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Biomimetics is the transfer of ideas and concepts borrowed from nature in order to develop solutions to technological issues. Research in biomimetic vision as a whole has focused on several aspects ranging from development of optical devices and sensors, innovative solutions to visual problems and building intelligent systems, all based on findings from nature. In this review, we discuss the diversity of animal eyes, optical systems inspired by natural eyes and their optical properties in nature that has the potential for biomimicry. [ABSTRACT FROM AUTHOR]

A well-balanced curriculum is critical for ensuring that students graduate with the necessary skills. There is growing interest in evaluating the functional value of non-clinical courses compared to clinical courses. The purpose of this study was to evaluate the views of optometry and vision science professionals on the utility and relevance of optics-based courses. A web-based survey was designed to assess the perceived significance of the optics-based courses. All respondents were alumni of two universities in Jordan that offer an undergraduate degree in optometry. The survey included questions about the professional relevance of optics courses. Respondents were asked to rate several statements related to the relevance and importance of optics courses in current optometry practice on a 5-point Likert scale. In total, 205 respondents completed the online survey. There were 161 (78.5%) women and 44 (21.5%) men, with an average age of 28.76 (± 4.86) years. Overall, respondents rated the perceived usefulness of optics courses for their careers with a mean collective value of 20.78 out of a possible 30 points. Female alumni perceived the courses as significantly more useful in their workplace than male alumni did (p =.020). Optometrists in different age groups perceived usefulness differently (p =.001). Alumni who preferred to learn these courses on-site and by hybrid methods perceived optics courses as significantly more useful than those who preferred to learn online (p =.006 and p <.001, respectively). The perceived importance of optics-based courses varied according to several factors. However, in general, these courses were deemed helpful in terms of curricular content and practical relevance to practice, regardless of specialisation or the workplace. In terms of the value offered to the professional competencies that an optometrist needs, the practical utility of optics courses in optometry curriculums is contested. Optometrists' perceptions of optics courses were examined using a cross-sectional survey. Respondents rated the perceived usefulness of optics courses for their career, with a mean collective value of 20.78 out 30 points. The highest percentage of respondents in this study expressed their preference for the face-to-face learning method rather than the hybrid method. Male optometrists perceived learning optics courses as significantly less helpful than female optometrists. [ABSTRACT FROM AUTHOR]

Nagar kirtan is a Sikh travelling court of poetry, prominent during the Punjabi harvest festival, Vaisakhi. Critics and celebrators alike overfocus on its visual optics, but there is an alternative bottom-up assemblage by which participants generate transformative power. This article decentres the politics of representation favoured by state apparatuses, politicians, and religious elites. I mobilize a decolonial feminist conceptualization with a walk from off the centerstage. Deploying the subaltern figure of the bride, I argue for an interpretation of nagar kirtan as embodied engagement with a poetics of a humanity. Fieldwork was carried out in Hong Kong, Vancouver, and Toronto. [ABSTRACT FROM AUTHOR]

At a follow-up 6 months after dispensing, the WFG lens provided a similar level of higher-order aberration correction (residual RMS 0.498 m; 94% less than unaided) - this agreed with lens durability expectations.[9] Corrected visual acuity remained within typical levels; letter contrast sensitivity was not measured in clinic. Keywords: Aberration; keratoconus; scleral lens; visual performance; wavefront-guided EN Aberration keratoconus scleral lens visual performance wavefront-guided 86 88 3 01/11/22 20220101 NES 220101 Introduction As corneal ectasias progress in severity, the range of viable ophthalmic correction modalities decreases, and visual symptoms are most successfully alleviated using rigid contact lenses. [Extracted from the article]

