eye conditions Flashcards
Retina
light-sensitive tissue lining inner surface of eye
like film on camera
light strikes this and initiates a cascade of chemical and electrical events that ultimately tigger nerve impulses that are sent to various visual centers of the brain through optic nerve fibers
retinopathy of prematurity (ROP)
scarring, vessel overgrowth and detachment of the retina
due to extreme prematurity
usually have small optic nerve too
visual deficits of ROP
blur
visual field deficits
nystagmus
nearsighted
mobility deficits
blindness
educational implications of ROP
priority seating
magnification
learning media assessment
O&M
technology
auditory input
retinitis pigmentosa (RP)
inherited retinal degeneration can be associated with hearing loss (usher)
rods start to decrease (night blindness & loss of peripheral)
can start with good vision and lose it ~30
visual deficits of RP
blur
glare
dark adaptation
visual field deficits
nystagmus
color vision deficits
mobility deficits
educational implications of RP
O&M
braille
counseling
technology
auditory
magnification
modifications to maps/charts
reassessment each year
retinoblastoma
eye cancer
visual deficits of retinoblastoma
both eyes – braille
one eye – can maintain without intervention
educational implications of retinoblastoma
braille
O&M
counseling
retinal detachment
a split in the layers of the retina resulting in a decrease in nutrition and visual function
vision over -5 has higher risk
visual deficits of retinal detachment
field restrictions
reduced acuity ( near & distance)
depth perception
educational implications of retinal detachment
braille (because unstable eye condition & can cause blindness if severe)
optical devices
O&M
technology
macular degeneration (stargardts)
deterioration of the macular area of retina
lose central vision
visual deficits of stargardts
central field loss
reduced acuity (near and distance)
visual field deficits
educational implications of stargardts
learning media assessment
O&M
optical devices
assistive technology
optic nerve
connects eye to brain
optic disc at end and can progressively change appearance and lose function when affected by eye cancer
optic nerve atrophy
difficulties for visual stimuli to be transmitted to the brain
visual deficits of optic nerve atrophy
blur
visual field deficits
color deficits
mobility deficits
reduced acuity
educational implications of optic nerve atrophy
O&M
optical devices
technology
braille (possible)
LMA
optic nerve hypoplasia
optic nerve fails to develop
visual deficits of optic nerve hypoplasia
blur
visual field deficits
nystagmus
mobility deficits
educational implications of optic nerve hypoplasia
LMA
O&M
optical devices
technology
cortical visual impairment (CVI)
absence of vision caused by damage to the blood supply to the occipital lobes of the brain
visual deficits of CVI
visual clutter
lack of visual interest
misinterpretation of visual stimuli
educational implications of CVI
reducing visual clutter in classroom
viewing center (black area, no distraction)
use of preferred color
preferred side of presentation
anterior segment
front third of eye that includes structures in front of vitreous humor
cornea
iris
ciliary body
lens
lens
transparent biconvex structure that helps cornea refract light to be focused on retina
changes shape to change focal distance so it can focus on objects at various distances allowing a sharp real image of the object to be formed on retina
cataract
congenital
opacities of the lenses
glaucoma can develop
visual deficits of cataracts
blur
glare
nystagmus
reduced visual acuity
educational implications of cataracts
aphakia
modifications of surroundings
optical devices
technology
aphakia
absence of lens resulting from cataract removal
iris
thin, circular structure in eye
responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina
color of this = eye color
In response to the amount of light entering the eye, muscles attached to this expand or contract the pupil (center of this)
larger = the more light can enter
aniridia
Absence of the iris
usually occurs in both eyes
can be congenital or caused by a penetrant injury
Congenital is not just an isolated defect in iris development but is a panocular disorder with macular and optic nerve hypoplasia, cataract and corneal changes
visual deficits of aniridia
blur
glare
nystagmus
bright light
educational implications of aniridia
Non Optical Devices (Sunfilters)
Optical Devices
Controlled environment
coloboma
A hole in one of the structures of the eye, such as the iris, retina, choroid or optic disc
The hole is present from birth and can be caused when a gap called the choroid fissure between two structures in the eye fails to close up completely before a child is born
The classical description in medical literature is of a key-hole shaped defect
can occur in one or both eyes
visual deficits of coloboma
Blur
Glare
Visual Field Deficits
Nystagmus
educational implications of coloboma
Control environment
Optical devices
Orientation and mobility
nystagmus
form of involuntary eye movement
visual deficits of nystagmus
Blur
Glare
Visual Field Deficits
educational implications of nystagmus
magnification
eye fatigue
lebers congenital amaurosis (LCA)
Congenital defect, blindness or near blindness in both eyes
May be accompanied with a nystagmus
Marked reduction in visual function of the retina (RP)
visual deficits of LCA
Nystagmus (Most usually)
Light sensitivity
Visual deficits
Acuity reduction
Visual Stimulation behaviors result in “sunken eye”
educational implications of LCA
Braille
Environmental control
Orientation and Mobility
Technology
Optical Devices
Non optical devices
albinism
Hereditary deficiency of pigmentation that could involve the entire or just parts of the body
non progressive condition
visual deficits of albinism
Light sensitivity
Nystagmus
Reduced acuity (near and distance)
educational implications of albinism
Environmental controls
Optical Devices
Non optical devices
Orientation and Mobility
Technology
LMA
FVA
glaucoma
Intraocular pressure becomes higher and damages the nerves of the retina and optic nerve
happens because of obstruction of the drainage of the aqueous between the iris and cornea.
medical implications of glaucoma
blindness
unstable condition
treatment of glaucoma
laser to open the canal
drops
educational implications of glaucoma
Braille
Optical devices
Orientation and Mobility
Technology
Non Optical devices
amblyopia
A reduction in visual acuity because of non-use of the eye
There is marked differences in the refractive error of both eyes
The eye itself may be normal but the brain tends to suppress or ignore the picture received by the eye
medical implications of amblyopia
muscle imbalance
focusing issues
educational implications of amblyopia
reduced visual function (when being treated)
treatment of amblyopia
patching (good eye)
drops
strabismus
Defects of the eye muscle system
Eye misalignment or eyes that do not move normally
One fovea is not directed at the same object as the other.
achromatopsia
Congenitally defective cones
rare inability to distinguish colors
non progressive
extreme form of color deficiency
complete lack of cone function.
medical implications of achromatopsia
Light sensitivity
Color dysfunction
Reduced visual acuity
Nystagmus
**Since rod function is generally intact, magnification may help by spreading the image over a larger portion of the retina.
educational implications of achromatopsia
Control environment
Optical devices
Orientation and Mobility
Technology
Non Optical Devices
Modify color related assignments
