Reproducibility of corneal, macular and retinal nerve fiber layer thickness measurements using the iVue-100 optical coherence tomography

Purpose: To determine the intra-session and inter-session reproducibility of corneal, macular and retinal nerve fiber layer thickness (RNFL) measurements with the iVue-100 optical coherence tomography in normal eyes.Methods: These parameters were measured in the right eyes of 50 healthy participants with normal vision. Six scans each for corneal thickness, macular and optic nerve head were taken on one day (intra-session), followed by similar repeated measures on five separate days (inter-session). Reproducibility was computed using intra-class correlation coefficient (ICC), coefficient of variation (COV), and test-retest variability (TRV).Results: For intra-session reproducibility, the ICC, COV and TRV values for mean corneal thickness were 0.924, 2.82%, and 3.06 μm respectively. For the mean macular thickness, they were 0.978, 4.64% and 4.51 μm respectively, while for mean RNFL thickness they were 0.946, 3.19%, and 5.66 μm respectively. Inter-session values for mean corneal thickness were 0.926, 2.65% and 3.48 μm, and 0.916, 2.24% and 2.03 μm for mean macular thickness. For mean RNFL thickness, they were 0.962, 2.21%, and 4.72 μm respectively.Conclusion: There was good reproducibility of all measured parameters. However, mean RNFL thickness measurements were the most reproducible, suggesting that this may be the best parameter to use to determine measured changes over time.Keywords: Corneal thickness, macular thickness, retinal nerve fiber layer thickness, iVue-100, reproducibilit

Optometric education at Westville: past, present and future

This article presents historical information, current activities and future plans with regards to optometric education at the Department of Optometry, Westville campus of the University of Kwa-Zulu-Natal (UKZN) in Durban. The Department, established in 1979 under the political dispensation of apartheid was intended to cater to the needs of Indian students but now admits students of all races. Also, it has been developing in every aspect of optometric education, staffing and facilities. The undergraduate optometric curriculum at the Department has expanded tremendously over the years and there are now master and doctoral programmes. The number of full-time academic staff has increased from four in 1980 to eleven in 2009. The undergraduate student enrolment has increased from twelve in 1980 to one hundred and sixty in 2009. Research activities and publication output have increased over the years. Community engagement activities have been expanded to meet the needs of the community. Also, physical and training facilities have improved over the years to meet the increasing number of students. The content of this article will be of interest to alumni, current and future students and staff of the Department as well as other stakeholders in the optometric profession and education.(S Afr Optom 2010 69(1) 14-20

Contact lens prescribing patterns in Abuja, Nigeria

Purpose: To determine contact lens prescribing patterns among optometrists in Abuja, Nigeria. Methods: One hundred and twenty registered optometrists were randomly selected from practices in Abuja and were surveyed about contact lenses prescribing patterns in their practices from January to December 2016. Demographic data for each patient prescribed with contact lenses were taken. In addition, data relating to lens type, design, replacement methods and the care regime advised to each patient were recorded. The data collected were analysed using the Statistical Package for Social Sciences (SPSS). Results: The optometrists that participated were 38% males and 62% females. A total of 321 contact lens were fitted among patients aged 15 to 55 years with a mean age of 27.3 ± 6.6 years by the optometrists. Two hundred and ninety-two (91%) patients were females and 29 (9%) were males. A good number of the patients (86.6%) were between 20 to 40 years and most (91.8%) contact lenses prescribed were daily wear. Conventional sort contact lenses (96.9%) and 3 month replacement modality (70%) were the most prescribed contact lens and modality of wear respectively. Majority (78.4%) of the contact lenses prescribed were spherical contact lenses and a good number (62.5%) were refits. Most (78.2%) contact lenses fitted were for refractive purposes. Multipurpose lens care system was the most (98.2%) prescribed lens care system. Conclusion: This survey showed that contact lens prescribing pattern in Abuja follows the global trend of contact lens prescribing.Keywords: Contact lens, prescribing pattern, Abuja, Nigeri

