| Vision |
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| Vision provides |
-Info about environment |
-Alerts us to danger |
-Anticipatory- allows planning (critical for our ability to adapt) |
-Adaptation (static vs dynamic environment) |
-Fast and reliable |
-People let go of vision use what they have (even if nothing left) |
| System- light enters cornea |
-goes through lens to hit the retina (visual receptor) |
-fovea (in the macula in the retina)has rods and cones for acuity |
-goes to the nerve to the chiasm to the tract |
-to the lat gen nuc in thalamus via optic radiations |
-to primary visual cortext where infor is recognized and shared with occipital |
-to pariatal, pretemporal, and frontal area |
| Visual perceptual hierarchy 1 |
-adaptation-(highest level) (needs cognition) |
Visual cognition( interprets visual info-)(manip. objects in brain to make sense of them) |
Visual memory (map s/t in mind youv seen before-categorize,recall, and store info so you can recognize it. ex- know its a pen) |
pattern recognition (identify salient (sig) feat so then you see whole ex see the shape of the pen) |
Visual scanning- ( scan for detail or scan room for objects (1) automatic-get the whole picture (2) voluntary- specific such as signs ticketbooth) |
Visual attention (critical skill - what you attend to depends on visual info you get (1)focal attention-find s1 specific (2)peripheral attention - to get over to the person |
| Visual perceptual hierarchy2- foundation skills- necessary for vision |
occulomotor control( control movement of eyesso stable and brain gets info) |
visual field (how much you see straight ahead- the whole picture) |
visual acuity (how clearly you see)( size/ contrast/ color) |
If don't have these skills you won't have an image in CNS= blindness |
if there is an impairment in one of these skills your vision will be faulty |
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| Role of the OT |
-look at how vision affects occupational performance |
-functional significance is that person will interact differently wit the environment--need to find underlying problem |
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| Deficits in visual acuity |
disruption of focusing of image on retina ( myopia, hyperopia, astigmatism, cataracts-spots) |
inability of retina to process image 2 damage((1) age related -macdegen, glaucoma (2) systemic disease- diabetic retinopathy) |
inability of optic nerve to transmit(optic atrophy after head injury) |
contrast acuity (street curb and gutter-black/black ppl with MS have problems with this) |
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| Screening for Visual Acuity |
Size and Symmetry |
Pupil response to light |
eye dominance( tube/cross hand small hole) |
Acuity/snellen chart and clinical observation |
contrast acuity (with water or coffee white mug) |
color vision |
| Occulomotor function |
need to maintain foviation( putting objects in line of sight)for |
Binocular vision/sensory fusion- (each eye sends a message to brain but brain interprets it as one) |
complex extensive inegration (int of dif parts of brain and nerves- damage results in occulomotor dysfunction) |
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| Occulomotor Movement |
Saccades- (jump from one object to another)(changes line of sight) |
Tracking/Smooth persuit-(focused on one object even when head and body move/ or if object moves)( line of sight stays the same ) |
Diplopia-( eyes look in different directionsimages aren't fused)( double vision) |
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| Functional problems of occulomotor dysfunction |
postural motor control will be off |
can't identify things quickly |
hard to accomodate from far to close vision |
fine motor problems/headachs/reading |
to reduce person may 1) close an eye 2)adapt a fixed head image |
Dysfunction usually seen with TBI |
| Occulomotor dysfunction screening |
-Eye alignment (look for light spot in eye- symmetry) |
-Binocular eye movement- ( 9 cardinal points) |
-Convergence ( bring light close to face) |
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| Clinical observation of occulomotor dysfunction( trying to decrease dbl vision) |
-complain of blurry |
-head fixation |
-shut eye or tilt head |
-squint of blink a lot |
-complain of headache or eye fatigue when looking at s/t near by |
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MedTemCP5 Word+Pics
