Journal of Environmental and Occupational Science

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   J Environ Occup Sci 2012; 1(2):83-90 ISSN: 2146-8311 http://www.jenvos.com 83 JJoouurrnnaall oof f  EEnnvviirroonnmmeennttaall aanndd OOccccuuppaattiioonnaall SScciieennccee   available at www.scopemed.org  Original Research Effect of the working environment on oculo-visual health of some sand and stone miners in Ghana George Asumeng Koffuor 1 , Samuel Kyei 2 , Linda Gyanfosu 3 , Clement Afari 4   1  Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, College of Health Sciences,  KNUST, Kumasi, Ghana 2  Department of Optometry, University of Cape Coast, Cape Coast, Ghana 3 Optometrist, Golden Jubilee Eye Centre, St. Michael’s Catholic Hospital, Jachie -Pramso, Ashanti Region, Ghana 4  Department of Optometry and Visual Science, College of Science, KNUST, Kumasi, Ghana eceived:  June 13, 2012  ccepted:  July 19, 2012 ublished:  July 21, 2012 OI :  10.5455/jeos.20120719050427  Corresponding Author: eorge Asumeng Koffuor, epartment of Pharmacology, College of ealth Sciences, Kwame Nkrumah niversity of Science and Technology, umasi, Ghana koffuor@yahoo.com ey words:  Pterygium, Pingueculae isual acuity, Protective Eye Wear, oreign body sensation  Abstract The health of the working population is an important prerequisite for productivity. The study therefore aimed at investigating the effect of the working environment on the oculo-visual health of some sand and stone mine workers in Ghana.   A cross-sectional survey involving 247 sand and stone mine workers and 250 non-mine workers was conducted between February 2010 and May 2011. Structured interview was used to obtain information on demographics, ocular protective wear use, and ocular symptoms. External ocular assessments and distance visual acuity measurements were performed. While 45.7% of mine workers used either sunglasses or safety goggles, none of non-mine workers wore safety goggles; a few (8.8%) occasionally wore sunglasses. A significant proportion ( P ≤ 0.0001) of non -mine workers (59.2%) did not show ocular symptoms relative to the sand and stone miners. The vast majority (P ≤ 0.0001) of non -mine workers (75.2%) had no visible ocular findings compare to the sand and stone miners (32.4%). Among quarry workers, pterygium (24.3%), pingueculae (5.7%), inflammed eyes (18.2%), and scleral pigmentation 13.8% were significant (P ≤ 0.0001) findings which was not the case with non-mine workers. Visual acuity was however not significantly different (P > 0.05) with only approximately 5% from both categories recording moderate to very low (6/18 - 6/60) acuities. Although the working environment in the sand and stone mines seems to have no effect on visual acuity, it has detrimental effect on ocular structure which eventually could affect vision. Using appropriate ocular protectives and regular ocular examinations would be beneficial. © 2012 GESDAV   INTRODUCTION Mining of natural aggregates, including both sand and gravel and crushed rock, represents the main source of construction aggregates used throughout the world, including Australia [1], France [2], Italy [3], the USA [4], Belgium [5] and Britain [6]. Sand and stone mining in Ghana consists mostly of smaller-scale operations that produce sand, gravel, cement, limestone, and granite [7]. This mining practice has for long been an important vocation for many rural dwellers and especially for communities that are closer to urban or metropolitan centres. The escalation of this mining activity in recent times has been the result of the high demand for shelter, an important component of life for the ever-increasing population [8]. Four Districts; namely Offinso, Ejisu, Efiduase Sekyere, and Barekese; in the Ashanti Region of Ghana which has sand and stone mining industries were selected randomly for the study. The Ashanti Region is centrally located in the middle belt of Ghana (lying  between longitudes 0.15W and 2.25W, and latitudes 5.50N and 7.46N). It is the third largest of ten administrative Regions in Ghana, occupying a total land surface of 24389 square kilometers or 10.2 per cent of the total land area of Ghana. The Region has seen very rapid growth in recent times due to increased   Journal of Environmental and Occupational Science. 