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.
What would a pt do with double vision?
Cock the head to the side to focus the two images into one or close one eye to see more clearly
Exophthalmos
Protrusion of the eye, “bulging”
Enophthalmos
Sunken appearance of eye
Anisocoria
Unequal pupils
Nystagmus
Involuntary rapid twitching of the eyeball. Normal finding for the far lateral gaze
Ishihara Chart
Tests color vision by showing numbers composed of dots of one color within a circle of dots of a different color. Test each eye seperately
Slit-Lamp Exam
Magnifies the anterior eye structures. Pt leans chin on a rest
Corneal Stain
Places fluorescein/topical dye into conjunctival sac. The dye outlines irregularities of corneal surface. Used for problems with contacts, and corneal traumas. Noninvasive, performed under aseptic conditions. Viewed through a blue filter, non intact areas of the cornea stain a bright green color
Tonometry
Measures IOP. Indicated for pts over 40, adults w/ family history of glaucoma should test twice a year.
Ophthalmoscopy
Views eye’s external and interior structures. Can be done by a nurse. Start 12-15 inches away. Red reflex is a reflection of the light on the retina. Absent red reflex may indicate a lens opacity or cloudiness of the vitreous. Avoid this test w/ a confused pt and use an interpreter for one who doesn’t speak your language.
Angiography
Provides detailed image of eye circulation. Used for assessing problems of retinal circulation or diagnosing intraocular tumors. Instill mydriatic eyedrops to dilate pupils 1 hour before the test. The dye may cause the skin to appear yellow or green for hours after test. IT eliminates through the urine, which will be bright green, drink fluids. Start an IV and inject 5 mL of 10% fluorescein. A digital camera takes pictures, takes only a few minutes. See results immediately.
Perimetry
Screens visual fields. Pt looks straight ahead and presses a control button when a light enters peripheral vision. Draws a “map” of peripheral vision.
Gonioscopy
Performed when a high IOP is found and determines whether open angle or closed angle glaucoma is present. Uses a special lens that eliminates the corneal curve, is painless, allows visualization of the angle where the iris meets the cornea.
Looks at the bony eye structures and EOM, used for detecting tumors in the orbital space. Not painful, must keep head still. Use contrast dye unless trauma is suspected
CT
Examines orbits and optic nerves, evaluates tumors. DO NOT use with metal in the eye
MRI
Most common method to measure IOP by an ophthalmologist
Goldman’s applanation tonometer with a slit lamp. IOP is usually hight in the morning but may peak at any time of the day. Record the time of procedure and tell pts to measure IOP at the same time each day.
When is easiest to examine the fundus?
When the room is dark bc the pupil will dilate.
How many times does a normal person blink per minute?
5-10
Inflammation of the eyelid edges
Blepharitis
Blepharitis is caused by what in older adults?
Dry eye syndrome
Seborrhea
Greasy and scaly, draining eye. Occurs with blepharitis
Pt’s eye is itchy, red, and burning.
Blepharitis
How to treat blepharitis
Warm compress, dilute baby shampoo, don’t rub
Turning inward of eyelid causing lashes to rub against eye. Corneal abrasion may result from constant irritation
Entropion