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 Table of Contents  
ORIGINAL ARTICLE
Year : 2020  |  Volume : 8  |  Issue : 2  |  Page : 56-61

Comparison of refractive error and related ocular morbidities between Saudi and Indian school children in Riyadh, Saudi Arabia


Research Department, King Khaled Eye Specialist Hospital, Riyadh, Kingdom of Saudi Arabia

Date of Submission04-Feb-2019
Date of Decision16-Mar-2019
Date of Acceptance30-Oct-2019
Date of Web Publication2-Jul-2020

Correspondence Address:
Ziaul Haq Yasir
Research Department, King Khaled Eye Specialist Hospital, 2775 Alurubah Road, Umm Alhamam Algharbi, Riyadh 12329-8139
Kingdom of Saudi Arabia
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jcor.jcor_6_19

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  Abstract 


Purpose: In children, refractive error (RE), especially myopia, is influenced by both genetic and environmental factors. We compared the magnitude and determinants of RE among Saudi and Indian students in Riyadh, Saudi Arabia. Methods: This study was conducted in 2017–2018 and evaluated students in preparatory and secondary grades. A “Spot Screener” was used to determine if the child passed or failed a refraction test. Data on vision, RE, anisometropia, and strabismus were compared between Indian and Saudi students. P < 0.05 was considered statistically significant. Results: The study sample was comprised of 770 Indian and 708 Saudi students. There were more Indian students (35.3%) with moderate visual impairment (<20/60–20/200) than Saudi students (6.1%) (odds ratio [OR] =8.4). The prevalence of RE in Indian and Saudi students was 50.1% and 43.6%, respectively. There were 45.6% Indian and 35.9% Saudi students with myopia (P < 0.001). The prevalence of hyperopia in Indian and Saudi students was 4.5% and 7.8%, respectively (P < 0.001). The prevalence of strabismus was significantly higher in Indian students (11%) compared to Saudi students (4.1%) (P < 0.001). The rate of anisometropia was higher in Indian than Saudi students (P = 0.001). A family history of RE was significantly lower in Indian students compared to Saudi students (OR = 0.7). Spectacle compliance was similar between Indian (78.9%) and Saudi (74.8%) students. Conclusions: Preparatory and secondary students of Indian and Saudi nationalities sharing the same environment had different rates and types of RE. Integrating RE services within the school healthcare system is required in both Indian and Saudi schools in Riyadh.

Keywords: Childhood blindness, eye screening, myopia, refractive error, Spot Screener


How to cite this article:
Yasir ZH, Khandekar R, Al-Dhibi H, Banaeem AS, Al-Shangiti AK, Balous MA. Comparison of refractive error and related ocular morbidities between Saudi and Indian school children in Riyadh, Saudi Arabia. J Clin Ophthalmol Res 2020;8:56-61

How to cite this URL:
Yasir ZH, Khandekar R, Al-Dhibi H, Banaeem AS, Al-Shangiti AK, Balous MA. Comparison of refractive error and related ocular morbidities between Saudi and Indian school children in Riyadh, Saudi Arabia. J Clin Ophthalmol Res [serial online] 2020 [cited 2020 Sep 28];8:56-61. Available from: http://www.jcor.in/text.asp?2020/8/2/56/288849



The World Health Organization (WHO) estimates that 19 million children under 15 years of age are visually impaired. Uncorrected refractive error (RE) was the main cause of visual impairment (VI) in 12 million children.[1] RE includes myopia, hyperopia, and astigmatism.[2] The magnitude of RE is a factor and changes in refractive status as children grow warrant frequent reassessment and management.[3] Unfortunately, undetected VI in children can have a lifelong impact on learning ability, academic performance, personality, and quality of life.[4] Therefore, in children, early detection and treatment of RE is essential. The WHO also recommends vision screening of “12–13” and “15–16” years old schoolchildren and to provide refractive services.[5]

The development of RE is influenced by both environmental and genetic factors.[6] The interplay between genes and environment may account for a substantial proportion of the phenotypic variance.[7] RE is the leading cause of VI in Saudi children.[8] The pattern of ocular disease varies from country to country and even within regions in a country.[9] RE ranges from 26.4% among children younger than 18 years old in southern Saudi Arabia to 34.9% among 3–10 years old children in western Saudi Arabia.[10],[11] Among Indian children, there is a 13% prevalence of myopia in Delhi.[12] In contrast, children in a southern region of rural India had a 2.2% prevalence of RE.[13]

Expatriate children of Indian origin share the same environment as Saudi children but are a different genotype. This could result in variation in the magnitude and determinants of RE even if they reside in the same region of the Kingdom. Therefore, we evaluated the magnitude and determinants of RE, other ocular morbidities and compliance of visual aids among Indian and Saudi children studying in schools in the Riyadh region of Saudi Arabia.


