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Novel Applications of Speckle Metrology
Published in Rajpal S. Sirohi, Speckle Metrology, 2020
There are several applications of laser speckles in biomedical metrology. One well-established application is in optometry. When objective laser speckles on a surface are viewed, the apparent speckle motion in comparison with the head movement indicates far-sighted, near-sighted, or perfect eye. This simple property of the image formation by a lens (an eye in the present situation) resulted in considerable interest in speckle optometry. The early developments are summarized by Hennessy and Leibowitz [81]. The principle deals with the functional aspect of vision rather than just the refractive errors. Sinclair [82] used different wavelengths to address chromatic aspects also. Phillips et al. [83] addressed the question of the cylindrical axis of power. Mathematical derivations and literature reviews are also available [84, 85]. Bahuguna et al. [86] introduced a white light speckle optometer that is competitive with the laser speckle optometer. More recently, Bahuguna et al. [87] gave further insights into the perceived size of laser speckles.
Descriptive Statistics
Published in William M. Mendenhall, Terry L. Sincich, Statistics for Engineering and the Sciences, 2016
William M. Mendenhall, Terry L. Sincich
Contact lenses for myopia. Myopia (i.e., nearsightedness) is a visual condition that affects over 100 million Americans. Two treatments that may slow myopia progression is the use of (1) corneal reshaping contact lenses and (2) bifocal soft contact lenses. In Optometry and Vision Science (Jan., 2013), university optometry professors compared the two methods for treating myopia. A sample of 14 myopia patients participated in the study. Each patient was fitted with a contact lens of each type for the right eye, and the peripheral refraction was measured for each type of lens. The differences (bifocal soft minus corneal reshaping) are shown in the following table. (These data, simulated based on information provided in the journal article, are saved in the MYOPIA file.) Find measures of central tendency for the difference measurements and interpret their values.Note that the data contains one unusually large (negative) difference relative to the other difference measurements. Find this difference. (In Section 2.7, we call this value an outlier.)The large negative difference of -8.11 is actually a typographical error. The actual difference for this patient is -0.11. Rerun the analysis, part a, using the corrected difference. Which measure of central tendency is most affected by the correcting of the outlier?
Deep Learning for Retinal Analysis
Published in Ervin Sejdić, Tiago H. Falk, Signal Processing and Machine Learning for Biomedical Big Data, 2018
Henry A. Leopold, John S. Zelek, Vasudevan Lakshminarayanan
The content throughout this chapter draws parallels between the biological and computational elements being discussed, weaving together applicable concepts in a meaningful way. The reader should be able to come away from this chapter understanding the deep learning methodology and their applications with an appreciation of the biological counterparts from which the computational systems have been derived. While there have been many innovations in retinal imaging in the last 20 years, this chapter focuses on fundus images, which are retinal images captured utilizing a fundus camera—a widely used method in clinical optometry and ophthalmology. As such, retinal images will always refer to fundus images herein.
Vecto-keratometry: determination of anterior corneal astigmatism in manual keratometers using power vectors
Published in Expert Review of Medical Devices, 2023
Raquel Salvador-Roger, Rosa Vila-Andrés, Vicente Micó, José J. Esteve-Taboada
Characterization of the anterior corneal surface is an important aspect in the clinical management of refractive data. Since 1619 when the first attempts were made to measure corneal curvature using glass spheres [1], the study of anterior corneal curvature has evolved from some rudimentary methods to today’s modern measurement [2]. Included in this cornea characterization, corneal astigmatism (understood as dioptric power difference between principal meridians of the anterior surface of the cornea) plays a determinant role for many optometric and ophthalmic procedures and methodologies such as total astigmatism determination in a patient’s eye by using Javal’s or Grosvenor’s rules [3,4], intraocular lens power determination, and contact lens fitting processes [5,6]. Thus, measurement of complete and accurate corneal astigmatism is of capital importance in optometry and ophthalmology practice.
May the best-sighted win? The relationship between visual function and performance in Para judo
Published in Journal of Sports Sciences, 2021
Kai Krabben, Evgeny Mashkovskiy, H. J. C. (Rianne) Ravensbergen, David L. Mann
A direct assessment of the visual function of all VI athletes is obtained during classification, a process that aims to determine the eligibility of athletes to compete in Para sports and to allocate eligible athletes to sport classes (Mann & Ravensbergen, 2018). VI classification is performed by certified classifiers who have a background in optometry or ophthalmology (International Blind Sports Federation, 2018). Most VI athletes are classified on the basis of their impaired visual acuity (VA), which is a measure of their sharpness of vision. Alternatively, some athletes may be classified eligible to compete on the basis of visual field (VF) loss. VF is a measure of the area of peripheral vision with which an individual can see (i.e. without moving their eyes). The data on VA and VF of judokas obtained during classification hold promise for a more direct analysis of the impact of vision impairment on judo performance, yet previous studies did not have access to this information and were therefore constricted to comparisons between sport classes.
The changing scope of Optometry in New Zealand: historical perspectives, current practice and research advances
Published in Journal of the Royal Society of New Zealand, 2019
Joanna M. Black, Robert J. Jacobs, John R. Phillips, Monica L. Acosta
There are numerous examples of research in vision sciences in New Zealand starting before the establishment of the Optometry programme. The research discussed in this review is confined to that by current or past members of SOVS, but it is acknowledged that there are many other vision science groups at the University and around New Zealand. Many of the studies completed within SOVS represent collaborations with these groups and with other disciplines at a national and international level. The data included in this review were obtained from PubMed using affiliation to the University of Auckland and Department (or School) of Optometry and Vision Science (Figure 1).