The Correlation Between Eye Strain on Visual Acuity with Refractive Error Among Children

ABSTRACT

Background:

Visual impairment is a significant public health problem. Computer use by children especially school-aged children is growing rapidly. In these decades, therefore, extensive viewing of the computer screen can lead to eye discomfort, fatigue, blurred vision and headaches, dry eyes, and other symptoms of eyestrain. But nowadays, in this hazardous situation, visual impairment in children has negative impacts on socio-emotional competence and academic development. Uncorrected refractive error is the leading cause of vision loss.

Materials and Methods:

A true experimental study that met the inclusion criteria was randomly allocated into the study group (n = 85) and the control group (n = 85) sociodemographic variable and eye health variable assessed by structured questionnaire. Convergence insufficiency symptom survey assessed.

Results:

The experimental group exhibited a significant reduction in eye strain level and refractive error with improvement in visual acuity. In the post-test, the experimental group showed complete to moderate recovery compared to the control group. It showed the significance difference where P < 0.001. Pearson correlation analysis was used for refractive error between the groups. Refractive error was reduced − 0.5 diopters in each participants. There is a significant change in the experimental group considered as a P value < 0.001 statistically significant, respectively. In contrast, the control group had no significant improvement in visual acuity reduction in refractive error.

Conclusion:

This finding concludes that the children were having eye strain, which impacts the visual acuity could be incorporated with sociodemographic variables and eye health variables with convergence insufficiency symptoms among participants.

INTRODUCTION

Vision is a crucial component of a child’s communication and learning processes, with experts estimating that 80% of learning occurs through the eyes The development of a child’s vision is a complex process that involves not only the eyes but also the brain and the intricate network of nerves that connects them. At birth, the visual system is still immature, and its development continues through the early years of a child’s life. Ensuring that a child has a clear vision which is essential for their cognitive, motor, and social development. It is estimated that there are 1.4 million blind children in the world 2/3 of whom live in developing countries. It is estimated that 2,70,000 live in India. Uncorrected refractive errors are responsible for 19.7% of blindness. Uncorrected refractive errors about 13% of the Indian population are in the age group of 7–15 years.[1] Children are the valuable assets of a country. A total of 12.8 million are in the age group 5–15 years. If a child has an uncorrected vision problem, it may affect their ability to learn and reach their highest potential. Having a routine eye exam is important to keep their eyes healthy. It is important to distinguish between sight and vision.[2] Sight refers to the physical ability of the eyes to perceive light and shapes, while vision involves the brain’s interpretation and understanding of that information. In classrooms, children use their eyes continuously, whether it is for reading, using computers, or looking at the board. This constant use of sight makes clear vision an indispensable part of their educational experience. In the current digital age, children are increasingly exposed to screens for both educational and recreational purposes.

MATERIALS AND METHODOLOGY

The true experimental design to evaluate the ocular exercises on the physiological parameters such as eye strain visual acuity with refractive error government school children at Theni district, Tamil Nadu. Approved by the Institutional Ethical Committee at Government Theni Medical College, (Ref No 1515MEIII/21), the research featured 170 participants aged 8 to 15 years of children who had eye strain and refractive error selected using a simple random sampling technique. In the pre-test sociodemographic variable, eye health variable was assessed by a structured questionnaire.[3] Convergence insufficiency symptom survey and eye strain (seven-point Likert scale) were assessed by questionnaire and retinoscopy with the help of an optometrist. Visual acuity was assessed by trial set, Jagger’s chart, and Landolt chart. The experimental group received the ocular exercises weekly for five days to the participants twice a day for 30 minutes over 6 weeks along with regular use of glasses. While the control group was only wearing glasses, pre- and post-intervention were analyzed by using SPSS version 14.5 outcome compared via Chi-square and independent paired t tests Pearson correlation aimed to quantify the benefits of the intervention on physiological markers such as eye strain visual acuity with refractive error.

RESULTS

Sociodemographic characteristics

The study involved 170 participants from school-age children split equally into experimental (85) and control groups (85). The average age group of children 8–9 years had 14%, 10–12 years had 45 (53%), 13–15 years had 28 (33 diet pattern represented as vegetarian had 13 (15%), and non-vegetarian had 65 (76%) and also use glasses 52 (61%) children not wearing glasses 33 (39%) children. In the control group, sociodemographic variables were age group of children 8–9 years 25 (29%), 10–12 years had 43 (51%), 13–15 years had 17 (20 diet pattern represented as vegetarian had 13 (15%), and non-vegetarian had 72 (85%) and also use glasses 25 (29%) children not wearing glasses 60 (71%) children. (1) There is a significant relationship between variables such as gender, birth order, class studying, type of diet pattern, and wearing glasses expressed P < 0.001 value statistically.

