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135 Cards in this Set
- Front
- Back
what does Rose Bengal stain
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1. epithelial surface that has been deprived of mucin protein protection
2. has exposed epithelial cell membranes |
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Sclerotic scatter is used to illuminate what part of the eye?
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limbus
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what is the color indicator for Rose Bengal?
what light is it viewed under? |
light bluish red->dark red->intense red
the deeper the hue, the more damaged the cells are WHITE LIGHT!! |
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Sclerotic Scatter can be used
to see what problems? |
1. central corneal edema
2. central corneal haze 3. scarring 4. gross view of the angle |
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what is Rose Bengal used to diagnose
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keratitis
severe dry eye |
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What can be found with Retroillumination?
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Media opacities
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how will Rose Bengal look on a Herpes Simplex Keratitis patient
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brightly stains the damaged epithelial cells on the ulcer border
sometimes HSK wont stain with Fluorescein because the epithelial lesion has healed...but will stain with Rose Bengal |
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what is Specular Reflection?
what mag is it done on? |
Used to view corneal endothelium, done at 25X mag
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Difference between Lissamine Green and Rose Bengal
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Lissamine Green is LESS irritating but is NOT an instant stain (have to wait a little bit to stain)
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What is Tangential illumination used for?
how is it done? |
Viewing the iris-
beam and oculars are at right angles to each other (good to examine contact lens fits.) |
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how does Fluorescein look under white light? cobalt blue?
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white light: yellow-orange
cobalt blue: green-yellow |
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What does the anterior lens capsule resemble?
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Orange peel
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what is Fluorescence?
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ability of certain substances to absorb light of certain wavelengths and emit light at longer wavelengths
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What does posterior lens capsule look like?
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Onion layers
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how does Fluorescein work?
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cannot penetrate that cell membranes of the epithelial cells nor the zonula occludens (tight junctions between epithelial cells) but it shows BREAKS IN THE CELLULAR SPACES
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What is the purpose of tonometry?
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To measure intraocular pressure in mmHg
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clinically how does Fluorescein work if there IS epithelial loss?
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the dye can spread into the stromal tissue and enter the anterior chamber where it appears as a green aqueous flare
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What is the imbert-fick law?
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Pressure= Force/Area
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how is Fluorescein used to assess retinal leakage
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Fluorescein is injected and the retina is viewed with cobalt blue. green-yellow spots is indicate leakage
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What is applanation?
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Amount of force required to flatten a known area
of cornea to determine IOP |
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what are the 3 MAIN LAYERS of the tear film
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outer lipid layer*
middle aqueous layer inner mucin layer* *serves as protection from evaporation for the aqueous layer |
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What might you notice after multiple tonometry readings on the same patient?
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Decrease in IOP because of outflow of aqueous
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how will dry spots look on a NaFl stained cornea (TBUT)
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black spots/streak against a solid green glow
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Schiotz Tonometry
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Influenced by ocular rigidity
measures depth of indention caused by a known weight. |
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what is a normal TBUT? reduced?
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Normal: ~15 seconds
Reduced: <10 seconds |
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Goldmann Tonometry measures what?
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Force required to flatten a known area of the cornea
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what should TBUT be performed in relation to the chronology of slit lamp
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prior to instillation of any topical anesthetics/dilating agents
hold their lids if the blink too much |
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Non-contact tonometry measures what?
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1.force of air necessary to applanate a known area
2.area is measured with a photo-electric cell |
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(TBUT) how should you handle a patient with soft contacts lenses? hard contact lenses?
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soft contact lenses will absorb the dye, so you must rinse the dye out before putting the soft contact lenses back in
hard contacts lenses will NOT ABSORB the stain. |
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How much area does a goldmann tonometer applanate the cornea?
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3.06mm
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what do you do if you come across paradoxical findings
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if a patient complains of dry eye and shows OVER TEARING...retest with TOPICAL ANESTHETICS
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What is 1 gram of force in IOP?
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10mmHg
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Advantages to Direct Ophthalmoscopy
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1.greatest patient comfort (rheostat)
2.you see as well as the patient sees out 3.portable 4.used w/ small pupils 5.most accurate estimation of media opacification 6.estimate patients refractive error |
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When do you change the axis
on the side of the tonometer? |
When the patient has more than 3D of cylinder power
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how do you enhance field of view for ophthalmoscopy
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Panoptic
Dilation Move closer to patient |
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Where should the light source be
if you are checking IOP? |
60 degrees
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what type of image is seen through ophthalmoscopy
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15X Magnification
virtual erect |
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What must you record after tonometry?
