Flashcards in Txtbk Ch 63 Deck (52):
What are most irritating solutions used for?
Most irritating solutions are used to clean the external lids to maintain lid hygiene, to irrigate the external corneal surface to regain normal pH ( chemical burns), to irrigate the corneal surface to eliminate debris, or to inflate the globe intraoperatively.
What are irrigating solutions composed of?
These solutions have various compositions that include, sodium, K+, mg,Ca, bicarbonate, glucose, and glutathione( substance found in the aqueous humor)
Name a sterile irrigating solution and tell what it is used for?
Dacriose is used for lid hygiene
What is commonly used to irrigate the corneal surface when chemical burns occur?
What do lubricants such as artificial tears help alleviate?
They help alleviate corneal irritation, such as dry eye syndrome
What are artificial tears?
Artificial tears are topical preparations of carboxymethylcellulose or hydrooxypropyl methyl cellulose that are prepared as eye drop solutions, ointments or ocular inserts( inserted in the lower conjunctival cul- de-sac once each day. The eye drops can be instilled as often as every hr, depending on the severity of symptoms.
Why is absorption of eye drops by the nasolacrimal duct undesirable?
Because of the potential systemic side effects of,ocular medications.
Before the administration of eye drops what does the nurse warn the pt. About?
The nurse warns the patient that blurred vision, stinging, and a burning sensation are symptoms that ordinarily occur after instillation and are temporary.
What should a pt. do if the cannot feel the eye drops when they are instilled?
They may be refrigerated, cold eye drops are easier to detect.
What is glaucoma?
The term glaucoma is used to refer to a group of ocular conditions characterized by optic nerve damage.
What does increased IOP do?
IOP damages the optic nerve and nerve fiber layer, the degree of harm is highly variable.
The optic nerve damage Is related to the IOP caused by congestion of aqueous humor in the eye.
Glaucoma is more prevalent in what age group?
In ppl older than 40.
It is the 3rd most common age related eye disorder.
Is there a cure for glaucoma?
It can only be controlled.
Where does aqueous humor flow?
It flows between the iris and the lens, nourishing the cornea and the lens.
90% of the fluid then flows out of the anterior chamber, draining through the spongy trabecular mesh work of the canal of Schlemm and the episcleral veins.
About 10% of the aqueous humor exits from where?
Exits through the ciliary body into the suprachoroidal space and then drains into the venous circulation of the ciliary body, choroid, and sclera.
Unimpeded outflow of aqueous humor depends on what?
On an intact drainage system and an open angle ( about 45 degrees) between the iris and cornea.
** a narrower angle places the iris closer to the trabecular mesh work diminishing the angle.
What happens to aqueous humor as we age?
It tends to decrease with age, in systemic diseases such as diabetes, and in ocular inflammatory conditions.
How is IOP determined?
It is determined by the rate of aqueous production, the resistance encountered by as the aqueous humor flows out of the passages, and the venous pressure of the episcleral veins that drain into the anterior ciliary vein.
When aqueous fluid production and drainage are in balance the IOP is at what mmHg?
What systemic conditions have been assoc with increased IOP?
Diabetes, intraocular conditions such as uveitis and retinal detachment.
What are the 2 theories that suggest how IOP damages the optic nerve?
1.) the direct mechanical theory- suggests that high IOP damages the retinal layer as it passes thru the optic nerve head.
2.) the indirect ischemic theory- suggest that high IOP compresses the microcirculation in the optic nerve head, resulting in cell injury and death.
Some glaucoma appears as exclusively mechanics. And some are exclusively ischemic types. Typically most cases are both.
What are the clinical forms of glaucoma?
Open -angle glaucoma
Angle closure glaucoma
And glaucoma assoc with other conditions such as developmental anomalies or corticosteroid use.
What types of examinations are used in glaucoma?
Tonometry; to measure the IOP
opthalmoscopy; to inspect the optic nerve
Central fied testing
What are the changes in the optic nerve related to glaucoma?
Pallor and cupping of the optic nerve disc.
The pallor of the optic nerve is caused by a lack of blood supply
Cupping is characterized by exaggerated bending of the blood vessels as they cross the optic disc, resulting in a enlarged optic disc that appears more bask like compared with a normal cup.
What is the progression of cupping caused by?
