important trials in glaucoma
TRANSCRIPT
IMPORTANT TRIALS IN GLAUCOMA
Presenter-Dr RavneetModerator- Dr Hetal Shah
Dr Rita Dhamankar Dr Vijay Shetty
Landmark studies in glaucoma
Ocular Hypertension Treatment study (OHTS)Collaborative Initial Glaucoma treatment Study
(CIGTS)
Advanced Glaucoma Intervention Study (AGIS)Early Manifest Glaucoma trial (EMGT)
Collaborative Normal Tension Glaucoma (CNTGS)Tube versus Trabeculectomy study (TVT)
European Glaucoma prevention study(EGPS)Low Tension Glaucoma prevention Study(LoGTS)
Ocular Hypertension Treatment study (OHTS)
3 Arch Ophthalmol 120: 701-713, 2002.
Ocular Hypertension Treatment study (OHTS)
Objective:To evaluate the safety and efficacy of topical
ocular hypotensive medications in preventing or delaying onset of visual field loss and or optic nerve damage in subjects with ocular hypertension.
Identify baseline demographic and clinical factors that predict which participants will develop POAG
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Ocular Hypertension Treatment study (OHTS)
Participants: 1637 patients with ocular hypertension
recruited between 1994 and 1996
Study design:Multicentre randomized controlled
clinical trial comparing observation with medical therapy for ocular hypertension.
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Methods:
1637 participants
no evidence of glaucomatous damage,
40 to 80 years
IOP 24 mmHg - 32 mmHg in one eye
21mmHg and 32 mmHg in other eye
The goal in the medication group was to reduce the IOP by 20% or more and to reach an IOP of 24 mmHg or less.
Ocular Hypertension Treatment study (OHTS)
OHTS Phase 1Begins February 28, 1994
Eligibility Criteria
MedicationTopical treatment to lower IOP 20%
and IOP < 24 mm Hg
ObservationNo topical treatment to lower IOP
Randomization
Reproducible Abnormality3 consecutive visual fields and/or 2 consecutive sets of optic disc photographs
MonitoringHumphrey 30-2 q6 months
Stereoscopic disc photos annually
POAGVisual field and/or optic disc changes attributed to
POAG
Adjust therapy if target not met
Ocular Hypertension Treatment study (OHTS)
Results :At 5 years followup
Incidence of POAG
9.5% in controls
4.4% in treatment group
22.5% decrease in IOP in the treatment group
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OHTS Summary of results
CCT < 555 & IOP > 25 CCT < 555 & CD > 0.5 Risk 36% Risk 22% CCT > 588 &IOP > 25 CCT > 588 & CD >0.5 Risk 6% Risk 8%
Ocular Hypertension Treatment study (OHTS)
Increased risk of the onset of POAG was associated with:
Increased age
Vertical and horizontal cup disc ratio
Pattern standard deviation
IOP at baseline
Central corneal thickness (CCT) was found to be a powerful predictor for the development of POAG.
Ocular Hypertension Treatment study (OHTS)
The corneas in OHTS subjects were thicker
lower corneal thickness in black subjects than whites.
The effect of CCT may influence the accuracy of applanation tonometry in the diagnosis, screening and management of patients with glaucoma and ocular hypertension.
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Clinical useful points from OHTS
OHT – What to do * Treat all * Treat no one * Treat some -- Is treatment effective
DOES OHTS HAVE ANSWERS FOR THIS
Clinical useful points from OHTSTreat only patients at high risk.
Risk factors – risk calculator www.discoveriesinsight.orgImportance of CCTONH & VF monitoring at every FUStudy – Rx effective , of the 9.6% that
converted half could be prevented by Rx
OHTS - ? Conversion after longer FU
Age Vertical C/D
IOP DM+
CCT PSD
If not high risk waiting to treat OHT till conversion- better strategy ( vision related QOL)
OHTS PHASE2
March 2010
OHTS Phase 2
Medication GroupN = 694
Medication is continued in the Medication group
OHTS Phase 2N = 672
Medication is Initiated in the Observation group
OHTS Phase 2: Rationale OHTS Phase 1 provides proof of
concept: medication reduces the incidence of POAG.
