OHTN

Question 1

OHTN

Answer 1

Statistically elevated IOP in the presence of an open angle on gonio and healthy optic nerves. The OHTS defined OHTN as an IOP 24-32mmHg. Clinically it is often classified as an IOP >22mmHg

Question 2

OHTS study

Answer 2

Included patients with elevated IOP 24-32 with an open angle on gonio, a healthy ONH, and no VF defects

• patients were randomized into a treatment group (drops), and a control group. The target IOP for patietns in the treatment group was at least a 20% IPO reduction from baseline IOP and an IOP <24mmHg
• patients were followed for 5 years. The primary endpoint was progression to POAG, defined as glaucomatous damage to the ONH, glaucomatous VF defects or both

After 5 years, 9.6% of patients in the control group progressed to POAG, compared to 4.4% in the treatment group

Question 3

Average CCT

Answer 3

473-597

Question 4

What is the clinical average of CCT considered

Answer 4

555

Question 5

Thicker CCT gives an ______ of IOP readings

Answer 5

Overestimation

Question 6

Thinner CCTs give an _____ of IOP readings

Answer 6

Underestimation

Question 7

CCT and glaucoma risk

Answer 7

OHTS concluded that thin pachs are an independent risk factors for he progression to POAG, even after controlling for the effect of CCT on IOP and other risk factors. Recall that it is no longer recommended to use a correction factor to determine the true IOP based on CCT, as the various proposed correction factors are unreliable; CCT should only be used to assign risk

Question 8

High risk CCTs

Answer 8

<555

Question 9

No change in risk on CCTs

Answer 9

555-588

Question 10

Lower risk of POAG progression with CCTs

Answer 10

> 588

Question 11

POAG risk: race

Answer 11

AA (as well as Hispanics and Latinos) have an increased prevalence compared to Europeans and caucasians

Question 12

POAG and famHx

Answer 12

Positive famHx of POAG (first degree relative) increases the risk development of POAG by 3-4x

Question 13

What is the most important risk factor of progression to POAG

Answer 13

Elevated IOP

• the only risk factor that can be treated
• as IOP increases, the risk of POAG also increases

Question 14

Baltimore eye study

Answer 14

Followed patients with OHTN without treatment for 40 months and noted that 2.7% of patietns with an IOP 21-25mmHg, 12% of patients with an IOP 26-30mmHg, and 41.2% of patients with IOP >30mmHg developed POAG

Question 15

Age of 90% of patients with POAG

Answer 15

> 55

Question 16

Other potential risks for POAG

Answer 16

History of blunt trauma
Chronic use of systemic or topical ophthalmic steroids
Possibly myopia

Question 17

P value of >5% on OCT

Answer 17

A p value >5% is assocaited with sectors marked as green on an OCT and indicates the thickness value is within the normal range for 95% of healthy patients in the population. A yellow sector is associated with a p value <5% but >1% and indicates the thickness value is normal for 1-5% of healthy patients in the population. A red sector is associated with a p value of <1% and indicates the thickness value is normal for less than 1% of the healthy patients in a population

Question 18

Looking at red and yellow sectors on RNFL

Answer 18

Does not indicate that the patient has glaucoma. It indicates that the thickness value is normal in few healthy patients in the population. Always look at the optoc nerve rim tissue and the VF in addition to the OCT prior to making the diagnosis of glaucoma

Question 19

HRT

Answer 19

Uses confocal scanning laser tomography to obtain a 3d image of the optic disc and the retina

Question 20

GDx

Answer 20

Uses scanning laser polarimetry to measure the RNFL thickness

Question 21

OCT

Answer 21

Uses optical coherence tomography to measure the RNFL thickness and macualr thickness

Question 22

TSNIT pattern

Answer 22

Shows the RNFL thickness around the optic nerve. A normal TSNIT will have a double hump pattern, the shaded are of the map represents the range of the normative database

