Glaucoma 4 therapy of glaucomas, dr.k.n.jha,09.11.16

1. Management of Glaucomas
Professor K N Jha,MS.

2. Learning Aim
• Approaching a case of glaucoma
• Treatment aims in glaucoma
• Medical therapy of glaucoma
• Surgical and LASER therapy of glaucoma
• Complications of glaucoma surgery

3. Management of Glaucomas
• Early diagnosis and therapy
• Life long therapy and follow-up
• Patient counseling
• Baseline parameters: IOP , field , fundus

4. Goal of Glaucoma Therapy
• To preserve visual function by reducing IOP.
• The treatment should have:
-minimum side effect.
-cause least disruption in patient’s life.
- should take into consideration the cost.
Risk benefit ratio need to be factored in case of
new medications.

5. Target pressure
• It is a range of IOP with an upper limit that is
unlikely to lead to further damage.
• Initial reduction: 20% from baseline.
• Target pressure need constant reassessment
dictated by IOP fluctuation , ONH changes,
and/or visual field progression.

6. Target pressure
• Target pressure goal depending on
-initial IOP
-severity of damage
-life expectancy
-associated risk factors like , family history.

7. Medical or, surgical treatment?
• Pupillary block glaucoma Surgery/Laser
• Infantile glaucoma Medical therapy is
secondary.
• POAG -Initially medical
-Surgery, if medical
therapy fails or, it is not
tolerated.
• Treatment of secondary glaucoma is comparable to
the primary glaucoma that it closely resembles.

8. Therapy of Glaucomas
• Medical
• Surgical
Internal drainage ( iridectomy)
External subscleral drainage ( Trabeculectomy)
Cyclodestructive procedure
( cyclocryopexy/DLCP)
• Laser
Argon laser trabeculaoplasty(ALT)
Gonioplasty
Laser peripheral iridotomy

9. Medical agents: Mechanism of action
- aqueous humor
secretion
- outflow of humor
through
- pupil
- TM
- uveoscleral path

10. Medical agents
-beta-adrenergic antagonists e.g. Timolol 0.5 %
-Parasympathomimetics(miotics):cholinergic and
anticholinesterase agents e.g. pilocarpine 2 %- 4 %
-CAI e.g. Acetazolamide (oral) parenteral, topical ( dorzolamide )
-Adrenergic agonists( non-selective and selective alpha₂ agonists)
e.g. brimonidine.
-Prostaglandin analogues and hypotensive lipids e.g. latanoprost
-Combination medications
- Hyperosmotic agents ( Injection Mannitol 20 % I.V. )

11. beta-adrenergic antagonists
-Lower IOP by inhibiting cAMP production in the ciliary
epithelium,
thereby reduce IOP by reducing aqueous secretion.
-Effect starts within 1 hour and can be present for up to 4 weeks
after discontinuation.
-Decrease IOP by 20-30%
-Timolol 0.5 %, Betoxolol 0.5 % b.i.d.
-Twice a day dosing, can be combined with other agents.
-Side effects: systemic and local.

12. Parasympathomimetic agents
-Direct-acting cholinergic affects motor endplate in the
same way as acetylcholine at postganglionic
parasympathetic junction, as well as other autonomic,
somatic and central synapses. e.g. Pilocarpine
-Indirect-acting anticholinesterase agents inhibit
acetylcholinesterase e.g. echothiophate iodide. May
precipitate angle closure.

13. Parasympathomimetic Agents
(miotics)
Mechanism of action of IOP reduction:
-They reduce IOP by causing contraction of longitudinal
ciliary muscle, which exerts pull on the scleral spur to
tightens the trabecular meshwork, thus increasing the
outflow aqueous humor.
- Miosis (pupillary constriction) that pulls away the
peripheral iris away from the trabecular meshwork has IOP
lowering effect in ACG.

14. Parasympathomimetics
• Reduce IOP by 15-25 %
• Uses: Prophylaxis for angle closure
glaucoma(ACG), in eyes with failed glaucoma
surgery.

15. Pilocarpine
• Direct-acting parasympathomimetic
• Primarily used in PACG pending iridectomy.
• Strength and dose:1-2% drop q.i.d.
• Side effects: ocular , systemic.

