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ORIGINAL ARTICLE
Year : 2017  |  Volume : 24  |  Issue : 4  |  Page : 190-194  

Investigating the visual status of preschool children in Riyadh, Saudi Arabia


1 Department of Optometry, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia
2 Department of Ophthalmology, Optometry Division, Prince Sultan Military Medical City, Riyadh, Saudi Arabia

Date of Web Publication12-Jan-2018

Correspondence Address:
Ali M Alsaqr
Department of Optometry, College of Applied Medical Sciences, King Saud University, Riyadh
Saudi Arabia
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/meajo.MEAJO_123_17

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   Abstract 

PURPOSE: The purpose of the study was to explore the vision status of preschool children aged 3–6 years in Al Riyadh and to identify children at risk of amblyopia.
MATERIALS AND METHODS: This was a cross-sectional population-based study. Visual acuity (VA) was measured using 15-line Lea symbols, refractive error was assessed using the Mohindra near retinoscopy technique, and peak contrast sensitivity (CS) was measured with the aid of the numerical CS test. We recruited 335 children, with their parents' written consent, from 14 kindergartens.
RESULTS: A total of 335 children were recruited; 42 children (13%) exhibited reduced VA (Median [interquartile ranges (IQRs)], 0.00 [0.01]); most were emmetropic (87.7%). Myopia (4.2%), hyperopia (8.1%), and astigmatism (20%) were also observed. Most children had normal CSs. About 14% of children were at risk of amblyopia. It has been observed that 26% of families have some kind of refractive error.
CONCLUSIONS: It is important to perform vision screening of preschoolers. Early detection of abnormalities in refractive errors could help to minimize the effect of visual impairment.

Keywords: Al-Riyadh, amblyopia, preschool children, refractive error, Saudi, vision screening


How to cite this article:
Alsaqr AM, Ibrahim G, Sharha AA, Fagehi R. Investigating the visual status of preschool children in Riyadh, Saudi Arabia. Middle East Afr J Ophthalmol 2017;24:190-4

How to cite this URL:
Alsaqr AM, Ibrahim G, Sharha AA, Fagehi R. Investigating the visual status of preschool children in Riyadh, Saudi Arabia. Middle East Afr J Ophthalmol [serial online] 2017 [cited 2019 Dec 13];24:190-4. Available from: http://www.meajo.org/text.asp?2017/24/4/190/223103




   Introduction Top


Refractive error is a principal cause of treatable visual impairment and one of the most common vision problems of childhood.[1] Uncorrected refractive errors have long-term impacts on education, employment, familial and societal activities, and the quality of life.[2] Failure to correct refractive errors may indicate that families are not aware of the problem, no efficient public health program is available, and/or that the cultural environment discourages compliance.[2]

Preschool children (aged 3–6 years) are at high risk of amblyopia caused by strabismus and significant refractive errors.[3] Such children are screened in many countries.[4] In Saudi Arabia, vision screening is inadequate.[5] Vitale et al. found that even in economically advantaged societies, children refractive errors may be go undetected or under-corrected.[6] Only a few reliable studies have explored the prevalence and pattern of refractive errors in preschool children.

In Saudi Arabia, few studies have investigated the visual status of children of any age.[5],[7] Saudi Arabia is a large country, with regional variations in geographical, climatic, and environmental conditions. Therefore, countrywide studies are required to gather evidence on visual status. The purpose of the present population-based study was to assess the prevalence and nature of vision disorders among preschool children in Al Riyadh, Saudi Arabia. The proportion of children at risk of amblyopia was calculated.


   Materials and Methods Top


Ethics statement

Institutional Ethics Committee, the Ministry of Education, and all school headmasters approved the study. Parental consent forms, study information, and questionnaires were given to children during school visits. Parents were asked to complete the questionnaire and to sign the consent form.

Sample calculation and identification

We performed a cross-sectional study on kindergarten schoolchildren aged 3–6 years employing multistage cluster sampling methodology. We used EpiInfo software version 7 (CDC, Atlanta, GA, USA; http://wwwn.cdc.gov/epiinfo/7/) to calculate the required sample size. We considered that approximately 40,000 children attended government and private kindergartens (Al Riyadh Directorate of Education, February 2015) and that the prevalence of refractive error would be about 10% as was found by Bardisi and Bin Sadiq who targeted the same population but in a different part of the countries (the Western coast).[5] The cluster sampling method was applied with a margin of error of 5% (95% confidence level [CI]) and a design effect of 2. The required sample size was 280. Fourteen large schools in the vicinity (north, south, east, and west) of Al Riyadh were selected using a random clustered sampling design. The schools educate children from the upper, middle, and lower middle classes. We collected general and ophthalmological histories for all children and their families. The data collection was over the period January–July 2015.

