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

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

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

  1. 1. Management of Glaucomas Professor K N Jha,MS.
  2. 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. 3. Management of Glaucomas • Early diagnosis and therapy • Life long therapy and follow-up • Patient counseling • Baseline parameters: IOP , field , fundus
  4. 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. 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. 6. Target pressure • Target pressure goal depending on -initial IOP -severity of damage -life expectancy -associated risk factors like , family history.
  7. 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. 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. 9. Medical agents: Mechanism of action - aqueous humor secretion - outflow of humor through - pupil - TM - uveoscleral path
  10. 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. 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. 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. 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. 14. Parasympathomimetics • Reduce IOP by 15-25 % • Uses: Prophylaxis for angle closure glaucoma(ACG), in eyes with failed glaucoma surgery.
  15. 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. 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. 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. 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. 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. 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. 21. Nonselective Adrenergic Agonists • Nonselective adrenergic agonists( e.g. epinephrine and depivefrin) increase conventional trabecular and uveoscleral outflow.
  22. 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. 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. 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. 25. Combined medications • Improved efficacy , convenience, compliance, and reduced cost. • Examples: Timolol 0.5%+ dorzolamide 2% bid.
  26. 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. 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. 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. 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. 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. 31. TRABECULECTOMY Surgery for open angle glaucoma
  32. 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. 33. Complications of filtering surgery • Early: infection , flat anterior chamber, uveitis • Late: cataract, endophthalmitis , hypotony

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