Masters Degrees (Optometry)

Permanent URI for this collectionhttps://hdl.handle.net/10413/6741

Browse

Now showing 1 - 20 of 26

Assessment of visual function amongst motor vehicle drivers in Maseru, Lesotho.
(2021) Moledi, Zubeta.; Van Staden, Diane Beverly.
Background: Driving is a primary mode of travel in many countries. It relies primarily on the function of vision to navigate roads and traffic safely. Ensuring good vision for motor vehicle drivers is therefore important to promote safety for all road users. Lesotho is a developing country, with road transportation central to the movement of people and goods within, and across the borders of the country. The absence of clear minimal requirements for visual function among holders of motor vehicle licences in Lesotho motivated this study. Aim: To assess the visual function of motor vehicle drivers in Maseru, Lesotho. Methods: A descriptive, mixed methods cross-sectional study employing systematic random sampling was conducted at the Traffic Department in Maseru, Lesotho. Active licensed drivers, both males and females, from 22–76 years of age participated in the study. Data was collected by means of key informant interviews, structured questionnaires and a comprehensive vision examination of all participants. Quantitative data was analysed using Strata version 14 software, while qualitative data was analysed descriptively. Results: The study included 460 licensed drivers with an overall mean age of 42.9 years, of which 64% (n=294) were men. One in five participants had not had an eye examination before obtaining their driving licence. Most participants (70.87%) had normal vision (6/9 or better) in the better-seeing eye, while 29.13% had visual acuity worse than 6/9 in the better-seeing eye. Among those with sub-normal vision, 29% had visual acuity ranging between 6/18 and 6/48 in the better-seeing eye. More than one third (39%) of participants had some form of refractive error, with myopia showing the highest distribution (46.46%), followed by astigmatism (32.96%) and hyperopia (24.59%). Of those with hyperopia, the majority (98%) were classified as having mild hyperopia (+0.50DS up to +2.00DS). Although myopia had the highest distribution, most cases were mild to moderate myopia (-0.50DS up to -5.75DS). The majority of participants (97.61%) passed the colour vision test, 53.70% achieved contrast sensitivity of up to 6/12 in the better eye and 99.6% achieved a measurement of 100 degrees for visual field test screening. Most participants did not wear spectacles when driving, with 37% of these having previously been advised to wear them based on identified need. Almost half (44%) of the participants reported to have been involved in road traffic accidents. Discussion: While most participants in this study presented with good vision for driving, it is concerning, that almost one in three (29%) had mild to moderate visual impairment and 39% had refractive error, yet they continued to drive without any form of refractive correction. Also, almost half of the participants (44%) had been involved in road traffic accidents, with almost one in five (19%) who had refractive error. It is possible that refractive error and visual impairment could have contributed to their involvement in road traffic accidents. The visual function findings in this study suggest that the Traffic Department in Lesotho should have guidelines on the minimum visual requirements for driving, as well as routine screening procedures. Conclusion: A significant proportion of the motor vehicle drivers in Lesotho have some form of compromised visual function, with many not undergoing an eye examination before obtaining a driver’s licence. If drivers are advised to have their eyes examined regularly, many visual function anomalies could be detected early and their vision corrected accordingly. The absence of effective screening methods for drivers in Lesotho could possibly be a contributor to the incidence of road traffic accidents in the country with the resultant negative socio-economic impacts.
The availability and accessibility of low vision services in Ashanti and Brong Ahafo Regions of Ghana.
(2018) Kyeremeh, Sylvester.; Mashige, Khathutshelo Percy.
Background: The prevalence of low vision on the African continent is generally high and varies across and within countries, as well as in people of different socioeconomic status. While regional studies on the prevalence of blindness and low vision in Ghana have been conducted, there is a lack of information on the availability and accessibility of low vision services in these regions. The aim of the study was to assess the availability and accessibility of low vision services in the Ashanti and Brong Ahafo regions of Ghana. Methods: This was a descriptive, quantitative, cross-sectional study design. Hand-delivered semi-structured questionnaires were used to collect information from eye care professionals selected from 58 eye care facilities within the Ashanti and Brong Ahafo regions of Ghana. In addition, face-to-face interviews were conducted with 29 low vision patients from the same regions. Results: Forty-four eye care facilities from the Ashanti region and 10 from the Brong Ahafo region responded to the questionnaire, giving an overall response rate of 93%. A total of 29 patients including 16 males and 13 females with a mean age of 33.79±17.42 years were interviewed from four different eye care facilities. Out of 50 eye care facilities who reported that they had low vision patients attending their clinics, 33 (66%) did not provide low vision services and 17 (34%) offered some form of this service. Eleven out of 15 (73.3%) patients reported that it was either difficult or very difficult to acquire optical low vision devices while 10 (83.3%) out of 12 patients reported the same about non-optical low vision devices. Of the 15 patients who responded to the questions on where they obtained their optical devices, 7 (47%) reported that they were donated to them, 2 (13%) obtained them from the market while 6 (40%) reported getting their devices from the hospitals or eye care facilities. For non-optical devices, the patients reported obtaining them from the market 5 (31%) and through donations 5 (31%). Others obtained them from the society for the blind 2 (15%), hospitals or eye clinics 2 (15%) and a resource centre 1 (8%). Barriers to the provision and uptake of low vision services included the lack of testing equipment, lack of assistive devices and high cost of services. Conclusions: Availability and accessibility of low vision services are limited in the Ashanti and Brong Ahafo regions. These findings should help to inform interventions to make low vision services available and accessible as well as to overcome the barriers to providing and utilising these services to minimise the impact of visual impairment.