Determination of visual status

A certified optometrist performed the following ophthalmic examinations in an average of 30 min.

  1. Distance visual acuity (VA): Assessment of unaided monocular VA (and corrected VA if possible) using the 15-line Lea symbols chart (Good-Lite Co., Elgin, IL, USA) in a well-lit room at a distance of 3 m. The chart meets the standards of the National Research Council Committee on Vision
  2. Contrast sensitivity (CS): This was assessed using the numerical version of the MARS CS test (Mars Perceptrix Corporation, NY, USA). The chart was held 0.5 m distant from the child under illumination of about 85 cd/m2. Monocular and then binocular vision was assessed by matching the indicated numbers with the high-contrast numbers on a control chart
  3. Noncycloplegic near retinoscopy: Monocular refractive error was measured using the near retinoscopy (Mohindra) technique in a completely dark room. Several studies have shown that refractive error data are similar when either the near retinoscopy technique or cycloplegic retinoscopy is used to evaluate infants and young children[8],[9]
  4. The cover-uncover test: Eye alignment was assessed using the cover-uncover test, with correction (if required), at both 3 m and 40 cm. First, the left eye was occluded for approximately 3 s. The examiner watched the left eye to determine if it refixated. The procedure was repeated for the right eye.


Data management and analysis

Refractive errors were expressed as spherical equivalents refractive errors (SEREs) using the cutoffs derived by Négrel et al.[10] to facilitate comparison of the data with those of other studies. Myopia was defined as a SERE ≥−0.50 D in one or both eyes. Hyperopia was defined as a SERE ≥+2.00 D in one or both eyes. Astigmatism was defined as a cylinder power ≥1.00 DC if one or both eyes were astigmatic. Emmetropic was considered present if neither eye was myopic or hyperopic. Unilateral amblyopia was defined as an interocular difference in the best-corrected VA of two or more chart lines. Bilateral amblyopia was defined as a best-corrected VA in both eyes <0.40 logMAR (6/15) for 3 year olds and <0.30 logMAR (6/12) for 4–6 year olds.[11] We identified children at risk of amblyopia using the American Association of Pediatric Ophthalmology and Strabismus (AAPOS) criteria.[12] These are:

  1. Hyperopia ≥3.50 D, myopia ≥3.00 D, or astigmatism ≥1.5 D (at 90° or 180°) or ≥1.0 D on the oblique axis
  2. A VA <20/50 in either eye in those aged 3–<4 years and <20/40 in either eye in children aged 4–<6 years
  3. Anisometropia or anisohyperopia ≥1.0 D or anisomyopia ≥3.0 D and anisoastigmatism ≥1.5 D.


Experimental procedure

The data were not normally distributed (Kolmogorov–Smirnov, P < 0.05). Therefore, we report medians with interquartile ranges (IQRs), and we used nonparametric tests as appropriate. The SERE, unaided VA, and CS of either eye were similar. Spearman's rank correlation analysis showed that right and left eye scores were closely related (r = 0.96, P < 0.0001; r = 0.98, P < 0.0001; and r = 0.95, P < 0.0001, respectively). Therefore, the SERE, unaided VA, and CS values reported here are the lower scores of the two eyes. Three children had high myopia (−10 D to −17.50 D) that biased all statistical analyses. Therefore, these scores were treated as outliers and analyzed separately.


   Results Top


We enrolled 335 children from 14 schools. The male-to-female ratio was 1.16:1 (180:155). The mean age was 4.50 years (range: 3–6 years; standard deviation [SD]: ± 0.87 years). The ages of the children were 36 months (46 children, 13.7%), 42 months (8, 2.4%), 48 months (96, 28.7%), 54 months (6, 1.8%), 60 months (139, 41.5%), 66 months (3, 0.9%), and 72 months (37, 11%). Children who did not participate did not differ significantly in terms of demographic characteristics.

