Optometry

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Browsing Optometry by Subject "Dissertation (M. Optometry (Optometry))--University of the Free State, 2020"

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    Amplitude of accommodation in 9 to 13 year old school children of Mankweng circuit, Limpopo province
    (University of the Free State, 2020-09) Mafeo, M. E.; Oberholzer, M.; Rasengane, T. A.
    Background: Amplitude of accommodation (AA) is the function of accommodation referred to as the dioptric difference between the far point (the eye is at rest) and near point (when the eye is fully accommodated) and is known to reduce with increase in age. To determine if an individual has low, normal or high amplitude of accommodation (AA) for his / her age, norms calculated from Hofstetter’s formulae are still used as reference all over the world. However, these norms were found to be irrelevant to Ghanaian and Swedish children. Out of the few accommodation studies conducted in South Africa, none of the studies documented the AA of learners from the Mankweng circuit, Limpopo province in South Africa. Aim of the study: The aim of this study was to investigate the AA in 9 to 13 year old school children of Mankweng circuit, Limpopo province. Method: A cross - sectional, analytical, descriptive study was conducted on 291 learners aged 9 to 13 years of age (median age = 11.3 years). Learners were conveniently selected but schools were randomised. Learners who passed visual screening tests consisting of habitual visual acuity at 6 m and 40 cm right eye and left eye (RE and LE), +2.50 D lens test at 6 m (RE and LE), prism cover test at 40 cm and direct ophthalmoscopy (RE and LE), were included in this study. One hundred and eighty - five (185) learners met the inclusion criteria and proceeded to the measurements of AA which were determined subjectively using the push - up (PU) to - blur (first data set) and pull - away (PA) to - clear (second data set) techniques, and objectively using the dynamic retinoscopy (DR) (fourth data set). The PU and the PA results were thereafter used to determine the average AA for each participant, which were regarded as the third AA measurement data set for the current participants. Results: The subjective and objective techniques of measuring AA yielded different results among the same participants aged 9 to 13 years. Dynamic retinoscopy (DR) technique measured the highest AA (median = 19.7 D), with PU (median = 14.3 D), PA (median = 13.4 D) and the average results of PU / PA techniques (median = 13.8 D) measuring lower. The median AA were reducing from 21.2 D to 18.3 D as age increased in 9 to 13 year old participants when measured with DR; from 15.5 D to 12.9 D with PU; from 14.4 D to 12.2 D with PA and from 15.0 D to 12.5 D when using the average results of PU / PA measurements. The rate at which AA changed between different age groups was found to be inconsistent. Furthermore, a significant difference existed between the AA of groups of 2 years or more apart. There was no statistical significant difference between the AA in female and male participants. The results further showed that the type of technique used to collect AA measurements, may have influenced the prevalence rate of a LOW AA. The results showed a high prevalence of LOW AA with PA technique 18.4% (CI of [13.5% to 24.6%]), followed by the average results of PU / PA techniques 12.4% (CI of [8.4% to 18.0%]) and lastly PU technique 7.6% (CI of [4.6% to 12.3%]). For the same participants, the DR technique did not measure LOW AA amongst any of the age groups. In each technique, there were outliers reported, with the majority in the 9 - year - old age group. Conclusion: The measured AA decreased with increasing age with all the techniques used, although the rate of reduction was not constant between the age groups. Furthermore, the AA between the age groups 12 and 13 years was statistically significantly different and also between the age groups of two or more years apart (e.g. 9 and 11 years). The AA in female and male participants showed no statistical significant difference. The prevalence of LOW AA determined, was higher with the PA technique as compared to the PU technique. The objective measurements were statistically significantly higher to the subjective measurements.
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    The prevalence of aniridia and associated visual and ocular complications among learners in schools for the visually impaired in central South Africa
    (University of the Free State, 2020-07) Hatia, Sherazadh; Rasengane, T. A.; Henderson, B. D.
