Visual Acuity

Visual Acuity

Overview of exam

There are two types of visual acuity tests: "naked vision", which is measured without wearing glasses, and "corrected vision", which is measured after correcting refractive errors (nearsightedness, farsightedness, astigmatism, etc.) by wearing glasses or optometry lenses. . The test method is to look at the visual acuity test chart from a distance of 5m and check whether the break in the ring of the "C" mark (Landolt's ring) can be seen. The eyesight meter at the health center is set to look at the instrument from a distance of 5m.

Standard value 1.0 or more (reference)

Normal and abnormal results

Although there are some differences in visual acuity standards for each inspection institution, in order to drive a car, the corrected visual acuity needs to be 0.7 or better with both eyes, 0.3 or better with a single eye, and if the vision is less than 0.3 in one eye, the vision in the other eye needs to be 0.7 or better. The field of view must be at least 150 degrees left and right. If you see a decrease in vision, it is mostly due to "refractive errors" such as nearsightedness, farsightedness, and astigmatism. However, other diseases such as cataract, glaucoma, uveitis, vitreous opacity, diabetic retinopathy, and retinal detachment may be hidden in some of them. See an ophthalmologist if you have a problem.


Presbyopia: A condition in which near objects become more difficult to see with age. This is because the lens hardens with age, making it difficult to focus.
Cataract: Occurs when the lens becomes cloudy with age.
Glaucoma: Caused by an imbalance in the production and drainage of the fluid in the eye (aqueous humor), which increases intraocular pressure and puts pressure on the surrounding nerves. It is said that many Japanese people have normal-tension glaucoma.
Age-related macular degeneration: The macula, the central part of the retina, becomes damaged, making it difficult to see. Genetic factors and lifestyle influences.

These diseases cannot be detected by visual acuity tests alone. If you have any symptoms that concern you, we recommend that you have a detailed examination by an ophthalmologist. Each district health center does not have an ophthalmologist. You can also consult with the internal medicine department about the results of your vision test, but if you would like to consult with an ophthalmologist, please let us know so that we can guide you to a nearby ophthalmologist.