2012; 1(2):83-90 84 http://www.jenvos.com   activities especially in the fields of engineering, estate development, roads, bridge construction and other infrastructure development. This has made sand and stone mining activity very prominent in the Region. It is documented that the working power of the workforce sustains the economic and material base of society [9] therefore the health of the working  population is an important pre-requisite for productivity and is of essential consequential impact on all socioeconomic parameters and sustainable development [10]. The International Labour Organization (ILO) estimated that the total costs of occupational accidents and work-related diseases are 4% of the gross national product [11]. In the sand and stone mines the common chemical and physical substances that cause hazards include fumes, gases, dust, debris and ultraviolet radiation (UVR) mainly from the sun, all of which are associated with ocular adverse effects [12, 13]. Repeated exposure to natural UVR sources such as sunlight is thought to be associated with slowly degenerative changes of the conjunctival epithelium such as pterygium and  pingueculae [14] seen in some outdoor workers [15]. The sand and stone mining environment therefore, is  potentially hazardous to the eye. This suggests the need for adequate ocular protection during quarrying activities and appropriate occupational health measures to ensure optimum oculo-visual health and well-being required for productivity. In view of the absence of previous ocular health-related studies among sand and stone miners in most Districts in Ashanti Region of Ghana where this activity is  predominant, the oculo-visual health status of the sand and stone miners and non-mine workers in four selected districts was investigated. MATERIALS AND METHODS Sampling Technique A map of the Ashanti Region was obtained from the Geological Survey Department, Kumasi, Ghana and four Districts namely Offinso, Ejisu, Efiduase Sekyere, and Barekese, in the Ashanti Region were selected at random. One major sand and stone mining site in each of the randomly selected Districts was selected and used in the study between February 2010 and May 2011. Sample Size The entire workers (247) of the selected sand and stone mines and 250 non-mine workers in the areas around the mines were used in this study. The survey grouped the sand and stone mine workers into office workers, manual workers (comprising of loading boys, mechanics, „crusher‟ operators, cooks, electricians and welders), casual workers (mainly in the sand weaning sector, who are just hired hands for the job), security men, blast men (drillers, explosive engineers) and drivers. The non-mine workers were made up of food stuff sellers and hawkers, cart pushers, laborers, head  porters, and drivers randomly selected from open market places and lorry stations in the districts.  Data Collection Instrument A structured interview guide was used to collect data on demography, level of education, years of work at the sand and stone mining sites or other work places, use and non-use of protective eye wear, frequency of eye examination and case history to establish visual symptoms among the workers. Ophthalmic Assessment Both distance and near visual acuity measurements (using Snellen Acuity Chart and M Chart respectively),  pinhole, ophthalmoscopy and external assessment (using pen light) were used to assess their oculo-visual health status.  Data Analysis Data obtained from the study was presented as number of individual (frequency) and/or percentage distribution. Data was compiled using the Statistical Packages for Social Sciences (SPSS) version 17 (SPSS Inc., Chicago, IL, 2008). Significant differences in measured parameters were assessed with Yates‟ correction of Pearson‟s chi -square test (X 2 ) using GraphPad Prism version 5.00 for Windows (San Diego California USA, www.graphpad.com), calculated as follows: where: O i  = an observed frequency  E  i  = an expected (theoretical) frequency, asserted by the null hypothesis  N   = number of distinct events P ≤ 0.05 was considered significant. Graph was plotted using SigmaPlot 11 (Systat Software, Inc., San Jose, CA, 2008). Ethical Consideration The proposal for this study was approved by the Department of Optometry and Visual Science Research and Ethics Committee, KNUST, Kumasi, Ghana.   