Eye health variables

While comparison of control and experimental groups in baseline variables, only the reading method was significant at P ≤ 0.05 level. Chi-square test was used to find the homogeneity between control and convergence insufficiency symptom survey [Table 1].

Table 1.

Comparison of control (Con) and experimental (Exp) groups on eye strain level

Variables	Eye strain level	Exp		Con		Chi Square
		Pre	Post	Pre	Post
Headache	None/Slight	0 (0.0%)	0 (0.0%)	0 (0.0%)	85 (100%)	χ2=364.907
	Moderate	29 (34.1%)	40 (47.1%)	13 (15.3%)	0 (0%)	P<0.001*
	Severe	56 (65.9%)	35 (41.2%)	72 (84.7%)	0 (0%)
Dryness	None/Slight	0 (0.0%)	0 (0.0%)	0 (0.0%)	85 (100%)	χ2=363.575
	Moderate	45 (52.9%)	48 (56.5%)	23 (27.1%)	0 (0%)	P<0.001*
	Severe	40 (47.1%)	37 (43.5%)	62 (72.9%)	0 (0%)
Watery eyes	None/Slight	0 (0.0%)	0 (0.0%)	0 (0.0%)	85 (100%)	χ2=358.738
	Moderate	27 (31.8%)	35 (41.2%)	13 (15.3%)	0 (0%)	P<0.001*
	Severe	58 (68.2%)	50 (58.8%)	72 (84.7%)	0 (0%)
Blurred vision	None/Slight	0 (0.0%)	0 (0.0%)	0 (0.0%)	85 (100%)	χ2=398.158
	Moderate	25 (29.4%)	55 (64.7%)	15 (17.6%)	0 (0%)	P<0.001*
	Severe	60 (70.6%)	30 (35.3%)	70 (82.4%)	0 (0%)
	Moderate	41 (48.2%)	46 (54.1%)	54 (63.5%)	0 (0%)
	Severe	40 (47.1%)	27 (31.8%)	21 (24.7%)	0 (0%)

n, 85 each in control and experimental groups; *Highly significant. 1 and 2 – None/slight; 3 – Moderate; 4 and 5 – Severe

Convergence insufficiency symptom survey was analyzed by Chi-square test; while comparing the control and experimental group, there is a significant relationship of homogeneity between the two groups. Eyes feel tired and uncomfortable while doing the close work, double vision loss of concentration, words moving jumping, pulling around the eyes blurred vision headache and discomfort, and burning sensation while doing close work. Identified the children accommodate the lens ineffectively. The P value is <0.001 considered as significant statistically [Table 1].

Level of eye strain

Post-intervention, the experimental group showed a significant reduction in eye strain level by Chi-square and Fisher exact test combining experimental and control groups. Eye strain was reduced after the intervention in the experimental group. It expressed that the 7-point Likert scale stinging eyes, itching, aching, gritty feeling, double vision, redness headache, dryness of the eye, watery eyes, blurred vision, and burning of the eye are the significant variables, i.e., P ≤ 0.001 [Table 1].

Refractive error

While comparing of experimental and control groups, the types of refractive errors were as follows: myopia had 79 (93%), hyperopia had 5 (6%), astigmatism had 1 (1%), and myopia had the same frequency analyzed. Hyperopia had 4 (5%), and astigmatism had 2 (2%). Data were analyzed by frequency table and Chi-square test.

Visual acuity

Regarding the visual acuity of right eye 6/6, 6/9, 6/12, 6/18, 6/24, 6/36, 6/60, X2 = 261.395, with P < 0.001. For the visual acuity of left eye 6/6, 6/9, 6/12, 6/18, 6/24, 6/36, 6/60, X2 = 272.731, with P < 0.001. In the post-test, the experimental group showed complete to moderate recovery compared to the control group. It showed the significance difference where P < 0.001. The results show that vision-enhancing interventions are beneficial [Table 1].

Refractive error

Correlation of refractive error in control and experimental group: Pearson correlation analysis was used for refractive error between the groups. Refractive error was reduced by − 0.5 diopters in each participant. There is a significant change in the experimental group considered as a P value < 0.001 statistically significant, respectively [Table 2].

