Eyes & ears Flashcards
Rods - what type of vision?
Responsible for peripheral vision
Cones - what type of vision?
Responsible for color and central vision.
Canal of Schlemm
Extends around the eye and allows fluid to drain out of the eye into systemic circulation to maintain eye pressure.
Fluorescein angiography
Dye is administered and then photographs are taken of the eye. Assesses retinal circulation problems including - diabetic retinopathy, retinal bleeding and macular degeneration.
Tonometry
Assesses for an increase in ocular pressure and potential glaucoma. Non-contact involves puffs of air into the eyes, contact - a flattened cone pushes on the cornea.
Myopia
Nearsightedness
Hyperopia
Farsightedness
Astigmatism
The cornea has an irregular shape causing light to focus on two areas of the retina instead of one.
LASIK
Treatment for refractive errors (myopia, hyperopia and astigmatism), flap of cornea is cut and deeper cornea underneath is reshaped.
Legal blindness
20/200 or worse with 20% field in better eye.
Cataracts
Lens opacity which distorts the image projected onto the retina.
Early signs of cataracts
Blurred vision, decreased color perception.
Glaucoma
Group of ocular diseases which are characterized by an increase in ocular pressure. Increased pressure damaged the optic nerve and can lead to blindness.
Acute angle glaucoma
Blockage to the ocular drain. This is A MEDICAL EMERGENCY. Patient will see halos around lights, have blurred vision and ocular erythema.
Retinal Detachment
Separation of the retina from the epithelium. Blindness occurs with complete detachment.
Signs and symptoms of retinal detachment
- Flashes of light
- Floaters or black spots
- Increasing blurred vision
- Painless loss of central or peripheral vision.
Macular degeneration and its treatment
Deterioration of the macula (central area of vision). Treatment aims to maximize remaining vision with laser, photodynamic or other therapies.
Eneucleation
Removal of the eyeball
Exenteration
Removal of the eyeball and surrounding tissues and bone.
Hyphema
Blood in the anterior eye chamber. Usually resolves in 5-7 days.
Tomography
Done with or without contrast and is used to diagnose acoustic tumors.
Audiometry
Measures hearing acuity.
Electrostagmagraphy (ENG)
Evaluates spontaneous and induced eye movements. NPO and no caffeine for 24-48 hours pre-op. No unnecessary meds 24 hours pre-op.
Risk factors for ear disorders
- Aging process
- Infection
- Medications
- Ototoxicity
- Trauma
- Tumors