bluuebunny/crossref_metadata_2025_split huggingface dataset:
Induced prismatic effects due to poorly fitting spectacle frames
Authors: Moodley V. R. , Kadwa F. , Nxumalo B. , Penciliah S. , Ramkalam B. , Zama A. 
Published: October 2016

To provide patients with the best vision possible practitioners undertake comprehensive visual examinations and optical dispensing procedures. Ensuring proper frame alignment is an important part of the spectacle dispensing process. Ideally,for maximum optical benefit, patients should look through the optical centers of their lenses. Rays entering a lens at any point other than the optical center will be deviated as long as the lens has power, thus inducing prismatic effects. These prismatic effects may lead to visual complaints such as asthenopia,blurry vision and headaches. The aim of the study was to investigate the prevalence of induced prismatic effects due to poorly fitting spectacle frames. A sample of 100 spectacle wearing subjects was selected as participants. Questionnaires were completed and any symptoms experienced recorded. The habitual spectacle position in the primary position of gaze was noted, pupil and optical centers marked and where relevant, induced prism was calculated. Data was analysed using the ANOVA Kruskal-Wallis and Mann-Whitney tests. On initial observation of frame position, about45% of subjects were wearing their spectacles incorrectly. A comparison of the marked pupil centers in primary gaze and optical centers revealed that 100% of participants were found to not be looking through the optical centers of their lenses. Fifty one percent were within horizontal and 3.12% within vertical ANSI tolerances. Symp-toms were reported by 50% of subjects experiencing base-out, 0% base-in and 47% vertical induced prismatic effects. However, no correlation existed between those subjects experiencing induced prism and symptoms reported. Prism adaptation may account for some participants being asymptomatic. Sixty three percent of subjects were not aware of the importance of properly fitted spectacle frames. Proper optical dispensing with associated patient education is necessary to achieve optimal optical benefits of spectacles and careful attention should be given to this aspect by practitioners. It is recommended that patients return periodically to their optometrists to have the frame alignment assessed and the fit modified if necessary. (S Afr Optom 2011 70(4) 168-174)
Aperture referral in dioptric systems with stigmatic elements
Authors: Harris W. F. 
Published: October 2016

A previous paper develops the general theory of aperture referral in linear optics and shows how several ostensibly distinct concepts, including the blur patch on the retina, the effective cornealpatch, the projective field and the field of view, are now unified as particular applications of the general theory. The theory allows for astigmatism and heterocentricity. Symplecticity and the generality of the approach, however, make it difficult to gain insight and mean that the material is not accessible to readers unfamiliar with matrices and linear algebra. The purpose of this paper is to examine whatis, perhaps, the most important special case, that in which astigmatism is ignored. Symplecticity and, hence, the mathematics become greatly simplified. The mathematics reduces largely to elementary vector algebra and, in some places, simple scalar algebra and yet retains the mathematical form of the general approach. As a result the paper allows insight into and provides a stepping stone to the general theory. Under referral an aperture under-goes simple scalar magnification and transverse translation. The paper pays particular attention to referral to transverse planes in the neighbourhood of a focal point where the magnification may be positive, zero or negative. Circular apertures are treated as special cases of elliptical apertures and the meaning of referred apertures of negative radius is explained briefly. (S Afr Optom 2012 71(1) 3-11)
The perception amongst a population of high school students in South Africa about ocular manifestations of HIV/AIDS*
Authors: Melwa I. T. , Oduntan O. A. 
Published: October 2016

