Optical Appliances Research Articles

Opto-electronic, crystallographic, and Judd-Ofelt analysis of novel gadolinium-based europium doped BaSrGd4O8 nanophosphor for advanced pc-WLEDs

• Red-light emanating BaSrGd 4 O 8 :Eu 3+ nanocrystals have been prepared for first time via urea assisted solution combustion approach. • The detailed structural and photoluminescence analysis are done effectively. • SEM, TEM, EDAX, and TGA characterizations are done to explore morphological aspects, elemental analysis and thermal stability. • Kubelka-Munk hypothesis has been utilized to determine band-gap energy using DR spectra. • Significant utilization in various photonic and solid-state lighting applications. A sequence of novel BaSrGd 4 O 8 :Eu 3+ nanophosphor was fabricated with the aid of solution combustion (SC) methodology. Phase formed and morphological attributes were examined by PXRD, SEM, and TEM techniques. Rietveld refinement confirmed the Space group Pnma (62) and Orthorhombic phase. Diffuse reflectance, decay curves, and photoluminescence spectra were utilized to look into the photoluminescent features. Exclusive red emission was observed due to the 5 D 0 → 7 F 2 transition with optimal composition found at 15.0 mol %. The decay lifetime and quantum efficiency for the optimized nanophosphor were found to be 1.5495 ms and 72.5 %. Energy band gap values for the host matrix as well as optimized sample were also calculated that were found to be 5.27 and 3.46 eV respectively. CIE and CCT coordinates confirmed an efficient red emission that enhances its application vision in optical appliances.

Referral in a routine Italian optometric examination: towards an evidence-based model.

Italian optometrists refract patients and prescribe optical appliances. The routine optometric examination that is currently conducted in Italy, however, does not include a comprehensive ocular health assessment. Like many other countries, in Italy ophthalmologists are solely responsible for the diagnosis and treatment of ocular pathologies, yet, the care an optometrist provides must be done with the aim of promoting the general and ocular health of patients seen in practice. Such scope has to be pursued using a close collaboration with ophthalmologists, ultimately facilitating the earliest medical diagnosis and minimisation of visual impairment. Referral represents the basis of optometrist-ophthalmologist collaboration, yet, no guidance is available to Italian optometrists indicating when referral is warranted. The purpose of this study was to identify the circumstances deserving a referral in a routine Italian optometric examination in adults, ultimately constituting preliminary evidence-based indications of a referral model oriented to enhance the ocular and general health of patients. A literature review was conducted on Pubmed and the Cochrane Library, mainly targeting high quality secondary literature such as systematic reviews, meta-analysis and clinical guidelines. Several reasons for referral were identified. Further, while a wide range of anomalies of the visual system are likely to be discovered by the Italian optometric examination, up to 20% of patients could suffer an underlying condition undetected by the current assessment. This results in the need to refer seemingly healthy patients if they have not attended routine ophthalmological examinations within optimal time frames. In Italy, and countries with similar settings, the referral is an essential instrument that optometrists must largely use to ensure early diagnosis of ocular conditions by ophthalmologists and minimisation of avoidable visual impairment.

Fundamentals of ophthalmic dispensing 18: Law and regulation – part 1

The sale of optical appliances is governed partly by ordinary consumer legislation and specifically through the Opticians Act and the various orders of the General Optical Council. Here Tina Arbon Black and Peter Black take a look at the legislation, regulations and standards that apply to ophthalmic dispensing.

Assessing the Skills of Alberta’s Refracting Opticians: Can Opticians Safely and Independently Refract and Prescribe Optical Appliances?

