In most states, you only need one eye to maintain a driver’s license. Most states require one eye to have at least 20/40. In addition, a certain degree of peripheral vision, or continuous field of vision, is required to qualify for an unrestricted license. A restricted license may still be obtained with slightly lower requirements. Please check your own state laws.
Can I Drive? Obviously, loss of independence is one of the biggest concerns a patient has after being told of permanent vision loss. While many eye doctors may not be comfortable with this conversation, most retina specialists, dealing with diabetic retinopathy and macular degeneration, have to be well versed.
Professional Driving Fortunately, in most circumstances where there may be significant vision loss in one eye, the fellow eye is still in good shape. I am usually quick to point out that one eye is all that is required to maintain a driver’s license. There are a few professional exceptions; those with commercial driver’s license (CDL), pilots and locomotive engineers require both eyes to see well. I am sure there are a few others, but my point is that loss of vision in one eye does NOT usually cause a change in careers.
Failing the Vision Test When you take the vision test at the motor vehicle department, keep in mind that these are screening tests. Patients that do not see well out of both eyes will fail, but this does not mean loss of the driver’s license. Screening tests are designed to make sure that “one-eyed” patients are seen by an eye doctor.
Most states have a separate form that must be completed by an eye doctor upon failing the screening test. Completion of this form ensures passing or failing the vision requirements of the driver’s license exam.
The Visual Requirements One eye must have a visual acuity of at least 20/40 and have a continuous field of vision. We have mentioned different ways to measure visual acuity in other articles. The peripheral vision, however, is measured in degrees. The continuous field of vision pertains to the amount of peripheral vision and is measured in the number of degrees of intact, peripheral vision.
Diabetic retinopathy and macular degeneration involve central vision. There can be complications from retinal detachment that may affect the peripheral vision, but basically, diabetic retinopathy and macular degeneration would decrease central acuity. Other diseases such as glaucoma, or certain strokes, might reduce the peripheral vision. Though patients may have excellent central vision, the peripheral vision may be so compromised (e.g. tunnel vision), that passing the driver’s license requirements are impossible.
What Does This Mean? Remember, in most cases of diabetic retinopathy and macular degeneration, the chance of significant vision loss is low. Still, in many more instances, the fellow eye may be good enough so that independence is not jeopardized.
Another reason to see your eye doctor……………..early.
Randall V. Wong, M.D.
Ophthalmologist, Retina Specialist