Contribution of refractive errors to vision impairment in the Ashanti Region, Ghana.
(2014) Afari, Clement.; Naidoo, Kovin Shunmugam.; Amedo, Angela O.
Purpose: To determine the prevalence and causes of vision impairment with particular emphasis on uncorrected refractive error (URE) in Ashanti region, Ghana. A baseline vision impairment study in the Ashanti region is necessary to effectively plan for refractive services and blindness prevention strategies. Methods: A cross-sectional multistage cluster sampling was conducted in 24 communities in Ashanti region, Ghana. A total of 1420 participants aged 18 years and above were enumerated using a modified Rapid Assessment of Vision impairment (RAVI) protocol. This was limited to unaided visual acuity (VA) using a Snellen chart at a distance of 6 meters, near binocular visual acuity and direct ophthalmoscopy for all participants after obtaining an informed consent. The VA was repeated using a pinhole for participants with VA ≤ 6/12. A non-cycloplegic refraction was done for those whose pinhole VA improved. Near vision refraction was also assessed for each participant whose near vision was less than N8. Simple proportions were used to compute the prevalence of vision impairment and refractive error in the studied population. The results were analyzed using STATA 11. Results: One thousand three hundred (1300) of those enumerated (1420), participated in the study, a response rate of 91.5%. The mean age of the participants was 46.29 (CI 95% 45.29-47.29). The minimum age was 18 years and the maximum 99 years. Prevalence of vision impairment was 16.15% (n= 210, 95% CI, 14.15 – 18.16). Refractive error was the leading cause of vision impairment with 47.14% (n = 99, 95% CI of 40.33 - 53.9) Conclusion: Refractive error was the main cause of visual loss in Ashanti region, Ghana.
Cosmetic contact lens awareness, procurement and usage amongst students at a university in Cape Town South Africa : a descriptive study.
Hendricks, Angelique Laetitia.; Moodley, Vanessa Raquel.
No abstract available.
Design, reliability and validity of a paediatric rate of reading (PRR) chart.
(2012) Nirghin, Urvashni.; Oduntan, Olalekan Alabi.
Background: Reading rate is a measure of fluency, reflecting the level of reading performance especially in children, which is not typically measured during routine eye examinations. Optometric clinical tests such as Snellen visual acuity are often poor predictors of everyday reading performance, as they test the smallest print a person is able to read rather than fluency. Conventional reading rate tests for educational purposes presents with many limitations; they concentrate on linguistic skills, increase in complexity as the reading progresses, limited by the readers vocabulary but more importantly, they do not take the level of the child's vision into consideration. There is currently no reading rate chart that is designed with optometric notations specifically for children with normal vision and low vision. It is therefore necessary to design a reading rate chart that takes the above limitations into consideration. Aim: This study aimed to design a chart that can be used to measure reading rates in normal sighted and low vision primary school children. Methods: The aim of the study was achieved in four parts; the design, reliability, validity of a reading rate chart and finally the testing of the chart on low vision participants. In the design of the chart, ten frequently used words in grade one English reading books were randomly selected from five primary schools in KwaZulu-Natal province, South Africa. The reliability and validity of the chart were established on normal sighted children, aged nine to twelve years from two primary schools in the Durban area chosen by convenience sampling method, with sample size of 100 for reliability and 100 for validity. Reliability was established with test and retest reading rates using the new chart while validity was established by determining the reading rates using new the chart and the Wilkins reading rate chart. Data were analyzed using the Paired t-test, Pearson correlation, and Bland and Altman method. Finally, the testing of the new chart without and with low vision device, on fourteen low vision children, aged eight to nineteen years, attending a school for the visually impaired in KwaZulu-Natal. Data was analyzed using Paired t-test and Pearson correlation. Results: The words were arranged in random order, ten words per row and ten rows per paragraph. The chart consisted of six paragraphs (versions A, B, C, D, E and F) with six acuity levels and four optometric notations. Each version was printed on a separate sheet, in Arial and Times New Romans fonts and printed in black ink on approximately white cardboards. In reliability, the mean test and retest reading rates were 77.65 ± 25.30 and 78.23 ± 24.70 (p = 0.29, R² = 0.95). In Bland and Altman method, the mean difference was −0.58 with confidence limits at +10.07 and -11.23. In validity, reading rate for Wilkins chart and the new chart were 75.82 ± 23.64 and 74.92 ± 23.58 (p = 0.01, R² = 0.99) respectively. In Bland-Altman method, the mean difference was +0.90, upper limit at +6.33 and lower limit at –4.53. The mean reading rate, of the low vision children, without and with the low vision device were 59.32 ± 24.08 words per minute (wpm) and 67.04 ± 25.63 words per minute (wpm) respectively (p = 0.09 and r = 0.82). Conclusions: This chart can be used for reading rate assessment for both normally sighted and low vision children and is statistically reliable and valid.