HIV and AIDS can result in visual impairment, therefore it is important that those who have or atrisk of contracting the disease have a basic knowledge of its ocular manifestations, so that they may seek eye care early. This study assessed the per-ceptions of a sample of senior high school students at the Capricorn district, Limpopo Province, South Africa about the ocular manifestations of HIV/AIDS and its management. Questionnaires were distributed to the students in their classrooms after school hours and upon completion were collected the same day. Data analysis revealed that 27.8% of the participants agreed that HIV/AIDS can affect the eyes. Another 27.8% responded that HIV/AIDS could cause dry eyes. Less than a third (31.4%) indicated that the disease could cause red eyes, 31.5% and 38.1% respectively indicated that HIV/AIDS could cause cancer of the eyelids and the eyeball. About half of the respondents (52%) agreed that the disease could cause swollen eyelids; while about 46% agreed that vision loss or blindness could occur in HIV/AIDS. Many (65.6%) indicated that an ophthalmologist or an optometrist should be consulted for HIV/AIDS-related eye problems and only 16.5% reported that traditional healers could be consulted. Perception about the ocular manifestations of HIV and AIDS is poor among the participants, suggesting a need for awareness campaigns and education. (S Afr Optom 2012 71(3) 117-122)
A comparative study of central corneal thickness (CCT) and intraocular pressure (IOP) in University of KwaZulu-Natal students of Black and Indian ethnicity*
Authors: Sardiwalla Z. , Moodley D. , Ndawonde T. , Madikizela A. , Ngobese N. , Thobela N. 
Published: October 2016

Thisstudy compared central corneal thickness (CCT) and intraocular pressure (IOP) of Black and Indian students from the University of Kwa-Zulu-Natal. Two hundred (100 Black and 100 Indi-an) participants of both genders aged 18-25 years (mean and standard deviation; 20.1±1.6 years) participated in this study. CCT and IOP were measured for the right eye of each participant using a Tono-Pachymeter (NT530P) and a Goldmann applanation tonometer (GAT) respectively. Data was analyzed with descriptive, t-test and Pearson’s cor-relation statistics. In the total sample (N = 200), the mean CCT value was 519.5 ± 38.6 μm and CCT was higher in the Indians (526.5 ± 37.2 µm) than in the Blacks (512.4 ± 38.9 µm) (p = 0.01). Also, it was higher in the females (522.3 µm) than in males (516.7 µm), but the difference was insignificant (p = 0.07). The mean CCT was higher in the Indian males (520.1 µm) than in the Black males (513.2 µm), but the difference was insignificant (p=0.39). However, it was significantly higher in the Indian females (533 µm) than in the Black females (511.6 µm) (p = 0.003). In the total sample, the mean IOP was 14.6 mmHg and IOP was greater in Indiansthan Blacks (mean = 15.3 ± 2.9 mmHg and 13.8 ± 2.6 mmHg respectively) (p = 0.01). Also, the mean IOP (N = 200) value was slightly higher in the females (14.7 mmHg) than in males (14.5 mmHg) (p = 0.51). The mean IOP was higher in the Indian males (15.0 mmHg) than in the Black males (14.0 mmHg) (p = 0.07) and the mean IOP value was higher in the Indian females (15.7 mmHg) than in the Black females (13.6 mmHg) (p < 0.001). The higher mean IOP value in the Indian than Black participants was attributed to the higher mean CCT values. A positive, but inconsistent association between CCT and IOP was found in this study, the coefficient in the total sample (r = 0.382, p = 0.000), in the Blacks (r = 0.196, p = 0.05) and in Indians (r = 0.498, p = 0.000). A national population study comparing CCT and IOP in the various South African ethnic groups is recommended. Cognizance of these differences should be taken in the diagnoses of glaucoma in these ethnic groups. (S Afr Optom 2012 71(4) 171-177)
Time-domain versus spectral-domain optical coherence tomography: Findings in acute central serous chorioretinopathy*
Authors: Selver O. B. , Aslankara H. , Oner F. H. , Saatci A. O. 
Published: October 2016

