NURS 133 Eye anatomy and disorders

jasmine's version from 2016-05-22 03:54

Section 1

Question Answer
Cornea Clear front window of the eye that transmits and focuses light into the eye
Iris Colored part of the eye that helps regulate the amount of light that enters
Pupil Dark aperture in the iris (black circular opening in the center of the iris of the eye, through which light passes to the retina [from the tiny image reflected in it]) that determines how much light is let into the eye
Lens Transparent structure inside the eye that focuses light rays onto the retina
Retina Nerve layer that lines the back of the eye, senses light, and creates electrical impulses that travel through the optic nerve to the brain
Macula Small central area in the retina that contains special light-sensitive cells and allows to see fine details clearly
Optic nerve Connects the eye to the brain and carries the electrical impulses formed by the retina to the visual cortex of the brain
Vitreous Clear, jelly-like substance that fills the middle of the eye
To maintain a healthy level of pressure within the eye A small amount of aqueous humor is produced constantly, while an equal amount flows out of the eye through a microscopic drainage system called the trabecular meshwork

Section 2

Question Answer
Glaucoma A group of eye diseases that affect the optic nerve and may cause vision loss
Optic nerve damage in glaucoma Primarily due to elevated intra-ocular pressure (IOP) within the eye. Classified as either open-angle (more common chronic condition, which is painless) or angle-closure glaucoma (more usual condition, which often occurs suddenly [acutely] and is associated with pain and redness of the eye)
Open-angle glaucoma The most common form of glaucoma, and is progressive and characterized by optic nerve damage; Usually no symptoms, yet eye pressure gradually builds, and at some point the optic nerve is impaired, and peripheral vision is lost; If untreated, blindness results
Risk factors for open-angle glaucoma include High eye pressure (IOP; intraocular pressure); Family history of glaucoma; High myopia (nearsightedness); Diabetes; Eye surgery or injury; High blood pressure; Use of corticosteriods (e.g., eye drops, pills, inhalers, and creams); Age 40 and older for African Americans; Age 60 and older for the general population, especially Mexican Americans; Thin cornea; and Suspicious optic nerve appearance with increased cupping (the size of cup, the space at the center of optic nerve, is larger than normal)
Closed-angle glaucoma A less common and more urgent form of glaucoma; The drainage angle of trabecular meshwork becomes blocked by the iris; IOP builds up very fast; May be acute or chronic; Must be treated as medical emergency
Acute closed-angle glaucoma The normal flow of eye fluid (aqueous humor) between iris and the lens is suddenly blocked
Symptoms of acute closed-angle glaucoma include Severe pain, nausea, vomiting, blurred vision and seeing a rainbow halo around lights
Acute closed-angle glaucoma is A medical emergency and must be treated immedicately or blindness could result in one or two days
Chronic closed-angle glaucoma progresses more slowly and can damage the eye without symptoms, similar to open-angle glaucoma
Question Answer
Symptoms of Closed-angle glaucoma include Severe eye or brow pain, redness of the eye, decreased or blurred pressure
Risk factors for closed-angle glaucoma include Age; Family history; Poor short-distance vision (farsightedness); Eye injury or eye surgery; East Asian and Inuit ethnicity
Normal-tension glaucoma Occurs when eye pressure is normal, yet the optic nerve is damaged and peripheral vision is lost; Lowering eye pressure through medication sometimes slows the progress of the disease, yet this type of glaucoma may worsen despite low pressure; Treatment is generally the same as for open-angle glaucoma with high eye pressure
Risk factors for normal-tension glaucoma include Cardiovascular disease; Family history of glaucoma; Japanese ethnicity; Low eye pressure IOP
Congenital glaucoma Affects infants born with defects that prevent the normal drainage of fluid from the eye
Juvenile glaucoma Open-angle glaucoma that affects children, adolescents, and young adults
Secondary glaucoma Can be open-angle or closed-angle, and is the result of some other medical condition in the eye or the body
Examples of secondary glaucoma Pigmentary glaucoma; Pseudoexfoliation syndrome; Neovascular glaucoma; Iridocorneal endothelial syndrome
Pigmentary glaucoma Rare form; Pigment granules form the iris flake off into the eye fluid (aqueous humor) and clog the eye’s drainage system (trabecular meshwork)
Pseudoexfoliation syndrome Occurs when white material appears to flake off the lens of the eye and block normal flow of the aqueous humor
Neovascular glaucoma Occurs when abnormal blood vessel growth blocks the eye’s fluid drainage channels and leads to increased eye pressure; Can be caused by low blood supply to the eye due to diabetes, insufficient blood flow to the head due to blocked neck arteries, or blood vessel blockage in the back of the eye
Iridocorneal endothelial syndrome Has a number of features, including the breaking off of cells from the cornea, which blocks the drainage channels in the eye and leads to increased eye pressure; Scars may also connect the iris to the cornea

