vision and driving-2.27.175c2cabd466efc6790a0a-6728e7c952118b70f16620a9fc754159.r37.… ·...
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Vision&Driving‐Elizabeth Green/ADED 3/9/2017
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Vision and DrivingElizabeth Green, OTR/L, CDRS, CAE
Pacific Northwest Driver & Traffic Safety Conference
March 5, 2017Portland OR
Objectives
• The attendee will understand basic visual function and anatomy
• The attendee will learn common visual perceptual functions and how they apply to the task of driving.
• The attendee will gain a better understanding of common visual impairments on the driver’s ability to manage traffic and avoid hazards.
What you need for today’s session
• Grab a partner• 2 pens or pencils or dum-dums (ha!)• 2 pieces of blank paper
Vision&Driving‐Elizabeth Green/ADED 3/9/2017
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Visual FieldThe visual field is the portion of the viewing area that can be visualized without turning the head, irrespective of acuity.
Normal Visual Field
180 degrees
Visual Fields
References: http://www.utoronto.ca/neuronotes/NeuroExam/cranial_2b.htm
Understanding Low vision,
Randall T. Jose
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Anatomy of the EyeSCLERA –the “white” of the eye
CORNEA–the clear covering over the iris
IRIS–the colored muscular “aperture” surrounding the pupil
Anatomy of the EyeLENS–changes shape to focus light on retina
RETINA–the nerve layer in the back of the eye that senses light and creates neural impulses that travel through the optic nerve to the brain
Anatomy of the EyeMACULA–the portion of the retina that processes sharp, clear, central vision.
FOVEA–the pit or depression within the macula that provides greatest visual acuity
OPTIC NERVE–Carries signals from the retina to the brain
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Cranial Nerves• II – Optic Nerve
• transmits visual information from retina to the brain
• III – Oculomotor Nerve• Controls eye movements
• IV – Trochlear Nerve• Controls eye movements
• VI – Abducens Nerve• Controls eye movements
Extraocular Muscles
Oculomotor skills
Scanning is the ability to search the environment in a coordinated manner to find specific things.
Localization is the ability to find a moving object---and follow it.
Tracking is the ability to follow a line-- of print, a curb, or the dividing line on a roadway
Oculomotor skills
• Smooth pursuits - the ability of the eyes to smoothly follow a moving object.
• Saccades – the purpose of saccades is to move the eyes as quickly as possible, so that the point of interest will be centered on the fovea .
• Eye Alignment - Normal alignment of both eyes allows the brain to fuse the picture from each eye into a single 3-dimensional image.
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Eye Movement Disorders
•Strabismus•Amblyopia•Nystagmus
Binocular Vision Disorders
• Diplopia• Strabismus• Impaired
Stereopsis
Visual Acuity• *NORMAL : 20/20 to 20/50.
• *LOW VISION: worse than 20/70 and with reduced visual fields
• LEGALLY BLINDNESS: 20/200
• PROFOUND BLINDNESS: 20/400 to 20/1000
• NEAR TOTAL BLINDNESS: worse than 20/1000
What are the visual requirements in your state?http://lpp.seniordrivers.org/
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Acuity Loss-refractive errors• Myopia-nearsightedness
• Hyperopia-farsightedness
• Astigmatism-irregular curvature of the cornea or lens
• Presbyopia-decline of lens flexibility (age related)
Visual Field Disorders
• Homonymous Hemianopsia
• Scotoma
• Peripheral Field Loss
• Ptosis
Visual field defects associated with hemianopia. From Polaski and Tatro, 1996.
Deficits in Contrast Sensitivity
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Driver with visual impairmentClinical Vision Assessment
Visual Screening
• Acuity• Contrast Sensitivity• Night Vision, Glare Vision
and Recovery from Glare• Oculomotor Control
• Depth Perception• Color Perception• Visual Field Testing• Visual Scanning• Visual Perceptual Skills
Stereoscopic Vision Testing
• These are self-contained devices, similar to devices used by state DMV for the vision test.
• Enclosed, lighted box with slides to test acuity, color, fusion, phorias, depth perception, contrast, and glare.
• Commercially available testing equipment:
• Stereo Optical Company, Inc.• Keystone View
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Acuity Contrast SensitivityOptec Vision Tester with F.A.C.T slides
• Functional Acuity Contrast Test
FusionLeft Both
Right
Lateral Phoria Test
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Vertical Phoria TestCOLOR PERCEPTION
Depth Perception
• This tests for binocularity or the eyes ability to work together.