Aims: To evaluate the optic coherence tomographic (OCT) features in acute central serous chorioretinopathy (ACSC) with time-domain or spectral-domain OCT at Dokuz Eylul University, Department of Ophthalmology, Izmir, Turkey.Subjects and Methods: Clinical data from the Department of Ophthalmology (of Dokuz Eylul University) including fluorescein angiography (FA) and OCT findings of 39 eyes of 34 patients with ACSC were retrospectively analyzed. Eleven eyes (Ntd =11) were examined with time-domain (Stratus OCT 3, Version 4.0) and 28 eyes (Nsd =28) with spectral-domain OCT (Heidelberg HRA2 Spectralis).Results: Of the sample of 34, twenty-four patients (70.6%) were men and 10 women (29.4%). FA demonstrated smokestack type hyperfluorescence in five eyes (12.8%), a round ink blot type hyperfluorescence in 32 eyes (82.1%) and diffuse leak-age in two (5.1%) eyes. Twenty-five eyes (64.1%) had only one leakage site, five eyes (12.8%) hadtwo leakage sites and nine eyes (23.1%) had three or more leakage sites. Detachment of the neurosensory retina was detected in 37 eyes (94.9%, 11 eyes with Stratus OCT and 26 eyes with Spectral OCT). Pigment epithelial detachment (PED) was detected in nine eyes (23.1%, one eye with Stratus OCT and eight eyes with Spectral OCT). Protrusion of the RPE layer was detected in 10 eyes (25.6%, all eyes with Spectral OCT). Both fibrinous exudates and bridging between the neurosensory retina and PED was detected with Spectral OCT in four eyes (10.2%). Retinal dipping was detected with Spectral OCT in two eyes (5.1%).Conclusion: Spectral-domain OCT seems to yield more information and depicts RPE layer protrusion, fibrinous exudates and bridging better when compared to conventional time-domain OCT. (S Afr Optom 2012 71(4) 166-170)
Repeatability and reproducibility of Tearlab measurements
Authors: Gillan W. D. H. 
Published: October 2016

It is well established that the diagnosis of dry eye is difficult. Tear osmolarity is considered by some to be the only metric of dry eye that is repeatable with some claiming that osmolarity is the best diagnostic metric for dry eye. A recently developed system, the Tearlab osmolarity system, is now available that can give a measure of tear osmolarity in less than 60 seconds. It is important that any new instrument be evaluated for its repeatability and reproducibility. The aim of this study was to investigate the repeatability and reproducibility of the Tearlab system by taking multiple, successive measurements of osmolarity of a manufacturer supplied calibration/test solution. The results of this investigation show that the Tearlab osmolarity system provides reasonably accurate, repeatable and reproducible measurements of tear osmolarity. (S Afr Optom 2013 72(1) 19-24)
Pupillary axis of a heterocentric astigmatic eye
Authors: Harris W. F. 
Published: October 2016

The pupillary axis of the eye is a clinically useful concept usually defined as the line through the centre of the entrance pupil that is perpendicular to the cornea. However if the cornea is astigmaticthen, strictly speaking, the entrance pupil is blurred and the pupillary axis is not well defined. A modified definition is offered in this paper: the pupillary axis is the infinite straight line containing the incident segment of the ray that passes through the centre of the (actual) pupil and is perpendicular to the first surface of the eye. The definition holds for the naked eye and for an eye with an implant in the anterior chamber. It also holds for the com-pound system of eye and optical instrument such as a contact lens in front of it if the first surface is interpreted as the first surface of the compound system and the pupil as the limiting aperture of the compound system. Linear optics is applied to obtain a formula for the position and inclination of the pupillary axis at incidence onto the system; the refracting surfaces may be heterocentric and astigmatic. The formula allows one to examine the sensitivity of the pupillary axis to displacement of the pupil and any other changes in the anterior eye. Strictly the pupillary axis depends on the frequency of light but examples show that the dependence is probably negligible. The vectorized generalization of what is sometimes called angle lambda is easily calculated from the inclination of the pupillary axis and the line of sight. (S Afr Optom 2013 72(1) 3-10)
Surfaces of forced vergence disparity
Authors: Rubin A. 
Published: October 2016

Purpose: To introduce the concept of surfaces offorced vergence disparity using measurementsof fixation disparity from three young, healthy individuals.Method: Fixation disparities were measured in three individuals in relation to variation in stimulus distance and vergence demand. All measurementswere obtained by means of the Sheedy disparometerwhich can be used to measure not only fixation disparity but also associated phorias. For each individual, consecutive measurements of fixation disparity only were determined over a short time period at four stimulus distances (0.25 m, 0.4 m, 1 m and 2 m) and under five different vergence demands as produced with the application of different amounts of prism (either base in or base out) and also without any prism. Parametric and non-parametric statistical methods are used to understand short-term variation of fixation disparity and pseudo-3D and stereo-pairs represent thesurfaces of forced vergence disparity with which this paper is mainly concerned.Results: Surfaces of forced vergence disparity are very useful to study variation of fixation disparity inrelation to change in stimulus distance and vergence demand. They are effectively 3-dimensional equivalents of 2-dimensional Ogle curves of forcedvergence disparity.Conclusion: Surfaces of forced vergence disparity may be useful in many contexts - both in relation to normal or unusual binocular behaviour. This paper introduces such surfaces in relation to three individuals who were considered as having satisfactory binocular and accommodative-vergence function. The surfaces assist one in understanding complicated three-dimensional or trivariate data that involves fixation disparities, different stimulus locations and different accommodative-vergence demands upon the oculo-motor system. (S Afr Optom 2013 72(1) 25-33)
Post-destructive eye surgery, associated depression at Sekuru Kaguvi Hospital Eye Unit, Zimbabwe: Pilot Study
Authors: Kawome M. M. , Masanganise R. 
Published: October 2016