    Introduction Aniridia is a rare, sight-threatening ocular disorder characterised by partial or complete absence of the iris. It can affect multiple ocular structures and lead to visual complications. According to our knowledge, there is currently no recent published research on aniridia in the South African population, thus it would be beneficial to investigate the prevalence of aniridia and describe the ocular and visual complications in South Africa. Therefore, the aim of this research was to determine the prevalence of aniridia among learners in visually impaired schools in central South Africa (Free State and North West) and to describe its visual and ocular complications. In order to achieve the aim, the number of participants that had partial and complete aniridia was determined using an ophthalmoscope. Thereafter, the visual and ocular complications in participants with aniridia were determined. Methods A prospective descriptive study was conducted on learners in three visually impaired schools in central South Africa. A total of 117 consenting learners were screened with an ophthalmoscope to determine the presence or absence of aniridia and only the participants identified with aniridia were further examined. The visual acuity of the participants with aniridia was determined using a logMAR visual acuity chart, the refractive error was determined using an autorefractor, the intraocular pressure was measured using an iCare tonometer to determine the risk for glaucoma and the anterior and posterior segment of the eye was examined using a slit lamp, 90D lens and gonioscopy lens to determine the complications associated with aniridia. Results for each participant were recorded and participants who required further management were referred to the local Ophthalmology clinic. Data analysis was performed by the Department of Biostatistics (University of the Free State). Prevalence was calculated by dividing the number of participants with aniridia by the total number participants included in the study. Results Four participants were identified as having aniridia and thus the prevalence of aniridia was found to be 3,4% (4 out of 117). The ages of these participants were 10, 13, 17 and 20 years. Visual acuity for each eye individually ranged from no light perception to 0.86 logMAR (6/38). Corneal complications such as pannus, opacification and vascularisation were seen in all of the participants. Some form of cataract was seen in all four participants. The IOP ranged between 11mmHg and 19mmHg in 3 of the participants and was outside of the normal range (7mmHg – 21mmHg) in the 4th participant. Gonioscopy showed 75% of participants with grade 4 angles and the remaining participant with grade 2 angles. Cup-to-disc ratios varied between 0.5 and 0.8 with no glaucomatous changes. Foveal hypoplasia was present in 75% of participants and nystagmus was present in all of the participants. One participant presented with membrane-like structures in the posterior chamber of both eyes, making a view of the fundus unobtainable. Conclusion The prevalence found (3,4%) is representative of one school (Christiana School for the Blind in the North West) from the three that were included, not the whole of South Africa. Cataracts and nystagmus were the most prevalent ocular complications found in this group. The foveal hypoplasia and corneal abnormalities in conjunction with some form of cataract and nystagmus are all contributors to the reduced visual acuity observed in these participants. The findings from this study contribute to new information regarding aniridia in regions of central South Africa and enables the comparison of results with research conducted in other parts of the world. This research also provides information about the most recent prevalence of aniridia in this part of South Africa. Further research can be done in other parts of the country to support and add to these results.
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    Use of diagnostic techniques by private practising optometrists in South Africa
    (University of the Free State, 2020-09) Fraser, Johanna Antoinette; Naicker, N.; Rasengane, T. A.
    Introduction: In South Africa, the optometric profession has seen two expansions of the scope of practice within the last two decades. The first of the two allowed optometrists to make use of techniques that required the use of diagnostic pharmaceutical agents. Aim: The purpose of the study was to establish the extent to which the four specific diagnostic techniques are utilised and if there exist barriers to their utilisation. Methods: A cross-sectional study was conducted to ascertain the utilisation of diagnostic techniques. The data was collected through a self-administered online questionnaire. The questionnaire contained questions on demographics, practice trends, utilisation of diagnostic techniques, as well as the registration status of the optometrists. Results: A total of 141 responses were received, and 118 were included for data analysis. There were 46 (39.0%) male participants and 72 (61.0%) were female. Ninety-eight (83.1%) of the participants had a diagnostic qualification, of which 49 (50.0%) were correctly registered with the HPCSA for diagnostic practice. Only 13.4% participants indicated that they performed contact tonometry at every visit, while slit-lamp fundus examinations was performed at every visit by 18.6% of the participants. BIO was only performed on indication by 20.8% of participants and gonioscopy was similarly only performed on indication by 34.7% of participants. Diagnostic techniques and procedures were mostly underutilised as many did not perform applanation tonometry (67.0%), binocular indirect ophthalmoscopy (79.2%), slit-lamp fundus examination (41.2%) and gonioscopy (64.3%). While optometrists were more confident in performing applanation tonometry (52.0%) and slit-lamp fundus examination (64.3%), confidence was considered a barrier for binocular indirect ophthalmoscopy (62.3%) and gonioscopy (54.1%). The lack of reimbursement was regarded as a significant barrier for 63.3% of participants, and 82.5% of respondents indicated the cost of acquiring the specific equipment was prohibitive. Most participants (92.8%) agreed that diagnostic privileges were appropriate for optometrists as well as the therapeutic scope of practice expansion (96.9%). Of those participants who were not correctly registered for diagnostic practice with the HPCSA, the majority (69.4%) were aware of the process to amend their registration status. The administrative process being too cumbersome and time-consuming was the most commonly stated barrier to amending the registration status of participants who were incorrectly registered. Conclusion: The study indicates that diagnostic techniques are mostly underutilised and optometrists prefer non-invasive alternative techniques over methods that are considered to be the gold standard. Another finding of the study is that there exists a discrepancy between the number of optometrists who are registered for diagnostic practice and the number of optometrists who have acquired a diagnostic qualification. It is recommended that an audit be done on the registration status of optometrists as to ascertain the correctness of the register and to have it amended if needed. It is further recommended that further studies should be done to ascertain the compliance of optometrists concerning their registrations and scope of practice. The reimbursement models need to be revisited, as well as the training of optometrists to ensure appropriate levels of confidence in diagnostic techniques amongst practitioners. These models should be geared towards professional services, emphasising the diagnosis and management of ocular diseases to motivate optometrists to practice more extensively within their full scope of practice.