  Methods Top


In this cross-sectional study, we included student from Saudi schools and Indian schools in Riyadh, Saudi Arabia. This study was conducted between 2017 and 2018. The institutional research and ethics board approved this study (1633-P). Written informed consent was obtained from the school authorities. Students of preparatory (12–14 years old) and secondary grades (aged 15–18 years) were included. Students who were absent on the day of screening or did not want to participate were excluded.

Our team consists of an ophthalmologist, an epidemiologist, and medical students. Medical students were trained in using the Spot Screener (WelchAllyn, USA). Ophthalmologist supervised the field activities. A separate room was provided by the school authorities to undertake vision screening. Demographic data such as age and gender were collected from the school records. Data were collected on spectacle wear, contact lens usage, history of eye surgery, ophthalmic/optical consultation in the past, family history of RE.

We used the Spot Screener because it is easy to handle, user-friendly, the bilateral test can be performed simultaneously, and results are available in seconds. Hence, this is an adequate device for mass screening.

The Spot Screener was calibrated every day to minimize measurement bias. During measurements, it was held at a distance of 1 m from the student. The distance was then adjusted based on the message displayed on the monitor. If the message read “too far,” the Spot Screener was moved closer to the student. If it was “too close,” the Spot Screener was slowly moved away from the student while maintaining the eyes in focus. The device produces a noise to attract the Student's attention and keep the student fixating. In approximately 5–10 s, a “Pass” or “Fail” message is displayed on the monitor. A “Pass” indicates that the participant had no defects or marginal RE. A “fail” indicates that the eye has a visual defect. In addition to the test result, the refractive status of each eye is also displayed in the sphere, cylinder, and axis. The student was labeled with “failed test” based on the “Spot Screener” measured RE of more than ± 0.75D in either eye. We also assessed the visual acuity (VA) with the help of Lea symbol chart placed in the lightbox that was held at 3 m away from the student and recorded his/her distance VA in LogMAR notation. The finding of the Spot Screener was matched with the distance VA. If the WHO Grade of VI matched with severity of RE, we considered VI due to RE. These students were advised to consult an optometrist and/or an ophthalmologist for further eye care. If a message indicated that the pupils were constricted, the ambient room lighting was reduced, and the test was repeated.

The spherical equivalent (SE) was calculated using the standard formula:

SE = sphere + (cylinder/2). The higher value of RE between eyes of an individual defined his/her RE status. Emmetropia was defined as RE between <−0.5D and <+0.5D. Myopia was defined as ≥−0.5 D. Myopia was further graded into low myopia (≥−0.5 to <−3D), moderate myopia (−3D to − 6D), and high myopia (>6D).[14] Hyperopia was defined as RE ≥+0.5D. Hyperopia was further graded as low hyperopia (≥+0.5D to + 2D), moderate hyperopia (+2.25D to +5D), and high hyperopia (>+5D). Astigmatism was defined as an eye with RE ≥1D cylinder. Anisometropia was defined as RE difference greater 2.5 D between eyes.[15] Moderate VI was defined as presenting VA of <20/60 to ≥20/200 in better eye. Severe VI was define as presenting VA of <20/200 to ≥20/400 in better eye.[5]

The data were collected on a pretested collection form and subsequently entered into an Excel ® spreadsheet (Microsoft Corp., Redmond, WA, USA). The data were reviewed for errors and then transferred to the Statistical Package for Social Studies (SPSS-22; IBM Corp., Armonk, NY, USA). For qualitative data, the frequencies and the percentage proportions were calculated. For quantitative data, normality was tested, and the mean and standard deviations were calculated if the variable was distributed normally. To associate the outcome to the determinants, the odds ratio and the 95% confidence interval and a two-sided “P” value were calculated. A P < 0.05 was considered statistically significant.


  Results Top


We screened 770 Indian students and 708 Saudi students. [Table 1] presents the demographic data and other history for both groups. The gender distribution between groups was similar (P = 0.6). The proportion of preparatory and secondary students of Saudi and Indian descent was significantly different (P < 0.05). The coverage of RE services among Indian students was significantly greater than Saudi students. Seventy-five percent of students used spectacles, and the rate was similar between groups. The mean age of Indian preparatory students was 12.4 ± 1.0 years (range 10–15). The mean age of Indian secondary students was 15.6 ± 1.2 (range 14–18). The mean age of Saudi preparatory students was 12.9 ± 0.9 years (range 11–15). The mean age of Saudi secondary students was 16.2 ± 0.9 (range 15–18).
Table 1: Demographic features of Indian and Saudi school children with refractive error