Background: Low vision in children can be accompanied by pallor of the optic disc with little or no characteristic morphologic changes of the retina. A variety of diseases can be the underlying cause, including hereditary optic atrophy, Leber's congenital amaurosis (LCA), achromatopsia, and calcium channel, voltage-dependent, L-type, alpha-1F subunit gene (CACNA1F)-associated retinopathy (most widely known as incomplete congenital stationary night blindness: iCSNB). Differentiation at early age is desirable due to large differences in prognosis, but may be difficult because phenotypes overlap and electrophysiological testing is challenging in young patients. We present the case of a 6-year-old boy with unexplained low vision and pallor of the optic disc who originally had been diagnosed with hereditary optic atrophy in the absence of recordable full-field electroretinography (ERG) due to poor patient cooperation. Materials and Methods: Standard Sanger sequencing excluded mutations in the OPA1 gene (autosomal-dominant optic atrophy). To identify the underlying genetic cause, whole-exome sequencing was performed on patient's DNA. Recording of the full-field ERG was successfully performed 6 months later. Results: We identified a novel truncating mutation in CACNA1F gene (NM_001256789: c.3895C > T in exon 33) which led to the correct diagnosis of CACNA1F-associated retinopathy in the young boy. ERG recordings showed a negative scotopic mixed response with preserved oscillatory potentials and a flicker ERG with reduced amplitude and biphasic waveform, compatible with a CACNA1F-asssociated phenotype. Conclusions: We show that genetic testing may help to differentiate between optic atrophy, LCA, and CACNA1F-associated retinopathy at a much earlier age, in absence of electrophysiological examination and by widely overlapping phenotypes. [ABSTRACT FROM AUTHOR]

The management of non-muscle-invasive bladder cancer (NMIBC) has evolved from the first reports on bladder endoscopy and transurethral resection to the introduction of adjuvant intravesical treatment. However, disease recurrence and progression remain an ongoing risk, placing a heavy burden on healthcare resources and on patients’ quality of life. Deeper understanding of the molecular basis of the disease and developments in optics, lasers and computer science are already offering opportunities to revolutionize care and improve long-term prognosis. This article discusses developments likely to cause a paradigm shift towards the delivery of personalized care and reduced burden of disease in NMIBC. [ABSTRACT FROM AUTHOR]

The collaborative representation-based classification method performs well in the field of classification of high-dimensional images such as face recognition. It utilizes training samples from all classes to represent a test sample and assigns a class label to the test sample using the representation residuals. However, this method still suffers from the problem that limited number of training sample influences the classification accuracy when applied to image classification. In this paper, we propose a modified collaborative representation-based classification method (MCRC), which exploits novel virtual images and can obtain high classification accuracy. The procedure to produce virtual images is very simple but the use of them can bring surprising performance improvement. The virtual images can sufficiently denote the features of original face images in some case. Extensive experimental results doubtlessly demonstrate that the proposed method can effectively improve the classification accuracy. This is mainly attributed to the integration of the collaborative representation and the proposed feature-information dominated virtual images. [ABSTRACT FROM AUTHOR]

Background: The aim was to derive equations for the relationship between unaided vision and age, pupil diameter, iris colour and sphero-cylindrical refractive error.Methods: Data were collected from 663 healthy right eyes of white subjects aged 20 to 70 years. Subjective sphero-cylindrical refractive errors ranged from -6.8 to +9.4 D (mean spherical equivalent), -1.5 to +1.9 D (orthogonal component, J0 ) and -0.8 to 1.0 D (oblique component, J45 ). Cylinder axis orientation was orthogonal in 46 per cent of the eyes and oblique in 18 per cent. Unaided vision (-0.3 to +1.3 logMAR), pupil diameter (2.3 to 7.5 mm) and iris colour (67 per cent light/blue irides) was recorded. The sample included mostly females (60 per cent) and many contact lens wearers (42 per cent) and so the influences of these parameters were also investigated.Results: Decision tree analysis showed that sex, iris colour, contact lens wear and cylinder axis orientation did not influence the relationship between unaided vision and refractive error. New equations for the dependence of the minimum angle of resolution on age and pupil diameter arose from step backwards multiple linear regressions carried out separately on the myopes (2.91.scalar vector +0.51.pupil diameter -3.14 ) and hyperopes (1.55.scalar vector + 0.06.age - 3.45 ).Conclusion: The new equations may be useful in simulators designed for teaching purposes as they accounted for 81 per cent (for myopes) and 53 per cent (for hyperopes) of the variance in measured data. In comparison, previously published equations accounted for not more than 76 per cent (for myopes) and 24 per cent (for hyperopes) of the variance depending on whether they included pupil size. The new equations are, as far as is known to the authors, the first to include age. The age-related decline in accommodation is reflected in the equation for hyperopes. [ABSTRACT FROM AUTHOR]

A novel optical image encryption system is proposed using password key based on phase retrieval algorithm (PRA). In the encryption process, a shared image is taken as a symmetric key and the plaintext is encoded into the phase-only mask based on the iterative PRA. The linear relationship between the plaintext and ciphertext is broken using the password key, which can resist the known plaintext attack. The symmetric key and the retrieved phase are imported into the input plane and Fourier plane of 4f system during the decryption, respectively, so as to obtain the plaintext on the CCD. Finally, we analyse the key space of the password key, and the results show that the proposed scheme can resist a brute force attack due to the flexibility of the password key. [ABSTRACT FROM PUBLISHER]