OHTS Phase 1 does not indicate when medication should begin.
OHTS Phase 1 does not indicate if all OHT patients should receive early medication.
OHTS Phase 2: MethodsAfter 7.5 years of observation, participants
originally randomized to observation group start medication.
This creates:Delayed treatment group Observation group followed for 7.5 years then treated for 5.5
years
Early treatment groupMedication group treated for median of 13 years from the
beginning
Compare incidence of POAG at 13.0 years
OHTS PHASE 2 RESULTS Median Time to develop POAG:Observation group-6 yrsMedication group-8.7 yrsIncreased cumulative incidence of POAG at
13 yrs(22% vs 16%)More eyes with structural and functional
damage(8% vs 5%)More participants with bilateral disease (6%
vs 4%)
Ocular Hypertension Treatment study (OHTS)
The primary purpose of the follow up study was to determine whether delaying treatment resulted in persistently increased risk of conversion to glaucoma, even after the initiation of therapy.
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Ocular Hypertension Treatment study (OHTS)
Implications:Ocular hypertensives can be seperated into
categories of high,medium & low risk.
People with high risk factors may benefit from close followup and early treatment
Low risk patients can have less frequent followup and may not need early treatment.
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Ocular Hypertension Treatment study (OHTS
Subjects with corneal thickness of 555μm or less had three times the risk of developing primary open-angle glaucoma compared with those who had corneal thickness of 588μm or more.
Therefore, measure central corneal thickness of all new glaucoma suspects.
Early Manifest Glaucoma trial (EMGT)
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Early Manifest Glaucoma trial (EMGT)
Purpose:To compare the effect of immediate therapy
to lower the intraocular pressure versus late or no treatment on the progression of newly detected open-angle glaucoma,as measured by increasing visual field loss and or optic disc changes
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Early Manifest Glaucoma trial (EMGT)
Participants:Newly diagnosed POAG patients (255)
50 to 80 years of age
255 patients were randomized between 1993 and 1997.
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Early Manifest Glaucoma trial (EMGT)
Study design:
Multicenter randomized controlled
clinical trial comparing observation with
betaxolol and argon laser trabeculoplasty
for OAG.
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EMGT• Randomised to
-ALT and betaxolol-No treatment
• If IOP >25mmHg in treated (>35 untreated)→ Latanoprost added
• If remains high → individualised treatment
Early Manifest Glaucoma trial (EMGT)
Results:At 6 years, 62% of untreated patients showed
progression, whereas 45% of treated patients progressed. Treatment reduced IOP by 25%.
Median time to progression 66 months in treated versus 48 months in untreated .
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EMGTS – results Progression
62% - control45% - treated group
25% IOP - risk of progression by 50%
Risk of progression less with larger initial IOP drop
Risk of progression by 10% / mm Hg IOP from baseline
Early Manifest Glaucoma trial (EMGT)
In the control group , the rate of visual field progression was fastest in the subgroup of patients with exfoliation and slowest in those with normal IOPs at baseline.
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Early Manifest Glaucoma trial (EMGT)
Baseline risk factors:Higher IOP
Exfoliation
Older age
Lower systolic perfusion pressure
Lower CCT among patients with higher IOPs
follow up higher IOP,
disc hemorrhages.32
Early Manifest Glaucoma trial (EMGT) Implications:In eyes with glaucoma ,IOP that was
lowered by an average of 25%, treatment was of benefit versus no treatment .
There is beneficial effect of immediate therapy to lower the intraocular pressure versus late or no treatment on the progression of newly detected OAG
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Clinical ImplicationsEven small reductions in IOP can make a
difference.Every 1mm of IOP reduction was associated
with a risk reduction of 10% to 13%, depending on the analysis,
But that doesn't necessarily mean all patients must be treated, because we can't know which patients will progress, in some cases, we can observe closely and tailor management to the individual patient
It's beneficial to lower pressure in patients progressing quickly, even if IOP levels have been in the range of 15 to 18mm Hg,
Clinical useful points from EMGTS
25% IOP - progression from 62 – 45%Regular FU every 3 – 6 months with ONH & VF must – not commonly practiced.Pts with low risk of progression left untreated – no effect on QOL till lifetimeDrawbacks – Rx options limited – better drugs now
Collaborative Initial Glaucoma treatment Study (CIGTS)
Am J Ophthalmol 1998;126:498-505
Collaborative Initial Glaucoma treatment Study (CIGTS)
Purpose:
To determine whether patients with newly diagnosed open angle glaucoma (OAG) are better treated by initial treatment with medications or by immediate filtering surgery.