Parental characteristics were analyzed. About 26% of families reported that one parent had some kind of refractive error. Parental educational levels were similar. Of mothers, 67 mothers (20%) had high school certificates, 208 mothers (62%) bachelors' degrees, and 60 mothers (18%) postgraduate degrees. Of fathers, seventy fathers (21%) had high school certificates, 168 fathers (50%) bachelors' degrees, and 97 fathers 29% postgraduate degrees.

Visual acuity, refractive error, and anisometropia

Unaided VA assessment showed that 46 children (13.70%) had a VA ≤0.20 (logMAR [6/9.5]) with a median (IQRs), 0.00 (0.01) [Table 1].
Table 1: Unaided visual acuities (logarithm of the minimum angle of resolution) of all children

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The SERE varied widely. The refractive error did not vary markedly by age; the 60-month-old group exhibited the greatest SERE range. Most affected children were emmetropic (291 children, 87.7%). The SERE differed significantly between the sexes (χ2 = 41.33, P < 0.0001, Friedman test). The myopia prevalence was 4.2% (14 children); the median (IQR) was −0.88 D (0.75), ranging from −0.50 to −1.75 D. Myopia was more prevalent in girls than boys (9 and 5, respectively; χ2 = 14, P < 0.0001). The prevalence of hyperopia was 8.1% (27 children); the median (IQR) was +2.00 D (0.50) and ranged from +2.00 to +4.50 D. Hyperopia was more prevalent in girls than boys (15 and 12, respectively; χ2 = 27, P < 0.0001). Astigmatism was observed in 67 children (20%); the median (IQR) was −1.25 D (1.00), and the range −1.00 to −3.00 D. Anisometropia (defined as a difference ≥2.00 D) was observed in two children (0.67%). Three children (0.90%) had high myopia; the SEREs were −10.00 D, −13.50 D, and −17.50 D.

Relationship of contrast sensitivity with visual acuity and refractive error

The binocular CS was 1.68 log, except in the three children with high myopia (1.41 log) [Table 2]. The monocular CS figures revealed that some children had an element of CS limitation. The unaided VA was moderately associated with both CS and astigmatism (r = 0.48, P < 0.01 and r = 0.48, P < 0.01, respectively). CS was poorly associated with the SERE and astigmatism (r = 0.20, P < 0.01 and r = 0.31, P < 0.01, respectively). Gender and age association to VA, SERE, and contrast outcomes was investigated; there was no significant relationship between neither the gender nor the age to the other visual outcomes (r < 0.20, P > 0.05).
Table 2: Peak contrast sensitivity (lower eye score) for all children

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Children at risk of amblyopia and refractive error

The percentage of children at risk of amblyopia (defined using the AAPOS criteria) was 14.92% (50 children). The amblyopic risks are listed in [Table 3]. As it has been stated earlier about 26% of the families had some form of RE, this might be a prominent risk factor for having RE later on the children life [Table 3].
Table 3: Children at risk of amblyopia

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   Discussion Top


We measured the prevalence of refractive error and the percentage of children at risk of amblyopia in Al Riyadh. We included privileged, middle class, and lower middle-class children. We found significant proportions of myopia (4.2%), hyperopia (8.1%), astigmatism (20%), and anisometropia (0.60%). The prevalence of refractive error differed between girls and boys. SERE varied by age; those aged 5 years exhibited the widest range of SERE values. From our observation, the fast majority of the visual limitations were detected for the first time during the screening; however, the rest was detected early on, but the children were not always wearing their vision corrections. Unfortunately, we did not take records of this observation and therefore cannot be analyzed further. This might be a limitation of this study and should be taken into account in future studies.

Many studies worldwide have screened children aged 3–6 years for refractive error and amblyopia.[13],[14],[15],[16] However, few studies have been performed in Saudi Arabia. Al-Rowaily (2010) examined children in Al Riyadh.[7] However, all parents were military personnel; the children were thus not representative of the Riyadh population, which is very diverse in terms of education and socioeconomic status. Furthermore, the vast majority of military parents had no vision disorders; it is well known that refractive errors (e.g., myopia) have genetic components.[17],[18]

