week period. They underwent a standardised ultrasound examination at one time point during the pregnancy (15-43 weeks), measuring 12 foetal biometric parameters that have previously been identified as useful for GA estimation. MAIN OUTCOME MEASURES: A total of 189 equations that estimate GA based on foetal biometry were examined and compared with GA estimation based on foetal CRL. Comparisons between the observed GA and the estimated GA were made using R2, calibration slope and intercept. RMSE, mean difference and 95% range of error were also calculated. RESULTS: A total of 2741 pregnant women were examined. After exclusions, 2339 participants were included. In the 20 best performing equations, the intercept ranged from -0.22 to 0.30, the calibration slope from 0.96 to 1.03 and the RSME from 0.67 to 0.87. Overall, multiparameter models outperformed single-parameter models. Both the 95% range of error and mean difference increased with gestation. Commonly used models based on measurement of the head circumference alone were not amongst the best performing models and were associated with higher 95% error and mean difference. CONCLUSIONS: We provide strong evidence that GA-specific equations based on multiparameter models should be used to estimate GA in late pregnancy. However, as all methods of GA assessment in late pregnancy are associated with large prediction intervals, efforts to improve access to early antenatal ultrasound must remain a priority. TRIAL REGISTRATION: The proposal for this study and the corresponding methodological review was registered on PROSPERO international register of systematic reviews (registration number: CRD4201913776).

Generalised models of the vertebrate eye.

PURPOSE: To present a set of closed-form analytical equations to create a consistent eye model balance based on clinically measured input parameters in a single step. These models complement the existing iterative approaches in the literature. METHODS: Two different approaches are presented, both considering the cornea and lens as equivalent thin lenses. The first, called the Gaussian model, starts by defining the refractive error as the difference between the axial power (or dioptric distance) and the whole eye power, which can be expanded by filling in the formulas for each power. The resulting equation can be solved for either the refractive error, axial length, corneal power, lens power or the distance between the cornea and the lens as a function of the other four parameters. The second approach uses vergence calculations to provide alternative expressions, assuming that the refractive error is located at the corneal plane. Both models are explored for a biometric range typically found in adult human eyes. RESULTS: The Gaussian and vergence models each instantly balance the input data into a working eye model over the human physiological range and far beyond as demonstrated in various examples. The equations of the Gaussian model are more complicated, while the vergence model experiences more singularities, albeit in trivial or highly unlikely parameter combinations. CONCLUSIONS: The proposed equations form a flexible and robust platform to create eye models from clinical data. Possible applications lie in creating animal eye models or providing a generic reference for real biometric data and the relationships between the ocular dimensions.

The effect of cycloplegia in the accuracy of autorefraction, keratometry and axial length using the Myopia Master.

BACKGROUND: Assessing refractive errors under cycloplegia is recommended for paediatric patients; however, this may not always be feasible. In these situations, refraction has to rely on measurements made under active accommodation which may increase measurements variability and error. Therefore, evaluating the accuracy and precision of non-cycloplegic refraction and biometric measurements is clinically relevant. The Myopia Master, a novel instrument combining autorefraction and biometry, is designed for monitoring refractive error and ocular biometry in myopia management. This study assessed its repeatability and agreement for autorefraction and biometric measurements pre- and post-cycloplegia. METHODS: A prospective cross-sectional study evaluated a cohort of 96 paediatric patients that underwent ophthalmologic examination. An optometrist performed two repeated measurements of autorefraction and biometry pre- and post-cycloplegia. Test-retest repeatability (TRT) was assessed as differences between consecutive measurements and agreement as differences between post- and pre-cycloplegia measurements, for spherical equivalent (SE), refractive and keratometric J0/J45 astigmatic components, mean keratometry (Km) and axial length (AL). RESULTS: Cycloplegia significantly improved the SE repeatability (TRT, pre-cyclo: 0.65 D, post-cyclo: 0.31 D). SE measurements were more repeatable in myopes and emmetropes compared to hyperopes. Keratometry (Km) repeatability did not change with cycloplegia (TRT, pre-cyclo: 0.25 D, post-cyclo:0.27 D) and AL repeatability improved marginally (TRT, pre-cyclo: 0.14 mm, post-cyclo: 0.09 mm). Regarding pre- and post-cycloplegia agreement, SE became more positive by + 0.79 D, varying with refractive error. Myopic eyes showed a mean difference of + 0.31 D, while hyperopes differed by + 1.57 D. Mean keratometry, refractive and keratometric J0/J45 and AL showed no clinically significant differences. CONCLUSIONS: Refractive error measurements, using the Myopia Master were 2.5x less precise pre-cycloplegia than post-cycloplegia. Accuracy of pre-cycloplegic refractive error measurements was often larger than the clinically significant threshold (0.25 D) and was refractive error dependent. The higher precision compared to autorefraction measurements, pre- and post-cycloplegia agreement and refractive error independence of AL measurements emphasize the superiority of AL in refractive error monitoring.

