Neuro - Anat & Phys (Eye Applications Pt. 1) Flashcards
Pg. 478-479 in First Aid 2014 Sections include: -Glaucoma -Cataract -Papilledema -Extraocular muscles and nerves -Testing extraocular muscles
What is glaucoma, and its characteristic sign? What other 2 signs/symptoms are associated with it?
Optic disc atrophy with characteristic cupping, usually with increased intraocular pressure (IOP) and progressive peripheral visual field loss
What are 3 factors associated with open angle Glaucoma?
Associated with (1) Increased age, (2) African-American race, (3) Family history.
What kind of pain do patients with open angle glaucoma experience?
Painless
What are the types of glaucoma? Which is more common in the U.S.?
(1) Open angle (More common in U.S.) (2) Closed/Narrow angle
What is the cause of primary versus secondary open angle glaucoma?
PRIMARY: cause unclear; SECONDARY: blocked trabecular meshwork from WBCs (e.g., uveitis), RBCs (e.g., vitreous hemorrhage), retinal elements (e.g., retinal detachment);
What is the pathogenesis of primary closed/narrow angle glaucoma and its effects?
Primary - enlargement or forward movement of lens against central iris (pupil margin) leads to obstruction of normal aqueous flow through pupil –> fluid builds up behind iris, pushing peripheral iris against cornea and impeding flow through trabecular network
What is the pathogenesis of secondary closed/narrow angle glaucoma and its effects?
Secondary - hypoxia from retinal disease (e.g., diabetes, vein occlusion) induces vasoproliferation in iris that contracts angle
How does chronic closure glaucoma often present? With what 2 kinds of damage is it associated?
Often asymptomatic with damage to optic nerve and peripheral vision
Which type of glaucoma is a true ophthalmic emergency?
Acute closure (of closed/narrow angle) - true opthalmic emergency
What is the cause and effect associated with acute closure glaucoma?
Increase IOP pushes iris forward –> angle closes abruptly
What are 5 signs/symptoms associated with acute closure glaucoma?
(1) Very painful, (2) Sudden vision loss, (3) Halos around lights, (4) Rock-hard eye, (5) Frontal headache.
What drug should not be given to patients with acute closure glaucoma, and why?
Do not give epinephrine, because of its mydriatic effect.
What is catarct, and how does it present?
Painless, often bilateral, opacification of lens –> decrease in vision
What are 10 risk factors associated with cataract?
Risk factors: (1) Increased age, (2) Smoking, (3) EtOH, (4) Excessive sunlight, (5) Prolonged corticosteroid, (6) Classic galactosemia, (7) Galactokinase deficiency, (8) Diabetes (sorbitol), (9) Trauma, (10) Infection.
What is papilledema, and what causes it? Is it usually bilateral or unilateral?
Optic disc swelling (usually bilateral) due to increased intracranial pressure (e.g., secondary to mass effect)
What is seen on fundoscopic exam of patients with papilledema?
Enlarged blind spot and elevated optic disc with blurred margins seen on fundoscopic exam.
Draw the eye and label the following extraocular muscles attached to it: (1) Superior rectus m. (CN III) (2) Superior oblique m. (CN IV) (3) Trochlea (4) Medial rectus m. (CN III) (5) Inferior rectus m. (CN III) (6) Inferior oblique m. (CN III) (7) Lateral rectus m. (CN VI).
See p. 479 in First Aid 2014 for visual in middle of page
Which cranial nerves are associated with each of the following extraocular muscles: (1) Superior rectus m. (2) Superior oblique m. (3) Lateral rectus m. (4) Medial rectus m. (5) Inferior rectus m. (6) Inferior oblique m.
(1) CN III (2) CN IV (3) (CN VI (4) CN III (5) CN III (6) CN III; Think: “cn VI innervates the Lateral Rectus, cn IV innervates the Superior Oblique, cn III innervates the Rest. The chemical formula LR6SO4R3.”
What are the symptoms seen with CN III damage?
Eye looks down and out; Ptosis, pupillary dilation, loss of accommodation
What are the symptoms seen with CN IV damage?
Eye moves upward, particularly with contralateral gaze and head tilt toward the side of the lesion
What are the symptoms seen with CN VI damage?
Medially directed eye that cannot abduct
What is a problem that these patients with CN IV may have? What is a way that they compensate for this damage?
Problems going down stairs, may present with compensatory head tilt in opposite direction
What 3 actions does the superior oblique have on the eye?
The superior oblique abducts, intorts, and depresses while adducted
Draw an image depicting the direction the patient must look in order to test each of the extraocular muscles.
See p. 479 in First Aid 2014 for visual at bottom
Where should your patient look if you are trying to test the Inferior Oblique?
IOU: To test Inferior Oblique, have patient look Up
In what direction do the oblique muscles (superior and inferior) move the eye in reference to each other?
Obliques move the eye in the Opposite direction