It is caused by the gradual loss of retinal nerve fibers and the loss of blood supply
As optic nerve damage increases, what happens?
Visual perception decreases.
Open angle glaucoma
usually bilateral but one eye may be more severely affected than the other.
In all 3 types of open angle glaucoma, the anterior chamber is open and appears normal.
What are the three types of open angle glaucoma?
1.) Primary open angle glaucoma (POAG)
2.) normal tension glaucoma
3.) ocular hypertension
What is POAG?
Primary open angle glaucoma;
Optic nerve damage, visual field defects, IOP above 21mmHg.
May have fluctuations IOP's.
Usually no symptoms, but possible ocular pain, headache and halos.
What is treatment of POAG?
If medical treatment is unsuccessful, LT can decrease IOP by 20%.
Glaucoma filtering surgery if continued optic nerve damage despite medication therapy and LT.
What is ocular hypertension?
Elevated IOP. Possible ocular pain or headache
What is treatment for ocular hypertension?
Treatment is similar to POAG; however the best management for normal tension glaucoma management is yet to be established. Goal is to lower the IOP by at least 30%
What is normal tension glaucoma?
IOP pressure less than 21mmHg.
Optic nerve damage, visual field defects
What is angle closure glaucoma?
Obstruction in aqueous humor outflow due to the complete or partial closure of the angle from the forward shift of the peripheral iris to the trabecula. The obstruction results in increased IOP.
Name the 3 types of angle closure glaucoma
1.) Acute angle closure glaucoma
2.) subacute angle closure glaucoma
3.) chronic angle closure glaucoma
What is acute angle closure glaucoma?
Rapidly progressive visual impairment, periocular pain, conjunctival hyperemia, and congestion. Pain may be assoc with nausea, vomiting, bradycardia, and profuse sweating.
Reduced central vision acuity, severely elevated IOP, corneal edema. Pupil is vertically oval, fixed in a semidilated position and unread rice to light and accommodation.
What is treatment for acute angle closure angle glaucoma?
administration of hyperosmotics, acetazolamide, and topical ocular hypotensive agents such as pilocarpine and beta blockers ( betacolol)
Possible laser incision in the iris (iridotomy) to release blocked aqueous and reduced IOP.
other eye is also treated with pilocarpine eye drops and or surgical management to avoid a similar spontaneous attack.
What is subacute angle closure glaucoma?
Transient blurring of vision, halos around lights; temporal headache and or ocular pain
Pupil may be semidilated.
What is treatment of subacute angle closure glaucoma?
Prophylactic peripheral laser iridotomy
Can lead to acute chronic angle closure glaucoma if untreated
What is chronic angle closure glaucoma?
Progression of glaucomatous cupping and significant visual field loss. IOP may be normal or elevated; ocular pain and headache
Treatment is similar to POAG which includes laser iridotomy and medications.
What is the aim of all glaucoma treatment?
To prevent optic nerve damage
What are miotics?
Medications that cause pupillary constriction
What ocular meds are used to treat glaucoma?
Miotics, beta blockers, alpha2 agonists, carbonic anhydrase inhibitors and prostaglandins.
What does cholinergics do in regards to the eye?
Cholinergics( miotics) increase the outflow of the aqueous humor by affecting ciliary muscle contraction and pupil constriction , allowing flow thru a larger opening between the iris and the trabecular meshwork.
What decreases aqueous production?
Beta blockers and carbonic anhydrase inhibitors
What reduces IOP
Prostaglandin analogues reduce IOP by increasing aqueous humor outflow.
Peripheral neuropathy (disorder of the nervous system)
Is a disorder affecting the peripheral motor and sensory nerves.
How is peripheral neuropathy characterized?
By bilateral and symmetric disturbance of function, usually beginning in the hands and feet.
Most common cause I'd diabetes with poor glycemic control.
What are the major symptoms of peripheral nerve disorders
Loss of sensation, muscle atrophy, weakness, diminished reflexes, pain and paresthesia of the extremities.
How are peripheral nerve disorders diagnosed
By history, physical examination, and electrodiagnostic studies such as EEG.
What is mononeuropathy?
Is limited to a single peripheral nerve and its branches. It arises when The trunk of the nerve is compressed or entrapped, as in carpal tunnel, traumatized, as when bruised by a blow, or overstretched as in joint dislocation.