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 congenital CVD 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.

Comparison of measured with calculated amplitude of accommodation in Nigerian children aged six to 16 years.

PURPOSE: Amplitude of accommodation varies with race and ethnicity and Hofstetter's equations are commonly used in Nigeria to calculate expected amplitude of accommodation for clinical purposes. The aim of this study was to present normative values for amplitude of accommodation for Nigerian children and to compare the measured values with those calculated using Hofstetter's equations. METHODS: A total of 688 children aged six to 16 years from three selected cities in Nigeria were included in the study. Push-up technique was employed to measure the amplitude of accommodation. The measured values were compared with the calculated values (Hofstetter's equations) using the paired t-test and Bland and Altman plots. RESULTS: The measured amplitude of accommodation for the subjects ranged from 8.00 to 25.00 D with a mean of 15.88 ± 3.46 D. The calculated minimum amplitude of accommodation ranged from 11.00 to 13.50 D with a mean of 12.09 ± 0.55 D and the calculated average amplitude of accommodation ranged from 13.17 to 16.50 D with a mean of 14.62 ± 0.73 D. The calculated maximum amplitude of accommodation ranged from 18.60 to 22.60 D with a mean of 20.34 ± 0.88 D. The t-test indicated a significant difference between the measured and calculated minimum, average and maximum amplitudes of accommodation (p < 0.0001). Also, the Bland-Altman plot suggested that there was a lack of agreement between the measured and calculated amplitudes of accommodation. CONCLUSION: The mean values of amplitude of accommodation in this study are different from those reported in the literature. Also, the measured values differed from the calculated values using Hofstetter's equation. This suggests that the use of Hosftetter's equations to predict amplitude of accommodation may not be accurate for Nigerian children.

Retinal nerve fibre layer thickness values and their associations with ocular and systemic parameters in Black South Africans.

PURPOSE: To measure the retinal nerve fibre layer (RNFL) thickness values and investigate their associations with other parameters in healthy eyes of Black South Africans. METHODS: 600 participants with healthy eyes, of whom 305 (50.83%) were males and 295 (49.17%) were females, with a mean age of 28.15 ± 13.09 years, underwent a detailed ophthalmic examination. RNFL thickness was measured by iVue SD-OCT. RESULTS: The mean global RNFL thickness was 110.01 ± 7.39 µm. The RNFL was thickest inferiorly (135.06 ± 9.66 µm) and superiorly (131.72 ± 10.46 µm), thinner nasally (87.24 ± 13.22 µm), and thinnest temporally (73.63 ± 15.66 µm). Multivariate analysis showed that thicker mean global RNFL thickness was significantly associated with younger age, shorter axial length (AL) and hyperopia (p < 0.001). Mean RNFL thickness decreased by approximately 0.11 µm per year of aging life, and by 1.02 µm for each 1-mm of axial elongation. There was a 0.62 µm RNFL thickness increase for every dioptre change in spherical power towards more hyperopia. CONCLUSION: Mean RNFL thickness values and their associations established in this population may be of clinical value when assessing factors that influence this parameter and diagnosing diseases affecting it.

Opinions of South African optometry students about working in rural areas after graduation.

BACKGROUND: Eye and vision problems have been reported to be more prevalent in rural than urban areas; and a large proportion of South Africans live in the rural areas. AIM: To investigate the opinions of South African optometry students about working in rural areas after completion of their training and to identify factors that may influence their decisions. METHOD: This was a cross-sectional quantitative study using a survey instrument containing both closed and open-ended, semi-structured questions. RESULTS: Four hundred and thirty-eight students responded to the questionnaire (85.4% response rate). Overall, many of the respondents did not want to open their first (66%) or second practices (64.6%) in the rural areas. However, most respondents from rural backgrounds reported that they would open their first (77.2%) or second (79.4%) practice in the rural areas. The main reasons cited by the respondents for their unwillingness to work in the rural areas were financial concerns (81.2%), personal safety (80.1%) and poor living conditions (75.3%), with a significantly higher number (p < 0.05) being from urban respondents for the latter two issues only. CONCLUSION: Many students were not in favour of opening practices in rural areas, but were willing to work for the government or a non-governmental organisation after graduation. Efforts should be made to address financial incentives, safety and living conditions in the rural areas. The results of this study have implications for the future of availability and accessibility of eye care services to those living in the rural and remote areas of the country.

Prevalence and causes of visual impairment in patients seen at Nkhensani Hospital Eye Clinic, South Africa.