Journal of Environmental and Occupational Science. 2012; 1(2):83-90 http://www.jenvos.com 85 Permission was obtained from the managers of the quarrying and individual workers before the commencement of the study. A research consent form was given to each participant for completion and those who needed assistance were assisted by the researchers. The workers were alerted that participation in the study was voluntary and that they were free to withdraw from  participation at any stage. RESULTS Socio Demographics Characteristics A total of 247 mine workers were interviewed comprising 37 (15%) females and 210 (75%) males. The modal age was 36-45years (30%). Those over 55 years were in the minority (8.9%). The study identified 3 (1.2%) of the workers as having worked in the sites for over 25 years while 108 (43.7%) had worked  between 1-5 years (Table 1). One hundred and twenty four (50.2%) were manual workers. The educational levels of the various workers are as shown in Table 2 with those with intermediate level education (Junior and Senior High/Technical School) being in the majority (64.05%). Of the total mine workers interviewed, 74 (30%) had visited an eye care facility once, 19 (7.7%) twice and 9 (3.6%) three times (Table 2). The non-mine workers interviewed were 250 comprising of 46.8% females and 53.2% males. The modal age was 36-45 years (48.8%), with those over 55 years being in the minority (9.2%). The study identified that 93 (37.2%) had been working for 1-5 years, 81 (32.4%) 6-10 years, and the remaining, more than 10 years (Table 1). Of the participants, 88 (35.2%) were laborers, 67 (26.8%) were foodstuff sellers, and 58 (23.2 %) were vehicle drivers. Cart- pushers, hawkers and head porters made up 14.8%. The educational level was mainly basic school (46.0%) and Junior High School levels (40.4%) (Table 2). Non-mine workers were less likely to visit eye clinics with 67.2% having no previous visits to the eye clinic and Fifty five (22%) visiting an eye care facility just once (Table 2). Table 1 . The category of workers, their educational levels and their visits to eye clinics for sand and stone mine and non-mine workers Category of Workers Educational Level Eye Clinic Visits SSMW NMW Levels SSMW NMW Visits SSMW NMW Office 17 (6.9) Foodstuff sellers 67 (26.8) No formal 9 (3.6) 11 (4.4) None 145 (58.7) 168 (67.2) Manual 124 (50.2) Hawkers 18 (7.2) Basic 59 (23.9) 115 (46.0) Once 74 (30.0) 55 (22.0) Casual 31 (12.6) Cart Pushers 6 (2.4) JHS 118 (47.85) 101 (40.4) Twice 19 (7.7) 22 (8.8) Security 9 (3.6) Labourers 88 (35.2) SHS/Tech 40 (16.2) 19 (7.6) Thrice 9 (3.6) 5 (2.0) Blastmen 43 (17.4) Headporters 13 (5.2) Tertiary 21 (8.5) 4 (1.6) Drivers 23 (9.3) Drivers 58 (23.2) Data is presented as number of individual with percentage distribution in parenthesis. Sand and Stone Mine Workers (SSMW), Non-Mine Workers (NMW). JHS- Junior High School Level; SHS/Tech- Senior high school/Technical School level Table 2.  Socio-demographic characteristics of sand and stone mine workers and non-mine workers in four selected Districts of the  Ashanti Region of Ghana Gender Distribution Age Distribution Years of Work Sex SSMW NMW  Age range SSMW NMW Year range SSMW NMW Males 210 (75) 133 (53.2) 15-25 27 (10.9) 33 (13.2) 1-5 108 (43.7) 93 (37.2) Females 37 (15) 117 (46.8 ) 26-35 57 (23.1) 42 (16.8) 6-10 69 (27.9) 81 (32.4) 36-45 74 (30.0) 122 (48.8) 11-15 25 (10.1) 29 (15.6) 46-55 67 (27.1) 29 (12.0) 16-20 23 (9.3) 21 (8.4) > 56 22 (8.9) 23 (9.2) 21-25 19 (7.7) 11 (4.4) > 25 3 (1.2) 5 (2.0) Data is presented as number of individual with percentage distribution in parenthesis. Sand and Stone Mine Workers (SSMW), Non-Mine Workers (NMW)   Journal of Environmental and Occupational Science. 