Alberta is one of three Canadian provinces that permits optician-performed refractions. Recently, the Alberta College and Association of Opticians (ACAO) has requested an expansion of opticians’ scope of practice to include the ability to prescribe optical appliances, an activity currently restricted to optometrists and ophthalmologists. For the remainder of this paper, the term “prescribe” should be interpreted as the prescription of an optical appliance, not a therapeutic pharmaceutical agent. In this paper, we investigate whether designated refracting opticians in Alberta have adequate training and knowledge to safely and independently perform a refraction and prescribe an optical appliance. To answer this research question, we composed a list of 27 skills we deem necessary to safely and independently refract and prescribe. We then evaluated the Northern Alberta Institute of Technology’s (NAIT) opticianry programs and the entry to practice examinations administered by the National Association of Canadian Optician Regulators (NACOR) and the Optometry Examining Board of Canada (OEBC) in terms of their coverage of these 27 skills. Our findings show that NAIT’s optical science programs either do not cover or do not practically assess students on over half (59 percent) of the skills required to safely and independently refract and prescribe, and the NACOR examination fails to cover 77 percent of the skills required to safely refract and prescribe. Based on this information, refracting opticians in Alberta do not possess adequate training and knowledge to safely and independently perform a refraction and prescribe an optical appliance. Granting opticians the legislative authority to independently refract and prescribe may result in a public health issue, as there may be an increase in the number of un-diagnosed or un-detected eye and systemic diseases.

Fundamentals of ophthalmic dispensing part 15: Visual task analysis – part 1

At its simplest level a visual task analysis can be considered an assessment of the interaction between a patient, their optical appliance and the visual elements of their environment – the things they are trying to see and do. In this, the first of two articles, Peter Black introduces the topic and tackles the often confusing subject of photometry bringing it up to date for a world illuminated by low energy light bulbs.

The toolbox of porous anodic aluminum oxide\u2013based nanocomposites: from preparation to application

Anodic aluminum oxide (AAO) templates have been intensively investigated during the past decades and have meanwhile been widely applied through both sacrificial and non-sacrificial pathways. In numerous non-sacrificial applications, the AAO membrane is maintained as part of the obtained composite materials; hence, the template structure and topography determine to a great extent the potential applications. Through-hole isotropic AAO features nanochannels that promote transfer of matter, while anisotropic AAO with barrier layer exhibits nanocavities suitable as independent and homogenous containers. By combining the two kinds of AAO membranes with diverse organic and inorganic materials through physical interactions or chemical bonds, AAO composites are designed and applied in versatile fields such as catalysis, drug release platform, separation membrane, optical appliances, sensors, cell culture, energy, and electronic devices. Therefore, within this review, a perspective on exhilarating prospect for complementary advancement on AAO composites both in preparation and application is provided.Graphical abstract

Facile combustion synthesis of Sm3+ activated orange-red light emanating Sr6Y2Al4O15 nanophosphor for photonic applications

A cost effective, environmentally benign and most convenient solution combustion scheme was utilized for preparing a series of Sr6Y2-2xSm2xAl4O15 (x = 0.5–10 mol%) crystalline nanophosphors. The morphological study and phase formation were examined via SEM (Scanning Electron Microscope) image, TEM (Transmission Electron Microscope) micrograph and measured PXRD (powder X-ray diffraction) patterns. The crystal structure information is gathered with the help of Rietveld refinement technique. Photoluminescence excitation-emission spectra revealed about the photometric characteristics of the synthesized down-conversion nanophosphors. The diffuse reflectance spectral measurements yield optical energy band gap of 5.96 eV and 5.88 eV for the host (Sr6Y2Al4O15) and optimized matrix (Sr6Y1.94Sm0.06Al4O15) respectively. The estimated CIE (international commission on illumination) chromaticity coordinates values were revealed to be located in orange-red section specifying their importance for solid state illumination. The optimum concentration of trivalent samarium ion as a dopant ion for this particular kind of matrix was observed to be 3.0 mol%, since, beyond this concentration, a fall in photoluminescence intensity occurred due to concentration quenching trend. The prominent feature of orange-red light emission by the prepared nanocrystalline phosphors upon excitation via near ultraviolet (NUV) light makes them potential contender for red emitting luminescent optical appliances.