Table 2.

Pearson’s correlation analysis of refractive error of control and experimental groups, pre-test and post-test

Variable 1	Variable 2	R	N	P
Con-right eye	Con-right eye	0.987	85	<0.001*
Pre-test	Post-test
Con-left eye	Con-left eye	0.988	85	<0.001*
Pre-test	Post-test
Exp-right eye	Exp-right eye	0.972	85	<0.001*
Pre-test	Post-test
Exp-left eye	Exp-left eye	0.993	85	<0.001*
Pre-test	Post-test
Con-right eye	Con-left eye	0.977	85	<0.001*
Pre-test	Pre-test
Con-right eye	Con-left eye	0.999	85	<0.001*
Post-test	Post-test
Exp-right eye	Exp-left eye	1.0	85	<0.001*
Pre-test	Pre-test
Exp-right eye	Exp-left eye	0.977	85	<0.001*
Post-test	Post-test

Con, Control; Exp, Experimental. *Highly significant. r, correlation coefficient; n, number; P, probability

DISCUSSION

Impact of visual impairment

John H Kempen (2005) has been identified as a cause of public health and economic concern.[4] Studies also provide evidence supported by Maduka-Okafor, et al. (2021), who revealed that refractive error is not common. Refractive error primarily affects children more frequently in metropolitan schools. Refractive error is the primary source of visual impairment, and the majority of children who required corrective glasses did not have them. The activities were grouped into near work and outdoor activities, average hours spent reading handled on mobile and computer. A study conducted by Maduka-Okafor, F. C., Okoye, O., Ezegwui, I., et al. (2021) revealed that refractive error is not common. Refractive error primarily affects children and occurs more frequently in metropolitan schools. Refractive error is the primary source of visual impairment, and the majority of children who required corrective glasses did not have them.[5]

Impact of eye strain in children

The data reveals that the parameters studied, viz., stinging eyes, itching, gritty feeling, aching, double vision, redness, headache, dryness, watery eyes, blurred vision, eye fatigue, and burning eyes, showed in both groups. Bilal et al.[6] assessed a hospital-based descriptive cross-sectional study on the frequency of refractive error in school-going children visiting eye OPD with complaints of headache and eye strain in Pakistan. The sample consists of 220 school-going children between the ages of 5 and 15 years. A convenient sampling technique was used in this study. The data were collected by Snellen chart, trial box, occludes, pen torch, retinoscopy, and auto refractometer

Visual acuity with refractive error

Karma Loday Bhutia, Sonam Choden Bhutia, Nisha Gupta, and Diki O Shenga (2021) conducted a cross-sectional study on the prevalence of refractive errors among school-going children in East Sikkim. The sample consists of 15,954 schoolchildren. A random sampling technique was used in this study. The data were collected by Snellen chart. The results show that 6.7% of children had refractive error, with (31.1%) having myopia, (29.4%) having astigmatism, and (2.6%) having hyperopia. Astigmatism was the second most prevalent error, present in 317 children.[7]

Vision enhancement on visual impairment

Vision-enhancing interventions reduce eye strain, strengthen weak eye muscles, and tone improving blood circulation; eye muscles should be toned to achieve the sharpest vision. Eye exercise motivation improves myopic visual symptoms and eye fatigue.[8] Socioeconomic variables such as gender, birth order, class studying, type of diet pattern, wearing glasses, and eye health variables convergence insufficiency incorporate with eye strain and visual acuity among children.[9,10] Vision-enhancing interventions reduce eye strain, strengthen weak eye muscles, and improve blood circulation; eye muscles should be toned to achieve strengthening and revitalize muscles.[11]

Recommendations

Future research studies will be conducted long duration of intervention along with nutritional supplementation. Nutritional deficiency influences the eye health. Promotion of eye screening regularly among school children every 6 months once is recommended.

CONCLUSION

Nurses play a crucial role in implementing eye screening, monitoring refractive error in children, and preventing visual impairment, thereby promoting the quality of vision.[12] Doing tasks that require the eyes to focus for extended periods can lead to dry eyes and muscle problems. Regular eye exercises and eye muscle relaxation techniques revitalize the eye muscles. Further relaxation of the tension of the eye muscles improved the coordination of the medial-lateral muscles and balanced the upper and lower eyeball muscles, hence improving the accommodating and focusing power of the lens.