• If a client reports having monocular vision, you will not need to test depth perception.
Night Vision, Glare Vision, Glare Recovery
AAA Night Vision Tester APP: Night Glare, by McAtayl LLC
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Oculomotor Skills
• Smooth Pursuits• Saccadic Eye Movements• Shifting Fixation from Near to Far Points
Vision Field Testing
• Confrontation Testing• Goldmann field exam • Automated Perimetery – Computerized Visual
Field Testers• Humphrey Visual Field Analyzer
Visual Scanning
Dynavision 2000
Trail-Making Test, Part B• Tests working memory,
visual processing, visual-spatial skills, divided attention and psychomotor coordination
• Patient connects in alternating order numbers and letters
• Test is scored by time (sec) to complete
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Clock Drawing Test
•INSTRUCTIONS:
• DRAW THE FACE OF A CLOCK• ADD ALL NUMBERS FROM 1-12• DRAW THE HANDS TO SHOW 11:10
Clock Drawing Test• CDT can assess:
• memory• visual perception & visual
spatial skills• selective attention• executive skills
• Draw clock face, numbers, and set time
• Scoring based on 8 components of Freund Scoring Criteria
Picture courtesy of Barbara Freund, PhD Eastern Virginia Medical School
Useful Field of ViewAnother tool which has shown some
correlation to increased crash risk is the Useful Field of View (UFOV), a 15-30 minute computerized test. This test assesses central vision and processing
speed, selective attention, and divided attention.
Functional Vision TestingObserve the client doing functional tasks without revealing that you are evaluating their performance
• Observe how he /she:• fills out forms• Reads • negotiates the environment
• Inside• outside
• finds items in purse or wallet
• Can the client identify objects of different sizes at various distances?
• How does lighting affect performance?
• Difficulty adjusting to indoor and outdoor lighting
• Rain, snow, or clouds, versus a bright and sunny day?
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Ask Vision Related Questions
• Do they have trouble locating things: keys and other small objects, curbs, uneven pavements, clothing, etc.
• What can they read? Medicine labels, newsprint, the medium headlines, or just the big headlines, labels, instructions, bills, cards and letters.
• General observations may give clues: mismatched clothes, misaligned buttons, stains on clothing, and how they interact with the environment, including the therapist.
• Talk to family and friends about how they do completing daily routines.
Visual Deficits and the Driving Evaluation
The following slides are problems that are noted during the driving evaluation and are most
probably related to visual deficits:.
Use of an Eye Check Mirror
• Note the clients ability to use and the frequency of use of:
• the rear view mirror• the side view mirrors• head checks
• Note if the client:• Stares at road scene• Moves eyes randomly and is distracted
by any movement
Visual Deficits and the Driving Evaluation Misjudging Distance or Speed
• Client lacks an understanding of time and or space requirements for an unprotected right or left turn.
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Visual Deficits and the Driving Evaluation Failure to Note Road Conditions and Details
Client fails to note:• Signs
• Pot holes and other debris
• Pedestrians
• Animals
• Items to the sides of the road or in other lanes of the roadway
Visual Deficits and the Driving Evaluation Deficits in Glare Recovery or Contrast Sensitivity
• In varying light or weather conditions the client has difficulty with:
• Seeing lane markings• Traveling in areas from shade to bright sun or vice
versa• Recovering vision when traveling under bridges
(such as underpasses on the highways)
Visual Deficits and the Driving Evaluation Difficulty Maintaining Lane Position
• Client fails to maintain a central lane position.
• Client crosses or drives on the left or right lane markings
• Client hits, swipes or is too near curbs or road dividers.
Visual Deficits and the Driving Evaluation Recognizing and AnticipatingThe ability to recognize and anticipate are related to many visual skills. More specifically it is often related to looking forward. Lead zone, forward scan, looking to the horizon etc. may be problematic due to driving habits or visual deficits.
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Visual Deficits and the Driving Evaluation Difficulty in Shifting the Eyes and Gaze
• Examples include:• from the road to the dash, from the dash to the road,
from the road to the mirrors• Observe how the client completes checks such as:
• Locating instruments-signal gear • Looking from the front of the vehicle to focus on
the dash indicators• Reading the odometer and speedometer• Reading the gear selection
Other Driving Skills That Require Adequate Visual Acuity:• Recognizing traffic light color• ID arrow signals• ID street signs• ID highway informational
signs• ID regulatory signs.
