Special considerations should be taken with elderly drivers
To the Editor:
I have a few questions regarding the article, “Legal, ethical quandaries muddle debate over vision of elderly drivers,” in the March 2013 issue (pages 1 and 6).
How does Dr. Spear “check cognitive ability, reaction time, decision-making ability by interviewing the patient and the family”? Are these checks not within the realm of various disciplines outside optometry? Would they not be extensive and specific in each case and require referrals?
On the other hand, when it comes to family, let us not forget that patient confidentiality is paramount and obligatory. It is left up to the discretion of the patient to agree to share information with a family member. So, before discussing the legal driving issue with the family member, the professional needs the express consent of the patient.
Also remember that recently patients gained the right to examine their records almost instantly on a secure website. We, therefore, have to be careful how we report our assessments in the record, especially if it an electronic health record. Altered mental status statements are to be used judiciously and with caution.
The idea of a referral to an occupational therapist is a good step. In fact, it is the department of motor vehicles that administers the driving test after a medical review unit accepts the low vision doctor’s report.
Dr. Bailey said that people with “significant visual field loss” worry him. However, under special circumstances people can have a limited driving license with the help of field expanders – such as is the case in New York State. My question is: How many patients does Dr. Bailey encounter with both visual field loss and visual acuity loss who come to be fitted with a bioptic? In New York at least, the granting of a restricted license to patients with either loss is mutually exclusive. In order to qualify for a bioptic the patient needs a full field in that eye.
I do not disagree with Dr. Bailey’s decision not to fit a bioptic in a patient who is legally blind in one eye and has low vision in the other. The question is, then, whether there is any such legal restriction aside from the individual eye doctor’s discretion and comfort level. Again, in New York, if a patient is legally blind in one eye but the other eye satisfies all of the following: visual acuity between 20/70 and 20/100; 20/40 or better vision through a telescope; and a full field of 140° in that eye, this patient qualifies for driving with a bioptic telescope only after taking a road test. This test is administered by the state motor vehicle department. Therefore, I would like to know what Dr. Bailey means by the second eye having “reasonable vision” or being “reasonably functional.”
Is a table listing the various legal requirements by state available? Such requirements and restrictions vary for regular, commercial and restricted driver’s licenses. Such a table would be clinically relevant and practical.
Joseph Hallak, PhD, OD
Dr. Hallak makes some good points in his thoughtful letter.
Visual acuity, contrast sensitivity and visual fields are all relevant to driving tasks. Most low vision patients have eye diseases that produce deficits in more than one of these three main visual functions. The magnitudes of the visual deficits can be unusually dependent on the illumination conditions. It really is necessary to consider the individual characteristics of each visually impaired driver as the clinician decides what advice should be given about visual abilities and driving.
The most common field-expanders prescribed for low vision patients are minifying telescope systems to help with severely constricted visual fields and prism strips or peripheral prism segments that may be used to help patients with substantial peripheral loss – hemianopia is the classic example. I recommend that patients with severe constrictions or hemianopic field loss should not drive. I prescribe no field-expanders for driving. My position on driving with hemianopia is disputed by some experts. I freely acknowledge that I do not have evidence to support my position – I simply use prima facie argument and logic.
As was pointed out in the article, at the University of California – Berkeley low vision clinic we only fit a bioptic telescope before one eye for driving, and we insist on “reasonably functional’ vision in the second eye. We have no set formula for determining what is reasonably functional. Given full peripheral fields and good contrast sensitivity, I could be satisfied with a visual acuity of 20/400 in the second eye. However, serious reductions in contrast sensitivity or substantial temporal visual field loss in the second eye could cause me to recommend against driving with a bioptic telescope, regardless of the visual acuity.
Dr. Hallak asked about regulations related to vision and driving. About 10 years ago, Peli and Peli published the prevailing regulations related to vision and driving for the various states. The American Medical Association website is another source of such information.
Ian L. Bailey, OD, MS, DSc(hc), FCOptom, FAAO
Great question, Dr. Hallak. You are correct; in most optometry offices this would fall out of the normal scope of practice. However, in our office, we have a vision rehabilitation center with a full-time occupational therapist. Our occupational therapist administers the Mini Mental State exam as well as the Montreal Test to evaluate cognitive function. He uses the Trail Making Test to help determine decision making skills. We also have a sports vision trainer, who we utilize to assess reaction time.
For optometry offices who do not have these capabilities, I would encourage finding a driving rehabilitation facility to refer patients who may need this additional testing.
Katie Gilbert Spear, OD, MPH