Glaucoma Flashcards
What is glaucoma?
Glaucoma is an increase in intraocular pressure that results in a
decrease in blood flow to the optic nerve and it can progress to
optic nerve damage and loss of vision.
Fleisher LA. Anesthesia and Uncommon Diseases. 6th ed.
Philadelphia, PA: Elsevier Saunders; 2012: 4.
What are the two types of glaucoma?
Open-angle (chronic) glaucoma and closed-angle (acute)
glaucoma.
Fleisher LA. Anesthesia and Uncommon Diseases. 6th ed.
Philadelphia, PA: Elsevier Saunders; 2012: 4.
What glaucoma medication can prolong the effects
of succinylcholine?
Echothiophate is used to treat glaucoma and irreversibly
antagonizes cholinesterase. Because of this effect, it will
prolong the duration of action of succinylcholine. The duration
of paralysis usually does not exceed 20-30 minutes, however.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 763.
What is the normal intraocular pressure?
The normal intraocular pressure is about 10 to 21 mmHg.
Pressures above 22mmHg are considered intraocular
hypertension.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 1376.
What are the two factors that determine intraocular
pressure?
The two factors that determine intraocular pressure are the rate
of formation of aqueous humor and the rate of drainage of the
aqueous humor.
Fleisher LA. Anesthesia and Uncommon Diseases. 6th ed.
Philadelphia, PA: Elsevier Saunders; 2012: 4.
What physiologic factors will increase intraocular
pressure?
Factors that increase the intraocular pressure include:
increased central venous pressure, increased arterial blood
pressure, increased PaCO2 (hypoventilation), and hypoxia.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 760.
At what point during the day is intraocular pressure
the highest?
Intraocular pressure is higher in the morning, presumably from
venous congestion due to the eyes being closed.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 1376
What is the pathophysiologic difference between
open-angle and closed-angle glaucoma?
Open-angle glaucoma is characterized by a patent anterior
chamber angle and the drainage of aqueous humor is impaired
by sclerosis of the trabecular tissue. In closed-angle glaucoma,
the drainage of aqueous humor is impaired by a shallow
anterior chamber and a narrow iridocorneal angle that results in
the trabecular network being obstructed by the iris.
Fleisher LA. Anesthesia and Uncommon Diseases. 6th ed.
Philadelphia, PA: Elsevier Saunders; 2012: 4-5.
What are the symptoms of acute angle-closure
glaucoma?
Ocular pain, blurred vision, and fixed, mid-dilated pupils. If not
treated promptly, permanent visual loss can occur due to
damage to the optic nerve.
Fleisher LA. Anesthesia and Uncommon Diseases. 6th ed.
Philadelphia, PA: Elsevier Saunders; 2012: 6.
What is the treatment for acute angle-closure
glaucoma?
If reduction in intraocular pressure doesn’t occur promptly with
medical treatment, surgical iridotomy/iridectomy should be
performed.
Fleisher LA. Anesthesia and Uncommon Diseases. 6th ed.
Philadelphia, PA: Elsevier Saunders; 2012: 5-6.
What is the principal treatment for open-angle
glaucoma?
Treatment consists of medications that produces miosis and
stretching of the trabeculae.
Fleisher LA. Anesthesia and Uncommon Diseases. 6th ed.
Philadelphia, PA: Elsevier Saunders; 2012: 4.
How does mannitol affect intraocular pressure?
Mannitol, dextran, urea, and sorbitol all decrease intraocular
pressure by exerting a hyperosmotic effect that decreases
aqueous humor formation by the ciliary body.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 1376.
Is atropine contraindicated in patients with
glaucoma?
The amount of atropine typically administered preoperatively
(0.4 mg IV) results in approximately 0.0001 mg absorbed by the
eye which many practitioners regard as having an insignificant
effect on intraocular pressure. Scopolamine has a greater
mydriatic effect than atropine and is not recommended for use
in patients with glaucoma.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 1377.
What specific actions should you incorporate into the
anesthetic for patients with glaucoma? What factors
will increase intraocular pressure?
Preoperatively, instill miotic drops to enhance aqueous humor
drainage, avoid venous congestion and overhydration, avoid
coughing (which increases venous pressure), and avoid
hypotension that could promote thrombosis in retinal vessels.
Succinylcholine can increase intraocular pressure (IOP).
Nondepolarizing agents either decrease the IOP or have no
effect on it. Volatile anesthetics, nitrous oxide, opioids,
benzodiazepines, and barbiturates all decrease the IOP.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 760-761
