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Statistics in Medicine Jun 2004This article gives an overview of sample size calculations for parallel group and cross-over studies with Normal data. Sample size derivation is given for trials where... (Review)
Review
This article gives an overview of sample size calculations for parallel group and cross-over studies with Normal data. Sample size derivation is given for trials where the objective is to demonstrate: superiority, equivalence, non-inferiority, bioequivalence and estimation to a given precision, for different types I and II errors. It is demonstrated how the different trial objectives influence the null and alternative hypotheses of the trials and how these hypotheses influence the calculations. Sample size tables for the different types of trials and worked examples are given.
Topics: Biometry; Cross-Over Studies; Humans; Randomized Controlled Trials as Topic; Research Design; Sample Size; Therapeutic Equivalency
PubMed: 15195324
DOI: 10.1002/sim.1783 -
Singapore Medical Journal Dec 2003
Topics: Biometry; Causality; Data Collection; Data Interpretation, Statistical; Humans
PubMed: 14770254
DOI: No ID Found -
American Journal of Public Health Aug 2008
Topics: Biometry; Diffusion of Innovation; Epidemiologic Methods; Humans; Public Health Practice; Research Design
PubMed: 18612137
DOI: 10.2105/AJPH.2008.142802 -
Current Opinion in Ophthalmology Jan 2012Obtaining precise postoperative target refraction is of utmost importance in today's modern cataract and refractive surgery. Given the growing number of patients... (Review)
Review
PURPOSE OF REVIEW
Obtaining precise postoperative target refraction is of utmost importance in today's modern cataract and refractive surgery. Given the growing number of patients undergoing premium intraocular lens (IOL) implantations, patient expectation continues to rise. In order to meet heightened patient expectations, it is crucial to pay utmost attention to patient selection, accurate keratometry and biometry readings, as well as to the application of correct IOL power formula with optimized lens constants. This article reviews recent advances in the field of clinical biometry and IOL power calculations.
RECENT FINDINGS
Recently developed low-coherence reflectometry optical biometry is comparable to older ultrasonic biometric and keratometric techniques. In addition, the new IOLMaster software upgrade has improved reproducibility and enhanced signal acquisition. Further, the modern lens power formulas currently determine the effective lens position and the shape of the intraocular lens power prediction curve more accurately.
SUMMARY
In order to reach target refraction, precise biometric measurements are imperative. Understanding the strengths and limitations of the currently available biometry devices allows prevention of high variability and inaccuracy, ultimately determining the refractive outcomes.
Topics: Biometry; Cornea; Humans; Lenses, Intraocular
PubMed: 22081032
DOI: 10.1097/ICU.0b013e32834cd63e -
Sensors (Basel, Switzerland) Aug 2022Biometrics have been used to identify humans since the 19th century. Over time, these biometrics became 3D. The main reason for this was the growing need for more... (Review)
Review
Biometrics have been used to identify humans since the 19th century. Over time, these biometrics became 3D. The main reason for this was the growing need for more features in the images to create more reliable identification models. This work is a comprehensive review of 3D biometrics since 2011 and presents the related work, the hardware used and the datasets available. The first taxonomy of 3D biometrics is also presented. The research was conducted using the Scopus database. Three main categories of 3D biometrics were identified. These were face, hand and gait. The corresponding percentages for these categories were 74.07%, 20.37% and 5.56%, respectively. The face is further categorized into facial, ear, iris and skull, while the hand is divided into fingerprint, finger vein and palm. In each category, facial and fingerprint were predominant, and their respective percentages were 80% and 54.55%. The use of the 3D reconstruction algorithms was also determined. These were stereo vision, structure-from-silhouette (SfS), structure-from-motion (SfM), structured light, time-of-flight (ToF), photometric stereo and tomography. Stereo vision and SfS were the most commonly used algorithms with a combined percentage of 51%. The state of the art for each category and the available datasets are also presented. Finally, multimodal biometrics, generalization of 3D reconstruction algorithms and anti-spoofing metrics are the three areas that should attract scientific interest for further research. In addition, the development of devices with 2D/3D capabilities and more publicly available datasets are suggested for further research.
Topics: Algorithms; Benchmarking; Biometry; Databases, Factual; Humans; Iris
PubMed: 36080821
DOI: 10.3390/s22176364 -
Korean Journal of Anesthesiology Apr 2020Properly set sample size is one of the important factors for scientific and persuasive research. The sample size that can guarantee both clinically significant... (Review)
Review
Properly set sample size is one of the important factors for scientific and persuasive research. The sample size that can guarantee both clinically significant differences and adequate power in the phenomena of interest to the investigator, without causing excessive financial or medical considerations, will always be the object of concern. In this paper, we reviewed the essential factors for sample size calculation. We described the primary endpoints that are the main concern of the study and the basis for calculating sample size, the statistics used to analyze the primary endpoints, type I error and power, the effect size and the rationale. It also included a method of calculating the adjusted sample size considering the dropout rate inevitably occurring during the research. Finally, examples regarding sample size calculation that are appropriately and incorrectly described in the published papers are presented with explanations.
Topics: Biometry; Humans; Patient Dropouts; Research Design; Sample Size
PubMed: 32229812
DOI: 10.4097/kja.19497 -
Computational Intelligence and... 2021With the rapid development of brain-computer interface technology, as a new biometric feature, EEG signal has been widely concerned in recent years. The safety of... (Review)
Review
With the rapid development of brain-computer interface technology, as a new biometric feature, EEG signal has been widely concerned in recent years. The safety of brain-computer interface and the long-term insecurity of biometric authentication have a new solution. This review analyzes the biometrics of EEG signals, and the latest research is involved in the authentication process. This review mainly introduced the method of EEG-based authentication and systematically introduced EEG-based biometric cryptosystems for authentication for the first time. In cryptography, the key is the core basis of authentication in the cryptographic system, and cryptographic technology can effectively improve the security of biometric authentication and protect biometrics. The revocability of EEG-based biometric cryptosystems is an advantage that traditional biometric authentication does not have. Finally, the existing problems and future development directions of identity authentication technology based on EEG signals are proposed, providing a reference for the related studies.