Development of Physics Teaching Materials of Optical Devices Based on Learning Assisted Guided Inquiry Crossed Puzzles

This research aims to produce the teaching materials based on the inquiry learning model with valid, effective, and practical crossword puzzle of a physics lesson, especially in the optical appliance material of junior high school. The type of this research is developmental research using a 4 D model. The 4-D model consists of 4 stages of defining, designing, developing, and distributing. This research uses the development model. The methodology used is quantitative descriptive. Likert scale is used in this research as the validity analysis. Furthermore, the practical analysis is achieved from observation instrumental of lesson plan implementation, which written in the observation sheet, and student and teacher response questionnaire. The result of the research showed that the validity analysis of teaching material is valid. Moreover, the result of lesson plan implementation, teacher response questionnaire, student response questionnaire, categorized to very practical. The findings of this research showed that inquiry learning with a crossword puzzle in optical appliance material was very valid, practical, and useful.

Frames: A little extra care sometimes makes a big difference

Dr Narendra Kumar presents some cases where careful modification of optical appliances have addressed particular patient needs

Paediatric eye care – part 1 Paediatric dispensing

Jessica Gowing describes how best to dispense an optical appliance to a child

New thermoplastic poly(carbonate-urethane)s based on chain extenders with sulfur atoms

New thermoplastic segmented polyurethanes were obtained by a one-step melt polyaddition using 40, 50 and 60 mol% poly(hexane-1,6-diyl carbonate) diol of bar{M}_{n} = 860 g mol−1, 1,1′-methanediylbis(4-isocyanatobenzene) and 2,2′-[sulfanediylbis(benzene-1,4-diyloxy)]diethanol, 2,2′-[oxybis(benzene-1,4-diylsulfanediyl)]diethanol or 2,2′-[sulfanediylbis(benzene-1,4-diylsulfanediyl)]diethanol as a chain extender. FTIR, atomic force microscopy, differential scanning calorimetry and thermogravimetry were used to examine the polyurethanes’ structure and thermal properties. Moreover, their Shore A/D hardness, tensile, adhesive and optical attributes were determined. They were transparent high-molar-mass materials showing good tensile strength (up to 51.9 MPa). The polyurethanes exhibited improved adhesion to copper taking into consideration that of conventional ones, and middle or high refractive index values (1.57–1.60), and both these parameters increased with an increase of the content of sulfur atoms in the polyurethane chain. The newly obtained polyurethanes can be considered as materials for numerous medical and optical appliances.

Addressing inequalities in eye health with subsidies and increased fees for General Ophthalmic Services in socio-economically deprived communities: a sensitivity analysis

ObjectivesPoor knowledge of eye health, concerns about the cost of spectacles, mistrust of optometrists and limited geographical access in socio-economically deprived areas are barriers to accessing regular eye examinations and result in low uptake and subsequent late presentation to ophthalmology clinics. Personal Medical Services (PMS) were introduced in the late 1990s to provide locally negotiated solutions to problems associated with inequalities in access to primary care. An equivalent approach to delivery of optometric services could address inequalities in the uptake of eye examinations. Study designOne-way and multiway sensitivity analyses. MethodsVariations in assumptions were included in the models for equipment and accommodation costs, uptake and length of appointments. The sensitivity analyses thresholds were cost-per-person tested below the GOS1 fee paid by the NHS and achieving break-even between income and expenditure, assuming no cross-subsidy from profits from sales of optical appliances. ResultsCost per test ranged from £24.01 to £64.80 and subsidy required varied from £14,490 to £108,046. Unused capacity utilised for local enhanced service schemes such as glaucoma referral refinement reduced the subsidy needed. ConclusionsIn order to support the financial viability of primary eye care in socio-economically deprived communities, income is required from additional subsidies or from sources other than eye examinations, such as ophthalmic or other optometric community services. This would require a significant shift of activity from secondary to primary care locations. The subsidy required could also be justified by the utility gain from earlier detection of preventable sight loss.

