About driving with BiOptics
By Dr. Dennis Kelleher
Many people with stable low vision want to drive a car. The vast majority of driving decisions are based upon vision. This page discusses controversies about the minimum visual acuity necessary for safe driving, and about driving with BiOptic telescopes, to help people make decisions about driving. It also addresses ways of learning to drive and seeking a license for those who cannot pass the standard driver license vision screening test.
The Decision to Drive
It is critical that any low vision driver has a strong sense of responsibility and willingness to voluntarily exercise good judgment by restricting themselves from driving in situations they know to be unsafe. It is a fact, regardless of whether it is fair or not, that all low vision drivers are judged by the safety record of the entire group. It is important for us all to drive in the most responsible way possible so all low vision drivers will not be in jeopardy of losing their driving privilege.
Driving is not for everyone, and neither is it for everyone in the general population. Some people don't have the physical or mental ability, the temperament, the desire, or the need to drive. The decision to drive is a very personal one that must be made collaboratively between you, your eye doctor and your local licensing agency.
Many persons with albinism, for example, have central visual acuity in the range of 20/70 to 20/200 with standard corrective lenses. The visual acuity requirements or screening standards used in the United States for driving without restrictions ranges from 20/30 to 20/70, and the average is 20/40. Some states will accept a visual acuity of 20/100 with corrective lenses for a restricted driver's license with the recommendation of an eye doctor and demonstration of the ability to operate a motor vehicle safely.
Restrictions imposed upon the license may limit the driver to a geographic area or particular routes, and may limit driving to certain hours of the day. The license may require a particular vehicle using special equipment or devices. The driver license agency may require more frequent and rigorous testing or special training that is not required of other drivers.
In order to meet the state requirement, some type of magnification device may be necessary, such as a BiOptic telescope or Telecon system (a combination of contact lenses and glasses) to increase the corrected visual acuity.
The American Optometric Association endorses "individual evaluation of individuals wearing spectacle-mounted BiOptic telescopes for driving." However, the American Association of Motor Vehicle Administrators passed a resolution in 1983 to ban all BiOptic drivers in all states. In 1984, the US Department of Transportation expressed concern that some state departments of transportation "discriminate against visually handicapped individuals who wear BiOptic lenses." The DOT position is "that the use of BiOptic lenses on a person's eyeglasses should not automatically disqualify him or her from being licensed to drive, [and] that all driver license applicants, whether or not they wear BiOptic lenses, should be provided the opportunity to take tests of vision, knowledge and driving skills." Even though the AAMVA resolution appears to be contrary to the position of the DOT, the use of BiOptic telescopes is still not legal in some states. Those states are a diminishing minority.
In an effort to address the question of the minimum acuity necessary to drive safely, studies have been conducted as early as 30 years ago comparing static visual acuity, which is measured in a stable environment, versus dynamic visual acuity, which is measured in an interactive environment that approximates the driving task. Although dynamic visual acuity tests may predict driver safety more accurately, most American States use static tests because of time and cost factors.
Most American States will permit persons with low vision to substitute documentation from an eye doctor for the standard vision test. The US Department of Motor Vehicles will want specific information about visual function such as:
Low Vision and Driving
Depressed central visual acuity, or low vision, is one of the characteristics of albinism. However, albinism is a genetic condition that is stable, so the vision does not deteriorate over time. People with albinism usually have normal color perception and near normal peripheral visual fields. In addition, albinism is not usually accompanied by scotomas (blind spots) within the visual field. There are other stable low vision conditions that are equally suitable for driving.
Even the normally sighted driver does not resolve details on a continuous basis at the 20/20 acuity level while driving. The driver uses 20/20 acuity only as a response to low resolution stimuli. Adequate peripheral vision is more important than central acuity, and persons with tunnel vision are unable to drive safely even if they have 20/20 central acuity.
All persons with low vision who drive must compensate for a reduced safety margin, which results from a delay in spotting hazards. Studies of visually impaired drivers found that these drivers had an accident rate 1.3 times higher than that of non-disabled drivers. But these same studies found that visually impaired drivers had an accident rate only half that of other medically disabled driver groups such as those with orthopedic disabilities, hearing impairments and seizure disorders. It was also found that visually impaired drivers had fewer citations than non-disabled driver.