2012; 1(2):83-90 86 http://www.jenvos.com    Foreign bodies and Ocular injury In totality 89.3% of the population interviewed had ever suffered foreign bodies in their eyes during work at their work places. Two hundred and thirty nine (96.8%) of the sand and stone miners and 205 (82%) of non-mine workers reported that sand was the most frequent foreign body on their eyes. The study identified however that the prevalence of foreign body was highest (51.2%) among manual workers in the sand and stone mines and laborers (61.9%) in the non-mining area. The prevalence of ocular injury was 59.2% and 43.7% respectively. Ocular Symptoms, Ocular Findings, and Visual Acuity The significant (P ≤ 0.0001) ocular symptoms established from frequent complains among the 247 workers relative to non-mine workers were gritty and foreign body sensations (30%), burning sensation and tearing (18.2%), or itchy eyes (8.5%). These symptoms occurred less frequently in non-mine workers as follows: Gritty and foreign body sensations (7.6%),  burning sensation and tearing (5.9%), and itchy eyes (3.7%). Other ocular symptoms recorded were not significantly different (P > 0.05) between the two categories. A significant proportion of non-mine workers (59.2%) however, did not show ocular symptoms relative to the sand and stone miners (22.8 %) (Table 3). Pterygium was found in 60 (24.3%) sand and stones miners upon penlight examination while 45 (18.2%) had red/inflammed eyes, 14 (5.7%) pingueculae and 34 (13.8%) scleral pigmentation. These findings were very significant (P ≤ 0.0001) compared to the non -mine workers. Of pterygia cases found 27 (43.5%) was unilateral and 35 (56.5%) bilateral and of the 14  pingueculae cases 11 (78.6%) were bilateral (Table 3). The occurrences of these ocular findings among the non-mine workers were low with only 4.8 % having  pterygium, 2.8% having inflamed eyes, with no  pingueculae found. Infact, while only about a third (32.4%) of the sand and stone miners had no visible ocular findings, the vast majority (P ≤ 0.0001) of non -mine workers (75.2%) had no visible ocular findings (Table 3). The visual acuities (VA) of the population were taken monocularly. Among the two categories of workers VAs were not significantly different (P > 0.05). One hundred and forty nine (60.3%) of the sand and stone miners had VAs between 6/5 - 6/6 in the right eye and 138 (55.9%) for the left eye. The poorest visual acuity (6/36 - 6/60) was 3.2% for the right eye and 0.4% for the left eyes (Table 4). Pinhole improved the visual acuity up to 2% in the right eye of the category with reduced visual acuity and 0.23% in the left eye respectively. A fogging lens of +1.00DS was used among those with distance visual acuities of 6/5 - 6/6 to rule out latent hyperopia. This revealed that 10% of the workers were hyperopic in the right eye and 12% in the left eye respectively. An assessment of the crystalline done to determine the presence of lens opacity showed that 15% of the workers had lens opacity of varying degrees. Similarly, 170 (68%) of non-mine workers had VAs between 6/5 and 6/6 in the right eye and 151 (60.4%) for the left eye. Five (2%) had VAs of category 6/36-6/60 in the right eye and 7 (2.8%) in the left eye. Pin hole improved the VA up to 1.8% in the right eye and 1.34% in the left eye respectively. Upon fogging, 11% were hyperopic in the eye and 10% in the left eye. An assessment of the crystalline lens showed 10 % of lens opacity. Table 3. Ocular symptoms and ocular findings of Sand and stone miners and non-miners interviewed Ocular Symptoms Ocular Findings Symptoms NMW SSMW P value Chi-square value, df Findings NMW SSMW P value Chi-square value, df None 154 (59.2) 56 (22.8) *** < 0.0001 77.16, 1 Pterygium 12 (4.8) 60 (24.3) *** < 0.0001 36.55, 1 Blur at near 22 (8.8) 23 (9.3) ns 0.9661 0.002, 1 Pinguecula 0 (0.0) 14 (5.7) *** 0.0001 12.58, 1 Blur at far 15 (6.0) 12 (4.9) ns 0.7162 0.132, 1 Scleral pigmentation 26 (10.4) 34 (13.8) ns 0.3108 1.027, 1 Photophobia 7 (2.8) 9 (3.6) ns 0.7805 0.078, 1 Red/inflamed eyes 7 (2.8) 45 (18.2) *** < 0.0001 29.91, 1 Headache 13 (5.2) 7 (2.8) ns 0.2654 1.240, 1 Other findings 17 (6.8) 14 (5.6) ns 0.7367 0.1131, 1 Burning Sensation with tearing 17 (6.8) 45 (18.2) *** 0.0002 13.81, 1 No visible findings 188 (75.2) 80 (32.4) *** < 0.0001 79.41, 1 Gritty/Foreign body sensation 19 (7.6) 74 (30) *** < 0.0001 39.38, 1 Itchy sensation 9 (3.6) 21 (8.5) * 0.0352 4.435, 1 Data is presented as number of individual with percentage distribution in parenthesis. Sand and Stone Mine Workers (SSMW); Non-Mine Workers (NMW). Significant differences in ocular symptoms and ocular findings between NMW and SSMW were established using chi- square with Yates’ correction. ns implies P > 0.05; * implies P ≤ 0.5; *** implies P ≤ 0.0001.  
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