The epidemiology of ocular injuries among patients presenting to provincial hospitals in KwaZulu-Natal, South Africa.
Sukati, Velibanti Nhlanhla.; Hansraj, Rekha.
Purpose: Ocular injuries are increasingly becoming the permanent cause of visual blindness (Mufti et al, 2004). Most of the previous studies in this area are done in countries outside the African context. A limited number of general surveys in ocular trauma appear in the ophthalmic literature in South Africa. The purpose of this study was to provide epidemiological data on ocular injuries among patients utilising the provincial hospitals eye services in KwaZulu-Natal, South Africa. Methods: A quantitative retrospective study design was carried out by collecting data on 660 patient’s record cards with ocular injuries presenting to four selected provincial eye care clinics for a four year period (January 2005-December 2008). Using a data sheet devised for capturing of the information, the following data was retrieved: (i) demographics details, (ii) place of trauma (iii) nature of trauma, (iv) type of injury, (v) management and (vi) visual outcomes following primary eye care. All patients who presented to the eye clinics with ocular injuries within the specified four years, both genders, all race groups and all age groups were included in the study. Results: There were 440 patients’ records reviewed at rural hospitals and 220 at urban hospitals. Males were more likely than females to have ever experienced an eye injury (72.3% versus 27.7%, respectively) and urban males were more likely than rural males to incur an eye injury (79.1% versus 68.9%, respectively). The Black population has a higher prevalence of ocular injuries than other race groups: Blacks 93.8% followed by Indians 3.9%, Coloureds 2% and the least in Whites 0.3%. Over one-third of all the patients were between 21 and 30 years old with second highest percentage of patients being in the age category of 31 to 40 years. A significant percentage of patients were children (13.8%) up to the age of 12 years. Open globe injuries were more frequent (56.2%) than closed globe injuries (43.8%). Blunt trauma/contusion was the most frequent type of injury (35.2%). More than half of patients (50.9%) had associated ocular signs with the predominance of haemorrhages (15.9%). The majority of the patients presenting with ocular signs had incurred blunt trauma (54%). Only 3.5% of all injuries were bilateral and 96.5% were unilateral. Solid objects were responsible for more than half of the injuries (54.4%) occurring either in the home or at work, followed by assaults (24.3%) and chemical burns (6.2%). Three percent of patients’ records (n=17) had substance (alcohol) abuse documented. The home accounted for the majority of the eye injuries (60.6%) followed by the social environment (15.2%), workplace or industry (13.6%), commercial workplace and agriculture had the same number of injuries (4.1%) and sports or leisure facilities (2.4%). The home remained the single most frequent place for an injury to occur across all age groups, highest in the 21 to 30 age group (26.8%, n=107) followed by 21.3% (n=85) in the 0 to 12 age group. Thirty patients (4.5%) required surgical intervention at initial presentation. Three hundred and forty patients (51.5%) returned for follow up examination. Only 9 (9.2%) patients with initial poor vision (<6/60) achieved 6/12 or better visual acuity after treatment. In 17 (38.6%) patients, visual acuity remained the same as initial visual acuity (6/15-6/60) and got worse in 5 (7.8%) patients (<6/60). Twenty six (59.1%) patients achieved between 6/15-6/60 vision after presenting with poor vision and 59 (92.2%) remained with poor vision after treatment. Conclusion: Ocular trauma is a relatively common problem in the province of KwaZulu-Natal, occurring most frequently in young adults and males warranting presentation to the eye casualty department for treatment. Ocular trauma is usually unilateral, but can also be bilateral and this remains a significant major public health problem. People engaged in agriculture, in industry, in the home, in the social environment, in sports and people living in rural communities are at highest risk. This warrants specific, targeted, prevention measures to be put in place to minimize the incidence of visually damaging trauma.
