Download Vision Handicaps Learning Aids

Vision Handicaps Learning Aids
Use old safety glasses, electrical tape and Elmer’s glue to make a set of vision handicap
simulators for your class
1.
a. Vision loss left eye – tape over left eye
b. Vision loss right eye – tape over right eye
2. In bitemporal hemianopsia vision is missing in the outer (temporal or lateral)
half of both the right and left visual fields. Information from the temporal visual
field falls on the nasal (medial) retina. The nasal retina is responsible for carrying
the information along the optic nerve, and crosses to the other side at the optic
chiasm. When there is compression at optic chiasm the visual impulse from both
nasal retina are affected, leading to inability to view the temporal, or peripheral,
vision. This phenomenon is known as bitemporal hemianopsia. Knowing the
neurocircuitry of visual signal flow through the optic tract is very important in
understanding bitemporal hemianopsia.
Bitemporal hemianopsia most commonly occurs as a result of tumors located at
the mid-optic chiasm. Since the adjacent structure is the pituitary gland, some
common tumors causing compression are pituitary adenomas and
craniopharyngiomas. Also another relatively common neoplastic etiology is
meningiomas. An etiology of vascular origin is an aneurysm of the anterior
communicating artery which arise superior to the chiasm, enlarge, and compress it
from above.
a. Bitemporal hemianopsia – lesion of optic chiasm
Tape over outer half of each lens
b. Left Homonynious hemianopsia – lesion of right optic chiasm
Tape over inner half of right lens and outer half of left lens
c. Right Homonynious hemianopsia –
Tape over inner half of left lens and outer half of right lens
3. Macular degeneration – loss of central vision due to retinal detachment
Put dime size piece of tape in center of each lens
4. Cataract – A cataract is a clouding that develops in the crystalline lens of the eye
or in its envelope (lens capsule), varying in degree from slight to complete opacity
and obstructing the passage of light. Early in the development of age-related
cataract, the power of the lens may be increased, causing near-sightedness
(myopia), and the gradual yellowing and opacification of the lens may reduce the
perception of blue colors. Cataracts typically progress slowly to cause vision loss,
and are potentially blinding if untreated. The condition usually affects both eyes,
but almost always one eye is affected earlier than the other.
Cover entire lens with thin layer of smeared Elmer’s glue and let dry
5. Glaucoma - eye disease in which the optic nerve is damaged in a characteristic
pattern. This can permanently damage vision in the affected eye(s) and lead to
blindness if left untreated. It is normally associated with increased fluid pressure
in the eye (aqueous humour). The term "ocular hypertension" is used for people
with consistently raised intraocular pressure (IOP) without any associated optic
nerve damage. Conversely, the term 'normal tension' or 'low tension' glaucoma is
used for those with optic nerve damage and associated visual field loss, but
normal or low IOP.
Cover both lens entirely with tape except for a dime size hole in the
middle of each lens
6. Diabetic retinopathy – caused by complications of diabetes, which can eventually
lead to blindness. It is an ocular manifestation of systemic disease which affects
up to 80% of all patients who have had diabetes for 10 years or more. Despite
these intimidating statistics, research indicates that at least 90% of these new
cases could be reduced if there was proper and vigilant treatment and monitoring
of the eyes. The longer a person has diabetes, the higher his or her chances of
developing diabetic retinopathy.
Cover each lens with small specks of tape