In addition, a secondary measure—a health-related quality of life questionnaire—looked at how the treatment affected the patient's lifestyle.
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Collaborative Initial Glaucoma treatment Study (CIGTS)
Participants:607 patients with OAG ( primary, pigmentary,
or pseudoexfoliative) recruited between 1993 and 1997.
Study design:Multicenter randomized controlled clinical
trial comparing initial medical with initial surgical therapy for OAG.
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First time the concept of Target IOP was used.
March 2010
CIGTS
MEDICATION GROUPN = 307
SURGICAL GROUPN = 300
CIGTSRESULTS
At 5 yrs both effective
Control of IOP lower by surgery (48%), medical (35%)
VF loss greater in surgery (cataract)
QOL initially better with medical group
CIGTS – Results at 5yrsMedical
TreatmentSurgical
TreatmentIOP reduction 28mmHg→17-
18mmHg(38%)
27mmHg→14-15mmHg
(46%)Progression at 5
yearsNo progression No progression
• Surgical group is at increased risk of visual loss initially but by 4yrs both groups are comparable•The rate of cataract removal was greater in the surgically treated group.
Collaborative Initial Glaucoma treatment Study (CIGTS)
Results
Patients with diabetes were more likely to
progress if treated with surgery first.
The quality of life (QOL) impact reported
by the 2 treatment groups was very similar.
Increased impact of local eye symptoms
reported by the surgery group
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Collaborative Initial Glaucoma treatment Study (CIGTS)
Results
The overall rate of progression of OAG in CIGTS was lower than in many clinical trials, potentially the result of more aggressive IOP goals and the stage of the disease.
CIGTS summarySurgery resulted in
Lower IOPMore cataractMore ocular side effectsInitial ↓ visionInitial ↓ visual field
Collaborative Initial Glaucoma treatment Study (CIGTS)
Implications In moderate to advanced disease initial surgical
therapy may be preferred. The results also revealed that either treatment
had a remarkably similar effect on patients' quality of life.
Though not associated with a particular treatment group, the fear of blindness was common, affecting 34% at diagnosis.
Patients who reported a decrease in visual functioning were more likely to experience depression and mood changes
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Clinical useful points from CIGTS
Early POAG – medical Rx effectiveOur scenario – compliance/cost – deciding factor for either modalityConcept of target IOP – must in our management.Drawback – study duration too short for Rx recommendation.
Advanced Glaucoma Intervention Study (AGIS)
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Advanced Glaucoma Intervention Study (AGIS)
Purpose:
To compare the clinical outcomes of 2 treatment sequences in cases of advanced glaucoma
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Advanced glaucoma intervention study (AGIS)Objective – to determine if ALT or surgery
is preferred Rx for advanced glaucoma on max tolerated medical Rx.
789 eyes
ALTTRABTRAB(ATT)
TRABALTTRAB(TAT)
Advanced Glaucoma Intervention Study (AGIS)
Participants: 789 eyes of 591 patients with medically
uncontrolled OAG recruited from 1988 to 1992.
POAG uncontrolled on maximum accepted and tolerated medical therapy(IOP ≥ 18 mm Hg)
35 to 80 yr
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Advanced Glaucoma Intervention Study (AGIS)
Study design:Multicenter randomized controlled clinical trial
comparing 2 treatment sequences (TAT and ATT ) for patients with OAG uncontrolled by medical therapy.
Advanced Glaucoma Intervention Study (AGIS)
Results: Black patients had less combined visual acuity
and visual field loss if treated with the ATT sequence.
