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Optometry

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Browsing Optometry by Author "Govender-Poonsamy, Pirindhavellie."

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    An evaluation of the accuracy of the Moorfields Motion Displacement Test.
    (2020) Chetty, Keshia.; Loughman, James.; Naidoo, Kovin Shunmugam.; Govender-Poonsamy, Pirindhavellie.
    Introduction: Recent statistics report a global blind population of 32.4 million and 191 million people with vision impairment, of which more than 90% of the world’s visually impaired live in developing countries. Glaucoma, the third leading cause of blindness in Africa (after cataract), is responsible for approximately 15% of blindness in the continent, requiring early detection, but goes undiagnosed in developing countries because of lack of awareness of the disease and its effects. Screening methods are not always affordable and relatively inaccessible in most developing countries, posing a barrier to identifying people at risk of glaucoma blindness. The Humphrey’s Visual Field Analyser (HVFA), considered as the gold standard in assessing visual fields, is not suited to mass screening due to cost, portability, test time, physical testing requirements among other issues, thereby making it inconvenient for mass screening programmes. These shortcomings motivated the development of the Moorfield’s Motion Displacement Test (MMDT), a new portable visual field instrument, at the Moorfield’s Eye Hospital in London. Aim: To determine the agreement and sensitivity between the Humphrey’s Visual Field Analyser (HVFA) and the Moorfield’s Motion Displacement Test (MMDT). Methods: The study followed a comparative design based on simple random sampling, comprising two hundred and seven subjects. Of the total number of subjects included in the study, the glaucoma group comprised sixty-two subjects, whilst the control group comprised one hundred and forty-five subjects. A total of 293 eyes were included in the study, of which 94 eyes were glaucomatous (case) and 199 eyes were non-glaucomatous (control), of participants who were selected via chart review from two district hospitals in KwaZulu-Natal (KZN), South Africa; McCords Provincial Eye Hospital (case) and Prince Mshiyeni Memorial Hospital (control). Both eyes were tested using the HVFA and the MMDT instruments. All subjects were asked to complete a questionnaire prior to and after testing on both instruments. Results: Non-parametric tests were used because results were not normally distributed. The diagnostic accuracy of the MMDT was high in terms of test sensitivity (100%), but performed less well in terms of specificity (63.3% and 65.3%) for case and control participants respectively. Despite the low specificity, there was a high level of similarity and a faster testing time (for both groups) in detecting glaucomatous visual field defects on the MMDT compared with the HVFA. A significant number of participants (83.5 %) across the different race groups, preferred the MMDT over the HVFA, and found the use of the mouse over a push button to be easier (74.5% across all race groups). Majority of participants (80.5%) reported focusing on a central white dot seemed more comfortable than a central amber light and found anxiety levels reduced whilst using the MMDT. Conclusion: The high sensitivity and design advantages of the MMDT for population screening may help improve glaucoma case finding in the community, and thereby facilitate earlier treatment and better health outcomes for those affected. The specificity issue should be addressed, however, to avoid service delivery problems associated with unnecessary false positive referrals.
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    Impact of low vision on quality of life of patients with low vision visiting the low vision center of the Eastern Regional Hospital, Ghana.
    (2017) Adamptey, Beatrice.; Naidoo, Kovin Shunmugam.; Govender-Poonsamy, Pirindhavellie.
    Introduction: Low vision impacts quality of life and more so when the vision loss is severe. Persons living with low vision have reduced functionality and psychosocial well-being with the potential for high dependence on others in carrying out everyday activities. Decreased quality of life and psychosocial well-being affect both the individual and the community economically as the productive labour force is affected. Low vision may also increase morbidity and mortality. Although the relationship between low vision and quality of life has been extensively studied in other parts of the world, with documented evidence of the adverse effect of low vision on a person’s quality of life, very little has been done in Ghana to understand the specific setbacks and challenges low vision brings to the patients in spite of the fact that there are such patients living in the country for which reason a center has been set up to manage and treat them. Understanding specific vision and functional challenges is important in ensuring management that is tailored to the needs of patients with low vision. This study aims to investigate the impact of low vision on quality of life, and as well to establish the relationship between severity of vision loss and level of impact on quality of life of subjects with low vision visiting the low vision center of the Eastern Regional Hospital in Ghana. Method: A descriptive case control study involving 41 cases and 41 controls was conducted. The cases were stratified into three categories of low vision namely moderate, severe and profound. The National Eye Institute Visual Function Questionnaire (NEI VFQ-25) which consists of twenty five questions was used in the collection of data. Descriptive statistics and logistic regression analysis were conducted to determine associations between various variables. Results: Case subjects had statistically significantly lower quality of life compared to control subjects (cases, median=46.09, IQR= 30.84-66.00, n=41), (controls, median= 98.09, IQR=94.94-100.00-, n=41), p<0.001). The functional and psychosocial subscales (driving, near and distance activities, social function and mental health) produced the lowest quality of life scores. There was, however, no statistically significant difference in the ocular pain and discomfort subscale between cases and controls ((cases; median= 87.50, IQR= 71.88-100), (controls; median= 87.50, IQR= 87.50-100), p=0.098). Regression analysis showed no significant relationship between demographic profile and quality of life. Cases with profound low vision were 0.49 (95% CI= 0.46-0.71) times less likely to have good quality of life compared to subjects with normal vision. Quality of life worsened with decreasing vision Conclusion: Quality of life is impacted by low vision especially in areas of functionality and psychosocial well-being. The degree of impact of low vision on quality of life is influenced by the severity of vision loss. Incorporation of social support services counseling and rehabilitation protocols that focus on improving functionality may be a step in the right direction in assisting persons with low vision adapt to their vision loss and improve their quality of life.
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    Validation of selected iPhone optometric screening applications in vision screening.
    (2020) Moodley, Therisha.; Hansraj, Rekha.; Govender-Poonsamy, Pirindhavellie.
    Introduction: There has been an unprecedent increase in the use of mobile technology to provide health care services. The eye care industry has also adopted the use of these innovative smart-technology devices to provide rapid, convenient and less time-consuming eye screenings through the use of applications (apps) however, the accuracy and reliability of these tests have not been fully established. Aim: To determine if the selected smartphone apps have comparable results to their equivalent standard clinical optometric tests. Method: The study employed a comparative research design that compared the results of two each, smartphone distance visual acuity (DVA), contrast sensitivity and astigmatism apps to the results provided by the standard Snellen DVA chart, Pelli-Robson chart and JCC test, respectively. A total of 113 participants were recruited using convenience sampling. The results were analyzed and the Wilcoxon Signed ranked test was used to assess for any comparisons. Results: The median DVA as determined by the Snellen test and both VA apps were found to be exactly the same (0.63) for both the right and left eyes. More participants passed the CS test with the smartphone apps as compared to the standard Pelli-Robson test. Statistically significant (p<0.001) lower percentages of participants were detected as having astigmatism by both smartphone apps when compared to standard clinical testing. Conclusion: The Kay iSight professional (paid) and Pocket Eye Exam (free) VA app testing, overall, showed promising results as they produced results similar to the standard Snellen test. Both the CS smartphone apps overestimated the results and both astigmatism apps significantly underestimated the number of participants with astigmatism. These apps therefore failed in providing accurate screenings results and need to be further modified before it can be used as a screening device. However, due to the lack of literature more studies need to be done before these devices can be used for home screenings or clinical use.