Exam 4 Flashcards
Hyperopia
Farsightedness, occurs when the eye doesn’t bend light enough
Myopia
Nearsightedness, occurs when the eye overbends light
Refraction
Bending light rays into the eye to the retina and reflecting back out so you can see an image
Emmetropia
Perfect refraction of the eye, 20/20 vision
Astigmatism
Refractive error caused by uneven curved surfaces in the eye, usually the cornea. The uneven surfaces distort vision
Miosis
Pupillary constriction
Mydriasis
Pupillary dilation
Older adults cornea
Flattens and blurs vision, worsens astigmatism. Encourage them to wear corrective lenses for best vision
Older adults’ ocular muscles reduce in strength, making it harder to maintain an upward gaze/maintain a single image. What do you tell them?
Normal, re-focus your gaze frequently to maintain a single image.
Older adults lens
- Hardens, compacts, forms cataracts, yellows
- Elasticity is lost, making the point of best vision farther away
- Encourage wearing glasses and yearly eye exams
Older adults iris
- Decreases in ability to dilate resulting in small pupils and poor adaption to darkness
- Teach good lighting to avoid falls
Older adults color vision
- Difficulty in discriminating among greens, blues, and violets
- Don’t use “dipstick” or other color indicator monitors of health status
- More light is needed to stimulate photoreceptors
Tear production in older adults
- Reduced, resulting in dry eyes, discomfort, increased risk for corneal damage/eye infections (more common in women)
- Teach pt to use saline eyedrops on a schedule, increase humidity in the home
Arcus senilis
An opaque, bluish white ring on the outer edge of cornea, caused by fat deposits. Very common with aging, doesn’t affect vision
Intraocular pressure in older adults
Slightly higher
Presbyopia
The point at which an object can be can be seen clearly decreases. Objects must be placed farther away. Commonly begins in 40s
Glaucoma
Increase intraocular pressure with aging causes hypoxia of photoreceptors and nerve fibers. Extra pressures push on capillaries and nerve fibers, preventing blood flow.
Cataract
A lens loses its transparency.
Lens
Circular convex structure behind the iris that bends rays of light through the pupil so they focus on the retina
Which drugs tend to dry the eye and increase IOP?
Decongestants and antihistamines
Systemic conditions which can affect vision
Diabetes, HTN, Lupus erythematosus, thyroid dysfunction, immune deficiency, sarcoidosis, cardia dz, multiple sclerosis, pregnancy
Vitamin A deficiency
Can cause dry eye, karatomalacia, blindness
Diet for eye health
Rich in fruit and red, orange, and dark green veggies. Lutein and beta carotene maintain retinal function
When do you notify an ophthalmologist immediately?
For sudden or persistent loss of vision within the past 48 hours, eye trauma, foreign body in eye, or sudden ocular pain.