16. Side effects of pilocarpine
• Systemic: stimulates of lacrimal and salivary
secretions.
• Ocular:
- disrupts blood retinal barrier
- Brow ache, ciliary spasm, and induced myopia.
- Retinal detachment
- impaired vision in dim illumination
- Lenticular opacities.
-Punctual stenosis

17. Carbonic anhydrase inhibitor (CAI)
• Decreases aqueous humor production by
-direct antagonist activity on ciliary epithelial
carbonic anhydrase.
- By producing generalized acidosis, on
systemic administration.

18. Carbonic anhydrase inhibitor (CAI)
• Systemic CAI e.g. Acetazolamide ,
methazolamide are used in emergency
situations in AACG.
• Topical carbonic anhydrase inhibitor e.g.
acetazolamide , Dorzolamide drop for
treatment of chronic IOP elevation in OAG

19. Carbonic anhydrase inhibitor
• Side effects:
-on systemic use: anorexia, abdominal
discomfort, diarrhea, unpleasant taste in mouth.
-Paresthesias of fingers or toes
-Formation of renal stones.
-Allergic reactions
-Blood discrasias
-Hypokalemia
- on topical administration: punctate
keratopathy, corneal decompensation.

20. Carbonic anhydrase inhibitor (CAI)
Preparations
Oral: -Acetazolamide(250 mg) t.i.d., or sustained
release tablet once a day.
-Methazolamide 20-50 mg t.i.d
Intravenous : Acetazolamide in emergency.
Topical : dorzolamide , brinzolamide t.i.d.

21. Nonselective Adrenergic Agonists
• Nonselective adrenergic agonists( e.g.
epinephrine and depivefrin) increase
conventional trabecular and uveoscleral
outflow.

22. Alpha₂-Adrenergic agonists
-Decreases IOP( by 26%) by decreasing aqueous
production and increasing uveoscleral outflow.
-Comparable in effect to non-selective beta blocker.
-Brimonidine 0.2% / 0.15 % is much more highly
selective for alpha₂ receptor. Dose: tid/bid.
-Alpraclonidine HCl used after laser procedure.
- Avoided in children and in patients on MAO inhibitors.

23. Hypotensive lipids
• Prostaglandin analogues: travoprost,
latanoprost ( increases uveoscleral outflow)
• They are pro-drugs.
• Reduce IOP by 25-32%.
• Prostamide: Bimatoprost ( both us +
trabecular outflow)
• Decosanoid: unoprostone isopropyl

24. Hypotensive lipids
Latanoprost( Xalatan),Bimatoprost (Lumigan), travoprost(
Travatan) are used once in 24 hours, at night.
Side effects:
-Darkening of iris and periocular skin.
- Conjunctival hyperemia, hypertrichosis, trichiasis,
distichiasis.
- Exacerbation of herpes keratitis , CME and uveitis.

25. Combined medications
• Improved efficacy , convenience, compliance,
and reduced cost.
• Examples: Timolol 0.5%+ dorzolamide 2% bid.

26. Hyperosmotic agent
• Used to control acute episodes of elevated
IOP.
• They reduce IOP by increasing blood
osmolarity and creating an osmotic gradient
between blood and vitreous humor.
• Water is drawn from vitreous and IOP falls.

27. Hyperosmotic agent
• Common agent mannitol 20 % solution.
• Dose : Mannitol1.5-2 gm/kg body weight
• Side effects: may cause rapid increase in
cardiac preload and may precipitate CCF.
• Contraindicated in patients with renal failure
or on dialysis.
• Glycerol 1-2 ounce with fruit juice.

28. ACG
• Laser/surgical iridectomy
• Chronic ACG: trabeculectomy
• Medical treatment is used for preparation for
laser surgery, to tide over sudden rise in IOP,
and prevent PAS formation

29. Open angle glaucoma
Medical treatment
-efficacy and compliance
- start with single drug
-agent is individualized
Laser ( ALT) initially ,as an alternative to drug
Surgery: Trabeculectomy

30. Drug therapy in OAG
First choice: hypotensive lipid( Bimatoprost) ,
beta-blocker (Timolol), alpha-2
agonist(Brimonidine) and topical CAI
(Dorzolamide)
-Add 2nd
agent if IOP is not controlled with one
-When individual requires 3 or more topical drop
compliance and complications are considered

31. TRABECULECTOMY
Surgery for open angle glaucoma

32. Trabeculectomy
• Creates a fistula in the sclera for bulk flow of
aqueous humor from anterior chamber to the
sub-conjunctival and sub- Tenon’s space
where a ‘filtering bleb’ is created.

33. Complications of filtering surgery
• Early: infection , flat anterior chamber, uveitis
• Late: cataract, endophthalmitis , hypotony