Driving with Low Vision: Confusion, Controversy, Assumptions Part One
By Steven Schoenbart, OD, FIALVS, Marc J. Gannon, OD, FAAO, FIALVS, and Richard J. Shuldiner, OD, FAAO, FIALVS, Chief Clinical Editor
Is driving a right or a privilege?
How much central vision is necessary for safe driving?
How much peripheral vision is necessary for safe driving?
How much contrast sensitivity function is necessary for safe driving?
Who should decide if a person is qualified to safely drive?
How long should a license be valid for?
What type of testing should be given to renew a license?
Should there be any age discrimination in driver licensing?
And, what is the role of the eye care practitioner in making decisions on driving?
Many questions, lots of opinions, no answers!
CASE REPORT: FROM DEPRESSION TO INDEPENDENCE
Gloria W. came in for a low vision examination on June 19, 2019. Gloria is 82 years old, has macular degeneration, and was, unhappily, driven to the exam by a friend because her license expired. Her ophthalmologist told her she was no longer qualified to drive.
Her goals were reading small print and seeing faces and the television better. She so wished she could drive but totally believed she was not qualified to get her license renewed.
Her belief was due to ignorance of the vision requirements by her primary eye care provider.
The exam results:BCDA: 20/100+ OD 20/240 OSVF: NORMALCSF: NORMALCan she qualify for a California driver’s license?
- The DMV eye test charts have 20/40 characters. Of course, she fails that test.
- The DMV “machine” has 20/40 characters. Of course, she fails that test.
- The DL-62 Report of Vision Examination Form states the following: DMV’s Visual Acuity Screening Standard is:
- 20/40 with both eyes tested together
- 20/40 in one eye, and
- 20/70, at least, in the other eye. Of course, she fails that test.
HOWEVER, the actual minimum visual acuity requirement in California, buried deep in the fine print, is: One eye must be better than 20/200!
So, Gloria DOES meet the minimum visual acuity requirement for driving.
She did not even attempt to renew because her eye care practitioner ASSUMED he knew the requirements. We all know what ASSUME means! And it can cause a devastating loss of independence for vision loss individuals.
Remember, even though she is meeting the minimum vision requirements, it does NOT mean she gets a driver’s license. She still must pass the DMV road test to show she is a safe driver. But at least she had the opportunity to renew. It is essential that every eye care practitioner become knowledgeable in the DMV requirements for their state. They are all different.
HISTORY OF ACUITY REQUIREMENTS
The history of how the acuity levels for driving came about is rather unique and a bit unconventional, states Dr. Marc Gannon, a Florida low vision optometrist and member of The International Academy of Low Vision Specialists.
Following World War 1 there were many soldiers who suffered injuries and were awarded disabilities. Some of the disabilities related to vision. If a soldier suffered vision loss to the point where his best corrected acuity was 20/200 or worse, he was given a 100% disability. If his best acuity was 20/70 or worse, he received a 50% disability, and if 20/40 or worse, a 25% disability.
In the mid 1920’s people began driving cars in significant numbers and the government needed to form some regulations relating to driving. It was apparent that vision was critical to operate a motor vehicle, but at what level? No one really knew so they chose to use the Post World War 1 disability standard for vision and apply it for driving. This standard really had nothing to do with driving, but it seemed like these may be logical starting point. They used the 20/200, 20/70 and 20/40 numbers, but left it up to each state as to how to utilize them. States like California accepted 20/200 or better as an adequate level of vision to operate a motor vehicle. Florida, for example, decided that if a driver had an acuity of 20/200 or worse in one eye then the other eye had to be 20/40 or better, and if the poorer eye was better than 20/200 then the weaker eye could be as poor as 20/70 and still qualify. Eventually the government began building Interstate highways and set a standard of 20/70 for all National Signage relating to motor vehicle operation. This standard was utilized by almost all states on Intrastate highways as well. Thus, 20/70 became an acuity recognized in some form by almost all states.
We can probably operate a motor vehicle at 20/200 acuity. However, we can’t read the signs in a proper interval if we are going the speed limit for which the sign is calibrated. Of course, the better the acuity the greater the distance we can see the signs, thus adding additional reaction time and distance to improve the safety and confidence of the driver.
In 1997, Richard Shuldiner, OD, began a project that took one year to complete. I contacted the main office of every state DMV in the United States and received a fax of their vision requirements. Of course, it revealed what we already knew, that every state has its own vision requirements.
Those results were placed on the website of our organization, The International Academy of Low Vision Specialists and are now updated each year (https://www.ialvs.com/dmv-driving-laws/). Because changes occur randomly, we can never be sure they are completely up to date.
So why are there 50 different requirements for 50 States? The truth is, there is no answer. All the rules are completely arbitrary! Every state has different VA requirements for licensing. Every state has different VF requirements for licensing. No state has any mention of Contrast Sensitivity Function. Every state has its’ own rules on bioptic telescopic glasses for driving, from no rules at all to not allowed at all!
This begs the question, if there was a scientific study that proved a certain level of visual function (VA, VF, CSF) was necessary for safe driving, wouldn’t every state have the same requirements? It turns out that there are no studies anywhere that demonstrate the amount of any of the visual functions as being necessary for safe driving. There are simply too many variables.
BIOPTIC DRIVING STATE LAWS
According to http://www.biopticdrivingusa.com/state-laws/ 2016, State laws authorizing bioptic driving began over three decades ago in the United States. Today, thirty-seven states allow driving in some form. Unfortunately, the laws vary greatly from state to state. States like Indiana have defined requirements for vision levels, training and ongoing monitoring of the vision status. Some states allow bioptic driving but fail to define the requirements for behind-the-wheel training.
Other states fail to address the issue at all, while other states like Florida have created “Catch-22 Laws” allowing patients to drive with bioptics, but the bioptic system cannot be used to pass the vision test. Copyright © 2016, Richard Windsor O.D.
In the next issue of Managing Low Vision, we will present the vision requirements of California and New York, as examples of the differences in driving rules and regulations. We will also present more information on the topic BIOPTIC DRIVING: CONFUSION AND CONTROVERSY.
- It is essential that every eye care practitioner become knowledgeable in the DMV vision requirements for their state.
- Eye care professionals should not, in the opinion of these authors, prejudge whether the person should or should not drive. That is the responsibility of The Department of Motor Vehicles.