1. Global prevalence of POAG
From systematic reviews of published population based studies
Global prevalence (2013):
3.05% of the year population has POAG
Highest : Africa with 4.2%
Estimated number globally(2013) : 44 million
Highest : Asia with 23.5 % ( mostly related to the largest population)
Tham et al. Ophthalmology 2014;121:

2. Tham et al. Ophthalmology 2014;121:2081-209

3. Risk factors Older age Male gender Urban residence African ancestry
Most glaucoma is undetected ( %, depending on the region)
Tham et al. Ophthalmology 2014;121:

4. Pathophysiology of Primary open angle glaucoma (POAG)
Primary open angle glaucoma is considered to be a chronic, progressive optic neuropathy characterised by typical optic nerve head and nerve fibre layer changes. Progressive ganglion cell loss and visual field changes are characteristic of the disease.
Damage to the optic nerve is most commonly intraocular pressure dependent.
Elevated IOP occurs secondary to changes in the trabecular meshwork

5. Components of the trabecular meshwork (TM )
TM beams
Endothelial Cells lining TM
Juxtracanalicular space
Extracellular matrix
Glycosaminonglaycans (GAG)
Originally thought to fill all the empty spaces – now thought to only coat them

6. TM and IOP fluctuations
Changes in the structure

7. TM and IOP fluctuations
Low IOP
High IOP
Collapse of TM
Widening of Schlemn’s canal
Expansion of TM
Collapse of Schlemn’s canal

8. In POAG Different theories
Changes seen in the Trabecular meshwork are consistent

9. Tabecular meshwork beams

10. Trabecular meshwork

11. Increased resistance
to outflow
Increased IOP

12. Low IOP
High IOP
Schelmn’s canal
Schelmn’s canal
Trabecular meshwork
Trabecular meshwork

13. Low IOP
High IOP
Schelmn’s canal
Schelmn’s canal
Trabecular meshwork
Trabecular meshwork
Collapse of Schlemn’s canal with
Persistently high IOP

14. Changes in POAG TM beams : Thicken
Cells lining TM : get lost – fusion of beams
? Also increase buildup of GAG
Plaque deposition
Juxtacanalicular space extracellular matrix
Glycosaminonglaycans (GAG)
Originally thought to fill all the empty spaces – now thought to only coat them
Collapse of Schlem’s canal with repeated high IOP