Architectural approach to evaluate the design and management of almond cultivars suitable for super high-density orchards.

Introduction: The almond tree is a major global nut crop, and its production has surged dramatically in recent years. Super high-density (SHD) planting systems, designed to optimize resource efficiency and enhance precocity, have gained prominence in almond cultivation. A shift in cropping systems toward sustainable intensification (SI) pathways is imperative, and so maximizing branching density within the canopies of SHD trees is crucial to establish and maintain productive potential, especially for hedge-pruned trees. This study investigates the influence of different almond cultivars grafted onto a novel growth-controlling rootstock on tree architectural and growth parameters in a SHD orchard. This open field research provided valuable insights for the development and application of new tools and methods to increase productivity and sustainability in almond growing. Methods: Three cultivars (Lauranne® Avijour, Guara Tuono, and Filippo Cea) were evaluated in Gravina in Puglia (BA) over a two-year period. Canopy growth parameters, such as canopy volume and trunk cross-sectional area, and architectural traits, like branching density, branching angle, number and length of subterminal shoots, and number of brachyblasts, were measured through qualitative and quantitative measurements. Results and discussion: Results revealed significant differences in tree height, canopy thickness, width, volume, and vigor among the cultivars. Architectural traits, including branch parameters, brachyblast parameters, and subterminal shoots, varied among the cultivars. Lauranne displayed a more compact well-distributed canopy and exhibited the lowest vigor. Filippo Cea showed the highest vigor and the greatest canopy volume. Tuono had a higher number of buds and bud density. The best ideotype for SHD orchards is a smaller tree, with high branching density and smaller trunk diameters, i.e. the vigor. Cv. Lauranne seemed to be the best cultivar, mostly with the lowest tree vigor of all the cultivars involved. These findings provide valuable insights for almond growers and breeders seeking to optimize orchard design and management for enhanced SHD orchards productivity and sustainability. Future research will explore the relationship between canopy architecture and yield parameters, considering different scion/rootstock combinations in different environmental conditions.

Comparison of Eye Axial Length Measurements Taken Using Partial Coherence Interferometry and OCT Biometry.

This study evaluates the inter-device measurement properties of partial coherence interferometry (PCI) and spectral domain optical coherence tomography (SD-OCT) in measuring axial length, particularly for myopia management. We recruited 82 eyes from 41 adult participants with a mean age of 31.0 ± 17.6 years and a mean spherical equivalent of -2.20 ± 2.28 D. Axial length was measured using SD-OCT and PCI for both the right and left eyes. Agreement between the two measurements was assessed using Bland-Altman analysis, and graphs and values were compared with linear mixed models. The results show a near-to-zero and non-significant bias between measurements. The 95% limits of agreement showed a value of 0.06 mm. Both devices can accurately measure the axial length. OCT biometry performed with SD-OCT can be successfully interchanged with partial coherence interferometry, but they should be cautiously interchanged when performing longitudinal comparisons.