Prevalence of Myopia and Its Related Factors Among University Students in Madinah, Saudi Arabia

Background: Myopia, a common refractive error, is a growing global health burden influenced by both genetic and environmental factors. Despite its high prevalence, studies on its prevalence and risk factors among university students are lacking. Objectives: The objective of this study is to investigate the prevalence of myopia and its associated factors among college students in Saudi Arabia's Madinah region. Methods: A cross-sectional study was conducted in Al-Madinah, Saudi Arabia, from February to June 2023, utilizing a survey that was distributed to college students through a social media application. Results: A total of 433 university students from Al-Madinah province were enrolled in this study; 66.3% were females and 33.7% were males. Participants’ ages ranged from 18 to 33 years with a mean of 21.3 ± 2.0 years. The prevalence of myopia among college students in Al-Madinah and its provinces was 57.3%, and 87.9% of them had myopia in both eyes. Respondents with an electronic screen time of more than three hours and a reading distance of less than 15cm were at significant risk of myopia with p-values of 0.037 and 0.019, respectively. Conclusions: A significant prevalence of myopia has been observed among university students in Madinah. Studying in scientific and medical fields, having eye diseases, prolonged use of digital devices, limiting daily outdoor activities to one hour, and having a reading distance of less than 15 cm significantly increased the risk of myopia. Encouraging education and screening programs for myopia prevention and control is crucial.


Introduction
Myopia, often known as nearsightedness or short-sightedness, is a spherical refractive defect that causes the eye to fail to see distant objects [1].It is caused by high refractive power relative to corneal curvature and lens thickness and increased anteroposterior eyeball diameter, resulting in light refraction to a focal point in front of the retina [2,3].Myopia is the most common refractive disease, particularly in adolescents and young adults [4].Its rapidly increasing prevalence and incidence worldwide in recent decades have sparked substantial international concern.Myopia is expected to affect 49.8% of the global population by 2050 [5].The current incidence of myopia in Saudi Arabia is 48.7% among adults in Riyadh [6] and 53.5% among college students in both Hail and Riyadh [7].Myopia manifests clinically as blurry distance vision, eye rubbing, and squinting [8].Myopia is considered a major global public health concern and has become a leading cause of vision impairment.
Myopia's exact cause remains unknown despite numerous studies that have attempted to explain it.However, myopia development and progression have been associated with several genetic and environmental risk factors.Several studies have associated having myopic parents with an increased likelihood of developing the condition [9][10][11].Younger age at myopia onset is thought to be a risk factor for myopia advancement [12].Other studies have found that myopia may be influenced by environmental factors, such as a higher level of education, more near work, and fewer outside activities [13,14].Furthermore, computer and smartphone use is widespread in daily life, and myopia may develop or worsen due to digital device use [15].Many factors might protect against myopia.An Australian cohort study found an inverse relationship between myopia and daylight exposure, which remained significant even after adjusting for sex, age, parental history of myopia, and educational level [16].Many studies have found a positive association between extensive schoolwork and the onset and progression of myopia.This association was explained by near work, including reading and writing [17].Therefore, reducing the burden of schoolwork, especially during the first educational years, could help prevent myopia.
Many studies have investigated the prevalence, risk factors, and progression of myopia in childhood.However, it remains understudied in adults.Despite having behavioral characteristics related to an increased incidence of myopia, this is especially true among university students.This study aimed to investigate the prevalence of myopia and its associated characteristics among university students in Saudi Arabia's Madinah region.

Materials And Methods
This cross-sectional observational analytical study was conducted from February to June 2023 in Al-Madinah, Saudi Arabia, using a survey sent via social media application to university students in the Al-Madinah region of Saudi Arabia.Students with ocular disorders such as cataracts, glaucoma, congenital eye issues, and refractive anomalies other than myopia were excluded from this study.The four sections of the pre-designed questionnaire were taken from a prior Chinese study: consent and confidentially, personal data, myopia pattern, and factors related to myopia.Before recruitment, participants were given details about the study's objectives, including duration and confidentiality.They were also informed that their data would be used for study-related purposes, but their identities would be kept confidential.On April

Results
The characteristics of the 433 university students who responded to the survey are summarized in Table

TABLE 1: Participants' characteristics (n = 433).
A history of any eye disease other than myopia was reported by 60 (13.9%) of the participants (Figure 1), and a history of any corrective refractive surgery was reported by 15 (3.5%).

Myopia prevalence
Approximately 248 (57.3%) of the participants had myopia; if those who did not know were omitted, the prevalence was 61.7%.Among affected participants, 218 (87.9%) reported that both eyes were affected.Two hundred and fifty-one (58%) of the participants reported wearing visual aids, mainly glasses in 167 (38.6%) or both glasses and lenses in 80 (18.5%) of the participants.One hundred and twenty-seven (29.3%) of the participants reported wearing visual aids all day.Two hundred and forty-four (56.4%) of the participants reported a usual reading distance of <15 cm.Two hundred and eighty-four (65.6%) of the participants reported never having undergone a visual assessment, whereas 120 (27.7%) had them annually.Two hundred and seventy-one (62.5%) of the participants reported a parental history of myopia, of which 123 (28.4%) reported that both parents were affected.

Vision-related behavior
Table 2 shows that 303 (70%) of the participants reported having poor posture when writing or reading and 309 (71.4%) of the participants were not taking breaks after 30 minutes of continuous reading.Three hundred and eighty-three (88.5%) of the participants spent >3 hours using digital devices daily.

