Special Tests II

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70% of the ONH is comprised of ________, and therefore any disease of the OHN will affect the ____.: Macular fibers, the macula
Red/green color abnormalities usually mean problems with the ____.: OHN
Blue/yellow color problems usually mean _______ problems.: macular
THe Red cap comparison test is AKA _____.: The Red desaturation test
Describe the purpose of the red cap test?: to test the integrity of the optic nerve and visual pathway by testing the sensitivity to the color red.
What is the major criteria for the red cap test?: One eye MUST be worse than the other
How far away do you hold the red cap from the better eye?: 40 cm
What question do you ask the patient when showing him the red cap to the "bad" eye?: 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?)
T or F: the CLinician defines the better eye as seeing 100%.: True. No matter the state of the "better" eye, that amount is ALWAYS 100%
What difference is normal between the 2 eyes?: less than or equal to 10% is NORMAL
Can media opacities affect the color difference b/t the eyes?: YES, so does anything that interferes with the optic pathway.
What is the correct documentation for the red cap comparison?: Red cap OD 100%, OS 25%

OR

Red cap comparison 75% red desaturation OS
Is it possible to test the visual fields using the red cap comparison?: yes, it compares the central visual field to the peripheral field.
How do you set of the caps in the red cap comparision confrontational fields?: You let the patient fixate on one red cap in front, while another cap is held in the temporal visual field. (15 cm apart)
What question do you ask the patient during RCC: CF?: Which cap looks more red, the one in the center--or off to the side? (DONT FORGET TO OCCLUDE ONE EYE)
What would you normally expect for the RCC:CF?: The CENTRAL to be more red.
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
How do you record for the RCC:CF?: Red cap CF (-) central scotoma OD, suspect central scotoma OS
If the temporal red cap is a considerable amount LESS red, what might you suspect?: subtle bitemporal desaturation
What is the purpose of the Brightness Comparison?: to compare the 2 eyes with regard to the perceived brightness of an intense light source.
What is the purpose of the intense light source during brightness comparsion?: so it will pentrate media opacities--this is better than the red cap.
Where do you place the bright light in front of the nonoccluded eye? How long do you hold it there?: 40 cm (just like the red CC)
5 seconds
What question do you ask the patient when you switch over to the other eye?: Rate the brightness of this light compared to the other eye?
Does one eye need to be better than the other for the brightness comparision test to work?: YES (just like RCC)
What can you use to quantify the brightness b/t the eyes?: a neutral density filter
Again, what difference b/t the eyes is considered abnormal for the brightness comparison test?: more than 10%
If a patient has decreased VA, but everything looks fine, what test should you do?: brightness comparision test
What is the purpose of the pupil cycle time test?: To test for bilateral and symmetric optic nerve disease
For the RCC and BC tests what do you use to decide if one eye is better than the other?: VAs
What are you looking for during the pupil cycle time?: The time is takes for the pupil to complete 30 cycles (dilation/comstriction)
What time is normal for the pupil cycle time?: 30 seconds for 30 cycles
When would you do a D-15 color test?: When you suspect an acquired color vision defect, or you have reason to rule out one.
What will a D-15 color test detect?: both acquired and congenital
What equipment do you need for the D-15 color test? What is one specific rule for taking this test?: D-15, MacBeth easel lamp

Test perpindicular to line of sight
What problems are associated with carotid artery occulsion?: Hollenhorst plaques, RA occlusion, assymetric retinal vascular disease, unilateral arcus
What is Ballottement?: Digital IOP. You decide the IOP by pressing and feeling for soft/firmness of eye relative to the other eye
How do you record for ballottement?: safe and equal
When would you NOT perform ballottement?: recent blunt trauma, recent eye surgury, corneal foreign body, angle closure glaucoma
What technique involves a-scans and B-scans?: Ultrasonography
A scans represent ____?: Amplitude, recorded as spikes on the time/x-axis
What do A-scans measure, what are they good at diagonsing?: they measure the axial length, they can differentiate b/t tumors.
You must do an A-scan before you give an IOLens implant
What do B-scans record?: Brightness, it evaluates the intraocular structures
What test would you do if you couldnt see through extremely dense media?: a B-scan
Can B-scans differentiate and monitor tumors?: yes
What are 5 clinical applications for doing a B-scan?: 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
What are 4 retinal scanning devices?: 1-OCT
2- GDx
3- HRT
4- RTA
What test is associated with Central corneal thickness? (CCT), What does it use?: Pachymetry\
Ultrasound
What are 3 uses for pachymetry?: 1- diagnose glaucoma
2- LASIK evaluation
3- monitor corneal edema
What is the normal CCT? What other test result could this affect?: 540/545,

It could change the goldmann tono results
IF the corneal is thinner than 540, what should you do to the IOP result?: add pressure (a thin corneal will underestimate)
If you got CCT= >540, and Goldmann is 18, how should you adjust goldmann?: Thick cornea--take away pressure. Adjusted Pressure should be 16 mmHg
Which tonometer is independent of CCT?: the Pascal tonometer
What does the pascal tono measure?: the ocular pulse amplitude due to the patients heartbeat/ it uses contour matching instead of applanation
What happens to the reliability of the amsler test, if the patient has reduced near vision?: it goes way down
Describe the purpose of the macular photostress recovery time.: To measure the return of the visual function to the macula after a timed exposure to a bright light stimulus.
What is exactly going on when you recover from photostress?: resynthesis of photoreceptor visual pigments
What could possibly lead to increased photostressed time?: any disease that disrupts the resynthesis of the photopigments, or separates the photoreceptors and RPE
What is the macular photostress test used to detect?: 1-subtle unilateral or bilateral MACULAR disease
2- to differentiate b/t ON and macular problems
What will the result of the macular photostress test be if the patient has an optic nerve problem/ some other conduction problem?: Photostress time is UNAFFECTED!!
(thus, if the time is affected, you can say it is a macular problem)
IS the patient fully dilated during the macular photostress time?: NO!!
Dose the patient wear their glasses during the photostress test?: NO!
What must you do before you begin the macular photostress test?: you must let the patient dark adapt for 1 minute
FOr the macular photostress test, if the BVA is 20/20, what line should you show the patient during the MPST?: 20/30 (one line above)
How far away from the tested eye is the light source during photostress?: 1 inch!
How long do you hold the light in front of the eye during photostress?: 10 seconds
(dont forget to let the patient put his glasses back on after you do this)
What is the testing criteria for photostress?: the TIME it takes to read 1/2 of the line!
What happens to the patient after the light is removed during the photostress test?: there is a positive afterimage--> a dense central scotoma which decreases VA
What is the normal macular photostress recovery time?: 30-60 seconds
What is the normal variation b/t the eyes during photostress?: 5-6 seconds
T or F: recovery photostress time increases with age.: true
What are several etiologies of delayed photostress time?: 1- retina is disconnected to RPE
2- macular disorder (ARMD)
3- ONH/conduction problem
Can taking chloroquine affect macular photostress time?: yes
What is the name of a test that uses the slitlamp to tesk the integrity of the macula?: the Watzke-Allen test
What are the deminsions of the watzke-allen slit beam?: vertical, tall and 2mm wide
What do you ask the patient during te watzke-allen test?: DO you see any gaps or curves in the line of light
If the patient sees a gap or curve, what do you predict?: a macular hole, or other compromise
What does a patient see if they have a full thickness macular hole?: a broken slit beam
What should the patient see if they have a partial macular hole, ERM or edema?: The slit beam has a portion that is wavy

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