An evaluation of a school based vision screening programme.
(1992) Shaik, Rieaz.; Bhagwanjee, Anil Mohanlal.; Turnbull, Duncan Kenneth.
The effectiveness of a vision screening programme in government schools in the Durban Functional Region under the jurisdiction of the House of Representatives was evaluated. For the purpose of the study a Comprehensive Vision Screening Programme (CVSP) was developed based on the Modified Clinical Technique (MCT) used in the Orinda Study. Of the represetative sample of 419 children assessed, the CVSP classified 85 (20.3%) as referrals. In comparison, the school health nurses referred 35 (9.6%) of the children for a complete ocular examination, 40 per cent of which were unwarranted. Analysis of the usable records showed that the school vision screening programme (SVSP) correctly categorised 307 (83.9%) of the children and incorrectly categorised 59 (16.1%) of them. The latter consisted of 3.8% over-referrals and 12.3% under-referrals. The school vision screening programme did not detect with a reasonable degree of accuracy those children with visual disorders. The effectiveness of the SVSP, as determined by the phi coefficient, was 0.35. Approximately two thirds of the children with visual disorders were not detected by the SVSP. One in every eight children classified as having no visual problem by the SVSP was an under-referral and two in every five children referred by the SVSP were over-referred. The high incorrect referral rates was attributed to the use of inappropriate screening techniques. The prevalence of visual disorders in the children was 20.3%; in boys 18.7% and 21.9% in girls. The relative risk of visual disorders in girls compared to boys was 1.2 (95% CI = 0.8 - 1.7). The prevalence of eye co-ordination disorders was 11.2%, refractive error problems 10.3%, visual acuity 4.5%, perceptual status (colour vision and stereopsis) 4.0% and organic disorders 1.2%. The binocular disorders were characterised as convergence insufficiencies and the disorders of accommodation were described as accommodative insufficiencies. Referable myopia (6.7%) was more prevalent than referable hyperopia (2.1%). Myopia was more prevalent in girls and hyperopia was more prevalent in boys. The clinical findings of the refractive error was compared to that measured by an autorefractor. The findings were remarkably similar and the study concluded that the difference between the two measures was not clinically significant. The study recommended that the MCT be used as the method of choice in school vision screening protocols.
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.
An evaluation of the public sector optometric service provided within the eThekwini and the surrounding health districts in KwaZulu-Natal, South Africa.
Maake, Moraka Ephraim.; Moodley, Vanessa Raquel.
No abstract available.
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.
The incidence and distribution of ametropia in blacks in Umlazi.
(1988) Rasengane, Tuwani A.; Simpson, T. L.; Turnbull, Duncan Kenneth.
Age, sex, race, heredity, environment and nutrition have been found to influence ametropia. In this study, the distribution of refractive errors has been investigated in relation to age, sex, race, education and near work, and lighting conditions. Visual awareness and vision screening in pre-school and schoolchildren were also investigated. Data were collected using the Nikon auto-refractor, retinoscope, Snellen V.A chart, and subjective techniques. 777 people were refracted, whose ages ranged between four and eighty years. Measurements were made in different sections of Umlazi township, therefore people of different socio-economic sectors were refracted. Four year-old children were found to be hyperopic. Hyperopia decreased and refraction shifted towards emmetropia. Myopia started to appear at the age of ten. Myopia increased until the age of twenty, and thereafter decreased slowly until the age of thirty three, where the average refraction was emmetropia. From age forty onwards, hyperopia was predominant. The incidence of high astigmatism, high hyperopia and high myopia is low in this community. Most people fall in the spherical refractive error region of between -1.000 and +1.000. The curve is leptokurtotic with highest peak around +0.250. The cylindrical error is between -0.500 and -1.000. No significant difference between sexes was found except at the fourth age group (40-51), where females are more hyperopic than males. The other sex difference is at ages ten to twelve, where females develop myopia earlier than males. Illumination plays no important role in the development of refractive errors in this community. Education and near work seem to account very little to the development of myopia. The influence of heredity on the development of ametropia was not investigated in depth. However, there is no evidence of heredity influencing the development of ametropia. There is a lack of vision screening and visual awareness.
An investigation of saccadic eye movement abnormalities in children with HIV/AIDS on highly active antiretroviral therapy.
(2013) Naicker, Nashua.; Moodley, Vanessa Raquel.
