A naked eye visual acuity of 4.5 indicates vision loss, but it is not necessarily due to myopia, and it is not possible to accurately estimate the degree of myopia through naked eye visual acuity. Under normal circumstances, the naked eye visual acuity should reach 5.0, and the current naked eye visual acuity of 4.5 indicates that there is a moderate degree of vision loss, the patient needs to go to the ophthalmology department of the hospital in a timely manner for an examination to find out the reasons for the vision loss, and should not be blindly attributed to myopia. Many ophthalmologic diseases can cause vision loss, such as astigmatism, hyperopia, amblyopia, cataracts, fundus lesions and so on. Even if the vision loss is caused by myopia, it is not possible to accurately determine the degree of myopia based on visual acuity alone, and the correct way to determine the degree of myopia is through an optometry examination.