PT 535: Pediatric Visual Impairments

what is the development of normal visual acuity?

requires both the eye and the neural pathway

at birth approx. to be 20/400 (can see about a foot to 18 inches away)

20/20 vision by about 3 years of age (infants do not see 20/20)

very plastic until 10-12 years of age

usually at about the 3rd-4th grade level is when glasses are used

what are the causes of visual impairment?

allowing the light to pass through the eye

focusing the light on the retina

photoreceptors of the retina

transmitting the information via the visual pathways

receiving and interpreting the visual information

integrating the information

providing appropriate feedback to the eye

what are visual deficits that are refractive errors?

myopia

hyperopia

astigmatism

what is myopia?

near sightedness

eye is too long (from the cornea to the retina

or cornea is too curved

light converges in front of retina

causes:

- distant objects to be blurry

- nearby objects clear

* more common

what is hyperopia?

far sighted

eye is too short (from the cornea to the retina)

or the cornea is too flat

light converges behind the retina

causes:

- close up objects blurry

- distant objects clear

what is astigmatism?

cornea is oblong

condition that causes blurred vision (all distances - distances do not matter because all are affected)

prevents light from focusing properly on the retina

what is strabismus?

eyes do not line up - untreated may lead to amblyopia (most of the time one eye is more stuck than the other)

what are the different types of strabismus?

esotropia - eye move inwards

exotropia - eye move outwards

hypertropia - eye move upwards

hypotropia - eye move downwards

what does amblyopia (lazy eye)?

eyes do not work together, one becomes the "stronger" eye (patch the good eye and make the lazy eye work)

what is the retinopathy of prematurity?

disorder involving the retinal blood vessels

<30 weeks of gestation, skin is translucent, eyes need to be protected from light

what is colorblindness?

difficulty differentiating between colors and shades of color, determining brightness of colors

what is a cataract?

cloudiness in the lens of the eye, causing the blurry vision (iris turns white)

what does the ventral stream allow for?

recognition

what does damage in the ventral stream do?

damage causes ability to recognize faces and objects

what does the dorsal stream do?

guides movement

what does damage to the dorsal stream stream cause?

damage causes difficulty in spatial processing

what side of the eyes does right visual field lay on?

left side

what side of the eye does the left visual field fall on?

right side

what are the general overall impacts of visual impairment on development?

motor

cognitive

social/emotional

speech language

what is an ocular disorder?

from eye doctor; never going to change

what is a cortical disorder?

inside the brain, impairment can vary based on mood, feeling, tiredness, etc

what signs do you think should alert you to a possible visual problem?

photophobia (avoidance of bright light/squint in bright light preference for dim light

stares at bright lights

non-directed or "roving" eye motions

does not seem to respond to parents face

does not seem to imitate parent's facial expressions

does not seem to follow movement of objects or people

does not reach for bottle when presented quietly

does not seem to show interest in toy/objects within reach

does not seem to show visual interest in watching television

does not seem to show an interest in books

seems to have limited interest in different kinds of toys

does not seem to recognize colors or shapes

bumps into objects

visual self-stimulatory behaviors (eye rubbing, pressing, or poking)

what are the causes of cortical visual impairments?

lack of oxygen or blood supply to the brain

prematurity

hydrocephalus

head injury

genetic conditions

infections

what is a cortical visual impairment (CVI)?

damage to posterior visual pathways and/or the occipital lobes of the brain

severity will vary depending on:

- age of the child at onset

- location of the insult

- intensity

not a cognitive impairment and not stable -> brain's fatigue so vision can change

what is not a CVI?

cognitive impairment

stable or unchanging

what are the common characteristics of visual function in children with CVI?

vision is often variable

peripheral sparing -> can see really well out of corner of eye

compulsive light gazers versus photophobic

color vision is generally better preserved

poor depth perception

moving target versus stationary targets

what are the general recommendations for testing children with visual impairment?

use other senses

lighting

reduce background clutter

increase contrast

positioning of child

positioning of the equipment

what are the teaching strategies?

energy conservation

positioning /use of supports

separate fine motor from visual tasks

simplicity and familiarity

allow increased processing time

contrast and bright fluorescent colors

mobile targets use to visual field

combine with other senses

what are the characteristics of play items?

textured features

high contrast colors; separated primary colors

shiny, mirrored reflective surfaces

sounds that help the child recognize the toy

sounds related to separate functions

imitative sounds responses

touch or sound activated

vibrating toys

3D toys with defined boundaries

differently shaped dials and switches

structured play environment

immediate sound response

what are some strategies to teach orientation and mobility?

mobility is difficult to teach in isolation

multiple impairments and cognitive ability are not justification for preventing a child for being considered for adaptive instruction

a cane should be introduced when the child moves from cruising to walking

how does exercise fall into these visually impaired children?

children who are visually impaired often do not participate in the same level of physical activity as their sighted peers

children with disabilities who regularly participate in physical activity show improved sleep patterns and self esteem as compared to children with disabilities who do not exercise regularly