Web BiOpticDrivingNetwork.org

     

 

 

 

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.

 

Driving Restrictions

 

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:

  • corrected and uncorrected visual acuity;

  • peripheral visual fields;

  • stability of eye condition;

  • depth and color perception;

  • ability to coordinate hand, neck, and eye movement;

  • contrast sensitivity, glare recovery, and luminance.

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.

  • scotoma (sko-to'ma) An island-like blind gap in the visual field.  Taber's Medical Dictionary.

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.

 

Driving Skills

 

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.

 

BiOptic

  • Use non-visual cues.

  • Keep eyes moving and be alert.

  • Check mirrors frequently.

  • See the whole picture and anticipate what the other driver will do.

  • Be sure you are seen and communicate your intentions.

  • Follow at safe distances, three or four seconds behind the proceeding vehicle at the current speed.

  • Watch for a last resort escape route.

  • Choose less demanding routes and know where to go in advance.

  • Check traffic over your shoulder before changing lanes.

  • Look backwards before backing up.

  • Use other aids as necessary (hats, visors, tinted lenses, magnifiers, etc.).

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.

 

BiOptic

 

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.

  • Rapidly locate stationary objects while you are still.

  • Rapidly locate moving objects while you are still.

  • Rapidly locate moving objects while you are moving (preferably as a passenger in a car).

  • Develop accurate visual perception skills to evaluate the environment rapidly.

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:

  • small visual field through the BiOptic telescope;

  • ring scotoma causing a hazardous blind spot;

  • vibration and speed blur;

  • telescopic parallax (shifting of view) and depth perception;

  • difficulty of using the BiOptic with mirrors;

  • critical adjustment of the BiOptic frame and angle of the lens.

Doctors experienced in fitting BiOptic drivers respond:

  • BiOptic drivers do not drive continuously through the BiOptic telescope but rather use the telescope intermittently much the way all drivers glance briefly into rearview mirrors. Perhaps less than 5% of the driving time is done through the BiOptic system. Most BiOptic drivers use the BiOptic for only 1 to 2 second intervals to see distance detail such as a traffic sign.
  • Additionally, when a BiOptic driver scans into the BiOptic, the driver still maintains an awareness of field of vision in the same manner that a non-BiOptic driver when looking into the rear mirror is still aware of peripheral visual information. The sudden movement of a passing car will still be perceived by a driver while viewing briefly in either a mirror or BiOptic.
  • Slight obstructions in the visual field may occur intermittently for all drivers such as when a driver looks into the rearview mirror. These occur for only 1 to 2 seconds and are lessened by the normal movements of our eyes and head. The constant motion and scanning of the driver's eyes and head prevents functional ring scotomas.
  • The information we receive through rearview mirrors, such as an approaching car, is usually not so detailed as to require the use of the BiOptic system, However, BiOptic systems are focused for optical infinity for driving which allows either their carrier lenses or the BiOptic to be used to view through the mirrors.
  • Speed and vibration may slightly affect the vision of all drivers. Since BiOptic drivers only utilize the BiOptic intermittently for 1 or 2 seconds, vibration and motion blur are easily managed. BiOptic drivers quickly learn to appreciate differences in image movement and relative distance perception through the BiOptic.
  • Today's BiOptics are durable and easily adjusted. BiOptics are fitted at a slight angle up so that on slight downward gaze, the BiOptic becomes parallel with the road. Highly trained low vision specialists fit BiOptics.

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.  

 

Conclusion

 

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

 

 

To see a detailed MS PowerPoint presentation given by Dr. Dennis Kelleher on factors concerning driving with BiOptic Telescope Systems, click here. (687 Kb)

 

 BiOptic Driving Network is supported by Vidahost

 

All 2000+ pages on this website were BOBBY level 1 compliant  We'd be grateful for expert assistance to develop this to modern standards. Please contact the Webmasters via facebook link above. Contact Webmasters Accessibility   This page last edited: 13 April 2012
Back to the top Hits since 29 March 2012

© 2001-2012 BiOptic Driving Network

 

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.