Driving is a privilege and not a right. US DMV records indicate that the characteristics of drivers who are most likely to be involved in an accident are those who are impulsive, emotionally unstable, overly aggressive, angry, inattentive, slow to react, substance abusers, risk takers, inexperienced or new drivers, teenagers younger than 18, or seniors over age 75.
In the US, the licensing agency will use the same performance standards to evaluate the low vision driver as it uses to assess driving skills in the general population. These will generally include vehicle speed control, shifting and braking, depth and spatial perception, steering, use of mirrors, backing up and parking, knowledge of rules of the road, and courtesy.
New drivers, whether or not they have a lower visual acuity, often experience typical problems. One common example is the difficulty almost all new drivers encounter when trying to steer the vehicle straight at high speeds the first time they drive on a highway. Because the new driver tends to look directly in front of the vehicle instead of focusing on a point in the distance, the driver 'oversteers', and the vehicle may move back and forth or in and out of the traffic lane. Patience and practice will allow the new driver to overcome these tendencies.
The most popular low vision aid utilized for driving is the BiOptic telescope. The BiOptic consists of a miniature Galilean or Keplerian telescope that is positioned in the upper portion of a carrier lens. The carrier lens, which incorporates the individual's standard refractive correction, is conventionally mounted in the frame. This arrangement allows the user to look through the telescopic portion for spotting and magnifying distant objects while permitting a rapid change in fixation to the large carrier lens for general viewing of the entire visual environment. The most commonly used BiOptic magnifications prescribed for driving are the 2.2X, the 3.0X and the 4.0X. The BiOptic telescope is a lens system that requires time and training for an individual to become proficient in its use. The following is an effective BiOptic training sequence that has been used by many individuals.
A BiOptic is used only intermittently, never constantly, during driving. The BiOptic is a spotting device. The amount one spots through the BiOptic varies depending on the type of driving. Generally the faster one is going, the more often the BiOptic will be used for spotting distant objects. The majority of driving tasks will use the vision through the carrier lens. Maximizing eye movement instead of head movement can decrease response time.
The Controversy over BiOptics
Critics of using BiOptics for driving raise several concerns including:
Doctors experienced in fitting BiOptic drivers respond:
The key to understanding the ability of mildly visually impaired individuals to safely drive with BiOptics is the concept that vision is a dynamic process. Ours eyes and head move constantly preventing stationery blind spots and our visual system learns to adapt to new ways of processing information. It is the ability of the brain to adapt, not our eyes that allows safe BiOptic driving.
"All great truths begin as blasphemes." - George Bernard Shaw
For more technical information regarding concerns over BiOptic driving, and/or questions about research: ask a senior and experienced Optometrist here. If you have a concern or question regarding the use of a BiOptic during the driving task, please post it here. ... And for more on controversies, click here.
If you have stable low vision, and are highly motivated to drive, you can do it as long as your eye specialist verifies that you meet the visual prerequisites for your location, and you put forth the time and effort to learn how to do it safely.
— Richard Windsor O.D. F.A.A.O.
Indianapolis Office (317) 844-0919
— Dennis Kelleher, Ed.D.
Special Education Consultant, Office of the Director, Special Education Division California Department of Education 428 J Street, Suite 550 Sacramento, CA 95814 916-327-0842 Voice 916-445-4550 FAX
— Charla McMillan, M.S.
Past President, NOAH
BiOptic Driving Network is supported by Vidahost
Disclaimer statement: BiOptic Driving Network does not sell, endorse, or offer opinions on products, manufacturers, or professionals whose services/products may be secured following posting on this website. Products and individuals pictures on this site have been specifically authorized by the relevant manufacturer or individual. We are a registered not for profit organization, and provide information to help make informed choices. We do not give individuals optometric or ophthalmologic advice, but may refer one to an eminent expert. A BiOptic Telescopic System does not itself make someone a safe driver; specialized training is prerequisite.