DIS - Glaucoma Assessment Tutorial I - Week 4 Flashcards
What is the standardised testing protocol for all glaucoma suspects (5)? List six additional supplementary tests you can do.
Standard protocol Pachymetry Gonioscopy Disc photos OCT Visual fields Supplementary Corneal hysteresis ERG and VEP Computerised colour vision testing Pupilography OCTa
List the 8 stages of glaucom in the leadup to blindness. List a test or symptom that can detect when a patient is at this stage if applicable (5).
Normal Acceleration of apoptosis Ganglion cell death -macular GGC scan RNFL change (undetectable) RNFL change (detectable) -optic nerve RNFL scan SWAP VF changes -humphrey/medmont SAP VF change -arcuate/nasal step/paracentral/temporal wedge VF change (moderate) VF change (severe) -tunnel vision Blindness
Is IOP useful in the detection and assessment of glaucoma?
Not useful in detection but very useful in assessment and treatment planning
Is IOP more variable in normals or glaucoma patients?
Glaucoma patients
It is still variable in normals
What is the ebst way to get a diurnal IOP curve for a glaucoma suspect?
Schedule appointments at different times of the day and measure IOP each time
Is it advisable to complete glaucoma assessment entirely in one appointment or schedule it across different visits?
Best not to do it all at once
Schedule for different times of the day and measure IOP each time
Keeping the variability of IOP and diurnal curve in mind, what is considered the baseline IOP when treating glaucoma patients?
The highest pressure recorded prior to treatment
What is the average measurement for ultrasound pachymetry?
555 microns
List the measurements for the following thicknesses of the cornea: Thick Nornal Thin Very Thin
Thick - 590 microns
Nornal - 555 - 590 microns
Thin - 525 - 555 microns
Very Thin - <525 microns
Describe which of the following IOP and cornea thickness combinations is a risk factor for glaucoma: Low IOP, thin pachymetry High IOP, thick pachymetry Low IOP, thick pachymetry High IOP, thin pachymetry
Low IOP, thin pachymetry - no problem
High IOP, thick pachymetry - no problem
Low IOP, thick pachymetry - no problem
High IOP, thin pachymetry - risk factor
Do thick corneas under-estimate or over-estimate IOP? What about thin corneas?
Thin - under-estimates
Thick - over-estimates
Is CCT a dependent or independent risk factor for glaucoma? Explain why by describing what it is a surrogate measure of.
Independent risk factor - it is a surrogate measure of the lamina cribrosa thickness
Can IOP be corrected or adjusted based on pachymetry?
No, the relationship is non-linear
What is the strongest predictor of the conversion from ocular hypertension to glaucoma? Is this a better predictor than C/D ratio and VF?
Thin pachymetry is the strongest predictor
What three key pieces of information does gonioscopy provide on a glaucoma suspect?
How narrow the angle is
If there are any restrictions to outflow
Most appropriate glaucoma treatment plan
Consider the five structures that may be visible in gonioscopy. Visibility of which of these is considered an open angle and which are occludable?
Ciliary body, scleral spur, and PTM are open angles
ATM and schwalbes line are occulable
Describe the gonioscopy classification of a primary angle suspect (2) and the chance of progressing to primary open angle glaucoma in 5 years.
PTM not visible in two or more mirrors without indentation
Opens fully on indentation
~20% chance of progress to glaucoma
Describe the gonioscopy classification of a primary angle closure (3).
PTM not visible in two or more mirriors
PAS present
Signs of ischaemia
-glaucomflecken
Describe the gonioscopy classification of a primary angle closure glaucoma (6).
PTM not visible in two or more mirriors PAS present Signs of ischaemia -glaucomflecken Optic nerve damage RNFL loss VF defect
What is glaucomflecken and why does it occur? Explain where it occurs specifically and why. What does it occur secondary to?
Central anterior cortical cataract only within the pupil zone
Occurs due to the lack of aqueous flow to the anterior lens, secondary to a pupil block
Lens becomes hypoxis and cataracts occurs only in that area