BACKGROUND: Knowledge of the prevalence and causes of visual impairment (VI) amongst hospital patients is useful in planning preventive programmes and provision of eye-care services for residents in the surrounding communities. AIM: The aim of this study was to determine the prevalence and causes of VI amongst eye clinic patients at Nkhensani Hospital. The relationship between VI and age was also investigated. SETTING: Nkhensani Hospital in the Greater Giyani subdistrict municipality, Mopani district, Limpopo Province, South Africa. METHODS: Four hundred participants aged 6-92 years were selected for the study using a convenient sampling method. Presenting and best corrected visual acuities (VA) were measured with a LogMAR E chart. Presenting VA (PVA) in the right and left eyes and in the better eye of the patients was used to determine the prevalence of VI, low vision (LV) and blindness. Ophthalmoscope was used to diagnose the eye conditions causing VI amongst participants. RESULTS: The prevalence of VI based on the PVA in the right eye was 34.8% and in the left eye, the prevalence was 35.8%. There was a significant association between age of the participants and VI in the right and left eyes (p = 0.00) in each case, respectively. Based on the vision in the better eye of each patient, the prevalence of VI was 28.0% and there was a significant association between VI and age of the participants (p = 0.00). The main causes of VI were uncorrected refractive errors, cataract and glaucoma. CONCLUSION: Findings in this study indicate that a large proportion of VI is preventable. Focusing on refractive error correction and surgical intervention for cataract would significantly reduce the burden of VI amongst patients utilising this hospital.

Risk factors for visual impairment and blindness amongst black adult diabetics receiving treatment at Government healthcare facilities in Mopani District, Limpopo province, South Africa.

BACKGROUND: Diabetes mellitus (DM) is a common systemic disease amongst Black South Africans. It may lead to diabetic retinopathy (DR), a common cause of visual impairment (VI) and blindness. DR may signifiantly increase the prevalence of VI and blindness. AIM: To assess risk factors for VI and blindness amongst a black diabetic South African population aged ≥ 40 years. SETTING: The study was conducted in seven Government healthcare facilities (two hospitals, four clinics and one health centre) in Mopani District, Limpopo province, South Africa. METHODS: This was a cross-sectional health facility-based quantitative study. Structured interviews were used to obtain information, which included sociodemographic profie, knowledge about DM and its ocular complications, presence of hypertension and accessibility to health facilities. Subsequently participants were examined for VI and blindness using an autorefractor, pinhole disc, ophthalmoscope and logMAR visual acuity chart. Anthropometric measurements (height, weight and waist) were also taken. Associations between 31 risk factors and VI as well as blindness were statistically examined. RESULTS: Participants (N = 225) included 161 women and 64 men aged 40-90 years (mean 61.5 ± 10.49 years); 41.3% of them had VI and 3.6% were blind. Cataracts (76.8%) and DR (7.1%) were the common causes of compensated VI and blindness. Risk factors that were associated with VI and blindness were age, monthly income, compliance with losing weight and physical activity. CONCLUSION: Findings suggest that lifestyle intervention and appropriate eyecare programmes may reduce VI and blindness in this population.

Optometric education in Africa: historical perspectives and challenges.

The African continent, with a population of more than one billion and 55 recognized developing countries, is still grappling in some countries with socioeconomic and other challenges inherent in developing countries. The continent is working toward a single political entity known as the African Union, and development is taking place faster than ever in most countries. The continent is known to have high levels of health problems, including visual impairment and blindness. Most nations in the continent are making efforts to reduce the scourge of health problems including visual impairment and blindness. Visual impairment in the continent is mostly caused by refractive errors. Consequently, optometry can help reduce the prevalence of visual impairment on the continent. The educational programs currently offered by the different institutions include Diploma in Optometry (DipOptom), Bachelor of Optometry (BOptom), and Doctor of Optometry (OD). There are 17 established institutions offering optometry degree programs on the continent, of which 14 are fully accredited. Considering the optometric manpower needed in the continent, more optometry institutions need to be established. Staffing and infrastructural and training facilities are major challenges facing the majority of the existing institutions. There is also a need to place greater emphasis on postgraduate education to meet the institutional, national, and international professional training standards and to ensure sustainability of optometry education. This article addresses the historical development, educational issues, challenges, and needs, as well as recommendations, for improving the standard and sustainability of optometric education.

Utilisation of public eye care services by the rural community residents in the Capricorn district, Limpopo Province, South Africa

Background: Visual impairment and blindness are major health problems worldwide; especially in the rural and remote areas of developing countries. Utilisation of eye care services is essential to reduce the burden of visual impairment and blindness; and it is therefore important that it is monitored. Objectives: The objectives of this study were to determine the level of utilisation of publiceye care services and factors that might have influenced their usage in rural communities; Capricorn district; Limpopo Province; South Africa. Method: A population-based cross-sectional study design was used. Participants were residents in selected rural villages located within approximately 5 km of six Government hospitals. Following ethical approval and receipt of informed consent; a questionnaire with closed and open-ended questions was used to collect information on the utilisation of eye care services and factors that might influence utilisation. Descriptive statistics and Pearson's Chisquare test were used to analyse and compare the data. Results: Many (62.7) of the respondents had used the government eye care services in the past. Over fifty-nine per cent (59.3) of them were satisfied with the services. Factors reported to influence utilisation (such as monthly income; knowledge of available services and the need for regular eye tests) were positively associated with utilisation of eye care services in this study (p 0.05). Conclusion: Utilisation of eye care services was relatively good; but varied significantly between sites. An awareness campaign by government and non-governmental organisations about eye care services may increase utilisation amongst rural communities