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1.mmHg for each eye
2.time of day 3.drops used 4.if you have to hold lids |
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who has more magnification myopes or hyperopes
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myopes: MORE magnification
hyperopes: LESS magnification AM=F/4, emmetropes=60D 3D Myopes=63/4=15.75X 3D Hyperopes=57/4=14.25X |
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What is an acceptable pressure difference between 2 eyes?
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3mmHg
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what are the three filters in the ophthalmoscope
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Spot Size
Streak/Slit Cobalt Blue Filter Red-Free Filter (green light) |
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What might you notice after multiple tonometry readings on the same patient?
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Decrease in IOP because of outflow of aqueous
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what is red free used for
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1.highlight small hemorrhages and nerve fiber layer loss
2.identify the position of a nevus |
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Schiotz Tonometry
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Influenced by ocular rigidity
measures depth of indention caused by a known weight. |
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how does red free filter determine the position of a nevus
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nevi behind the RPE will appear red because RPE acts as a red filter, the red free filter will cancel red from the nevus
nevus or other area of pigmentation located on or in the retina will still be seen with the red free filter in place |
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Goldmann Tonometry measures what?
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Force required to flatten a known area of the cornea
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disadvantages to direct ophthalmoscopy
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1.lack of stereopsis
2.close working distance 3.dependence on refractive error for clarity and magnification 4.small field of view 5.corneal reflex |
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Non-contact tonometry measures what?
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1.force of air necessary to applanate a known area
2.area is measured with a photo-electric cell |
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what is a normal cup to disc ratio
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0.3-0.5
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How much area does a goldmann tonometer applanate the cornea?
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3.06mm
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pupillary pathway-sympathetic
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1st order neuron: Hypothalamus to ciliospinal center of Budge (C8-T2)
2nd order neuron: Preganglionic fibers exit, ascend sympathetic chain to SCG to synapse again 3rd order neuron: Postganglionic fibers follow carotid artery to orbit as long ciliary nerve |
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What is 1 gram of force in IOP?
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10mmHg
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at the chiasm what % of the nerve cross and what % of the nerve uncross
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53% cross (nasal fibers)
47% uncross (temporal fibers) |
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When do you change the axis
on the side of the tonometer? |
When the patient has more than 3D of cylinder power
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what is the most common cause of rAPD? least common?
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MOST common: optic nerve condition
LEAST common: lateral geniculate region |
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Where should the light source be
if you are checking IOP? |
60 degrees
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pupillary pathway-sympathetic
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1st order neuron: Hypothalamus to ciliospinal center of Budge (C8-T2)
2nd order neuron: Preganglionic fibers exit, ascend sympathetic chain to SCG to synapse again 3rd order neuron: Postganglionic fibers follow carotid artery to orbit as long ciliary nerve |
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What must you record after tonometry?
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1.mmHg for each eye
2.time of day 3.drops used 4.if you have to hold lids |
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at the chiasm what % of the nerve cross and what % of the nerve uncross
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53% cross (nasal fibers)
47% uncross (temporal fibers) level of superior colliculus |
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What is an acceptable pressure difference between 2 eyes?
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3mmHg
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what is the most common cause of rAPD? least common?
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MOST common: optic nerve condition
LEAST common: lateral geniculate region |
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What is the purpose of binocular balancing?
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Equalize the stimulus to accommodation between 2 eyes.
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what happens at the Edinger-Westphal nuclei (APD)
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both neuron group (nasal and temporal) synapses
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What do you do if manifest refraction is desired?
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You balance the stimulus to accommodation in each eye
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Parasympathetic:
how does the efferent pupillomotor fiber get to the ciliary ganglion |
efferent pupillomotor fibers course with CN III superficially then synapse at ciliary ganglion
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What is balancing the refraction?
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When you equalize the stimulus to accommodation for 2 eyes
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Parasympathetic:
where does the postganglionic parasympathetic pupillary fibers go |
connect to globe as short ciliary nerves supplying ciliary body muscle and iris sphincter muscle
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What are the 5 methods of binocular balancing?
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1.Successive Alternate Occlusion
2.Vertical Prism Dissociation 3.Blurring (Humphriss Immediate Contrast) 4.Polaroid Vectograph 5.Turville Infinity balance (Septum technique) |
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APD DOES NOT CAUSE
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ANISOCORIA
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Describe Successive Alternate Occlusion?
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+1.00 D of fog over Rx, isolate 20/50 line,
ask which image is clearer, add +.25 to the clearer eye until you reach equal, come out of fog binocularly |
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what is the stance on BILATERAL APD'S...
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they DO NOT exist
APD's are RELATIVE to each eye...RAPD!!! |
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Describe Vertical Prism Dissociation.
