Lecture 12: Primary Glaucoma (Part 1)

Question 1

List the 5 objectives of initial glaucoma evaluation

Answer 1

• Address any treatable conditions that contribute to current IOP elevation
  
  • (or may cause future IOP elevation)
• Establish a baseline: quantify structural and functional status of the ONH
• Determine if glaucomatous damage already exists based on clinical examination, optic disc imaging, and visual field testing
• Decide if therapy is indicated, and if so, set a target pressure
  
  • Note: typically for IOPs >30mmHg the patient is treated prophylactically due to increased risk for glaucoma and risk for CRVO!
• Set an initial follow-up schedule

Question 2

Which test during glaucoma examination gives us the risk & evidence of glaucoma?

Answer 2

Optic nerve evaluation

Question 3

What are the 5 important questions to ask yourself when evaluating the glaucoma suspect?

Answer 3

• Is this glaucoma?
  
  • Is it something else? (ACTIVELY FORMULATE A LIST OF DIFFERENTIALS)
  • Is it glaucoma AND something else?
  • Especially important to consider in NTG
• Are there risk factors for glaucoma present?
  
  • i.e. does it make sense for the nerve to appear glaucomatous
• is it primary or secondary?
• Is it open angle or closed angle?
• Does this need treatment?

Question 4

Define glaucoma suspect

Answer 4

• Term often used when a pt has risk factors and we are in the process of evlauting for glc

Question 5

Physiological cupping veritical cup to disc ratio > __ is suspicious for glaucoma

Answer 5

0.6

Question 6

If you ask if glaucoma suspect runs in the family this could indicate what?

Answer 6

genetically large cupping

Question 7

glaucoma classification system is based on what 3 things?

Answer 7

• If angle is opened or closed
• IOP
• if the underlying disorder is primary or secondary

Question 8

Define primary glaucoma

Answer 8

classified as primary when there is no other identifiable ocular disease or condition (systemic or ocular) that could be causing the GON

Question 9

Define secondary glaucoma

Answer 9

When an increase in IOP and GON occurs secondary to another ocular disease or another process

Question 10

Does primary or secondary have greater risk of blindness?

Answer 10

secondary

Question 11

Define POAG

Answer 11

“A progressive, chronic optic neuropathy in adults where intraocular pressure (IOP) and other currently unknown factors contribute to damage and in which, in the absence of other identifiable causes, there is a characteristic acquired atrophy of the optic nerve and loss of retinal ganglion cells and their axons. This is associated with an anterior chamber angle that is open by gonioscopic appearance.”

and usually leads to a concomitant pattern of visual field loss

Question 12

__ is the most prevalent of all open angle glaucomas

Answer 12

POAG

Question 13

Baltimore eye survey: prevalence rates of POAG are higher in __ compared with __

Answer 13

blacks/whites

• Blacks: 1.2% (in 40-49 yo) to 11.2% (in >80 y/o)
• Whites: 0.9% (in 40-49 yo) to 2.2% (in >80 y/o)

Question 14

In the baltimore eye study (population-bsed survye of 5308 black and white americans aged _>_40 years) - prevalence of glaucoma was __%

• __% had NTG

Answer 14

2.4%, 24%

Question 15

The Beaver Dam Eye Study (4926 subjects) reported overall __% prevalence of OAG

• __% had NTG

Answer 15

2.1%, 32%

Question 16

World-wide population-based studies show prevalence NTG to be __-__% of OAG cases

Answer 16

20-39%

Question 17

Define NTG

Answer 17

• Describes an eye with a primary glaucoma and open angles. However, the IOP within what is considered normal (<21mmHg)
  
  • IOP independent factors may play a role in the development of NTG
    
    • E.g. vascular dysregulation, hypotension, and lamina cribrosa/CSF abnormalities
  • Part of a spectrum of Open Angle Glaucoma vs. Separate Disease Entity

Question 18

what is cerebral spinal fluid and CSFp and translamina cribrosa pressure (TLCp)?

Answer 18

• Behind the lamina, the ONH is surrounded by CSF
• Pressure across the lamina is translamina cribrosa pressure (TLCp) differential
• If TLCp goes up chronically, the optic nerve will develop cupping

Question 19

In NTG, CSFp is anbormally (high/low) which can lead to…?

Answer 19

low; which can lead to high TLCp difference

• Lower CSFp may explain why some people with normal/low IOPs get glaucoma (NTG)
• Higher CSFp may explain why some people don’t develop glaucoma (OHTN)

Question 21

Blood pressure: In addition, abnormalities in ocular blood flow are though to play a role in POAG and NTG.

• _______ was found to be strongly associated with the prevalence of glaucoma

Answer 21

low diastolic perfusion pressure (diastolic BP - IOP)

Question 22

___ subjects have been reported to have lower systemic blood pressure than __ patients

Answer 22

NTG/POAG

Question 23

How do you calculate ocular perfusion pressure (OPP) ?

Answer 23

BP - IOP

• BP is mean arterial pressure, diasoltic BP, or systolic BP

Question 24

Ocular perfusion pressire is likely lowest when?

Answer 24

night

Question 25

Baltimore eye survey (AA & Caucasian): __x increased incidence of POAG in subjects with the lowet category of OPP

Question 26

Egna-numarkt study (caucasian): lower diastolic OPP associated with __ fold increase in glaucoma risk

Answer 26

2.5

Question 27

Los Angeles Latino Eye Study (Latino/Hispanics): __ fold increase in glaucoma risk with lower OPP

Answer 27

1.9

Question 28

Proyecto Ver (Hispanic): Found lower DPP associated with__-fold increased risk of POAG

Answer 28

4

Question 29

Data from cross-sectionl studies show that when diastolic OPP falls below __ there’s increased risk of glaucoma

Answer 29

50

Question 30

Phelps & Corbett performed a case control study on the occurrence of __ and __. What were the results?

Answer 30

migraine & NTG; found positive migrain history in 37% of NTG patients - higher than that found in normal or POAG patients (22%)

Subsequent studies could not confirm this finding

Question 31

Location and degree of optic disc excavation should correspond with VF damage

• If the degree of VF loss is out of proportion to the extent of exacvation or it is vertically aligned, the possibility of __ should be considered

Answer 31

non-GON

Question 32

Pallor alone is the hallmark of __

Answer 32

non-GON

Question 33

T/F NTG patients with typical features of GON do require neuroimaging

Answer 33

F, DO NOT

Question 34

What were the outcome of collaborative NTG study (CNTGS) and early manifest glaucoma trial (EMGT)

Answer 34

• Large proportion of pt with NTG remain stable even without tx for a period of 5-6 years
• Treatment to lower IOP 30% reduces risk of disease progression by 66%