Prevalence & Risk Factors of Myopia Among Medical Students In Alexandria University, Egypt

ByAbdelhamid S Elhofi, MD, Frcophth Author has no financial interest

Myopia is one of the leading causes of visual impairment. It affects approximately 25% to 30% of individuals worldwide. Much research has been directed towards identifying genetic and environmental causal factors of myopia. Available evidence suggests a multifactorial etiology with interplay between environmental and genetic factors.

Aim of the WorkTo estimate the gender- and age-specific prevalence of myopia, To determine epidemiological characteristics of students particularly vulnerable to myopia andTo identify its potential risk indicators or determinants among a sample of students of Faculty of Medicine, aged 18 years and older in Alexandria, Egypt.

METHODSTo fulfill these aims a cross sectional study of 530 medical students was conducted in Alexandria University. Potential risk indicators were evaluated by administration of an interviewer led questionnaire.

The questionnaire assessed classical or conventional risk factors such as sex, medical and ophthalmic history, student’s education and parental and siblings myopia history.The questionnaire also asked how much near-work the student currently practiced in hours per week.

Myopia was defined as spherical equivalent, equal to or worse than -0.50 Diopters. It was measured using an on table mounted autorefractometer after cycloplegia. Students with ocular pathology (as retinal degeneration or cataract), drug induced myopia, amblyopia, or previous ocular surgery were excluded and replaced by others.

Informed consent was obtained from all students. Data analysis included descriptive and Univariate analyses. All variables analyzed by the initial univariate analysis were further analyzed using a multiple logistic regression model, from which the odds ratio can be easily estimated.

RESULTSThe mean age of the enrolled students was 20.111±1.260 years with a minimum of 18 and a maximum of 22 years. Males constituted 60.37% of the participants. Moreover, almost three fifths of the enrolled students were urban residents (58.49%).

The overall prevalence of myopia was 24.52% (130 students). Out of these, 87% had low myopia, 11% had moderate myopia and 2% had high myopia.

Myopia was more prevalent among females (p=0.018), and among students of high and low socioeconomic status compared with those of middle status. Urban versus rural residence had no statistical significance. Participants’ myopia was statistically related to positive family history (p<0.001) however the differences between parents and siblings were insignificant (p=0.062).

Medical students with myopia reported spending more time in near activities, as studying or reading, compared to non myopic ones. However, they spent nearly as much time watching TV as non myopic students (p=0.061).

Myopes spent significantly less time in sport than non myopes (p=0.0002). Mann Whitney test was used to test statistical significance between myopes and non myopes.Correspondingly, the difference between time spent in playing sports and time spent in near work was statistically significant (p=0.03).

Multivariate logistic regression model for significant predictors of Myopia among medical students

Risk Factor Regression coefficient (B) Odds ratio 95% CI

Age 1.488 3.430 2.749-7.139

Sex -0.690 0.413 0.254-0.672

Both Parents myopia 1.678 3.811 2.776-5.361

Extremes of Socioeconomic status 1.067 2.914 1.418-4.142

Weighted nearwork (DH/week) 1.858 1.021 1.000-1.003

ConclusionMyopia constituted a significant problem among Alexandria University students in Egypt.

Myopes were more likely to be females more than males, of high or low socioeconomic class rather than middle, had positive family history of myopia especially parental and near work activities.

The present study recommends controlling for the incriminated risk factors through early detection of cases of myopia, especially among students of positive family history and high educational achievement.