Personal and Medical Factors
In this study, 242 (62.9%) of the participants living in Medina had myopia, compared to 6 (35.3%) of those living outside Medina (p = 0.022).In addition, 143 (65.3%) of participants studying medicine and 81 (64.3%) studying science had myopia, compared to only 24 (42.1%) of participants studying literature (p = 0.004).Moreover, participants who reported a history of any eye disease other than myopia were more likely to have myopia than those who did not (76.3% vs. 59.2%;p = 0.013).Furthermore, participants who reported a usual reading distance of <15 cm were more likely to develop myopia than those who reported a distance of >15 cm (66.2% vs. 55.9%;p = 0.035).Finally, more participants who reported undergoing an annual visual assessment had myopia than those who reported never having such an assessment (88.3% vs. 47.0%;p < 0.001; Table 3).

Vision-Related Behavioral Factors
Participants who spent longer each day using digital devices (>3 hours) were more likely to have myopia than those who never used these devices (61.5% vs. 22.2%; p = 0.037).In addition, participants who spent, on average, <1 hour/day outdoors were more likely to develop myopia than those who spent >2 hours/day outdoors (72.8% vs. 57.2%;p = 0.041; Table 4).

Adjusted odds ratio 95% confidence interval p-value
History of having any eye diseases, other than myopia  Our study found a lower percentage of myopic students (57.3%) than earlier studies.A Chinese study by Huang et al. involving 1153 university students in Nanjing found myopia prevalence to be 86.8%[18].This difference might be explained by Asian individuals being more prone to developing myopia, leading to its higher prevalence in Asian populations in various studies [19,20].An observational study by Alamri et al. evaluating myopia prevalence among King Khalid University medical students reported that almost half of the participants were myopic [3].Our result is consistent with their finding since we found that about twothirds of medical students (65.3%) had myopia.In addition, another study on Norwegian medical students supports our findings of higher myopia prevalence among medical students [21].This increased myopia prevalence might be explained by individuals with higher educational attainment and academic achievement spending significantly more time on near-work activities such as reading with less outside activity [22].
Almost two-thirds (62.5%) of our participants reported a family history of myopia, of which 28.4% reported that both parents were affected.Other studies have suggested that having parents with myopia may increase the likelihood of developing myopia [18,23], implying a hereditary susceptibility to myopia.
More than half of our participants engaged in near work on screens.In addition, participants who typically read from a <15 cm distance were more likely to develop myopia than those who read from a >15 cm distance (66.2% vs. 55.9%).A Chinese study and an Australian study found that children who engage in near work had a higher risk of developing myopia [24,25].Our study suggests that continuous reading for >30 minutes increases the risk of myopia, possibly due to increased accommodative lag.Additionally, Dutheil et al. found that near work led to a higher myopia prevalence in adults, with the odds of myopia development increasing to 21% [26].Regardless, in many other studies, this risk has not been identified [13,18].The association between near work and myopia development and progression requires further evidence-based research.
A Chinese study in Nanjing concluded that taking breaks after continuous reading decreased the likelihood of developing myopia [27], indicating that this behavior is protective.Our study found similar protection.Our study did not find that eye exercise and eye washing were protective, consistent with the findings of the King Khalid University study [3].
Our study showed that students who spent 2-3 hours or more/day using digital devices were at increased risk of myopia.These results are consistent with a Spanish cohort study on 17,218 university students that found exposure to digital screens led to myopia development and progression [15].Nonetheless, there is much controversy regarding the relationship between myopia and exposure to digital devices, which is based on inconsistent findings from various studies and a systematic review by Lanca et al. [3,7,28].Therefore, additional studies are needed to better clarify their relationship.
Our study found that students who participated in outdoor activities for >2 hours were less likely to develop myopia.This finding likely reflects the inhibition of eye growth due to retinal dopamine release in response to exposure to higher light intensities in outdoor environments [29].Our finding is consistent with many research studies, including a cohort study on children aged 10-15 years, where the protective effects of outdoor activities led to less axial eye growth [30].
One limitation of our study was its use of a self-administered questionnaire, which risks subjective and recall bias.It also used a non-probability sampling method (convenience), which risks a non-representative sample.Using a validated and reliable questionnaire is one of our study's strengths.Furthermore, our selected population was academic students who could better understand the survey questions and terminology.Furthermore, 50% were from medical science colleges and are, to some extent, knowledgeable about their condition (i.e., minimizing understanding errors that could occur from the general population due to educational background).

Recommendations
Interventions that promote visual health and reduce myopia in society are desperately needed because it is a severe public health problem among children and adolescents.Therefore, additional education and screening programs for children should be encouraged to prevent and control myopia.The outcomes of our study may be crucial for visual health by identifying factors associated with myopia.The findings of our study may increase students' awareness of the importance of visual health and contribute to the creation of future vision health policies.More research is needed to better understand myopia's prevalence and risk factors.Future studies should strive for larger sample sizes, more cities in Saudi Arabia, and better study design.

Conclusions
In conclusion, our study revealed that myopia affected more than half of the university students in Madinah, Saudi Arabia.According to our findings, many factors were found to increase the risk of myopia some of which are family history, near reading, and reduced outdoor activities.There is a great need for myopia screening programs and education in order to control it and combat its progression due to its significantly high public health burden.

FIGURE 1 :
FIGURE 1: History of any eye disease other than myopia among the participants.
Two hundred and thirty-two (53.6%) reported having ≤7 hours of sleep.Three hundred and fifty-one participants (81.1%) spent 2-4 hours or more daily doing near work, whereas 186 (43%) spent 1-2 hours outdoors daily.One hundred and fifty-five participants (35.8%) reported a history of weekly exercise, and 68 (15.7%) reported regularly engaging in sports practice.The use of appropriate lighting for studying and practicing eye exercises was reported by 228 (52.7%) and 27 (6.2%) of the participants, respectively, while regular eye washing at night was reported by 82 (18.9%).