Synthesis and properties of flame-retardant poly(vinyl alcohol)/pseudo-boehmite nanocomposites with high transparency and enhanced refractive index

Abstract Flame-retardant nanocomposites with high transparency based on poly (vinyl alcohol) (PVA) and pseudo-boehmite nanorods have been fabricated by synthesis of pseudo-boehmite nanorods and subsequent solution blending with PVA. The morphology and physical properties of PVA/pseudo-boehmite nanocomposites have been characterized systematically. Scanning electron microscopy investigations showed the homogeneous dispersion of pseudo-boehmite nanorods within PVA matrix even at very high nanorods loadings. The nanocomposites with 37.5 wt% pseudo-boehmite nanorods exhibit limit oxygen index (LOI) as high as 30.0 with the transmittance of more than 90% at the visible region and the enhanced refractive index. Moreover, the incorporation of the pseudo-boehmite nanorods increases the modulus and the tensile strength of PVA, indicating the significantly enhanced surface hardness of the nanocomposite. It is considered that the prepared PVA nanocomposites are not only useful as flame-retardant fibers, a long term pursued target for PVA fabrics, but also as optical appliances with its excellent transparency and high refractive index.

Different Proposed Applications of Bacteriorhodopsin

Bacteriorhodopsin (BR) is an integral membrane protein found in "purple membrane" (the Archaea cell membrane) mainly in Halobacteria. This protein absorbs green light (wavelength 500-650 nm, with the absorption maximum at 568 nm) and converts it into an electrochemical gradient. This gradient in turn is used for ATP production. The ability of BR to convert light energy into chemical energy or sunlight into electricity has been used in different applications mainly optical appliances but also for therapeutic/medical applications and research. This review surveys some of these applications that have been patented in the last five years.

Morphometry of the human cochlear wall and implications for cochlear surgery

Objective—To study the lateral wall of the cochlea in human temporal bones (TBs), in order to evaluate the feasibility of performing micro-dissection of the spiral ligament and an endosteal electrode implantation.Material and Methods—We reviewed the database of the TB bank of The House Ear Institute in search of bones that did not distort the otic capsule or spiral ligament, and selected 36 horizontally sectioned TBs. All bones had been removed using the en bloc technique, fixed in formalin, decalcified in EDTA, embedded in celloidin and cut into 20-μm serial sections. We evaluated sections stained with hematoxylin–eosin under a microscope, and made several measurements of the lateral wall of the cochlea using optical appliances. A total of 20 measurements were made at 3 levels: midmodiolar sections; sections at the round window niche; and sections containing the anterior border of the stapes footplate.Results—The selected sections provide useful data when applied during surgery. All the numerical data were analyzed statistically and, although individual variability occurred, most of the measurements seemed to be quite homogeneous.Conclusions—A greater understanding of the microscopic anatomy and dimensions of the human TB will help to understand the surgical relationships at the lateral wall of the cochlea. Our study provides some numerical references for the dimensions of the cochlea that may help in cochlear surgery. These dimensions would be of particular interest in cochlear implantation, especially in the design of endosteal electrodes.

The maximum motor fusion test: A parameter for surgery for acquired esotropia

Purpose: The purpose of this study was to determine whether surgery for acquired esotropia based on the maximum capacity for motor fusion measured with a prism bar could be used to increase the number of millimeters of bilateral medial rectus recession that could be performed without producing an early overcorrection or a late consecutive exotropia, as a way safely to reduce the need for postoperative wear of glasses or a bifocal. Methods: Category I patients had residual deviations of esotropia (ET) of 12 PD or more with distance fixation, measured after a full hyperopic correction of +1.50 to +3.25 was placed, and had no significant anisometropia or astigmatism. Category II patients had residual deviations of esotropia of less than 11 PD with distance fixation and had residual deviations of esotropia with near fixation (ET') of at least 10 PD more than esotropia with distance fixation (“clinical high AC/A”). Category III patients had had previous bilateral medial rectus muscle recessions and had recurrent esotropia with near fixation of more than 10 PD. For patients in categories I and II, bilateral medial rectus muscle recessions were performed by using a published dose-response table from the national Prism Adaptation Study but with the maximum capacity for motor fusion as the input parameter instead of the prism-adapted angle. Patients in category III received re-recessions of one or both medial rectus muscles, according to a previously published system, with the distance fusional amplitude as the input parameter. Results: In category I, 24 of 30 (80%) patients needed no glasses after surgery, 1 of 30 had esotropia, and 2 of 30 had exotropia (XT) (10% reoperation rate). In category II, 35 of 36 (98%) patients needed no bifocals after surgery, and 3 of 36 had exotropia (9% reoperation rate). In category III, 10 of 10 patients needed no bifocals, and 2 of 10 had exotropia (20% reoperation rate). Conclusions: When a postoperative reduction in dependence on continuous wear of an optical appliance is a reasonable goal, the maximum motor fusional capacity, measured with a prism bar, is a good parameter for surgical design. (J AAPOS 2000;4:211–6)