Destructive eye surgery is associated with more complications than just loss of visual functions of the eye and aesthetics. Currently there is very little published literature on post-destructive eye surgery associated depression. Zimbabwe has been experiencing a surge in the rate of destructive eye surgery done at the National Tertiary Eye Unit. This situation could be churning out lots of unrecognized depressed clients into the community who require assistance in one form or another.Objectives: To determine the prevalence of post-destructive eye surgery associated depression among patients attending Sekuru Kaguvi Hospital Eye Unit and assess if the current management protocol of patients undergoing destructive eye surgery at the Eye Unit addresses the problem adequately.Methods: A cross-sectional study of 28 randomly selected patients who had destructive eye surgeries at Sekuru Kaguvi Hospital was conducted over five months from 1st March 2012 to end of July 2012. A structured questionnaire containing 15 questions on the following items: gender, age, diagnosis, surgical procedure done, expectations before and after surgery, adequacy of counseling given and involvement of family was used to collect data. Nine questions to assess depression were adapted from the Patient Health Questionnaire (PHQ-9).Setting: The study was conducted at SekuruKaguvi Hospital Eye Unit, Parirenyatwa Group of Hospitals in Harare.Results: Twenty-eight patients who underwent destructive eye surgery during the study period were selected using systematic random sampling. The gender ratio was 1:1 and the mean age was 38.7 years with a range from 24 to 65 years. Fifty percent of the patients in the study had orbital exenteration while the rest had enucleation (14%) and evisceration (36%). Twenty-eight percent of the study population had depression.Conclusion: Destructive eye surgery is frequently associated with depression and our current management protocol of patients undergoing destructive eye surgery does not address this problem.
A population-based study of visual impairment in the Lower Tugela health district in KZN, SA
Authors: Naidoo K.S. , Sweeney D , Jaggernath J , Holden B. 
Published: October 2016

A cross-sectional, population-based, epidemiological study of blindness and visual impairment was conducted to evaluate the prevalence of vision loss and various sight-threatening conditions in the Lower Tugela health district of the KwaZulu-Natal province, South Africa. This study was conducted on a randomly selected sample of 3444 individuals from the district. This number represented 84% of those who were visited and 80.1% of the total sample selected. The participants ranged in age from 5 to 93 years (mean of 29.2 years and a median of 20.0 years). The proportion of men to women differed between participants aged <30 years and those aged >30 years. In both age groups, women represented the majority of participants (66.5%), but the number of women to men in the older age group was approximately twice that found in the group aged less than 30 years. The difference in age between the men and women in the study was not statistically significant (p >0.5). The study revealed that 6.4% of the population studied were visually impaired. The distribution of uncorrected visual acuity was better for women than for men for both OD and OS (p = 0.000 for OD and OS). The main causes of visual impairment were refractive error (44.5%), cataract (31.2%), glaucoma (6.0%), hypertensive retinopathy (4.1%) and diabetic retinopathy (4.1%). Unilateral blindness (OD) was present in 0.78% (95% Confidence interval (CI): 0.42%-1.14%) of participants and unilateral blindness (OS) was present in 1.1% (95% CI: 0.70%-1.50%). Thirty-one participants (0.9%) were bilaterally blind with the main causes being cataracts (54.8%) and refractive error (12.9%). Glaucoma and hypertensive retinopathy were responsible for 6.4% of ..bilateral blindness. Diabetic retinopathy, other retinal conditions (coloboma) and corneal scarring were each responsible for 3.2% of bilateral blindness. Albinism, coloboma and age-related macular degeneration accounted for 9.7% of bilateral blindness. The data provides much needed information to support the planning of eye care programs in KwaZulu-Natal. (S Afr Optom 2013 72(3) 110-118)
Characteristics of eye injuries in urban KwaZulu-Natal Province, South Africa: 2005-2008
Authors: Sukati V.N. , Hansraj R. 
Published: October 2016

