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78 Cards in this Set
- Front
- Back
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70% of the ONH is comprised of ________, and therefore any disease of the OHN will affect the ____.
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Macular fibers, the macula
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Red/green color abnormalities usually mean problems with the ____.
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OHN
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Blue/yellow color problems usually mean _______ problems.
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macular
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THe Red cap comparison test is AKA _____.
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The Red desaturation test
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Describe the purpose of the red cap test?
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to test the integrity of the optic nerve and visual pathway by testing the sensitivity to the color red.
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What is the major criteria for the red cap test?
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One eye MUST be worse than the other
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How far away do you hold the red cap from the better eye?
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40 cm
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What question do you ask the patient when showing him the red cap to the "bad" eye?
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Based on the 100% red you just saw with the other eye, how much is this red? (ex. Is it 75% as red as the other cap?)
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T or F: the CLinician defines the better eye as seeing 100%.
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True. No matter the state of the "better" eye, that amount is ALWAYS 100%
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What difference is normal between the 2 eyes?
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less than or equal to 10% is NORMAL
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Can media opacities affect the color difference b/t the eyes?
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YES, so does anything that interferes with the optic pathway.
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What is the correct documentation for the red cap comparison?
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Red cap OD 100%, OS 25%
OR Red cap comparison 75% red desaturation OS |
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Is it possible to test the visual fields using the red cap comparison?
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yes, it compares the central visual field to the peripheral field.
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How do you set of the caps in the red cap comparision confrontational fields?
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You let the patient fixate on one red cap in front, while another cap is held in the temporal visual field. (15 cm apart)
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What question do you ask the patient during RCC: CF?
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Which cap looks more red, the one in the center--or off to the side? (DONT FORGET TO OCCLUDE ONE EYE)
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What would you normally expect for the RCC:CF?
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The CENTRAL to be more red.
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If the peripheral cap looks more red (during the RCC:CF test) what might be a possible cause?
What does the paitent need to do in this case? |
a central scotoma
-quantify the difference |
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How do you record for the RCC:CF?
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Red cap CF (-) central scotoma OD, suspect central scotoma OS
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If the temporal red cap is a considerable amount LESS red, what might you suspect?
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subtle bitemporal desaturation
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What is the purpose of the Brightness Comparison?
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to compare the 2 eyes with regard to the perceived brightness of an intense light source.
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What is the purpose of the intense light source during brightness comparsion?
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so it will pentrate media opacities--this is better than the red cap.
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Where do you place the bright light in front of the nonoccluded eye? How long do you hold it there?
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40 cm (just like the red CC)
5 seconds |
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What question do you ask the patient when you switch over to the other eye?
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Rate the brightness of this light compared to the other eye?
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Does one eye need to be better than the other for the brightness comparision test to work?
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YES (just like RCC)
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What can you use to quantify the brightness b/t the eyes?
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a neutral density filter
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Again, what difference b/t the eyes is considered abnormal for the brightness comparison test?
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more than 10%
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If a patient has decreased VA, but everything looks fine, what test should you do?
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brightness comparision test
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What is the purpose of the pupil cycle time test?
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To test for bilateral and symmetric optic nerve disease
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For the RCC and BC tests what do you use to decide if one eye is better than the other?
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VAs
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What are you looking for during the pupil cycle time?
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The time is takes for the pupil to complete 30 cycles (dilation/comstriction)
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What time is normal for the pupil cycle time?
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30 seconds for 30 cycles
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When would you do a D-15 color test?
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When you suspect an acquired color vision defect, or you have reason to rule out one.
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What will a D-15 color test detect?
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both acquired and congenital
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What equipment do you need for the D-15 color test? What is one specific rule for taking this test?
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D-15, MacBeth easel lamp
Test perpindicular to line of sight |
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What problems are associated with carotid artery occulsion?
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Hollenhorst plaques, RA occlusion, assymetric retinal vascular disease, unilateral arcus
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What is Ballottement?
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Digital IOP. You decide the IOP by pressing and feeling for soft/firmness of eye relative to the other eye
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How do you record for ballottement?
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safe and equal
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When would you NOT perform ballottement?
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recent blunt trauma, recent eye surgury, corneal foreign body, angle closure glaucoma
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What technique involves a-scans and B-scans?
