Primary open-angle glaucoma (POAG) is characterized by optic nerve damage and visual field loss due to increased intraocular pressure without obstruction of the eye's drainage angle. It has no known cause but risks include older age, family history, and higher eye pressure. Diagnosis is based on optic nerve head changes, visual field testing showing blind spots, and elevated intraocular pressure. Treatment aims to lower pressure through eye drops, laser therapy, or surgery to slow progression and preserve vision. Regular monitoring of pressure and nerve changes is needed for long-term management.

1. Primary Open-Angle Glaucoma
Professor K N Jha,MS

2. Learning Aim
• Definition of Open-angle glaucoma
• Primary open-angle glaucoma (POAG)
• Clinical features (IOP, fundus, and field
changes) of POAG
• Treatment of POAG

3. Primary open-angle glaucoma(POAG)
-POAG is characterized by a chronic, slowly
progressive, optic neuropathy with a
characteristic pattern of optic nerve damage
and visual field loss.
-Angle of the anterior chamber is open.
-There are no ocular or systemic disorders.

4. POAG
Risk factors
• IOP
• Race
• Central corneal thickness ( CCT)
• Age
• Family history
• Systemic and ocular associations: DM,
Myopia, HTN, CRVO

5. POAG: Contributory factors
• Reduced perfusion of the optic nerve head
- Inadequate auto-regulation in blood vessels
- Mechanical compression of capillaries
• Abnormality of axonal , or ganglion cell
metabolism
• Disorders of the extracellular matrix of lamina
cribrosa.

6. Pathogenesis
• Increased resistance to aqueous outflow
• Mechanical changes due to raised IOP
- Decreased axoplasmic flow
• Optic nerve head vascular perfusion
- Inadequate autoregulation in blood
vessels
- Mechanical compression of capillaries
• Glaucomatous Optic atrophy

7. POAG: Clinical features
• Onset : Insidious,
• Slowly progressive, and painless
• Bilateral: initially may manifest in one eye.
• Visual acuity remains unaffected until late
• Diagnosis : IOP, visual fields, and optic disc
appearance.
• Gonioscopy: open angles
• Associations: myopia, DM, CVS disease, CRVO

8. Diagnosis
Characteristic optic nerve head changes
Visual field changes
Raised Intraocular pressure (IOP)
At least two of the above three.

9. Optic disc(ONH) changes in glaucoma
• Increased vertical cup : disc ratio
• Asymmetry of cups between two eyes
• Notching and pallor of neuroretinal rim(NRR)
• Disc hemorrhage
• Baring of circumlinear vessels
• Peripapillary retinal atrophy

10. Optic Nerve head changes
Normal fundus oculi Glaucomatous cupping

11. Visual field changes in glaucoma
• Relative paracentral scotoma: smaller/
dimmer targets are not visualized.
• Nasal step: appearance of horizontal shelf in
nasal visual field
• Seidel scotoma: starting from one pole of
blind spot and arches over macula without
reaching horizontal meridian nasally.
• Arcuate scotoma
• Double arcuate or ring scotoma
• End-stage or near total field defect

13. POAG : Management
• Early detection and routine screening
• Meticulous documentation: IOP, optic nerve
damage and risk factors

14. Primary open-angle glaucoma
Treatment goal
• Modify and slow progression of optic nerve
damage.
• To lower IOP

15. 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.

16. Target pressure
Depends on
-Initial IOP
-Severity of damage
-Life expectancy
-Associated risk factors like , family history.

17. POAG: Management
• Patient education
• Cost and Compliance
• Medical or surgical therapy
• Progression and follow-up

18. POAG: Management
Modalities of treatment
Drug therapy
Laser
Surgery

19. POAG: Medical Therapy
Topical :
-Parasympathomimetics
-Adrenergic antagonists : beta-blockers
-Sympathomimetics: alpha-2 agonist
-Prostaglandin analogues and hypotensive lipids
CAH inhibitors : Acetazolamide, dorzolamide, brizolamide
Hyperosmotic agents

20. Primary open-angle glaucoma
• Laser therapy: Argon-laser trabeculoplasty
• Glaucoma surgery: Trabeculectomy

21. POAG: Prognosis
• Most patients will retain useful vision for their
entire life
• Incidence of blindness at 20 years follow-up is
27 % unilateral, 9 % bilateral.

22. Primary open-angle glaucoma
Summary:
• Clinical features
• Fundus changes
• Field changes
• Diagnosis
• Treatment
• Follow-up