Almost all children were cooperative during eye testing. The success rate was high (99%) compared with other studies.[19],[20] This is explained by the use of the Mohindra near retinoscopy technique. We used this technique because, previously, cyclopentolate refraction was refused by the vast majority of parents (personal communication). The absence of cycloplegic refraction data may be a limitation of our study. However, the Mohindra technique is simple and yields values similar to those obtained upon cyclopentolate refraction (Borghi and Rouse, 1985).[8] Wesson et al. (1990) found a significant difference between cycloplegic refraction and near retinoscopy data from young children. However, Saunders and Westall (1992) identified (and avoided) the limitations of previous studies,[9] noting that the Mohindra technique “can be usefully substituted for cycloplegic retinoscopy.”[9] The cited authors measured repeatability, interexaminer variation, and the associations between Mohindra and cycloplegic data. Some inter- and intra-observer variation was evident, suggesting that any difference between the two techniques is attributable to the low repeatability of retinoscopy in young children, thus not to any significant difference between the two techniques. A strong relationship was evident between data collected using the two techniques (r = 0.931, P < 0.05). The Mohindra technique was effective in children >2 years of age; the data did not differ significantly from those of cycloplegic refraction. Furthermore, the examiners were the best judges of the effectiveness of near retinoscopy. The examiners noted poor cooperation and changes in pupil diameters triggering fluctuations in accommodation. This affected 0.90% of the children of the present study. They were excluded and referred for full ophthalmic examinations.

Over 70% of parents had a higher school certificate or bachelor's degree but were unaware of the importance of vision screening. When parents were told that their children required spectacles, most complied. However, some did not either for cosmetic reasons nor because they believed that spectacles would cause progressive visual decline. These concerns were also apparent in an earlier study on a similar Saudi Arabian community (primary school children).[21]

The SEREs varied; the widest SERE range was apparent in the 5-year-old group. This may be because most children fell in this group (41%). It is not clear why the refractive error differed between girls and boys. The percentage of VA reduction was in line with the overall percentage of refractive errors (12.30%). The prevalence of myopia, 4.2%; hyperopia, 8.1%; astigmatism, 20%; and anisometropia, 0.60% were higher than those of a previous study conducted on the West Coast of Saudi Arabia.[5] Myopia, 3.50%; hyperopia, 1.75%; astigmatism, 1.27%; and anisometropia, 1.43%. Further, our prevalence was higher than those in the military population.[7] Myopia, 2.50%; hyperopia, 2.10%; astigmatism, 2.50%; strabismus, 0.50%; and amblyopia, 0.50%.[7] The variations may be attributable to differences in the cutoffs used or the nature of the population under investigation.

Most children (95%) had a CS ≥1.62 log and could thus detect lower contrast levels. These scores are similar to those of normal adults and in line with previous findings.[22] About 5% of children had lower CSs attributable to refractive errors (myopia and astigmatism). A small but significant relationship was evident between CS and SERE and astigmatism. No significant relationships were found between the gender and children age to VA and SERE and contrast outcomes. For the VA and SERE, this is might due to (1) the age range was limited to the preschool age (i.e., 3–6 years) which is a relatively narrow range and (2) the male:female ratio was relatively similar (1.16:1) in addition to the fact that those children are in a developmental process in terms of refractive errors. While in terms of the relationship to contrast this might be due to the fact that there was limited variation in this outcome scores as shown in [Table 2].

A 26% of the families had some form of RE; this might be a risk factor for the children to develop RE, amblyopia, strabismus, and contrast problems later on the children life. Specifically, developing myopia with age which has been previously found,[19],[23],[24],[25] and it has been suggested that genetic (i.e., parents having myopia) are associated with the progression and development of myopia.[26],[27],[28] The percentage of children at risk of amblyopia was 15% and this could be of public health concern. Yawn et al. found that schools experienced in vision screening were effective in detecting undiagnosed refractive errors.[29] The World Health Organization global initiative “Vision 2020: The right to sight” and International Agency for the Prevention of Blindness recommended preschool children screening. Therefore, an efficient, simple screening programme would greatly aid child health and well-being.[30],[31] A national screening programme shall follow these recommendations as are initiatives at the family level. Compliance must be improved as must the availability of refractive services and a number of trained operators.

Acknowledgment

The authors extend their appreciation to the College of Applied Medical Sciences Research Centre and the Deanship of Scientific Research at King Saud University for funding this research.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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    Tables

  [Table 1], [Table 2], [Table 3]



 

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