Purpose: To provide epidemiological data on ocular injuries among patients utilising the provincial hospitals eye care clinics in urban KwaZulu-Natal, South Africa. This data can be used in the future planning and intervention for ocular injuries at provincial hospitals.Methods: Record cards of 220 ocular injury patients seen at two selected urban provincial hospitals over a period of four years were reviewed.Results: Male presentation was higher (79.1%) compared to females (20.9%). The Black population (85.9%) experienced more ocular injuries than other race groups. The 21 to 30 age group incurred more injuries (32.3%) than other age groups. Open globe injuries occurred more frequent (56.4%) than closed globe injuries (43.6%). The frequent type of injury was blunt trauma/contusion (32.7%). More than half of the injuries were from solid objects (56.4%) followed by assaults (16.4%). The home was the common place to incur an injury (72.2%). Twenty four patients (10.9%) required surgical intervention at initial presentation. One hundred and fifty eight (71.8%) patients returned for follow up examination. Twenty five percent of the patients remained with poor vision following treatment. Conclusion: Ocular trauma due to burns is usually bilateral while that due to blunt trauma and intra ocular foreign bodies are generally unilateral. Solid objects were the most frequent cause of ocular injury and injuries due to this cause were most often incurred in the home. (S Afr Optom 2013 72(3) 119-126)
The Order of Knowledge and Robust Action. How to Deal with Economic Uncertainty?
Authors: Falkinger Josef 
Published: October 2016

Abstract
Uncertainty in economics is generated by “nature” but also by the model we use to “produce the future”. The production of the future comprises besides the allocation of resources on different instruments (technologies, financial products) also the design of the instruments. Specialization and diversification considerations point to the advantages of targeting instruments to a rich set of possible future states. But, if a rich state space comes with unreliable probability measures, the actions based on such a set will be unreliable, too. The proliferation of financial products is a salient example. This paper argues that an appropriate model for dealing with uncertainty keeps the knowledge required by the model from its user in line with the available knowledge. In particular, it proposes to order state spaces by their “granularity” and “coverage”. Appropriate upper bounds are derived for these characteristics. A practical implication of the presented approach would be to limit financial product innovation.
Biochar-carrying hydrocarbon decomposers promote degradation during the
early stage of bioremediation
Authors: Galitskaya Polina , Akhmetzyanova Leisan , Selivanovskaya Svetlana 
Published: October 2016

Abstract. Oil pollution is one of the most serious current environmental problems. In this study, four strategies of bioremediation of oil-polluted soil were tested in the laboratory over a period of 84 days: (A) aeration and moistening; (B) amendment with 1 % biochar (w ⁄ w) in combination with A; amendment with 1 % biochar with immobilized Pseudomonas aeruginosa (C) or Acinetobacter radioresistens (D) in combination with A. All strategies used resulted in a decrease of the hydrocarbon content, while biochar addition (B, C, D strategies) led to acceleration of decomposition in the beginning. Microbial biomass and respiration rate increased significantly at the start of bioremediation. It was demonstrated that moistening and aeration were the main factors influencing microbial biomass, while implementation of biochar and introduction of microbes were the main factors influencing microbial respiration. All four remediation strategies altered bacterial community structure and phytotoxicity. The Illumina MiSeq method revealed 391 unique operational taxonomic units (OTUs) belonging to 40 bacterial phyla and a domination of Proteobacteria in all investigated soil samples. The lowest alpha diversity was observed in the samples with introduced bacteria on the first day of remediation. Metric multidimensional scaling demonstrated that in the beginning and at the end, microbial community structures were more similar than those on the 28th day of remediation. Strategies A and B decreased phytotoxicity of remediated soil between 2.5 and 3.1 times as compared with untreated soil. C and D strategies led to additional decrease of phytotoxicity between 2.1 and 3.2 times.