Introduction: The Human Immuno-deficiency Virus (HIV) and the consequent Acquired Immuno-Deficiency Syndrome (AIDS) have cost the lives of millions of people globally over the past 30 years since the first cases of illness appeared. Due to the overlap in areas in the brain that are damaged by the HIV with those that control saccadic eye movements, screening of eye movement functions in children with HIV/AIDS could thus be a valuable early indicator of a declining neurological and immunological state. Therefore, movement testing through non-invasive means may give the optometrist valuable insight into the developing central nervous system (CNS) in HIV-infected children. Aim: To determine if abnormal saccadic eye movements in children with HIV/AIDS on HAART could be a predictor of the status of their immune system. Methodology: The study population comprised of 128 conveniently selected subjects aged 5 to 14years diagnosed with HIV/AIDS on HAART. This prospective study, used a descriptive design. The two significant biological parameters such as CD4 count and viral load (VL) data of patients were accessed and subjects performed the DEM test, which is a visual-verbal reading speed test, used to detect oculomotor function as well as automaticity skills. The subjects were then classified according to the different „behaviour types‟ as is specified in the DEM test based on their test performances. Statistical Analysis Software (SAS) version 9.2 was used to analyse the data. Results: Nine year olds were the most prevalent comprising of 23% of the sample. Subjects were categorised into three categories of their VL and CD4 count parameters from minimal to severe immunosuppression. Seventy eight percent (78%) of subjects had minimal immunosuppression with CD4 counts ≥500cells/mm3 with a median value of 778.5 cells/mm3. Sixty five percent (65%) of the subjects had undetectable VL (<40 copies/mm3) with the median value of <40 copies/mm3 in the sample. With the DEM test, 93% had vertical and 92% had horizontal times that were outside of the standardised DEM norm. The classification of subjects into behaviour types revealed that 53% were type 3 – automaticity problems, 22% type 4 – oculomotor problems and automaticity problems, 8% type 1 – normal performance and 3% were type 2 – oculomotor dysfunction. Fourteen percent were in the unspecified behaviour type category. The relationship between the VL with behaviour types (p=0.2) and the CD4 count against the behaviour types (p=0.17) were neither statistically nor clinically significant, hence no relationship could be established. Discussion: Since the cognitive functioning in children with HIV/AIDS was moderately affected, the DEM test could be a valuable tool, if not to only detect eye movement problems but to assess the automaticity skills, which shows the impact on their neurodevelopment. It therefore does prove to be worthwhile for optometrists and other health professionals to use the DEM test as part of a battery of neurodevelopmental tests to assess different neurocognitive functions, specifically in children with HIV/AIDS. Recommendation: DEM norms for a South African paediatric population should be established as the characteristics of this population differ from the population of English-speaking American children on which this test was standardised. Conclusion: Immunologic and virologic statuses in children with HIV/AIDS on HAART cannot be predicted from abnormal saccadic eye movements. Performances across all age groups were significantly below the standard DEM norms. Saccadic eye movement abnormalities were the least prevalent and automaticity deficiencies were the most prevalent across the sample with no associations to the CD4 count and viral load.
Lifestyle and gender influence on the relationship between hypertension and intraocular pressure amongst the South Nigerian population.
(2017) Igumbor, Brenda Avwerosuo.; Nirghin, Urvashni.
Hypertension and increased intraocular pressure (IOP) have been considered to be detrimental to systemic and ocular health respectively. Untreated and prolonged increase in blood pressure (BP) has been linked to increase in IOP for some populations. Lifestyle factors such as cigarette smoking, alcohol intake, obesity, salt, fat, fruit and vegetable intake could have great influence on the relationship between hypertension and IOP. However, this has not been investigated. Aim: The aim of this study is to investigate the influence of gender and lifestyle factors on the relationship between hypertension and IOP amongst the South Nigerian population. Method: A total of 570 subjects between 20-70 years old were included in the study. Subjects were randomly selected from six approved eye hospitals within the South Nigerian region. The population was divided into two groups comprising of 285 normotensive and 285 hypertensive subjects. All subjects were presented with the information document. Only those with signed consent forms participated in the study. With each subjects, blood pressure, intraocular pressure, weight and height measurements were taken using the mercury sphygmomanometer, schiotz tonometer, measuring scale and measuring tape respectively. Thereafter, a lifestyle questionnaire about cigarette smoking, alcohol intake, obesity, salt, fat and fruit and vegetable intake were administered. Data was analyzed using the Statistical Packages for Social Sciences (Version 22), using Pearson correlation coefficient and Analysis of variance (ANOVA) Results: The percentage of male and female normotensive subjects were 33% (N=94) and 67% (N=191) respectively and served as control for the study. For the hypertensive subjects, 36.1% (N=103) were male and 63.9% (N=182) were female. The mean age was 42.31 ± 9.98 years old and 46.45 ± 10.23 years old for the normotensive and hypertensive subjects respectively. The mean IOP of the hypertensive male subjects was 21.22± 3.22 mmHg (RE) and 20.12 ± 2.62 mmHg (LE) and for the female subjects was 19.83 ± 3.75 mmHg (RE) and 18.98 ± 2.91 mmHg (LE). There was no correlation of lifestyle factors and gender on the relationship between HBP and IOP from the study. A correlation was however observed among the hypertensive subjects showing moderate correlation for SBP and DBP for IOP RE (0.375 and 0.297), respectively. A weak correlation was observed for SBP and DBP for IOP LE (0.241 and 0.204) respectively. The relationship between hypertension and IOP was statistically significant with p≤ 0.05. Conclusion: There was significant influence of gender on both hypertension and IOP for the RE and LE. Alcohol intake amongst all other lifestyle had influence on SBP, DBP and IOP RE and LE for hypertensive subjects.