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    A vision checklist as a vision screening tool by Grade R to Grade 3 teachers in Quintile 1 schools
    (University of the Free State, 2020-08) Ramantsi, Boitumelo Monica Loraincia; Rasengane, T.A.; Jita, T.
    Background: Vision screening in schools has been shown to identify children with visual disorders who are thereafter referred for a comprehensive eye examination with an optometrist and or ophthalmologist. In South Africa, the government has introduced an integrated school health policy that includes vision screening which is conducted by few school health nurses, who cannot screen all school children. Teachers spend most of the time with children in their classrooms and thus, educating them on common vision disorders and training them to screen the learners in their classrooms can help identify children with vision disorders. Aim: This research aimed to investigate the use of a vision checklist as a screening tool by Grade R to Grade 3 teachers to detect visual disorders among learners in Bloemfontein. Methods: The study population comprised of 41 teachers and 1360 learners from the 11 Quintile 1 schools. Convenience sampling was done to enrol 36 teachers from 11 Quintile 1 schools and 1360 Grade R to Grade 3 learners aged between five and thirteen years around the Bloemfontein area in the study. The study was done in three phases. In the first phase of the research study, the researcher administered the first questionnaire with nine items to evaluate baseline teachers' knowledge and thereafter an educational session was done covering the most common visual disorders in children. A second questionnaire with nine items was administered after the educational session to assess the acquired knowledge of visual disorders and their management. The teachers were classified as having good knowledge if they obtain seven or more correct answers. The teachers were also trained on how to use the vision checklist in their classrooms as a vision screening tool. In the second phase of the study, the teachers screened the learners in their classrooms using the vision checklist. The learner would fail the screening if the teacher recorded any "no" response. In the last phase of the study, the research team screened learners from the two randomly selected schools (School A and School B) using the basic optometric vision screening tests to validate the screening results of the teachers. The two schools had 8 teachers and 261 learners from Grade R to Grade 3. The learner would fail the screening if any of the tests conducted were recorded as “fail”. The descriptive statistics and diagnostic tests were calculated per group. A p -value of less than 0.05 was considered to indicate statistical significance. Results: Phase 1: All 36 teachers who participated in this study were female whose ages ranged between 27 and 36 years. Most of the participants (n=16, 44.44 %) had been teaching for more than 10 years. The highest qualification attained by the participants was Bachelor of Education Honours (n=2, 5.56%), and most participants (n=10, 27.78 %) had an Advanced Certificate in Education. Thirty-four participants (94.44%) obtained a score of seven and higher in the first educational questionnaire. The second questionnaire results showed that all participants obtained a score of seven and higher. Twenty-one participants (58.33%) showed improvement in knowledge, while two participants (5.56%) regressed. Overall, there was a statistically significant difference ( p <0.0001) between the scores of participants before and after the educational. Phase 2 : A total number of 1360 Grade R to Grade 3 learners whose ages ranged from five to thirteen years old were screened by the 36 teachers using the vision checklist, five hundred and forty learners (39.7%) failed the screening. Phase 3 : The total number of children tested by both the teachers and the research team was 221; this was (84.67%) of the total amount of 261 learners in those schools. The research team found that 102 learners failed the vision screening, as a result the prevalence of the vision disorders in learners was 46% (95% CI: 39% – 53%). The teachers only identified 20 learners out of 102 to have vision disorders therefore, missed 82 learners with vision disorders. The sensitivity of the screening with a vision checklist was 19.61% (95% CI: 12% – 29%) and specificity of 83.19% (95% CI: 75% – 89%). Conclusion: The current study showed that teachers had adequate knowledge of common vision disorders in children which was improved through the educational session. However, the teachers missed 80% of the learners who had vision disorders when using the vision checklist as a screening tool. Thus, the results showed that the vision checklist used in this study was not a sensitive screening tool as it could only identify 19.61% of learners with vision disorders. It can be speculated that teachers’ current workload, large numbers of learners in classes and lack of motivation could have resulted in the high false-negative rate found in the study.