The provision of ophthalmic services for a rehabilitation day care centre population with multiple physical handicaps

The provision of the wide variety of support services necessary for patients with multiple handicaps is often poorly coordinated. In this study a group of 108 adults, aged from 19 to 90 years, who suffered from multiple physical handicaps and attended a rehabilitation day care centre, had their visual functions and requirements assessed by a multidisciplinary team. The programme consisted of five stages. Each patient was initially screened and subsequently referred for more detailed optometric, ophthalmological, low vision or rehabilitation assessments, where appropriate. Results indicated that many of the patients had not been receiving regular ocular assessments and would benefit from the provision of an optical appliance or ophthalmological treatment. The survey provided staff at the rehabilitation centre with information on the visual status of individual patients and enhanced general eye-care awareness.

Evaluation and Modification of Low Vision Aids

Many optical appliances provided for 2. the low vision patient are selected from a limited range of aids made available to the profession in Australia through local distributors. There is evidence to support the view that some of these aids have not been designed with the geriatric low vision patient in mind. The versatility and usefulness of some aids can be improved by means of relatively minor modifications. It is suggested that such modifications will provide the practitioner with a freedom to prescribe specifically for the patient. This is preferable to selecting the most suitable aids from a predetermined array followed by counselling the patient on ways of obtaining maximum benefit from them. It is anticipated that such an approach to low vision care will result in a simpler instruction code for the patient and a minimum of after care.

Presenile cataract. A follow-up investigation with special reference to occupational aspects.

A retrospective investigation was carried out of 100 patients below the age of 60 years operated for presenile cataract. The material has been divided into three occupational groups, depending on the visual requirements. The complaints prior to and after operation have been related to the patient ability to retain their employment. Of 78 patients who were still employed, only 45 were able to return to their former occupation after the first cataract extraction. The final result was that 62 patients could continue their former work, 12 changed their occupation due to aphakia problems, while four had to retire. The vision in the fellow eye, the type of work and the optical appliances have been found to be of primary importance. It is concluded that operation for unilateral cataract is inadvisable, if the vision of the fellow eye is good and contact lenses cannot be used, that the time between operations for bilateral cataract should be as short as possible, and that the use of contact lenses is essential.

Visual Characteristics of an Underprivileged Croup of Australian Children

Stewart House, at one of the seaside suburbs of Sydney, provides a unique service for the needy families of the state. Every three weeks it welcomes 70 to 80 schoolchildren and during this period it looks after them in a lavish way. Foremost amongst the services are entertainment, education and health. Our team provides comprehensive optometrical care. During the first week all children are screened with the aid of a well-established test battery that probes key aspects of the visuo-sensory and visuo-motor mechanism. Children who fail this screening receive a full refraction during the second week. Based on these two examinations the type of treatment is decided upon, which includes referral to the appropriate educational, psychological or health authorities. During the third week optical appliances are fitted and final check-ups are made on borderline cases. The aim of this paper is to report on the results obtained from 1166 consecutive cases. These results indicate a statistically significant difference both in the visuo-sensory and the visuo-motor characteristics of this group when compared to available figures obtained from children of similar age distribution.