Purpose: To describe longitudinal changes in lens thickness in myopic children in the Correction of Myopia Evaluation Trial (COMET) and to investigate the association between these changes and myopia progression. Methods: Four-hundred sixty-nine 6 to <12-year-old children with −1.25 to −4.50 D of myopia were enrolled in COMET, a clinical trial comparing single vision lenses (SVLs) versus progressive addition lenses (PALs) for slowing myopia. Children remained in their original lenses for 5 years and then could wear contact lenses, SVLs or PALs. Myopia by cycloplegic autorefraction (Nidek ARK 700A) and ocular components, including lens thickness, by A-scan ultrasound (Sonomed A2500) were measured annually over 11 years. Analyses of lens thickness were based on right eye data from 426 children with refractions fit with Gompertz functions. Longitudinal lens thickness measurements for each participant were fit with a third-degree polynomial function, and average polynomial functions were calculated for three groups of children previously identified based on Gompertz functions: 6–7 years at baseline (n = 40), ≥8 years with progressing myopia (n = 329), and ≥8 years with non-progressing myopia (n = 56). ANOVAs were used for comparing the lens curve-based parameters among the three groups. Associations between lens and Gompertz parameters were assessed using Pearson correlations. Results: Overall, between 6 and 18 years the lenses thinned and then thickened, with the minimum value of 3.37 ± 0.15mm reached at 11.56 ± 2.04 years. The minimum lens thickness did not differ among the three myopia groups (p = 0.09), nor was it correlated with the amount of myopia at lens minimum or amount of final myopia (r’s = −0.01 and −0.03, respectively,p’s > 0.05). Conclusion: As a similar pattern of change in lens thickness with age was found in all children, whether their myopia progressed or not, these results suggest that the association of lens thinning and thickening with the course of myopia is coincidental rather than causal. [ABSTRACT FROM PUBLISHER]

Optical models of the human eye have been used in visual science for purposes such as providing a framework for explaining optical phenomena in vision, for predicting how refraction and aberrations are affected by change in ocular biometry and as computational tools for exploring the limitations imposed on vision by the optical system of the eye. We address the issue of what is understood by optical model eyes, discussing the 'encyclopaedia' and 'toy train' approaches to modelling. An extensive list of purposes of models is provided. We discuss many of the theoretical types of optical models (also schematic eyes) of varying anatomical accuracy, including single, three and four refracting surface variants. We cover the models with lens structure in the form of nested shells and gradient index. Many optical eye models give accurate predictions only for small angles and small fields of view. If aberrations and image quality are important to consider, such 'paraxial' model eyes must be replaced by 'finite model' eyes incorporating features such as aspheric surfaces, tilts and decentrations, wavelength-dependent media and curved retinas. Many optical model eyes are population averages and must become adaptable to account for age, gender, ethnicity, refractive error and accommodation. They can also be customised for the individual when extensive ocular biometry and optical performance data are available. We consider which optical model should be used for a particular purpose, adhering to the principle that the best model is the simplest fit for the task. We provide a glimpse into the future of optical models of the human eye. This review is interwoven with historical developments, highlighting the important people who have contributed so richly to our understanding of visual optics. [ABSTRACT FROM AUTHOR]

Optical coherence tomography (OCT) and reflectance imaging are used in clinical practice to measure the thickness and transverse dimensions of retinal features. The recent trend towards increasing the field of view (FOV) of these devices has led to an increasing significance of the optical aberrations of both the human eye and the device. We report the design, manufacture and application of the first phantom eye that reproduces the off-axis optical characteristics of the human eye, and allows the performance assessment of wide-field ophthalmic devices. We base our design and manufacture on the wide-field schematic eye, [Navarro, R.J. Opt. Soc. Am. A,1985,2.] as an accurate proxy to the human eye and enable assessment of ophthalmic imaging performance for aexternal FOV. We used multi-material 3D-printed retinal targets to assess imaging performance of the following ophthalmic instruments: the Optos 200Tx, Heidelberg Spectralis, Zeiss FF4 fundus camera and OptosOCT SLOand use the phantom to provide an insight into some of the challenges of wide-field OCT. [ABSTRACT FROM PUBLISHER]