Question 23

What quadrants are most important to look at on scans for glaucoma

Answer 23

S and I

Question 24

ALT vs SLT

Answer 24

• ALT uses argon laser (same as PRP); SLT uses a selective frequency doubled Nd:YAG laser
• both ALT and SLT apply laser to the TM in order to lower IOP, although their proposed mechanisms differ: ALT causes scarring of the TM, causing tissue contraction that opens up the surrounding pores of the TM to improve AH outflow
• SLT stimulates the endothelial cell pumps and macrophages withi nthe TM to remove debris, resulting in an increase in AH outflow
• both have similar long term efficacy at controlling IOP, as well as similar side effects
• advantage of SLT of ALT is the repeatability of SLT due to reduced thermal damage to the TM compared to ALT

Question 25

How does NTG differ from other glaucoma

Answer 25

- japanese - IOP <24 (or less than 21) - more likely to get a France hemorrhage - paracentral VF defect - progresses much slower, if at all - much different risk factors and include vascular disorders (raynauds, sleep apnea)

Question 26

IOP and NTG

Answer 26

``` Plays less of a role here than in POAG Other risks -vascular conditions -low blood pressure -sleep apnea -hypercoagulation ```

Question 27

Most common VF defect in NTG

Answer 27

Paracentral

Question 28

Optic neuropathy and NTG

Answer 28

Since IOP is in the normal range in NTG, it is important to consider other possible causes of optic neuropathy, especially in cases of suspected unilateral NTG. Additionally causes include hemorrhagic shock, MI, anemia, syphilis, vasculitis

Question 29

Study question of OHTS

Answer 29

Does treating elevated IOP in a patient with OHTN decrease risk of progressing to POAG

Question 30

Conclusion of OHTS

Answer 30

Treating patients with OHTN reduces the risk of progression to POAG by 5% - the benefit of treatment is likely over-stated, as all patients who progressed to POAG based on glaucomatous optic nerve changes alone were asymptomatic, and even those patients that progressed based on VF defects were likely still asymptomatic - certain patietns may have a higher rusk of progressing to POAG based on multiple risk factors. The decision to treat an individual patient with OHTN is multi-factorial; not all patients with OHTN require treatment. VF defects should be confirmed with consecutive fields to ensure true progression to POAG

Question 31

EGPS study question

Answer 31

Does lowering IOP in patients with OHTN decreased the rare of progression to POAG

Question 32

Conclusion of EGPS

Answer 32

Treatment of OHTN does not reduce the risk of progression to POAG. However, note that this study is poorly designed compared to the OHTS, as there was a high drop out rate, patients had thicker than average CCTs, only one IOP drop was used and no target IOP was set

Question 33

EMGT study question

Answer 33

Should patients with newly diagnosed glaucoma be treated with IOP lowering drugs

Question 34

Results of EMGT

Answer 34

45% of patients in the treatment group progressed compared to 62% on the control group

Question 35

Risk factors to progression based on EMGT

Answer 35

Higher IOP (baseline and after treatment), bilateral disease, PXF, older age, and disc hemorrhages. For every 1mmHg of lowered IOP, there was a 10% reduction in risk of progression

Question 36

Conclusion of EMGT

Answer 36

Lowering IOP reduces the risk of progression in the patients with early glaucoma. However almost half of the treated patients still progressed

Question 37

CIGTS study question

Answer 37

Should patients with early (asymtaotmic) glaucoma (including pigmetnary and PXF) be initally treated with trab or with drops

Question 38

Conclusion of CIGTS

Answer 38

Trab and drops are equally effective in the treatment of early OAG. Both should be soldiered as inital treatment options, although drops are often recommended first due to quality of life issues and lower risk of ocular complications, including cataracts

Question 39

CNTGS study question

Answer 39

Does lowering IOP reduce the rate of progression in NTG

Question 40

Conclusion of CNGTS

Answer 40

Treament is effective at reducing the risk of pression to NTG, but 2/3 of patietns with non fixation threatened NTG will not progress, even without treatment

Question 41

AGIS study question

Answer 41

Should patients with advances glaucoma and inadequate IOP control on max therapy be treated with trab or ALT first

Question 42

Conclusion of AGIS

Answer 42

The lower the IOP, the less risk of VF progression; a less important (but often quoted) conclusion is that ATT resulted in less VA loss in AA and TAT resulted in less VF loss in caucasians, however, the risk benefit ratio of each treatment should be considered for every patient, regardless of race