The oxygen performance of a contact lens on the human eye.
(1989) Postum, Krishnachand.; Turnbull, Duncan Kenneth.; Govinden, H. S.
There is considerable evidence to indicate that most gas permeable contact lenses do not transmit sufficient oxygen to supply all the corneal oxygen requirement. This problem is further exacerbated by non-valid methods of characterizing the oxygen performance of such lenses. The current methods of using oxygen permeability (Dk) and oxygen transmissibility (Dk/L) as indices of oxygen performance of contact lenses is completely erroneous. Dk and Dk/L pertain to contact lens materials in flat sheet form having uniform thickness and equal diffusion path at all points on the surface. Finished contact lenses, of necessity, are curved surfaces and of varying thickness. Consequently the concept of Dk and Dk/L cannot be applied to contact lenses. To date there are no studies to determine the absolute oxygen tension under gas permeable contact lenses on the human eye. All attempts to quantify the oxygen tension under a lens have been by indirect methods or by predicting the p02 from Dk values, using mathematical equations. These results do not match the clinical findings. This study was done to show that oxygen flux through a contact lens, measured in vitro, is a better determinant of the in vivo oxygen performance of gas permeable contact lenses. A special cell was designed to measure the oxygen flux, in vitro under standardised conditions. Contact lens microelectrodes were designed to measure the oxygen tension in vivo. The data obtainedwas used to develop a model for the oxygen performance of rigid gas permeable lenses on the human eye.
Patient's knowledge of diabetes, its ocular complications and management in a private practice population in the Western Cape, South Africa.
(2011) Phillips, Kevin Clyde.; Mashige, Khathutshelo Percy.; Clarke-Farr, P.
The aim of this study was to determine management regimens and level of knowledge of diabetes and its‟ ocular complications among private patients in a sample of the population of the Western Cape region of South Africa. A population-based cross-sectional study design, using purposive accidental random sampling, was used. Questionnaires completed by diabetic patients who fund their condition privately outside of the South African Public Health sector were used. One hundred and twenty-two subjects participated in the research, 66 (54%) males and 56 (46%) females. There were 73 rural and 49 urban participants. The overall sample mean BMI was 30.7, average fasting plasma glucose (FPG) 8.1 mmol/l and the majority of respondents did not perform a daily FPG test or know the significance of the HbA1c test. The majority of participants were unaware of the serious ocular consequences of prolonged hyperglycaemia. Sixty-seven percent of respondents considered that they knew enough about diabetes to manage their own condition. From the data it is apparent that private patients‟ knowledge of the systemic and ocular complications of diabetes is sub-optimal. Whilst the majority considered annual eye examinations as important, less than one-third of respondents actually undertook them. Optometrists should be offered programmes to enhance their skills and co-manage and educate diabetic patients with other health care practitioners on a formal basis. Health insurance institutions should take cognisance of the value of patient education and preventative diabetic management and incentivize patients and health care providers in this regard.
Patterns of contact lens prescribing in KwaZulu-Natal.
(2015) Moodley, Veni.; Khan, Naimah Ebrahim.
Master of Medical Science in Optometry. University of KwaZulu-Natal, Durban 2015.
Prevalence and distribution of visual impairment, refractive error and their impact on quality of life among school-going children aged 6-18 years in Sekhukhune District (Limpopo), South Africa.
(2020) Magakwe, Tshubelela Sello Simon.; Xulu-Kasaba, Zamadonda Nokuthula Queen.; Hansraj, Rekha.