Colour vision deficiency among students in Lagos State, Nigeria

Background: Congenital colour vision defects are x-linked inherited, non-progressive and untreatable disorders that describe poor colour discrimination.Objective: To determine the prevalence of congenital colour vision deficiency among students in Lagos, Nigeria.Methods: A school-based cross-sectional, cluster sample study was conducted to test the colour vision of 2326 primary and high school students. Inclusion criteria were Snellen VA 20/20 or better and absence of known ocular pathologies. Colour vision deficiency (CVD) was evaluated with the Richmond-HRR colour vision test plates.Results: There were 1014 (43.6%) males and 1312 (56.4%) females with a mean age of 13.40 ± 2.40 years (range = 7−22 years). The prevalence of CVD was 58 (2.5%), which was higher in males 49 (4.8%) than females 9 (0.7%). The prevalence of congenitalCVD was significantly associated with males (p = 0.00), but not with females (p = 0.22). Of the 58 cases of CVD, 17 (0.7%) had protan deficiency, 38 (1.6%) had deutan deficiency and three (0.1%) were unclassified.Conclusion: The prevalence of congenital CVD among students in Lagos is comparable to findings in other parts of Nigeria but differs from other parts of the country. These results strengthen the need to establish school vision screening.Keywords: Colour vision deficiency, Richmond-HRR, prevalence, red-green defects, Nigeria

Ocular injuries and eye care seeking patterns following injuries among cocoa farmers in Ghana

Background: The work environment of cocoa farmers exposes them to several ocular hazards that predispose them to eye diseases and injuries. However, the extent of ocular injuries and health seeking patterns following these injuries are unknown among cocoa farmers in Ghana.Objectives: To determine the prevalence of ocular injuries and health seeking behaviour following injury among cocoa farmers in Ghana.Methods: Five hundred and fifty six participants were recruited through simple random sampling using a multistage approach from four cocoa growing districts in Ghana. A structured questionnaire was used to collect relevant information such as demography, ocular hazards and injuries experienced. An ocular examination was also conducted to assess the eye health of the participants. Descriptive and regression statistics were used to analyze the data. The rate of ocular injuries was calculated by using the number of injuries reported that resulted in lost work time/days divided by the number of worker years at risk of injury (sum of years worked in cocoa farms for all the participants).Results: The rate of ocular injuries was 11.3/1000 worker years (95% CI: 9.4 - 31) which led to lost work time of 37.3/1000 worker years (95% CI: 34.1 - 40.8). The major causes of ocular injury were plants/branches (n=73, 51.1%), chemicals (n=27, 18.9%), cocoa pod/husk (n=14, 9.8%) and occurred mostly during weeding, harvesting and chemical spraying. Few (n=34, 6.1%) participants reported the use of ocular protection. Fifty-five (38.5%) participants visited the local chemical shops, while 37 (25.9%) visited hospitals/clinics for ocular treatment of their injuries.Conclusion: There is a high rate of ocular injuries among cocoa farmers who make insufficient use of appropriate eye care services. There is the need for eye health education among cocoa farmers in Ghana.Keywords: Ocular injuries, cocoa farmers, ocular protective device, eye care service

Feminism and the politics of identity in Ingrid de Kok’s Familiar Ground

Through an analysis of selected representative poems from Ingrid de Kok’s Familiar Ground, this article examines the role played by feminist poetry in the quest to address gender-related issues as well as to contribute constructively to South Africa’s liberation from patriarchal apartheid. The article further argues that feminist writers desire to (re)negotiate the space within which they can (re)construct and articulate their identities as women and mothers, and that in such a context the politics of identity cannot be detached from other aspects within the struggle for socio-political and economic emancipation. Thus characteristics of apartheid oppression are contrasted with the patriarchal domination opposed by feminist writers

Identity and culture in Mi S’dumo Hlatshwayo’s worker poetry

Through an examination of selected poems from Mi S’dumo Hlatshwayo’s oeuvre, this article examines the role of worker poetry in the construction and articulation of a “worker identity”. The article furthermore examines the worker movement’s attempt, through this poetry, to present alternative symbols through an oppositional culture and confrontational performance. Drawing from a wealth of rural and urban poetic traditions, worker poets also redefine the power dynamics characterised by the relationship between the oppressor and the oppressed, the powerful and the powerless, typified in the employer-employee relationship to articulate their identity in their own terms