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The prevalence of different types of RE, strabismus, anisometropia, and grades of VI based on presenting vision were compared between groups. As shown in [Table 2], the prevalence of RE was significantly higher in Indian (50.1%) compared to Saudi (43.6%) students. The prevalence of hyperopia was significantly higher among Saudi students compared to Indian school students (P = 0.001). The prevalence of myopia was significantly higher among Indian students compared to Saudi students (P < 0.001). The prevalence of anisometropia was significantly higher in Indian students compared to Saudi students (P = 0.001). The prevalence of strabismus was significantly higher in Indian students compared to Saudi students (P < 0.001). The proportion of Saudi students with “functional normal vision” was significantly higher than Indian students (93.4% vs. 64.5%).
Table 2: Status of refractive error and related ocular morbidities based on the Spot Screener results

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The number of Indian males and females with RE was 211 and 176, respectively. The number of Saudi males and females with RE was 174 and 135, respectively. The risk of RE among both gender and nationals was similar (P = 0.6).

The number of Indian preparatory and secondary with RE was 258 and 129, respectively. The number of Saudi preparatory and secondary with RE was 109 and 200, respectively. RE was significantly higher among secondary grade Indian students than preparatory students, but RE was equal among both grades of Saudi students (P < 0.001).

Binominal regression analysis was performed to evaluate the interaction of different risk factors on the variation of myopia among students. As shown in [Table 3], Indian nationality and a family history of spectacles were significant risk factors. Although the rate of myopia was higher in secondary students compared to preparatory students, the element of chance in this variation in the presence of other risk factors (age and gender) cannot be ruled out.
Table 3: Risk factors for myopia between Indian and Saudi school children

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  Discussion Top


This study compared the refractive status and other related ocular comorbidities among Saudi and Indian students living in Riyadh, Saudi Arabia. Half of the participants had RE. The prevalence of RE was significantly higher in Indian students compared to Saudi students. Hyperopia was more common in Saudi, while myopia was more common in Indian students. Gender was not associated to RE in either group. Secondary grade Indian students had significantly higher rate of RE. Compliance with spectacle wear was equal in both groups. The association of family history of RE to the RE in a child was significantly higher in Saudi students than Indian students. The existing ophthalmic/optical services cover only 1/3 of the Saudi students and nearly half of the Indian students with RE. Anisometropia and strabismus were more prevalent in Indian compared to Saudi students.

This is perhaps the first study to compare RE and related ocular comorbidities in students of two races sharing a similar environment but with a different genotype. In the absence of universal school screening in Saudi Arabia, the outcomes of this study show the urgent need to implement WHO/IAPB recommended vision and RE services to preparatory and secondary school children.[5] The approach to prevent RE in Saudi students would be different than Indian students residing in Saudi Arabia. In the former, it could be targeting genetic counseling, while in the latter, it could identify and altered acquired factors responsible for the occurrence and progression of RE. High compliance among students with RE is a good sign, but all attempts should be to increase it further.

Myopia was significantly more prevalent among Indian students compared to Saudi students. Warkad et al.[9] in the Odisha province in India reported a 38% prevalence of myopia among 6-17 years of age group. Alsaqr et al.[16] reported a 53.3% prevalence of myopia among 12–20-year-old Saudi children in Riyadh. The findings of our study concur with these studies showing the wide variation in the prevalence of myopia. As the use of electronic gadgets increases among students, it reduces the amount of outdoor activities that children participate in. Outdoor activities are a known protective factor against myopia.[3] Sustained near work in low illumination is a risk factor for the development and rapid progression of myopia.[12] Among Indian students, there is the added social pressure of achieving higher scholastic performance for further higher education studies, and they have to compete with Indian students or take international entrance exams. Hence, these students engage a substantial amount of near work for and face a greater risk of myopia compared to Saudi students. The differing preponderance of myopia among Indian versus Saudi students indicates that the role of underlying factors should be studied through longitudinal research to confirm our explanations.

We noted that there were more Saudi students with hyperopia compared to Indian students. However, the element of a chance observation cannot be ruled out. Murthy et al.[17] reported that 7.7% of Indian children between 5 years and 15 years of age were hyperopic in Delhi, which is higher than 4.5% in the present study. Al Wadaani et al.[18] reported 9.9% of Saudi children between 6 years and 14 years old had hyperopia in the Al-Hassa province in Saudi Arabia. The combined results of these studies including ours indicate that hyperopia is consistently higher in Saudi students compared to Indian students.[17],[18] The prevalence of hyperopia between studies should be compared with caution as different studies document these rates based on different methods (cycloplegia vs. autorefraction).[8] As a child ages, hyperopia often decreases, but this is true only for younger children.[19] Students in our study were in preparatory and secondary levels. In these children, decreased hyperopia with age is less likely. Hyperopia is also associated with amblyopia and strabismus.[11] Therefore, these students should be further investigated through an ophthalmology referral.