Background: Refractive error (RE) and visual impairment (VI) remain major problems affecting school going children worldwide and impacting their quality of life. Aim: To determine the prevalence and distribution of RE and VI, and their impact on quality of life (QoL) of school-going children. Setting: This school-based study was conducted on school-going children residing within the borders of greater Sekhukhune district, Limpopo (South Africa). Methods: A multistage random sampling method was used to select schoolchildren aged between 6 and 18 years from Grades R to 12. A total of 400 learners where invited to participate in this study and 326 (81.5% [95% CI, 77.7-85.3]) learners underwent an eye examination. The examination assessed unaided and aided visual acuity using a LogMAR chart, binocular motor function, autorefraction under cycloplegia, media and fundus examination, and QoL measured with the National Eye Institute visual function questionnaire (NEI-VFQ-25). Results: The prevalence of uncorrected, presenting and best corrected visual acuity of 0.30 or worse in the better eye was 12.3% (95% CI, 8.7-15.8), 12.3% (95% CI, 8.7-15.8) and 2.1% (95% CI, 0.6-3.7) respectively. Refractive error accounted for 81% of all causes of VI. Myopia was the most prevalent RE (50.7% [ 95% CI, 38.8-62.7] ), followed by astigmatism (36% [95% CI, 24.3-47.3]), and hypermetropia (13.6% [95% CI, 5.30-21.6] ). There was no significant difference in the prevalence of RE and VI between males (50.7% [95% CI, 38.8-62.7]) and females (49.3% [95% CI, 37.3-61.2]). Refractive error and VI were highest among children aged between 14 and 18 years. Moreover, the highest prevalence of RE was observed in Grades 9 to 12 learners (46.3% [95% CI, 34.3-58.2]). Children with RE and or VI scored low on NEI-VFQ-25. Conclusion: The prevalence of RE and VI among schoolchildren in greater Sekhukhune district was high. This calls for attention from policymakers and all stakeholders responsible for eye care to devise strategies to address these conditions as they decrease the children’s QoL.
Prevalence and risk factors for Myopia among school children in Aba, Nigeria.
(2015) Atowa, Uchenna Chigozirim.; Munsamy, Alvin Jeffrey.; Wajuihian, Samuel Otabor.
Abstract available in PDF file.
Prevalence of Dry Eye syndrome in a South African diabetic paediatric population: a single-centre based case study.
(2023) Bisetty, Seyuri.; Ebrahim Khan, Naimah.
Background: Diabetes Mellitus is a chronic condition resulting from elevated blood glucose levels. Timeous intervention is vital as poor management may give rise to serious secondary complications, thereby impacting health status and quality of life of patients. The current incidence of diabetes in South Africa is 8.27%, with an occurrence rate of 0.8/100 000 for the younger population, aged 0 to 14 years. Numerous studies have highlighted the fact that diabetes mellitus affects the ocular surface in terms of tear stability and function. Dry eye syndrome is described as a lack of tears on or around the eye or a decrease in the quality of tears produced. An optimal production of tears ensures that the ocular surface is kept moist and healthy. Literature on the prevalence of dry eye in paediatric patients diagnosed with diabetes is sparse. Aim: To determine the prevalence of dry eye in a group of diabetic children and adolescents/young adults in eThekwini, South Africa. Methods: A mixed method, single-centre-based case study approach was employed. A quantitative approach was used to determine the prevalence of dry eye in children with diabetes, using the following tear function tests; Tear Break-Up Time (TBUT), Phenol Red Thread (PRT) and Tear Film Osmolarity (TFO). A qualitative approach was adopted to understand the dry eye- related signs, symptoms, and visual functions of children with diabetes mellitus, using two dry eye questionnaires, Ocular Surface Disease Index (OSDI) and McMonnies questionnaire. Duration of diabetes was used as a parameter in this study. Statistical data analysis was conducted using R Statistical computing software of the R Core Team, 2020, version 3.6.3 (R Studio, Boston, MA, USA). All inferential statistical analysis tests were be conducted at 5% levels of significance. A p-value of p<0.05 was considered statistically significant. Results: Thirty-seven children with diabetes and forty healthy, age group-matched controls who met the respective inclusion criteria, were enrolled in this study. The results of this study revealed that dry eye syndrome was more common among diabetics, with 40.5% participants being from the diabetic population compared to 10.0% from the control group. TBUT values were significantly reduced among the diabetics (p<0.001) indicating tear film instability. PRT results showed statistical significance (p<0.001) between the two groups and were found to be lower in the study group. TFO values were higher in participants with diabetes. No statistically significant differences were reported between the study and control groups, for both questionnaires. However, detailed question-analysis showed that participants of the control group were more symptomatic to dry eye. No relationship between the duration of diabetes and diagnosis of dry eye was established. Conclusion: Due to the constant increase in the number of children and adolescents diagnosed with diabetes mellitus, knowledge on the characteristics and prevalence of dry eye syndrome in this population has become a necessity. This study contributes to the literature by providing novel dry eye results as well as the prevalence in a select South African population. The findings accentuate a need to create awareness among healthcare practitioners working with children diagnosed with diabetes, to ensure timeous referral of ophthalmic assessment which ideally should include a complete dry eye assessment.
Prevalence of vision conditions in a South African population of African Dyslexic children.
(2010) Wajuihian, Samuel Otabor.; Naidoo, Kovin Shunmugam.