Topics: Biometric Identification; Biometry; Brain-Computer Interfaces; Electroencephalography; Technology
PubMed: 34976039
DOI: 10.1155/2021/5229576 -
Indian Journal of Ophthalmology Aug 2022To evaluate the repeatability of biometry and intraocular lens (IOL) power using Galilei G6 and to determine the agreement of its measurements with those of IOL Master...
PURPOSE
To evaluate the repeatability of biometry and intraocular lens (IOL) power using Galilei G6 and to determine the agreement of its measurements with those of IOL Master 700 and IOL Master 500.
METHODS
Hundred mature cataract eyes were examined twice with Galilei G6 and the results were compared with those of other two devices. Axial length (AL), minimum (K1), maximum (K2), and mean keratometry, anterior chamber depth (ACD), white-to-white (WTW) diameter, lens thickness (LT), and the calculated IOL power were the studied parameters. The correlation coefficient, within-subject standard deviation (Sw), Bland-Altman method, and 95% limits of agreement (LoA) were used for statistical analysis.
RESULTS
The intraclass correlation coefficient (ICC) was above 0.9 for all indices, and the LoA ranged from a minimum of 0.08 mm for AL to a maximum of 0.50 D for K1. Sw also ranged between a minimum of 0.02 for AL, ACD, and WTW and a maximum of 0.13 for K1. In the Galilei G6-IOL Master 700 pair, the narrowest and widest LoA were calculated for AL (0.07 mm) and K2 (0.49 D), respectively. In the Galilei G6-IOL Master 500 pair, the narrowest and widest widths of LoA were calculated for AL (0.17 mm) and K2 (0.92 D), respectively. In the first pair, the LoA of IOL power (0.57 D) were the best for Haigis formula and in the second pair, the best agreement (LoA: 0.35 D) was observed for Holladay-1.
CONCLUSION
Galilei G6 provided repeatable biometric measurements. The agreement between biometry and IOL power calculation was better in the Galilei G6-IOL Master 700 pair compared to the Galilei G6-IOL Master 500.
Topics: Axial Length, Eye; Biometry; Humans; Lenses, Intraocular; Reproducibility of Results; Tomography, Optical Coherence
PubMed: 35918927
DOI: 10.4103/ijo.IJO_249_22 -
Sensors (Basel, Switzerland) Sep 2021The large number of Internet-of-Things (IoT) devices that need interaction between smart devices and consumers makes security critical to an IoT environment. Biometrics... (Review)
Review
The large number of Internet-of-Things (IoT) devices that need interaction between smart devices and consumers makes security critical to an IoT environment. Biometrics offers an interesting window of opportunity to improve the usability and security of IoT and can play a significant role in securing a wide range of emerging IoT devices to address security challenges. The purpose of this review is to provide a comprehensive survey on the current biometrics research in IoT security, especially focusing on two important aspects, authentication and encryption. Regarding authentication, contemporary biometric-based authentication systems for IoT are discussed and classified based on different biometric traits and the number of biometric traits employed in the system. As for encryption, biometric-cryptographic systems, which integrate biometrics with cryptography and take advantage of both to provide enhanced security for IoT, are thoroughly reviewed and discussed. Moreover, challenges arising from applying biometrics to IoT and potential solutions are identified and analyzed. With an insight into the state-of-the-art research in biometrics for IoT security, this review paper helps advance the study in the field and assists researchers in gaining a good understanding of forward-looking issues and future research directions.
Topics: Biometric Identification; Biometry; Computer Security; Internet of Things
PubMed: 34577370
DOI: 10.3390/s21186163 -
Asia-Pacific Journal of Ophthalmology... 2020Investigators, scientists, and physicians continue to develop new methods of intraocular lens (IOL) calculation to improve the refractive accuracy after cataract... (Review)
Review
Investigators, scientists, and physicians continue to develop new methods of intraocular lens (IOL) calculation to improve the refractive accuracy after cataract surgery. To gain more accurate prediction of IOL power, vergence lens formulas have incorporated additional biometric variables, such as anterior chamber depth, lens thickness, white-to-white measurement, and even age in some algorithms. Newer formulas diverge from their classic regression and vergence-based predecessors and increasingly utilize techniques such as exact ray-tracing data, more modern regression models, and artificial intelligence. This review provides an update on recent literature comparing the commonly used third- and fourth-generation IOL formulas with newer generation formulas. Refractive outcomes with newer formulas are increasingly more and more accurate, so it is important for ophthalmologists to be aware of the various options for choosing IOL power. Historically, refractive outcomes have been especially unpredictable in patients with unusual biometry, corneal ectasia, a history of refractive surgery, and in pediatric patients. Refractive outcomes in these patient populations are improving. Improved biometry technology is also allowing for improved refractive outcomes and surgery planning convenience with the availability of newer formulas on various biometry platforms. It is crucial for surgeons to understand and utilize the most accurate formulas for their patients to provide the highest quality of care.
Topics: Aphakia, Postcataract; Artificial Intelligence; Biometry; Humans; Lenses, Intraocular; Optics and Photonics; Visual Acuity
PubMed: 32501896
DOI: 10.1097/APO.0000000000000293