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Flashcards in low vision Deck (18)
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1

disorders of the lens: what is refraction?

Refraction refers to deflection or bending of light as it it passes from one transparent medium to another in different density

2

Disorders of Refraction

Hyperopia or “farsightedness”
Distant objects may be seen more clearly than objects that are near (near objects are blurry)
Anterior-posterior dimension of the eyeball is too short
Point of focus: behind the retina

Myopia or “nearsightedness”
Close objects appear clearly, but far ones don’t
Anterior-posterior dimension of the eyeball is too long
Point of focus: in front of the retina

3

disorders of the lens: accommodation

Accommodation refers to the ability of the eye to adjust its focus from far to near objects by changing the shape of its lens.

4

disorders of accommodation

Cycloplegia

Presbyopia

5

what is paralysis of the ciliary muscles of the eye resulting in pupillary dilation

Cycloplegia

6

Presbyopia

With aging, lens thickens and its capsule becomes less elastic
Inability to read small print or discriminate close objects
Worsening of symptoms:
Dim light
Upon arising in morning
Fatigue

7

disorders of the retina: macular degeneration

characterized by degeneration in the central portion of the retina= resulting in loss of central vision

8

is leading cause of reduced vision in elderly

Age-related macular degeneration (AMD)

9

Affects 80-90% of individuals with AMD
Cause: Unknown
Progress more slowly than the wet type
Small white or yellowish deposits (drusen) form on the retina, beneath the macula, causing it to deteriorate or degenerate over time

Dry Macular Degeneration

10

Affects 10-15% of individuals with AMD
Accounts for approximately 90% of all cases of severe vision loss from the disease
Abnormal blood vessels under the retina begin to grow toward the macula
Blood vessels break, bleed, and leak fluid
Result: Damage to the macula, causing it to lift up and pull away from its base
Rapid and severe loss of central vision

Wet Macular Degeneration

11

disorders of the retina: AMD prevalence

>1.75 million individuals in U.S.
Age
Women
Caucasians
Cause: Unknown

12

risk factors of AMD

Risk factors:
Cigarette smoking
Obesity
Low dietary intake (lutein, omega 3 fatty acids, zinc, Vitamins A, C, and E)
Genetics
Race

13

Disorders Intraocular Pressure: glaucoma

Chronic, progressive disease of optic nerve
A pressure-induced degenerative neuropathy that produces changes in the optic nerve and causes visual field loss.

Etiology:
Cause: Unknown
Risk factors:
Genetic
Age
Race
Hypertension

14

leading cause of blindness in black ppl

glaucoma

15

symptoms of glaucoma

Decreased or blurred vision
Headache
Sudden eye pain

Progression, if untreated:
Initially asymptomatic
Slow loss of peripheral vision
Loss of central vision

16

types of glaucoma

extreme, advanced, early glaucoma

17

A health care provider who specializes in refractive errors, prescribes eyeglasses or contact lenses and diagnoses and manages conditions of the eye as regulated by state laws.
May also perform low vision examinations

optometrist

18

A physician who specializes in the medical and surgical care of the eyes and is qualified to prescribe ocular medications and to perform surgery on the eyes.

opthalmologist