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C CLINICAL RESEARCH

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Figure 15: Monitoring glaucoma using target pressure.

Diagnose OHT

or POAG

Stage disease,
consider age/life Low risk OHT: monitor
expectancy, IOP, structure/
determine individual function closely
concerns, set target without treatment
pressure
Initiate
treatment
Target pressure not
achieved: re-evaluate Target IOP achieved:
risk for progressive continue to monitor
loss of structure and/ for progression
or function

High risk for Minimal risk for
progression: lower progression: monitor;
target pressure no adjustment to
determination and/or treatment or target
alter therapy IOP

An adequate number of IOP measurements must be accumulated in order to develop a reasonably accurate estimate
of the baseline IOP. As mentioned above, assessments of 24-hour IOP would be very useful in understanding an in-
dividual’s disease, but are not practical within most clinical settings at this time. Accordingly, at least 3 IOP readings
should be collected at different times of day with at least two measures taken as early in the morning as possible.
Other recommendations suggest 4 to 6 measures at different times of day over at least 2 to 3 visits.

Once the level of glaucoma is staged as mild, moderate or severe (Table 6), the target IOP can be established based
on lowering IOP less for those at lower risk, and more for those at higher risk for progression. Generally, the highest
IOP reading is used as a pre-treatment baseline, and the target is set to lower IOP as little as 20% in mild/low risk
conditions to as much as 50% for severe/high risk situations (see Table 8). Consideration should be made for other
risk factors of concern, including young age (<50 years of age), certain races (African North American descent) and
if a sibling has advanced glaucoma. Of course, IOP can only be lowered a finite amount with medications and laser.
Further, the pressure lowering required in NTG has not been unequivocally determined, though 20 to 30% reduc-
tion is generally used, reflecting the conclusions of the CNTGS.
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