Term
| Do we consider individual edgepoints (perimeter) when diagnosing glaucoma? |
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Definition
| No, they are unreliable and highly variable. Ignore them. |
|
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Term
| When are VF considered reliable for glaucoma dx? |
|
Definition
Any of the following:
A single non-edge point if P < 0.5%
2 or more adjacent non-edge point at P<5% with one at P < 1%
3 or more adjacent non-edge points at P < 5%
2 adjacent points differ points differ from points across the horizontal midline by at least 10dB (nasal step) |
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Term
| What are the only glaucoma features that use VF edge points for dx? |
|
Definition
| Nasal steps can use edge points |
|
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Term
| What is the cutoff for corrected pattern standard deviation to be considered significant for dx'ing glaucoma? |
|
Definition
|
|
Term
| What corneal thickness is baseline for GAT? |
|
Definition
| 520 micron, however, mean CCT in caucasian is about 545 microns. So there is some built in error |
|
|
Term
| How does corneal thickness affect glaucoma risk? |
|
Definition
| higher corneal thickness is protective |
|
|
Term
| What is the average difference in CCT between those of caucasian vs african descent? |
|
Definition
|
|
Term
| When comparing NTG vs OHT, which has the tendency for higher CCT? |
|
Definition
| OHT, however, this is a very general rule. Many outliers in both directions. |
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Term
| When comparing ultrasound vs optical pachymeters, how do their results compare? |
|
Definition
| Both are reliable, but optical may be slightly lower |
|
|
Term
| How many measurements should be made with a pachymeter? |
|
Definition
| 3 for the result to be reliable |
|
|
Term
| Can we correct measured IOP (mIOP) by a factor dependent on CCT? |
|
Definition
| No, as the correlation is low enough that signficant error will be introduced |
|
|
Term
| Should any of the common nomograms for converting mIOP (measured IOP) to aIOP (actual IOP) be used? |
|
Definition
| No, they are not reliable enough |
|
|
Term
| What artificially raises IOP: a thicker or thinner cornea? |
|
Definition
| Thicker (more force to applanate the cornea itself) |
|
|
Term
| Why should we take baseline IOP's at different times of the day? |
|
Definition
| To get a diurnal variation baseline |
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Term
|
Definition
Aerobic Exercise (lower)
Lifting weights (raises)
Tonometry (lowers)
Apparel (tight necked shirt or tie raises IOP via pressure on carotids)
Gonioscopy (lower IOP by forcing AH out)
VF (30-2 threshold can cause a 5 mmHg increase) |
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|
Term
| How often should gonio be done on glaucoma pt's? |
|
Definition
|
|
Term
| Which glaucoma suspects should have gonio performed? |
|
Definition
|
|
Term
| What is a sampoelesi line? |
|
Definition
| pigment dusted on the ledge of schwalbes line in gonio |
|
|
Term
| How does a corneal wedge aid in finding Schwalbe's line? |
|
Definition
| With your light perpendicular to the angle, look at the optic section of the cornea. You will see the anterior and posterior cornea, it will angle together and joing at SL |
|
|
Term
| When should iris processes be recorded in gonio? |
|
Definition
| if they are numerous enough to prevent a view of the angle |
|
|
Term
| What % of the population has iris processes? |
|
Definition
|
|
Term
| What do the iris processes adhere to and thus help you identify on gonio? |
|
Definition
| lower 1/3 of trabecular meshwork |
|
|
Term
| How much angle recession indicates increased risk for glaucoma? |
|
Definition
| At least 180* of the angle |
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