• ID changes in roadway (bends/curves)
• Recognizes and avoids road dividers islands or curbs
• When navigating, notices other roads when trying to search for the intended street.
On the Road-Behind the Wheel
• When errors are observed, the evaluator needs to determine:
• Is there a pattern?• Does the error occur consistently?• Does the error occur during specific lighting conditions?• Do the problems relate to deficits noted on the clinical
assessment?
On the Road-Behind the Wheel
• Were there instances where the skill was adequate-what were the conditions?
• Was physical driver intervention required by the evaluator/instructor?
• Was verbal cueing required by the evaluator/instructor?
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On the Road-Behind the Wheel
• Did the driver note the problem and attempt to self correct?
• Did the driver make any accommodation or statement about how they “usually” handle that problem?
• Can they process the information they see quickly enough to make appropriate responses?
Consider this:
A client stops past the stop line (or stop sign) is this due to: A. a driving habit, B. poor observation skills, C. decreased depth perception, D. decreased attention or E. limited strength to push the brake pedal?
Consider this:The client had an episode of loss of lane position lasting for more than 5 seconds. The driver crossed the left lane markings. It occurred on a rural road when traveling from bright sun into a darkly shaded area. The client stated “that wouldn't happen if I had on my good sunglasses”.
What are some considerations for this driver?
Eye Diseases and Disorders Affecting Vision
Vision&Driving‐Elizabeth Green/ADED 3/9/2017
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Vision&Driving‐Elizabeth Green/ADED 3/9/2017
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Brain Injury and Stroke
The cause of the stroke and area of the brain affected will determine the type of vision impairment.
Stroke or Brain Injury can cause:• Blurred vision • Sensitivity to light, glare sensitivity • Reading difficulties; words appear to move • Comprehension difficulty • Attention and concentration difficulty • Memory difficulty
Brain Injury and Stroke
• Double vision • Aching eyes or headaches with visual tasks • Inability to maintain visual contact • Difficulties with:
1. Ocular pursuits (eye tracking ability) 2. Saccades ( difficulties with shifting gaze quickly from
one point to the other), 3. Accommodative inability ( focusing). 4. Binocular vision (eye alignment)
Visual Spatial Disorder & Visual Neglect
• When certain portions of the brain are damaged, the patient may fail to appreciate space to one side, which is usually to the left.
• Unlike visual field loss, this problem is not a physical loss of sensation, but rather a loss of attention to the area.
• Both neglect and field loss may occur together.
Various Conditions and Vision
Intellectual Disability (aka MR): refractive error, strabismus
Cerebral Palsy: refractive error, strabismus, amblyopia
Down’s Syndrome: refractive error, strabismus, cataracts, blepharitis
Deafness: refractive error, strabismus
Myelomeningocele (type of Spina Bifida): strabismus
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Various Conditions and Vision
Low Birth Weight: Retinopathy of prematurity, myopia, strabismus
Albinism: Depressed central visual acuity, or low vision, vision is stable and does not deteriorate over time, normal color perception and near normal peripheral visual fields
Congenital Nystagumus: All nystagmus degrades visual acuity by reducing the stability of fixation
Various Conditions and Vision
Stargardts Disease: form of macular dystrophy, small areas of vision loss or blindspots, difficulty adapting to the dark after sunlight exposure
Fetal Alcohol Syndrome: steep corneal curvature, astigmatism, telecanthus, ptosis
Multiple Sclerosis: optic neuritis, blurring of vision, double vision, delayed blink reflex, nystagmus, decreased acuity and blindness
Other WEB SitesAAAwww.aaa.com
AARPwww.aarp.org
ADED: Assn. Driver Rehabwww.aded.net
Insurance Institute for Highway Safetywww.highwaysafety.org
National Highway Traffic Safety Administrationwww.nhtsa.dot.gov
The USAA Educational Foundationwww.usaaedfoundation.org
US Administration on Agingwww.aoa.gov
Aim High
Keep Your Eyes Moving
Get the Big Picture
Vision&Driving‐Elizabeth Green/ADED 3/9/2017
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Failblog.com