Night vision and glare vision thresholds and recovery time in myopic and hyperopic eyes

The purpose of this study was to compare night vision and glare vision thresholds and recovery times in myopic and hyperopic eyes. Using a Night Sight Meter, these three parameters were measured in 44 myopic and 44 hyperopic eyes of Black male subjects age-matched 20.8 years ± 1.67 and 21.6 years ± 1.05 old respectively and compared. Thresholds were measured first by assessing the eye’s ability to see under conditions of low illumination and in the presence of a glare source. Glare recovery time was determined by measuring the minimum time neededto adjust to low levels of light illumination after exposure to a glare stimulus. Descriptive, two-sample t-test and Pearson correlation statistics were used to analyze and compare the sets of data from the two groups. The mean refractive error in the myopic eyes was –2.15 D ± 1.41 (range = –0.50 D to –4.50 D) and 1.76 D ± 1.22 (range = 0.50 D to 4.00 D) in the hyperopic group. The mean night vision thresholds for the myopic eyes was 32 cd/m2 ± 4.69 (range = 23 cd/m2 to 42 cd/m2) and 28.97 cd/m2 ± 4.90 (range = 18 cd/m2 to 37 cd/m2) for hyperopic eyes. The difference between the mean night vision thresholds of the myopic and hyperopic eyes wasstatistically significant (p < 0.05). For glare vision threshold, the mean for myopic eyes was 64 cd/m2 ± 5.81 (range = 53 cd/m2 to 78 cd/m2), while the mean for hyperopic eyes was 44.84 cd/m2 ± 5.69 (range = 32 cd/m2 to 59 cd/m2). Also, the difference between the mean glare vision thresholds of the myopic and hyperopic eyes was statistically significant (p < 0.05). The recovery times ranged from 0.45 s to 3.10 s for the myopic eyes and 0.30 s to 2.25 s for the hyperopic eyes. The mean glare recovery time for the myopic eyes (mean = 1.41 s ± 0.77) was significantly longer (p < 0.05) than the times for hyperopic eyes (mean = 1.04 s ± 0.65). There was a significant positive correlation between recovery times and the magnitude of myopia (r = 0.93, p < 0.05) while the relationship between recovery times and the magnitude of hyperopia was significantly negatively correlated (r = –0.76,  p < 0.05). These findings suggest that myopic persons would have more difficulty seeing under conditions of low illumination and in the presence of glare than hyperopic eyes. This could probably be due to aberrations resulting from larger pupils in the myopic eyes. (S Afr Optom 2010 69(3) 132-139

Short-term variation in central corneal thick- ness and intraocular pressure using the Tono-Pachymeter NT530P (Tonopachy™)

Measurements of central corneal thickness (CCT) and intra-ocular pressure (IOP) are important for both diagnostic and therapeutic purposes. The aim of this study was to investigate the short-term variation and intra-subject repeatability of CCT and IOP measurements made with the Tono-Pachymeter NT530P (Tonopachy™). Fifty one consecutive automatic measurements of CCT and IOP were taken for the right eyes of 15 subjects (11 females and 4 males) aged 20 to 57 years (mean = 32.3 ± 13.5 years). The measured values (CCT and IOP) were compared against each other to establish the intra-subject repeatability and bias of each individual measurement with respect to the means, standard deviations and variances. Three different  statistical tests of normality: Kolmogorov-Smirnov (K-S),Lilliefors and Shapiro-Wilks (SW) tests suggested that most of the data was normally distributed,with a few exceptions. The inter-subject or overall mean values and standard deviations for the CCT and IOP samples were 528.2 ± 27.4 μm and 14.4 ±4.3 mmHg respectively. Although possible outliers increased the variability of the measurements of both parameters (CCT and IOP), the data generally showed good repeatability. The results of this study suggest that over short periods of time, the Tonopachy™ gives precise and repeatable measures of CCT and IOP. (S Afr Optom 2012 71(1) 12-21