Steps to Driving with Hemianopsia  

We first test and eliminate those who are poor candidates. Only a small number of all homonymous hemianopsia patients will be candidates for returning to drive. Candidates must demonstrate no hemispatial inattention, no major physical or cognitive barriers as discussed above. Patients with strokes isolated to the occipital lobe only are often good candidates, as they do not show paresis, hemispatial neglect, impaired saccades or perceptual deficits. Additional neuropsychological or medical consultations may be considered in some patients.

Next, patients are usually fit with a visual field awareness system such as the EP Horizontal Lens, Chadwick Hemianopsia Lens or the Gottlieb VFAS on the side of the loss. The EP Horizontal Lens presents a continuous view and may offer some additional benefits in driving.These lenses are used to fill in the far peripheral vision on the side of the loss. They also help in city driving to aid in pedestrian detection. These systems are used in combination with head and eye movements to expand the visual field.

An exception to prescribing a visual field awareness system may be patients with exotropias (an eye turning out) with anomalous correspondence. These patients have a natural expanded visual field from the eye drifting out and thus may not require further optical field expansion.

We avoid the use of press-on prisms in driving candidates due to the loss of contrast compared to the much better optical quality of systems like the Gottlieb, EP Horizontal and Chadwick Hemianopsia Lens.

Next, the patient undergoes extensive training in scanning with the low vision specialist and/or occupational therapist. One excellent therapy is descriptive driving,  where the patient sits as a passenger and reports everything seen on both sides. The driver challenges the patient and provides feedback if something is missed. This therapy is used to improve scanning even when driving is not a goal. Another excellent therapy is table tennis. The back and forth and side to side action helps teach scanning and the proprioceptive feedback from the legs and torso is beneficial. Both of these therapies have the common theme that they occur in real time forcing the patient to demonstrate adequate reaction time.  An order for occupational therapy is often indicated. We work with many outside occupational therapists. Some area occupational therapists can use a Dynavision system to further develop quick accurate scanning. After saccadic eye movements to scan into the visual field loss have been improved, the patient will require a behind-the-wheel evaluation and training. 

Next, the patient undergoes a rehabilitation driving evaluation and training with a certified driving rehabilitation specialist including a behind-the-wheel evaluation. If the patient shows potential to drive safely, further behind-the-wheel training is performed. The amount of training is individually determined in each case. Upon the completion of training, the patient may be required to pass a BMV courtesy behind-the-wheel driving test. 

Additional mirrors may be added to further fill the visual field. We place a wide panoramic mirror over the rear view mirror. This allows the mirror to be aims slightly in the direction of the loss.  It is wide enough to provide the rear view while providing better view to the side. Then we add a small mirror to the windshield just to the side of the steering wheel opposite the field of loss. It is angled to show the front window and the side of the loss. This is used to catch movement in the window while looking ahead. 

When all of these items come together we have the patient scanning back and forth to scan the field ahead, we have the visual field expander increasing that range and giving constant feedback on the side of the loss. Then we add the mirrors to fill in the remaining areas.