A research group led by Professor Kazuo Tsubota of Keio University conducts myopia epidemiology research on about 1,400 elementary and junior high school students in Tokyo.We reported the prevalence of myopia in Japan for the first time in about 20 years, and found that myopia may be related to dry eye.
According to a report by the Ministry of Health, Labor and Welfare (2005), the fourth leading cause of blindness in Japan is severe myopia.Prevention of myopia is an urgent task, but the prevalence of myopia in childhood in Japan has not been reported since the 4s.
In myopia, when looking at a distant object, the object cannot be focused on the retina and the object is focused in the foreground, so the object cannot be seen clearly.Myopia is evaluated by refraction value, and the main cause is deformation of the eyeball, in which the axial length (depth of the eyeball) is excessively extended and the distance from the cornea to the retina is long.
In children, the axial length increases with growth, but especially in myopic eyes.Therefore, axial length examination is important for assessing myopia.In severe myopia, there is a risk of complications such as macular degeneration and optic nerve damage due to the increase in axial length.
This time, the research group measured both the refractive value (non-accommodative paralyzed objective refraction value) and the axial length as an evaluation of myopia.We also investigated the relationship between myopia and lifestyle using the questionnaire.As a result, the prevalence of myopia in 689 elementary school students was 76.5%, the prevalence of severe myopia was 4.0%, and the average axial length was 23.41 mm, which was almost the same as that of adults.The prevalence of myopia in 727 junior high school students was 94.9%, which was higher than previously reported in other countries, the prevalence of severe myopia was 11.3%, and the average axial length was 24.73 mm.In addition, elementary and junior high school students who answered that they had dry eye tended to have myopia.
The results of this research are data on the prevalence of myopia, including measurement of axial length, and are the latest basic data on myopia in elementary and junior high school students in Tokyo in recent years.It is expected that the results of this survey will sound a warning against the increase in myopia and stop the increase in myopia and severe myopia in the future.
Paper information:[JAMA Ophthalmology] Current Prevalence of Myopia and Association of Myopia With Environmental Factors Among Schoolchildren in Japan