White patients had less combined visual acuity and visual field loss at 7 years if treated with the TAT sequence.
Visual function scores improved after cataract surgery.
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AGIS - Results Relationship of IOP & VF progression.
Predictive analysis – IOP < 14 mm Hg did better
Associative analysis – low IOP & low IOP fluctuation - Decreased progression
Advanced Glaucoma Intervention Study (AGIS Results:
Lower IOP was associated with less visual field loss.
First 18 months after the first surgical intervention, or eyes with IOP of 18mmHg or less at all visits throughout the study had significantly less visual field loss
Approximately half of the study patients developed cataract in the first 5 years of follow up.
Trabeculectomy increases the relative risk of cataract formation by 78%.
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Advanced Glaucoma Intervention Study (AGIS)
Results
ALT failure is associated with
-younger age
-higher IOP.
Trabeculectomy failure associated with
-younger age,
-higher IOP,
-diabetes, and postoperative complications such as particularly
elevated IOP and marked inflammation.
-IOP fluctuation was an independent predictor of progression of
OAG in eye with lower baseline IOPs.
Results - AGIS
TAT IOPBetter for whites
ATT FailureBetter for blacks
Risk of cataract after TRAB after 5 years – 78 %
AGISEffects of IOP on visual field progression
were also specifically evaluated from AGIS data, and it was found that patients with an average IOP of greater than 17.5mm Hg had greater worsening of their visual fields than those with an average IOP of less than 14mm Hg.
AGIS was one of the first studies to show that lower mean IOP results in a decreased risk of visual field progression.
AGISEach patient requires individualized care. AGIS demonstrated that race is an important
consideration for surgical intervention in advanced glaucoma.
This is not to say, for instance, that a white patient with medically-uncontrolled glaucoma should only be offered the option of trabeculectomy.
Potential operative complications associated with the more invasive surgery may sway the patient toward laser intervention as a first option.
AGISConversely, a black patient presented with
the option of laser intervention should be warned of the likely future need for both additional medications and additional glaucoma surgery after the laser procedure is completed.
AGISThere is no magic number for target IOP. Patients in the AGIS group who consistently
maintained IOP less than 18mm Hg at every visit over six years, with mean IOP of 12.3mm Hg as a group, had good preservation of visual field—yet a number of patients in this group still showed progressive visual field loss.
Advanced Glaucoma Intervention Study (AGIS)
Implications:Keep race in mind when choosing therapy.
Lower IOP was associated with less visual field loss
IOP fluctuation was an independent predictor of progression of OAG in eye with lower baseline IOPs.
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Collaborative Normal Tension Glaucoma (CNTGS)
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Lowering IOP in patients with normal-tension glaucoma (NTG) can be challenging.
Is it even worth trying to lower an already-low IOP?
Collaborative Normal Tension Glaucoma (CNTGS)
Purpose:To determine if IOP plays a part in the
pathogenic process of NTG by comparing a treatment group (with a 30% reduction in IOP) to a no treatment group. .
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Collaborative Normal Tension Glaucoma (CNTGS)
Participants :230 patients
20-90 yrs
Patients had unilateral or bilateral NTG
Three reliable visual fields within 1 month
Average IOP ≤20 mmHg,no reading above 24 mmHg
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NTGS - methodsRandomised immediately if
VF defect threatening fixationPreviously documented disease progression
Others randomised when evidence of progression
NTGS145 (of 239) patients randomised One eye randomised to
Treatment Drops, ALT or surgery to achieve 30%
reduction in IOPNo treatment until evidence of progression Other eye could be treated in this group
Collaborative Normal Tension Glaucoma (CNTGS)
Study design:
In both arms, neither eye could receive beta-adrenergic blockers or adrenergic agonists, because they might have systemic cardiovascular effects that could conceivably alter the course of the treated or untreated disease, confounding the analysis of data.
