A recent review of the causes and prevalence of low vision and blindness world wide is lack-ing. Such review is important for highlighting the causes and prevalence of visual impairment in the different parts of the world. Also, it is important in providing information on the types and magnitude of eye care programs needed in different parts of the world. In this article, the causes and prevalence of low vision and blind-ness in different parts of the world are reviewed and  the  socio-economic  and  psychological implications are briefly discussed. The review is based on an extensive review of the litera-ture using computer data bases combined with review of available national, regional and inter-national journals. Low vision and blindness are more prevalent in the developing countries than in the developed ones. Generally, the causes and prevalence of the conditions vary widely in different parts of the world and even within the same country. World wide, cataract is the most common cause of blindness and low vision among adults and elderly. Infectious diseases such as trachoma and onchocerciasis result-ing in low vision and blindness are peculiar to Africa, Asia and South America. Hereditary and congenital conditions are the most common causes of low vision and blindness among chil-dren worldwide.

BACKGROUND: The onset and development of stereoacuity in children have been investigated by several authors. In addition to the study of those aspects of stereopsis, it is also important to collect normative data, which can be applied in the clinical setting. The purpose of this study was to establish Randot stereoacuity norms using a Saudi Arabian children population. METHOD: The Randot stereo test was used to measure stereoacuity for 791 male primary school children (aged six to 12 years) with normal vision. A battery of tests was used to establish that each child had normal eyes and vision prior to the stereoacuity measurement. RESULTS: The range of stereoacuities for all the age groups at 40 cm was 70 to 20 seconds of arc, except for the nine-year-old children in whom the range was 50 to 20 seconds of arc. More than one half (57.5 per cent) of the children achieved 29 seconds of arc. The mean stereoacuity for all of the children was 25.32 seconds of arc with a standard deviation of 9.93 seconds of arc. The mean stereoacuity for the children decreased from 29.11 seconds of arc at six years to 23.61 seconds of arc at 11 years. An inter-subject variation in stereoacuity development was observed. CONCLUSION: This paper provides normative data for Randot stereoacuity for children. The range and mean values presented here will be useful as reference data for clinical diagnosis of normalcy or otherwise of stereoacuity in children of similar ages when the Randot stereo test is used.

This article reports part of the findings of a study carried out to determine the causes, prevalence, and distribution of ocular dis-orders among rural primary school children in Mopani district of Limpopo Province, South Africa. Three hundred and eighty eight children aged 8 to 15 years were randomly selected from five randomly selected schools. Non-cycloplegic retinoscopy and auto-refrac-tion were performed on each child. The preva-lence of hyperopia, myopia, and astigmatism was 73.1%, 2.5% and 31.3% respectively. Hyperopia (Nearest spherical equivalent power (FNSE) ranged from +0.75 to +3.50 D for the right and left eyes with means of +1.05 ± 0.35 D and +1.08 ± 0.34 D respectively.Myopia (FNSE) ranged from –0.50 to –1.75 D for the right eye and –0.50 to –2.25 D for the left eye with means of –0.75 ± 0.55 D and –0.93 ± 0.55 D respectively. Regression model for myopia, shows that age had an odds ratio  of 1.94 (1.15 to 3.26), indicating a significant increased risk of myopia with increasing age. Correcting cylinders for the right eyes ranged from –0.25 to –4.50 D (mean = −0.67 ± 0.47 D) and for the left eyes from –0.25 to –2.50 D (mean = −0.60 ± 0.30 D). With-the-rule (WTR) astigmatism (66.5%) was more common, followed by against-the-rule (ATR)astigmatism (28.1%) and oblique (OBL) astigmatism (5.4%). With-the-rule astigmatism was more common in females than males; ATR astigmatism and OBL astigmatism werecommon in males. Regular vision screening programmes, appropriate referral and vision correction in primary schools in Mopani district are recommended in order to eliminate refractive errors among the children.

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Background: Welding is a common occupation in both developed and developing coun-