Ocular: Aqueous Compartment

Question 1

What separates the posterior and anterior chambers?

Answer 1

Iris

Question 2

Aqueous humor flow is ______.

Answer 2

Unidirectional

Question 3

The posterior and anterior chambers are filled with what?

Answer 3

Aqueous humor

Question 4

What is aqueous humor?

Answer 4

Clear fluid that pressurizes the eye

Question 5

The aqueous humor provides nutrients to what a vascular structures?

Answer 5

-lens
-cornea
-trabecular mesh work

Question 6

Aqueous humor is produced by…

Answer 6

The ciliary body

Question 7

How does the aqueous humor exit the eye?

Answer 7

The iridocorneal angle

Question 8

What prevents backflow of the aqueous humor?

Answer 8

Tight junctions between the posterior pigment epithelium of iris

Question 9

What is the approx. volume of the posterior chamber?

Answer 9

50 to 65 ul

Question 10

What are the three compartments of the posterior chamber?(both names)

Answer 10

1.Retro-zonular (canal of petit)
2.Zonular (canal of Hanover)
3.Pre-zonular (posterior chamber proper)

Question 11

What is the approx. volume of the anterior chamber?

Answer 11

200 to 250ul

Question 12

What happens with the anterior chamber depth as we age? And why?

Answer 12

Decreases due to expansion of size of lens
3.6mm to 2.7mm

Question 13

Which tunics fuse to form the iridocorneal angle

Answer 13

Uveal tunic and fibrous tunic

Question 14

What structures form the anterior chamber angle?

Answer 14

Cornea and iris

Question 15

Th longitudinal muscle of the ciliary muscle(uvea) attaches to…

Answer 15

The scleral spur(fibrous tunic)

Question 16

What are the structures of the iridocorneal angle from infringer to superior

Answer 16

-Iris root
-Ciliary body band
-Scleral spur
-Trabecular mesh work
-Schwalbe’s line

Question 17

For gonioscopy what are you looking for to see if the angle is open enough?

Answer 17

You are looking to see the trabecular mesh work

Question 18

What is the total volume of the aqueous compartment?

Answer 18

250-315 microL

Question 19

What is the rate that aqueous humor is secreted?

Answer 19

2.5ul/minutes

Question 20

How long odes it take for the entire volume of the aqueous compartment to turnover?

Answer 20

100 mintues

Question 21

Where is the iris root in relation to the anterior chamber angle?

Answer 21

-it inserts in the anterior face of the ciliary body
-literally in the corner of the angle

Question 22

Unlike the ciliary body in the posterior chamber, the ciliary body band does not have what?

Answer 22

Epithelial lining

Question 23

What is the widest band visible in the iridocorneal angle?

Answer 23

ciliary body band

Question 24

Why does the CBB NOT have an epithelial lining?

Answer 24

To allow aqueous humor to pass through and continue to the uveoscleral pathway

Question 25

What is the scleral spur?

Answer 25

An internal projection of sclera

Question 26

What muscle attaches to the scleral spur?

Answer 26

Longitudinal bundle of ciliary muscle

Question 27

What is the base of the trabecular mesh work?

Answer 27

The scleral spur

Question 28

How does the trabecular meshwork change during ciliary body contraction?

Answer 28

Trabecular meshwork is open and more aqueous outflow goes to uveoscleral pathway

Question 29

During what process are the TM spaces smaller and at their normal state?

Answer 29

During relaxation of the ciliary muscle

Question 30

The trabecular meshwork sits within what structure?

Answer 30

Internal scleral sulcus

Question 31

What is the filtration apparatus that provides the main resistance to keep the eye pressurized?

Answer 31

TM

Question 32

The TM has what percentage of aqueous humor outflow?

Answer 32

90%

Question 33

TM is the gate keeper for what structure?

Answer 33

Schlemm’s canal

Question 34

In what condition is resistance to aqueous is too high?

Answer 34

Primary open angle glaucoma

Question 35

Where does Schwab’s line terminate peripherally?

Answer 35

Descemet’s membrane

Question 36

What is the most superior structure in the iridocorneal angle?

Answer 36

Schwalbe’s line

Question 37

What is the normal appearance of SL? What is it called when it’s pigmented?

Answer 37

Normal: glossy and whitish Pigmented: Sampolesi’s line

Question 38

Where does 10% of the aqueous humor leave the eye?

Answer 38

Via iris root/ ciliary body band (uveoscleral route, unconventional pathway)

Question 39

When outflow of aqueous humor is impeded the pressure in the eye will _____ and damage ____.

Answer 39

Increase, retinal ganglion cells

Question 40

What are the possible causes of enhanced resistance to aqueous humor drainage through the TM

Answer 40

-Buildup of pigment, inflammatory cells, plaque-like material, excessive blood, or neovascularization within the TEM -Chronic corticosteroid use -Elevated Episcleral Venous Pressure (EVP) -Narrow angles (especially hyperopes) -Pupillary Dilation (mydriasis) in eye with narrow angle -Relative Pupillary Block -Peripheral Anterior Synechiae -Primary-Open Angle Glaucoma (?? Exact cause unknown).

Question 41

What is relative pupillary block?

Answer 41

-resistance in AH flow from PC to AC which leads to increased pressure in PC that causes iris bowing and decreasing angle

Question 42

What is laser iridomtomy?

Answer 42

Creation of a hole in the peripheral iris so the AH can flow better

Question 43

What is surgical iredectomy?

Answer 43

Precursor to laser, sam process but cutting out a chunk

Question 44

What is posterior synechiae?

Answer 44

Adhesions between post. Iris and ant. Lens due to inflammation

Question 45

Why is the mid-dilated pupil a cause for concern>

Answer 45

Iris root is bunched up when dilated so it can impede flow to the TM -high risk of contact between iris and lens

Question 46

What is peripheral anterior synechia?

Answer 46

Ant. Surface of iris adherent to TM or corneal endothelium -usually from inflammation

Question 47

What is an iris process?

Answer 47

Thread-like strands of iris tissue that extend to TM -NORMAL

Question 48

What is the differnce between peripheral ant. Synechia and iris process?

Answer 48

Iris processes are normal, synechia are not