In our study, there were no differences in magnitude of RE among genders of both groups. Vinay and Shruthi [20] in India and Al-Tamimi et al.[11] in Saudi Arabia also reported no differences in RE due to gender. In contrast, Saxena et al.[12] in India and other studies in Saudi reported a higher prevalence of RE in girls compared to boys.[18] We do not have an explanation of this difference in rates of RE by gender. Perhaps earlier growth spurts among girls compared to the boys may explain the higher rates of RE, especially of myopia. Further studies focusing on gender-related risk factors for RE are encouraged.

The prevalence of RE was significantly higher in secondary compared to preparatory students in Indian school. In contrast, they were similar among both grades of Saudi students. Perhaps Saudi students attain height in earlier ages than Indian students. Growing age is a known risk factor for the progression of RE, especially myopia.[20] The WHO, therefore, recommends vision screening of 1st preparatory and 1st secondary students on an annual basis.[5]

RE in students was positively associated to the history of RE among parents and siblings among both groups. This observation is consistent with Saxena et al.,[12] Mittal et al.[21] in India and Tabbara et al.[22] in Saudi Arabia. Consanguinity has a role to play in a cause of blindness including RE.[22] Counseling and screening for early detection of RE are recommended for children with a positive family history of RE.

Strabismus was more prevalent among Indian (11%) compared to Saudi (4.1%) students. Mittal et al.[21] reported strabismus was present in 6.1% of India children between 5 years and 15 years of age. Alsaqr et al.[16] noted 1.9% in Riyadh, Saudi Arabia. Further studies are required to confirm our observation of higher strabismus among Indians.

The prevalence of anisometropia was higher in Indian (6.6%) compared to Saudi (3%) students. Aldebasi [2] reported anisometropia among 3.6% of Saudi children aged 6–13 years old in Qassim province, Saudi Arabia. It can be treated by contact lens or refractive surgeries.[23] Children with anisometropia-related amblyopia should be monitored periodically.

In the current study, mild VI was more prevalent in Saudi (93.6%) than in Indian (64.5%) students. However, moderate VI was more prevalent in Indian compared to Saudi students. This could be the result of different type of RE in these two groups; Indians having a higher rate of myopia and Saudis had a higher rate of hyperopia. VI based on distant VA measurement will naturally be greater in Indian students due to the higher rate of myopia. It should be noted that this grading of visual disabilities is based on uncorrected VA. Students with mild VI are less affected in their daily activities and thus are less likely to accept visual aids such as spectacles. This explains the low uptake of refractive services among Saudi students compared to Indian students. Teachers and students should be counseled to note early signs of distant vision defects, including the inability to see writing the blackboard and should be referred for comprehensive eye examination.

A history of seeking assistance to eye professionals was much higher in Indians compared to Saudi students. This could also due to differing awareness of ocular conditions among parents of students in each group. Low awareness among Saudi parents was noted by Aldebasi in Qaseem, Saudi Arabia.[19] Health education initiatives directed at the public should relay the asymptomatic nature of the early stages of RE. In addition, the need for proactive steps to identify RE in students should be targeted at Saudi students and their parents.

Compliance with spectacle wear was high in both groups. In this age group (teenagers), the use of spectacle is somewhat undesirable. This could be due to the poor knowledge of the alternatives such as contact lens. In addition, the option of future (as an adult) refractive surgery should be discuss to reduce or eliminate spectacle wear.[23]

In the present study, we identified 21 new RE cases among Indian students and 78 new cases among Saudi students. This observation indicates the importance of universal vision screening and provision of refractive services to the needy. RE service also enables service providers to identify students whose prescription has changed. In our study, unfortunately, the power of previously prescribed spectacles was not checked. Hence, we could not estimate the progression of RE in these students.

This study has some limitations. The RE was based on the prescription generated by the Spot Screener and not the conventional method of cycloplegic refraction. The validity of this device as a vision screener compared to traditional cycloplegic vision screening has been established.[24] Therefore, the American Academy of Pediatric Ophthalmology and Strabismus and the American Academy of Pediatrics recommend the Spot Screener for instrument-based vision screening.[25] Strabismus evaluation was also based on the device report and not by clinical assessment. The Spot Screener is a valid device to use while diagnosing strabismus.[25] The prevalence of amblyopia could not be calculated in our study as we noted presenting vision only and not the best-corrected VA. Finally, the study was based on a cross-sectional study design, so the risk factors should be interpreted judiciously.

The RE and related ocular comorbidities in Saudi students seem to have a greater genotypic risk factors while phenotype risk factors seem to have a greater influence on Indian students. The prevalence of RE among Saudi and Indian students in Riyadh is high and disconcerting. There is an urgent need to introduce universal vision screening and refractive services for the preparatory and secondary students. A positive family history of RE seems to be a predictor for RE among students. The health promotion for preventing RE in Saudi and Indian students would vary based on the identified risk factors.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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