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+1.00 D fog over RX,
isolate 20/50 line put in Risley prisms with 4PD Base Down in the right eye and 4 PD base up in the left eye, add +.25 to the clearer eye until they are equal, bring out of fog binocularly |
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can CATARACTS, CORNEAL SCARS, VH cause APD?
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FUCK NO!!!
however: dense unilateral cataract can sometimes cause a pseudoAPD in the contralateral good eye |
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Which eye is seeing the bottom image in Vertical Prism Dissociation...OS=BU and OD=BD
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Left eye
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what is the grading APD
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3-4+
immediate dilation of pupil with swinging flashlight test 1-2+ no change in pupil size initially followed by dilation Trace: initial constriction, but greater escape to larger intermediate size with direct light stimulation compared to consensual stimulation (pupil size is smaller with consensual illumination) |
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What ways can the Duochrome test be preformed?
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Monocularly,
bi-ocularly(dissociated balance), or binocularly |
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0.3 log ND filter over AFFECTED EYE will enhance APD
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0.3 log ND filter over AFFECTED EYE will enhance APD
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If you have a patient with uneven VA's
what test would you use? |
Duochrome test
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how do you do APD testing in a patient with a fixed eye (dilated/constricted/traumatic)
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reverse technique:
1.shine light in fixed pupil and watch for miosis in other eye 2.move light over to non-fixed eye: if pupil dilates:APD in good eye if pupil constrict:swing light back to FIXED eye and watch good eye...if pupil dilates=APD in FIXED eye |
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What color would be clearer during the Duochrome test
if the patient is residually myopic? |
red
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what is angle kappa
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angle between papillary axis and the line of sight
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What is the most important thing to remember, when doing the Humphriss test?
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You work on the unfogged eye
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angle kappa is what type of visual testing
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MONOCULAR
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What is the Prism Dissociated Biochrome test?
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Bi-ocular test is similar to vertical prism except no fog is used.
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what is the purpose of angle kappa testing
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1.used with Hirschberg to determine STRABISMUS
2.OD compared with OS (monocularly) to determine ECCENTRIC FIXATION |
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When would you stop on a young person...on prism dissociated biochrome test?
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First Green
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POSITIVE KAPPA
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nasal displacement of CORNEAL REFLEX
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When would you stop on a old person...on prism dissociated biochrome test?
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Last Red
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NEGATIVE KAPPA
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temporal displacement of CORNEAL REFLEX
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What is the most natural binoncular balancing test?
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Polaroid Technique
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normal ranges of angle kappa
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1. ~0.5mm nasal to the center of the pupil (+)
2. +0.25mm to +0.6mm |
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On the Duochrome Test...If the patient reports that the red is clearer...what do you do?
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Add -.25 to the unfogged eye
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in angle kappa and Hirschberg
1mm deviation from center is equal to how many diopter prism |
1mm=22 diopter prism
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On the Duochrome Test...If the patient reports that the green is clearer...what do you do?
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Add +.25 to unfogged eye.
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Hirschberg is what type of visual testing
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BINOCULAR
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what is a normal result for Hirschberg
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symmetrical corneal reflex (no strabismus)
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what should you immediately perform if Hirschberg test yield a NON SYMMETRICAL reflex
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ANGLE KAPPA TESTING!!!!
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Hirschberg:
when the eyes are UNOCCLUDED, the reflex should remain in their monocular position...unless STRABISMUS is present |
Hirschberg:
when the eyes are UNOCCLUDED, the reflex should remain in their monocular position...unless STRABISMUS is present |
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what is near point convergence
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point in intersection of the lines of sight when the two eyes are maximally converged
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what type of target do you use when testing accommodation with NPC? convergence?
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accommodation: snellen one line above BCVA (blur and diplopia)
convergence: non-accommodative target (diplopia) |
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do you use habitual near Rx for NPC??
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YES!!!
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what is the subjective and objective results for NPC...which one do you use
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subjective: patient confirms diplopia
objective: doc. see one eye turn OUT use whichever comes first |
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what are NORMAL breaks and recoveries for NPC
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normal break: 3-5cm
normal recovery: +/- 3cm from break point abnormal break: greater than 12cm (receded) |
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unilateral cover test is used to detect...
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tropias
watch direct eye |
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alternating cover test is used to detect...
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phorias
watch NON-COVERED eye |
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for unilateral cover test you must allow both eyes too...on the target
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FIXATE!!!
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how do you orient the Maddox Rod when testing vertical deviation? lateral deviation?
