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56 Cards in this Set
- Front
- Back
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What are the 3 primary functions of the pupils?
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1. controls entering light
2. controls depth of function 3. varies optical aberrations |
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correctopia
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displaced or irregularly shaped pupil
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ectopic pupil
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significantly decentered pupil
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polycoria
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more than one pupil
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heterochromia
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different colored irises in the two eyes
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aniridia
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no iris and no pupil
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what is anisicoria and what are three possible reasons for it
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unequal pupil sizes. causes can be physiologic, pharmacologic, and pathologic
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what does the iris dilator muscle do and how is it innervated?
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dilates pupil, innervated sympathetic innervation.
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what does iris sphincter muscle do and how is it innervated?
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contstricts pupil, parasympathetic innervation. this is stronger than the dilator
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what is the parasympathetic route to constrict the pupil?
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1. EW nucleus with CN 3 toward eye
2. through cavernous sinus pierces globe 3. deviates from CN 3 to synapse with the ciliary ganglion 4. post ganglionic fibers reach iris sphincter through short ciliary nerves |
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What does the parasympathetic route mostly control? (efferent)
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accomadation only 3% of the fibers innervate the iris sphincter
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What is the sympathetic route to iris dilation?(efferent)
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1.originates in the hypothalamus
2.post-ganglionic neurons follow the ICA to the globe 3. reach the iris dilator via the long ciliary nerve (also goes to Mueller's muscle in the upper lids) |
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What is pupillary unrest or hippus?
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small oscillations in pupillary diameter that occur during maintained stimulation
-due to normal fluctuations of the parasymp/symp equilibrium. |
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What is the afferent response to light entering the pupil?
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1. light enters pupil
2. 1/2 fibers cross at the optic chiasm 3. follow optic tracks to superior colliculi 4. then go to the pretectal nuclei of the hypothalamus 5. both crossed and uncrossed fibers are sent to the EW nucleus synapse with efferent fibers RESULT--> direct and consensual response |
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What is the Triad near response?
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1.accomadation
2.convergence 3.miosis |
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If direct light response is present is it possible not to have the near reflex?
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NO!
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What should you do first if you notice a patients pupils are unequal in normal lighting?
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Measure the size of the pupils in dark and bright lighting.
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What does the swinging flashlight test look for?
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Differences in strength between the direct and consensual responses.
Detects an APD afferent pupillary defect. retinal anomalies or ON pathways anterior to the LGN. |
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What would you expect to find when preforming the swinging flashlight test?
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-rate and amount of constriction should be the same for both pupils
-direct should equal consensual for both eyes |
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If you notice that there is different amount of constriction while preforming the swinging flashlight test which eye has the APD?
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The eye with the least constriction
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What does PERRLA stand for?
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PE=pupils equal
R=round RL=reactive to light A=responsive to accomadation |
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afferent pupil anomalies result in what?
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APD or Marcus Gunn pupil
-severe retinal disease -Optic Nerve Disease or compromise -mass or lesion behind the eye compressing the Optic Nerve or chiasm |
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Efferent pupil anomalies result in what?
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usually anisicoria
-CN 3 compromise -sympathetic lesions |
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APD
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when the consensual response is greater than the direct response of one eye
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If a person has an APD what will happen when the light is directed to the affected eye?
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Both eyes will have less constriction
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describe the ranges for the APD grading system from trace to 4+.
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trace -initial constriction but escapes to larger size when compared with other eye
1-2+ -no change is size initially followed by a dilation 3-4+ -immediate dilation instead of constriction |
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What is an amourotic pupil
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severe of 4+ APD. patients have an eye with no light perception, near reflexes still intact.
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why would you use the reverse APD technique?
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If one pupil is fixed preform the swinging flashlight test but only observe the reactive pupil.
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if you notice anisicoria and check in both dark and bright conditions and find the same degree of anisicoria what is the cause?
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physiologic 20% of population, look at old photographs
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Big pupil problems are defects in what?
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The parsympathetic nervous system
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How can you tell you have a big pupil problem and what three things could it possibly indicate?
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You have a big pupil problem if anisicoria is greater under bright conditions.
This could indicate; Adies Tonic pupil, CN 3 palsy, or pharmacologic dilation |
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describe Adie's Tonic pupil
(who is it most common in, what does pupil do?, ect) |
most commonly in 20-40 year old women, unilateral semi-dilated pupil, vermiform motion of the iris, pupil has minimal and slow reaction to light, accommodation can also be affected.
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What is the etiology of Adie's tonic pupil?
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viral, lesion to the ciliary ganglion
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How do you diagnose Adie's Tonic pupil?
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.125% pilocarpine wait 10-15 minutes if it constricts it is Adie's if not it is either CN 3 palsy or pharmacological
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How does Cranial Nerve III usually present?
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Eye will be Down and out, (hypotropia and exotropia),ptosis
If pupil is involved it is a medical emergency (pupil fibers are outside of CN3 so if pupil is involved it is probably a compressive lesion) |
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What is CN 3 palsy's possible etiology?
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tumor, aneurysm, vascular disease causing ischemia
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How do you diagnose CN
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.125% pilocarpine will not constrict the pupil
1% pilocarpine will constrict the pupil |
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What are some of the possible causes of a pharmacological dilation?
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scopolamine, jimsonweed, anti-histamine drops, atropine, homatropine
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How do you diagnose a pharmacological dilation?
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neither .125% or 1% pilocarpine will constrict the pupil?
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When is anisicoria greatest if there is a little pupil problem?
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anisicoria is greater in dim conditions
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what are the possible etiologies of a little pupil problem?
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Horner's, pharmacological, Argyl-Robinson pupil
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How does Horner's Pupil present?
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-miosis
-ptosis -anhydrosis all on the same side as the lesion |
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What are the etiologies of horner's pupil?
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1. congenital
2. central lesions 3. pre-ganglionic lesions 4. post-ganglionic lesions |
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How do you diagnose Horner's?
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Look at old photographs, ask about history of trama, endardectomy, thryroidectomy, dilation lag test.
-Horner's pupil has a dilation lag in the dark of about 15 seconds Pharmacologically .5% aproclonidine, and 10% cocaine drops will dilate |
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Hod do you distinguish pre and post ganglionic horner's?
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1. test for anhydrosis post ganglionic lesions usually do not have anydrosis
2. 1% hydroxyamphetamine fails to dilate= definatly post-ganglionic |
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Describe features of Argyll-Robinson pupils
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bilateral, miotic, irregular pupils, hard to dilate, direct and consensual responses are absent or sluggish
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What is the etiology of AR pupil?
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Neurosyphalis or Neuropathy from diabetes or alchoholism
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What drugs can cause pharmacological constriction of the pupils?
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pilocarpine, physostigmine
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What happens in midbrain lesions?
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bilaterally reduced direct response, VA unafected, near reflex intact.
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what are etiologies of midbrain lesions?
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parinoud's opthalmoplegia, AR pupil
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What is iris coloboma?
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keyhole pupil usually affects the inferior nasal iris.
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What is an iridectomy?
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surgically created sector of the iris.
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What is the persistant pupillary membrane?
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persistant embryolic structure filament like strands, rarely affects pupillary movement.
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What is iridialysis?
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tear at the iris root causes a d-shaped pupil, can cause monocular diplopia if the tear is large
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What is a posterior synechia?
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attatchment of iris to anterior lens surface from active history of anterior uveitis or intraocular inflammation.
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what is iridonesis?
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quivering of the iris
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