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CNTGS
RESULTS30% drop achieved in half without surgery
Once 30% drop achieved rate of progressive field loss was lower than group that did not receive treatment (after allowing for cataract effect which was higher in treated group)
CNTGS RESULTS:Rate of progression in untreated NTG highly
variableHalf did not progress on VF in 5 yearsFactors associated with progression
FemaleMigraineDisc haemorrhages on presentation
CNTG – results Prog in 12% of Rxed eyes & 35% in untreated group.30% reduction possible even by medicines.Treated pts that progressed
Non IOP related target IOP wrong
CNGTSOverall, lowering IOP in NTG slows
progression.
However, over half of patients did not progress without treatment at 5 years.
Collaborative Normal Tension Glaucoma (CNTGS)
IMPLICATIONS:
The natural course of NTG is quite variable, some cases slow enough that they may never need treatment, but others progressing rapidly to potential blindness.
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Because of the variable natural course of NTG, it is important to distinguish between patients who have progressive vs. non-progressive disease.
In cases of mild NTG, consider monitoring until progression is confirmed.
However, factors that weigh more heavily for treatment are female gender, history of migraine and disc hemorrhage at diagnosis.
When you suspect progression, be sure to confirm that it is actual progression and not testing variability.
This may require multiple visual fields to prevent over-diagnosing progression.
Once the decision is made to begin treatment, set a goal (at least 30% IOP reduction) and be diligent in attaining it.
The large arsenal of IOP-lowering medications available today makes this goal much more achievable without surgery
TUBE V/S TRABECULECTOMY(TVT)
TVTPURPOSE: To report 5 year treatment
outcomes in the tube versus trabeculectomy study.
DESIGN: Multicenter randomized clinical trial
TVTSTUDY POPULATION: -Patients 18 to 85 years -Prior cataract or glaucoma filtering surgery- Uncontrolled glaucoma with IOP of 18mmHg
to 40 mmHg on maximum tolerated medical therapy
OUTCOME MEASURES-IOP, Visual acuity, visual fields, surgical
complications, glaucoma medications and treatment failure
TVTRESULTS:-Trabeculectomy with MMC and tube-shunt
surgery both produced sustained IOP reduction to the low teens during 5 years of followup
-Tube-shunt surgery was associated with use of more glaucoma medications than trabeculectomy with MMC during the first 2 yrs of study,but medical therapy equalized with longer followup
TVTRESULTS-Trabeculectomy with MMC had a higher
failure rate (46.9%)compared with tube shunt surgery(29.8%)
-Higher rate of reoperation for glaucoma(29%) compared to tube group(9%0
-vision loss occurred at similar rate in both groups
-Early postoperative complications occurred more frequently after trabeculectomy with MMC relative to tube shunt surgery.similar rate for late complications
TVTImplications-No procedure superior for treating glaucoma-Factors for selecting surgical procedureo Surgeons skill and experienceo Patients willingness to undergo repeat
glaucoma surgeryo Surgeons planned surgical approach should
failure occur
The researchers maintain that the TVT study does not demonstrate clear superiority of one glaucoma operation over the other, but that both surgeries are viable options.
Potential pitfalls exist with the use of tube shunts. Subsequent surgical options after failure of tube-shunt devices become limited—surgeons are left with the choice of a second, inferiorly placed tube or cyclophotocoagulation.
The TVT Study supports the expanding use of tube shunts beyond the surgical management of refractory glaucoma.
Tube shunt surgery was shown to be effective in a patient population at lower risk of surgical failure than has traditionally been designated for this procedure.
Trabeculectomy is not without its travails. It requires the surgeon to tailor the procedure to each patient (i.e., number of scleral flap sutures and dosage of an antifibrotic agent) whereas tube-shunt surgery is a more standardized procedure
Also, trabeculectomies require more frequent and more vigilant postoperative care than tube shunts.