Section 3

Question Answer
Two routine eye tests for regular glaucoma check-ups Tonometry and Ophthalmoscopy
Tonometry Eye pressure test IOP
Applanation tonometry Measures intraocular pressure either by the force required to flatten a constant area of the cornea (e.g., Goldmann tonometry) or by the area flattened by a constant force
Goldmann tonometry Stationary device requires anesthesia drops, requires contact with cornea, and is attached to a slit lamp; Used by an Ophthalmologist
Non-contact tonometry or air-puff tonometry Uses a rapid air pulse to applanate (having a horizontally flattened form) the cornea; Intraocular pressure is estimated by detecting the force of the air jet at the instance of applanation (method of checking eye pressure); Does not require anesthetic drops
Tono-pen A portable electronic, digital pen-like instrument that determines IOP by making contact with the cornea, after use of topical anesthetic eye drops-tip convers are used between patients
Newest advancement in tonometry Diaton tonometer
Diaton tonometer Measures intraocular pressure through the eyelid; Requires no contact with cornea, no anesthetic drops, and no risk of infection; Intended for use by inpatient and outpatient clinics; Can be used on children and adults, as it is safe, quick, efficient, painless, and noninvasive
Glaucoma must be monitored for Life
Is there a cure for glaucoma? No, and is leading cause of blindness-second leading in the world according to WHO
Ophthalmoscopy Allows a health professional to see inside the back of the eye (called the fundus) and other structures using a magnifying instrument (ophthalmoscope) and a light source; Atropine may be used to dilate the pupil
Perimetry Also called a visual field test
Gonioscopy Painless eye test that checks if the angle where the iris meets the cornea is open or closed, showing if either open-angle or closed-angle glaucoma is present

Section 4

Question Answer
Visual loss in Glaucoma Can only be halted Not reversed
Are there symptoms in early stages of Glaucoma? No, and by the time the patient notices vision changes, the visual loss can only be halted not reversed
Treatment for Glaucoma Eye drops, although lasers and surgery can also be used
What is the key to preserving sight in people with Glaucoma? Early diagnosis and treatment
Cataract Painless condition where the normally clear and lens of the eye starts to become cloudy; The result is much like smearing grease over the lens of a camera, which impairs normal vision
Causes of Cataracts Cortisone medication, trauma, diabetes, and aging; Will affect most people if they live long enough
Symptoms of early Cataracts may be improved what? New eyeglasses, brighter lighting, anti-glare sunglasses, or magnifying lenses
If eye glasses, brighter lighting, anti-glare sunglasses, or magnifying lenses does not relieve symptoms of Cataracts, what other measures are used? Surgically removing the cloudy lens and replacing it with an artificial lens is the only other effective treatment; Removal is only necessary when vision loss interferes with every day activities, such as driving, reading, or watching TV; In most cases, delaying Cataract surgery will not cause long-term damage to the eye or make the surgery more difficult
Retinal detachment Separation of the retina from its attachments to its underlying tissue within the eye; It is a medical emergency; Can cause blindness unless treated
What are most retinal detachments a result of? Retinal break, hole, or tear
What happens when the retinal tears? Liquid from the vitreous gel (clear gel that fills most of the inside of the eye) passes through the tear and accumulates behind the retina; It is the buildup of fluid behind the retina that separates (detaches) the retina from the back of the eye
Symptoms of Retinal detachment Flashing lights, floaters (little cobwebs or specks that float about the field of vision), or a curtain over the field of vision
At what age does Retinal detachment occur? Any age, yet occurs most commonly in younger adults aged 25-50, who are slightly nearsighted, and in older adults following Cataract surgery
Treatment of Retinal detachment Surgical repair, and more than one procedure may be necessary; Once retina is attached, vision usually improves and then stabilizes
Pink eye bacterial conjunctivitis or Conjunctivitis Redness and inflammation of the membranes (conjunctiva) covering the white of the eyes (sclera) and the membranes on the inner part of the eyelids