We compared monocular and binocular absolute thresholds of dark adaptation in two separate study populations. Eighteen healthy individuals (Group A) and 13 patients with chronic respiratory insufficiency (Group B) were examined three times each by computerised dark adaptometry with simultaneous but separate recordings from each eye and binocularly. The respiratory patients received oxygen supplement at visits 1 and 3. In Group A, at all three visits, binocular dark adaptation was significantly more sensitive (40.5%) than monocular dark adaptation with either eye. In Group B, at visits 1 and 3, binocular dark adaptation was also significantly more sensitive than monocular dark adaptation (40.5% higher than the right and 47% higher than the left eye). However, in Group B, at visit 2 without oxygen treatment, no significant differences were observed between monocular and binocular sensitivities. Binocular dark vision was superior to monocular dark vision in healthy individuals and in patients with respiratory insufficiency that were provided oxygen supplementation. Furthermore, deficit in oxygen seems to affect binocular summation, perhaps by impaired enhancement in the central nervous system. [ABSTRACT FROM AUTHOR]

Purpose: Both the plusoptiX photoscreener photoscreener and the SureSight autorefractor can be used to objectively screen for amblyogenic risk factors in children. We compare the plusoptiX and the SureSight to a pediatric ophthalmology examination on a single cohort of children. Methods: We performed a retrospective medical records review of 90 children. Each patient was screened with both the PlusoptiX A09 and SureSight devices on the same day as part of a comprehensive pediatric ophthalmic examination. The ages of the patients ranged from <1 to 17 years. All patients had a cycloplegic refraction on the day of their exam, or within the previous 6 months. Results: Of the children reviewed, 71% had amblyopia risk factors. The plusoptiX demonstrated a sensitivity of 98% and a specificity of 88%. The SureSight demonstrated a sensitivity of 95% and a specificity of 65% utilizing the manufacturer's criteria. Conclusion: The SureSight and plusoptiX were both found to be reliable objective vision screening devices, though the plusoptiX did have a higher sensitivity and specificity than the SureSight using the manufacturer's referral criteria. Using the Vision In Preschoolers Study (VIPS) referral criteria, the specificity of the SureSight improved but the sensitivity was reduced. [ABSTRACT FROM AUTHOR]

In this paper we describe the additive and multiplicative decomposition of refraction matrices with respect to a dihedral basis and show the effectiveness of that basis in developing new statistical summaries of refraction data. We also show that under certain projective restrictions the refraction matrices are homeomorphic to an open solid torus and discuss the many potential data-analytic consequences of that representation. A local analysis based on a class of Möbius transformations is introduced leading to a set of new summary statistics of potential use in comparative and correlational studies of refraction data. [ABSTRACT FROM PUBLISHER]

Hartmann–Shack images taken from an archived collection of SureSight refractive measurements of pre-school children in Oxford County, Ontario, Canada were retrieved and re-analyzed. Higher-order aberrations were calculated over the age range of 3 to 6 years. These higher-order aberrations were compared with respect to magnitudes of ametropia. Subjects were classified as emmetropic (range −0.5 to + 0.5D), low hyperopic (+ 0.5 to +2D) and high hyperopic (+2D or more) based upon the resulting spherical equivalent. Higher-order aberrations were found to increase with higher levels of hyperopia (p < 0.01). The strongest effect was for children showing more than +2.00D of hyperopia. The correlation coefficients were small in all of the higher-order aberrations; however, they were significant (p < 0.01). These analyses indicate a weak association between refractive error and higher-order aberrations in pre-school children. [ABSTRACT FROM AUTHOR]

In contrast to the Kryptok of 1919, Jalie[5] (a name synonymous with ophthalmic optics) reviews modern spectacle lens designs including free-form manufacturing techniques to minimise the visual impact of spectacle lens aberrations. Another technically challenging optical correction in contact lens practice is minimising the visual sequellae of elevated higher order aberrations in keratoconic eyes despite optimal standard contact lens correction. Nti and Berntsen[11] review the optics of modern overnight reverse geometry orthokeratology lens designs including their effects on accommodation, peripheral refraction and on axis higher order aberrations. [Extracted from the article]

The author focuses on the use of TM-24, An Optional Method for Adjusting the Recommended Illuminance for Visually Demanding Tasks Within IES Illuminance Categories P through Y Based on Light Source Spectrum, in applied illuminating engineering practices. It says that designers should consider some aspects of the TM-24 including the Equivalent Visual Efficiency (EVE) calculation, the need to decrease illuminance while increasing the S/P ratio for visual tasks, and architectural lighting systems.