Glaucoma 5 - Management of Glaucoma Flashcards
Why do clinicians Targeting IOP?
•The IOP that is expected to confer optic nerve stability in a patient with glaucoma
• Damaged optic nerves require greater IOP reduction. le. the worse the initial condition of the eye, the lower the tension needs tolbe to prevent further loss or blindness.
How do Clinicians determined to reduce the IOP?
Set initial target IOP at 30% and then modify
according to:
• How severe is the existing optic nerve damage?
• How high is the IOP?
• How rapidly has the damage occurred? (Rate of Progression)
•How many additional risk factors are present?
•Life expectancy
•Status of other eye
•Patient preferences
•Adverse consequences of intervention
General damage reduction IOP values:
• Mild damage 30%
• Moderate damage 35%
• Severe damage 35-40%
Once a target IOP is selected it should not be a fixed target but may need to be modified depending on the patients response to treatment
Aims of treatment in Glaucoma:
EGS guidelines:
• In general, the goal of glaucoma treatment can be summarised as follows: preservation of visual function adequate to the individuals needs with minimal or no side effects, for the expected lifetime of the patient without any disruption of his/her normal activities at a sustainable cost
Visual field vs survival:
Stage of disease, age ( life expectancy) and rate of progression are really the key to how aggressive we need to be in managing the lowering of IOP
The Ocular Hypertension Treatment Study:
• 1636 patients with OHT to observation or treatment to lower IOP less than 24 mmHg or by 20% min (22.5% vs 4%) 7 year follow up.
•At 5 years 4.4% of treatment group progressed vs 9%
- 90% of untreated group did not progress -By 13 years 22% of control gp and 16% of treatment group had progressed to glaucoma
OHTS Study IOP and Corneal thickness as risk factors:
• Looked at Groups that had progressed and found several significant baseline predictive factors
• Strongest was CCT, IOP, Age, CD ratio and
PSD >2.0
• So for some patients risk was high as 30+%
European Glaucoma Prevention Study:
• Similar findings to OHTS in terms of risk factors to progression from OHT to Glaucoma
• No statistically significant difference between treated group
Collaborative Normal Tension Glaucoma Study (NTGS):
• 5 yr study of 140 eyes in NTG (IOP=24) primary outcome measure was disease progression
• Randomised to IOP lowering (30% with any form of Rx vs controls)
- Results - 20% or treated group progressed vs 60% of untreated
• First multi-centre prosp random clinical trial to show IOP reduction is effective in any type of chronic glaucoma
• Summary when IOP lowered by 30% in NTG there was lower incidence of VF progression
Collaborative Initial Glaucoma Treatment Study (CIGTS)
• 607 patients followed for 4-5 yrs - Newly dx
- OAG randomised to either medication or trabeculectomy to achieve a target IOP
• Primary outcome variables were VF loss and QoL (no sig diff)
• Lower IOPs achieved with surgery (48%) vs medication (35%)
• Increase in cataract in surgery (17% vs meds 6%)
• VF progression similar and not significant over 5 years at these levels of IOP reduction (35% + Some differences when followed up for longer (TAGS)
The Advanced Glaucoma Intervention Study (AGIS)
AGIS (Advanced Glaucoma patients)
• 591 over 8 years randomised into TAT or ATT
• Eyes with Avg IOP > 18 mmHg over first 3 6/12 visits showed significantly greater VF deterioration compared to eyes with IOP <14 over same period and amount of deterioration inc with longer f/u
Early Manifest Glaucoma Trial
Results(EMGT)
• EMGT looked at 316 eyes over 10 years measuring the effectiveness of IOP reduction in early untreated OAG with IOPs < 30
• Patients were randomised to IOP lowering with ALT/B blockers or no Rx
• A 25% reduction of IOP from baseline (20.6mm to15.5mm Hg) resulted in a reduced risk of progression by 50%
• Risk of Progression decreased by 10% with each 1mmHg IOP reduction from baseline to firs F/U visit
General principles of treatment: In order from common ->uncommon
• Topical hypotensives (monotherapy to maximal therapy)
• YAG laser iridotomy if narrow angles (ITC)
• SLT
• Trabeculectomy /Deep Sclerectomy
• oral acetazolamide
• Angle Surgery (Phaco, istent, trabectome, canaloplasty)
• Cyclodiode Laser Ciliary Ablation
• Tube or valve surgery
Order of prescribing drops for glaucoma:
• 1st Line: Prostaglandin analogue or Beta-blocker
- Uniocular trials
• 2nd Line: Prostaglandin analogue or Beta-blocker
• 3rd Line: Carbonic anhydrase inhibitor or alpha 2 agonist
• 4th Line: rarely as 3 above or pilocarpine
Prostaglandin Analogues:(1st line)
- All Increased uveoscleral outflow by ciliary muscle relaxation
- 30-35% reduction in IOP
•Latanoprost (Xalatan, Generic, Monopost)
•Travoprost (Travatan) od
•Bimatoprost 0.01/0.03% (Lumigan) od
• Tafluprost (Saflutan) od