Dyslexia is a neurological disorder with genetic origin that affects a person’s word processing ability, their spelling, writing, comprehension and reading, and results in poor academic performance. As a result, optometrists are consulted for assistance with the diagnosis and treatment of a possible vision condition. Optometrists are able to assist with treatment as part of a multidisciplinary management approach, where optometric support is necessary. International studies have indicated that up to 20% of Caucasian school children are affected by dyslexia, while there are no similar figures for African children. Studies have been done to assess the extent of visual defects among Caucasian dyslexics, but not among African dyslexic children. The aim of the study is therefore to determine the prevalence of vision conditions in an African South African population of dyslexic school children, and to investigate the relationship between dyslexia and vision. The possible relationship between dyslexia and vision conditions has been recognized as an important area of study, resulting in research being conducted in many countries. Studies have been undertaken by optometrists and ophthalmologists, who differ in their approach and attitude on how vision conditions affect dyslexia. A review of the literature revealed three broad areas of vision that may impact on reading ability, these being acuity defects, binocular vision and ocular pathology. Acuity defects consist of visual acuity and refractive error. Areas of binocular vision evaluated in the literature include near point convergence, heterophoria, strabismus, accommodative functions, vergence facility and reserves. Hyperopia was the only vision variable that was found to be consistently associated with difficulties with reading, but not causally while findings on other variables were inconclusive. However, all the studies acknowledged the complexity of the condition, and the need for a comprehensive multidisciplinary management approach for its diagnosis and management. The study was undertaken in the city of Durban, South Africa, using a case-control study of two groups of African school children between the ages of 10 and 15. Both study groups consisted of 31 children of normal intelligence, who were matched in gender, race and socio-economic status. The case group attended a school for children with learning disabilities, while the control group attended a mainstream school. At the time of the study, only one school catered for African children with learning disabilities, and only 31 of its pupils were diagnosed with dyslexia. Ethical approval was obtained from the University of KwaZulu-Natal; permission to undertake the study in the identified schools was obtained from the Department of Education, and the school principals consented on behalf of the learners, as it was not always possible to reach the individual parent. The researcher (an optometrist) visited both schools by appointment where rooms were made available to do the testing, and the tests were explained to all participants. The LogMar Acuity Charts were used to assess visual acuity, and static retinoscopy was used to assess refractive error. Binocular vision was tested using the cover test for ocular alignment, the Hirschberg test for strabismus, RAF rule for near point of convergence, ± 2 D flipper lenses for accommodation facilities, Donder’s push up methods, using the RAF rule for amplitude of accommodation, plus and minus lenses for relative accommodation, monocular estimation technique for accommodation posture, and prism bars for vergence reserves. Ocular pathology was assessed using a direct ophthalmoscope. The dyslexic group presented with the following: Refractive errors: hyperopia 6.5%, myopia 6.5%, astigmatism 10%, anisometropia 6.5%, remote near point of convergence 33%, esophoria at near 3%, exophoria at near 9.5%, accommodative infacility 54% and lag of accommodation 39.28%. The dyslexic group had relatively reduced fusional reserve compared to the control group. The control group presented with the following: Refractive errors: hyperopia 3%, astigmatism 13%, anisometropia 6.5%, remote near point of convergence 48%, esophoria at near 0%, exophoria at near 0%, accommodative infacility 33% and lag of accommodation 41.93%. The prevalence of a remote NPC was higher in the control group than in the dyslexic group and there was a statistically significant difference between the two groups: NPC break (p=0.049) and recovery (p=0.046). The prevalence of poor binocular accommodation facility at near was higher in the dyslexic group than in the control group and there was a statistically significant difference between the two groups (p = 0.027). Vision defects such as hyperopia, astigmatism, accommodation lag, convergence insufficiency, poor near point of convergence and accommodative infacility were present in the dyslexic pupils, but they were no more at risk of any particular vision condition than the control group. This study provided the prevalence of vision conditions in a population of African dyslexic children in South Africa, the only vision variable that was significantly more prevalent in the dyslexic population being the binocular accommodation facility at near, although the study was unable to find a relationship between dyslexia and vision. The statistically significant difference may not imply clinical significance due to the small sample size. However, it is recommended that any vision defects detected should be appropriately compensated for as defective vision can make reading more difficult for the dyslexic child. The sample size may have been a limitation; however, this was comparable with studies reviewed, most of which had sample sizes of less than 41. Due to the range of possible ocular conditions that could affect dyslexia, it is recommended that a larger sample size be used to ensure more conclusive results. Testing for relative accommodation with a phoropter would provide more accurate results, and accommodation facility and fusional reserves would be better assessed with suppression control. The study provides information and an indication of research needs regarding the prevalence of vision defects in an African South African population of dyslexic children.

Browse

Browsing Masters Degrees (Optometry) by Title