OTHER IMPORTANT TRIALS
EUROPEAN GLAUCOMA PREVENTION STUDYOBJECTIVE Efficacy of reduction of IOP by dorzolamide
versus placebo in preventing or delaying POAG in patients affected by Ocular hypertension
EGPS PARTICIPANTS:-1081 patients-Age ≥30 yrs-IOP 22 to 29 mmHg-2 normal and reliable visual fields-Normal optic discsOutcome measures:Safety end point was IOP >35 mmHg on 2
consecutive examinations
EGPSRESULTS-Dorzolamide reduced IOP by 15-22% in 5 yrs
period-At 60 months ,cumulative probability of
converting to an efficacy end point was13.4%(dorzolamide group)14.1%(placebo group)-No statistically significant difference between
medical therapy and placebo group in reducing incidence of POAG
EGPSRisk factors for progression1.Older age2.Thinner CCT3.Higher vertical cup disc ratio4.Higher Pattern standard deviation
EGPSThe role of systemic blood pressure appears
importantRegression to the MeanMinimised by multiple IOP measurements at
different times of the day (diurnal variation) or on a different day.
For each mm Hg higher IOP per 12 months, the risk of converting to POAG in increased by 9% in the next 5 years.
LOW TENSION GLAUCOMA PREVENTION STUDYOBJECTIVE To evaluate visual field stability in low-
pressure glaucoma patients randomized to intraocular pressure reduction in both eyes with topical twice daily brimonidine tartrate 0.2% versus twice daily timolol maleate 0.5%
LOGTSPARTICIPANTS -Low-pressure glaucoma patients - 30 years of age or older -untreated pressure of more than 21 mmHg
and advanced visual field loss were excluded
Randomization of both eyes to double-masked monotherapy with brimonidine or timolol.
LOGTSFollow-up visits included Humphrey 24-2 full-
threshold perimetry, tonometry every 4 months, and annual optic disc photography.
MAIN OUTCOME MEASURE:- Progression of visual field loss.
LOGTS
RESULTSshowed similar IOP reduction for each
medication.patients on brimonidine had less visual field
loss (9.1%) compared with patients on timolol (39.2%) during an average of 30 months
28 of the 99 patients in the brimonidine arm of the study dropped out due to drug-related adverse events, compared with only 9 of the 79 timolol patients
LOGTS
RESULTSlow-pressure glaucoma patients treated with
brimonidine are less likely to have field progression than patients treated with timolol
Conclusion:Brimonidine better than Timolol??
The study attempted to find correlations between many other baseline factors of the 2 study groups and the slower progression of glaucoma in the group that received brimonidine.
Age, sex, family history, diabetes mellitus, risk factors for low-tension glaucoma (such as migraine and the Raynaud phenomenon), and ocular perfusion pressure were investigated..
LOGTS Drawbacks-Data may have been skewed due to the high
number of patients dropping out of the brimonidine group.
-No therapeutic goal for either medication -Baseline untreated IOP was just over 15mm
Hg and the mean treated IOP was around 14mm Hg
LOGTS For now,we should use the therapy that
reduces IOP in normal-tension patients to significant levels (minimum 30%), and modify treatment if the optic nerve, retinal nerve fiber layer or visual field changes.
Prostaglandins have superb efficacy and less effect than other agents in lowering heart rate. These should be used as a first-line treatment whenever possible.
Remember to check blood pressure and heart rate before initiating treatment with a beta-blocker such as timolol.
Also, check if the patient is already taking a systemic beta-blocker.
Be sure that patients use timolol earlier in the evening rather than before bedtime to avoid the hypotensive effect that might compromise ocular blood flow and induce systemic hypotension.
TAKE HOME MESSAGE
In OHT cases:Not all OHT need treatment – assess risk on
individual basis and then decidePeople with high risk factors may benefit from
close followup and early treatment
Low risk patients can have less frequent followup and may not need early treatment.
TAKE HOME MESSAGEIn NTG cases:Rate of progression in NTG highly variableOnly proven treatment is reducing IOPTreat if risk factors present
TAKE HOME MESSAGEPOAG casesStart early treatment in diagnosed cases of
POAGChoice of medical therapy first – change only
if target IOP not achieved.Surgical therapy safeIn moderate to advanced disease initial surgical
therapy may be preferred
TAKE HOME MESSAGEEfficient patient care – practice of evidence based
Rx
IOP is the main risk factor for all glaucomas
Recognize threat – lower IOP – lower risk of progression
Set a target IOP after assessing risk factors for progression