A vision of 4.9 before the age of 6 is normal and does not need to be corrected; a vision of 4.9 after the age of 8 needs to be improved through glasses and amblyopia training.
Under normal circumstances, visual acuity should reach 5.0 after the age of 8. 4.9 is an abnormal condition, and a visual acuity examination is needed to determine the situation. If it is caused by refractive error, if it is pseudomyopia, you need to pay attention to eye hygiene, develop good eye habits, and adhere to a period of time to get better. If it is true myopia, you need to wear glasses to correct it.
If it is caused by amblyopia, it needs to be treated and corrected by masking therapy, grating therapy, light brushing therapy, red light flashing therapy, etc., which can help the patient to improve his/her vision gradually.
A visual acuity of 4.9 after the age of 8 is an abnormal condition, which requires timely examination to determine the cause of the disease and treatment and correction as prescribed by the doctor.