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Ultrasonography
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A scans represent ____?
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Amplitude, recorded as spikes on the time/x-axis
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What do A-scans measure, what are they good at diagonsing?
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they measure the axial length, they can differentiate b/t tumors.
You must do an A-scan before you give an IOLens implant |
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What do B-scans record?
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Brightness, it evaluates the intraocular structures
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What test would you do if you couldnt see through extremely dense media?
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a B-scan
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Can B-scans differentiate and monitor tumors?
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yes
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What are 5 clinical applications for doing a B-scan?
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1- elevations of the retina
2- retinal tears and detachments 3- differential diagnosis of ONH edema vs. buried ONH drusen 4- post. staphyloma 5- retinal coloboma |
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What are 4 retinal scanning devices?
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1-OCT
2- GDx 3- HRT 4- RTA |
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What test is associated with Central corneal thickness? (CCT), What does it use?
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Pachymetry\
Ultrasound |
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What are 3 uses for pachymetry?
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1- diagnose glaucoma
2- LASIK evaluation 3- monitor corneal edema |
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What is the normal CCT? What other test result could this affect?
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540/545,
It could change the goldmann tono results |
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IF the corneal is thinner than 540, what should you do to the IOP result?
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add pressure (a thin corneal will underestimate)
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If you got CCT= >540, and Goldmann is 18, how should you adjust goldmann?
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Thick cornea--take away pressure. Adjusted Pressure should be 16 mmHg
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Which tonometer is independent of CCT?
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the Pascal tonometer
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What does the pascal tono measure?
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the ocular pulse amplitude due to the patients heartbeat/ it uses contour matching instead of applanation
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What happens to the reliability of the amsler test, if the patient has reduced near vision?
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it goes way down
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Describe the purpose of the macular photostress recovery time.
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To measure the return of the visual function to the macula after a timed exposure to a bright light stimulus.
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What is exactly going on when you recover from photostress?
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resynthesis of photoreceptor visual pigments
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What could possibly lead to increased photostressed time?
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any disease that disrupts the resynthesis of the photopigments, or separates the photoreceptors and RPE
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What is the macular photostress test used to detect?
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1-subtle unilateral or bilateral MACULAR disease
2- to differentiate b/t ON and macular problems |
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What will the result of the macular photostress test be if the patient has an optic nerve problem/ some other conduction problem?
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Photostress time is UNAFFECTED!!
(thus, if the time is affected, you can say it is a macular problem) |
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IS the patient fully dilated during the macular photostress time?
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NO!!
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Dose the patient wear their glasses during the photostress test?
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NO!
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What must you do before you begin the macular photostress test?
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you must let the patient dark adapt for 1 minute
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FOr the macular photostress test, if the BVA is 20/20, what line should you show the patient during the MPST?
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20/30 (one line above)
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How far away from the tested eye is the light source during photostress?
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1 inch!
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How long do you hold the light in front of the eye during photostress?
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10 seconds
(dont forget to let the patient put his glasses back on after you do this) |
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What is the testing criteria for photostress?
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the TIME it takes to read 1/2 of the line!
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What happens to the patient after the light is removed during the photostress test?
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there is a positive afterimage--> a dense central scotoma which decreases VA
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What is the normal macular photostress recovery time?
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30-60 seconds
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What is the normal variation b/t the eyes during photostress?
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5-6 seconds
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T or F: recovery photostress time increases with age.
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true
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What are several etiologies of delayed photostress time?
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1- retina is disconnected to RPE
2- macular disorder (ARMD) 3- ONH/conduction problem |
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Can taking chloroquine affect macular photostress time?
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yes
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What is the name of a test that uses the slitlamp to tesk the integrity of the macula?
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the Watzke-Allen test
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What are the deminsions of the watzke-allen slit beam?
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vertical, tall and 2mm wide
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What do you ask the patient during te watzke-allen test?
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DO you see any gaps or curves in the line of light
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If the patient sees a gap or curve, what do you predict?
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a macular hole, or other compromise
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What does a patient see if they have a full thickness macular hole?
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a broken slit beam
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What should the patient see if they have a partial macular hole, ERM or edema?
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The slit beam has a portion that is wavy
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