*topic 6 IOP (part 2)

Question 1

what is the normal IOP, diurnal variation (change in IOP throughout the day) and intraocular variation (diff in IOP between the 2 eyes) ?

Answer 1

normal IOP: 10-21 mmHg

normal diurnal variation: 4-6 mmHg (highest in the morning)

normal intraocular variation: < 3 mmHg

Question 2

what is the IOP, diurnal variation (change in IOP throughout the day) and intraocular variation (diff in IOP between the 2 eyes) of a GLAUCOMA SUSPECT?

Answer 2

glaucomic IOP: >21 mmHg

glaucomic diurnal variation: 8-10 mmHg (highest in the morning

glaucomic intraocular variation: >3 mmHg

Question 3

why is IOP highest in the morning?

Answer 3

low blood flow from when we are lying down during sleep

Question 4

what are 4 ocular factors that lead to increased IOP?

Answer 4

1. closed anterior chamber angle (CAG)

open anterior chamber angle (OAG) with:

2. shrinkage/ swelling/ blockage in TM (TM might still be seen but there is malfunction)
3. narrowing of schlemm’s canal
4. raised episcleral venous blood pressure (blood vessels are narrowed, decrease in drainage)

Question 5

why do these factors result in high IOP?

Answer 5

These factors causes a resistance to drainage. As a result, there is not enough draining of aq humour and aq humour accumulate. This causes IOP to rise

Question 6

What causes pupillary block in closed angle glaucoma?

Answer 6

1. iris is in contact with the lens
2. no space for aq humour to pass through
3. aq humour accumulate in the posterior chamber
4. IOP increases and could result in iris bulge

Question 7

what is IOP? how is it related to glaucoma?

Answer 7

it is the pressure within the eye maintained by the aq humour

if IOP increases, there is increased chances of glaucoma.
**it is a RISK FACTOR. Just because high IOP does not mean confirmed glaucoma