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vertical: orient lines vertically
lateral: orient lines horizontally |
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Maddox rod is horizontal OD, the light appears left of streak...what is the diagnosis
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ESOphoria OD
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Maddox rod is horizontal OD, the light appears right of streak...what is the diagnosis
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EXOphoria OD
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Maddox rod is horizontal OS, the light appears left of streak...what is the diagnosis
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EXOphoria OS
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Maddox rod is horizontal OS, the light appears right of streak...what is the diagnosis
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ESOphoria OS
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Maddox Rod: the light is above the streak
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right eye hyper or
left eye hypo |
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Maddox Rod: the light is below the streak
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the left hyper or
right eye hypo |
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what are four types of accommodations
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1. reflex (blur driven)
2. convergent 3. tonic 4. proximal |
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what is reflex accommodation
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1. automatic adjustment of refractive state
2. response to a blur input: which is a reduction in overall contrast (the visual system likes contrast...that is why it is easy to over minus) |
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what is vergence accommodation
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1. induced by the action of fusional vergence
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what is tonic accommodation
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1. absence of visual stimuli
2. range 0.50-1.00D 2. aka dark accommodation 3. explains night myopia 4. infrared autorefractor used to measure this 5. decreases with age (presbyopia) |
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what is the most accurate way to measure tonic accommodation...why?
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difference of gaussian grating (DOGG)
1. blur free 2. low center spatial freq 3. no blur driven or convergence accommodation 4. not completely precise, proximal accommodation is not eliminated |
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what are the 5 categories of abnormalities of accommodation
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1. Paralysis of accommodation
2. Accommodative excess 3. Fatigue 4. Failure 5. Accommodative inertia |
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what is fatigue of accommodation
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1. inability of the ciliary muscle to maintain contraction while viewing a near object
2. more common in hyperopes (greater demand) 3. increased LAG (accommodative response is less than the accommodative stimulus) |
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what is failure of accommodation
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inability to produce or maintain an appropriate accommodative response
1. accommodative insufficiency 2. ill-sustained accommodation 3. presbyopia |
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what is accommodative inertia
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1. aka accommodative infacility
2. problem changing their accommodation (~1s) 3. worked induced MYOPIA 4. trouble relaxing accommodation after prolonged periods of near point work |
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what is paralysis of accommodation
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1. unilateral, bilateral, sudden onset
2. pupil mydriasis 3. paralysis is extreme insufficiency (induced by stress) |
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what is accommodative excess
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1. spasm
2. pseudomyopia 3. hyperaccommodation, HIGH LEAD (>0.40D) accommodative response GREATER than accommodative stimulus |
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hofsetters formulae
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max=25-0.40(age)
avg=18.5-0.30(age) min=15-0.25(age) |
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what is the purpose of Donder's Push Up technique
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1. to identify the maximum amount the patient can accommodate
2. bring target to the first sustained blur 3. MONOCULAR |
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what is a LEAD? LAG?
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Lead: for distant target we tend to over accommodate
Lag: for close near point objects the response is slightly less than the stimulus |
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what is the purpose of Minus Lens Technique
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1. target is fixed @ 40cm and minus lenses are introduced until the patient cannot clear the target.
2. the total amplitude is the total amount of minus lenses plus the 2.50D (40cm) 3. MONOCULAR |
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what is the difference between minus lens and push up technique
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(-) lens: fixed target, proximal stimulus remains constant, minification from the minus lens
push-ups: angular subtense of the letters keeps increasing as it is brought in (increasing relative mag) |
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which technique is more natural...minus lens or push up techinque
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PUSH UP
better results |
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what are the four types of vergences
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1. tonic: physiological position of rest of the ocular muscles (distance findings)
2. proximal: convergence that arises because of psychological awareness of obj 3. accommodative: convergence that occurs with a change in accommodation 4. fusional: responds to keep obj of regard single |
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what are characteristics of convergence insufficiency
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1. orthophoria to low exophoria @ distance
2. high exophoria @ near 3. receded NPC 4. low BO ranges 5. low NRA 6. low AC/A ratio good candidate for visual training |
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what are characteristics of convergence excess
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1. orthophoria to low exophoria @ distance
2. high esophoria @ near 3. normal NPC 4. low BI ranges 5. low PRA 6. high AC/A ratio 7. large lag of accommodation good candidate for bifocal Rx |
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how do you calculate convergence stimulus
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C.S.=PD(in cm)/distance(in m)
PD: interpupillary distance distance: add 2.7cm for distance between the center of rotation of the eye and the spectacle plane. so 40cm test distance becomes 42.7cm |
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what is AC/A ratio
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the ratio of accommodative convergence to the change in stimulus to accommodation...the measured convergence is divided by the accommodative stimulus
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