CH 1. Normal Macula

Question 1

What is the maximal and minimal macular normal thickness

Answer 1

max: 0,55mm at the foveal margin.

Min: 0,13mm at the umbo.

Question 2

Where is the macula located?

Answer 2

Between the temporal arcades, centerd 4mm temporal to the optic disc, and 0,8mm inferior.

Question 3

Name the foveal diameter

Answer 3

1,5mm (1 disc diameter)

Question 4

Name the diameter of the foveola

Answer 4

350um

Question 5

Name the diameter of the foveal avascular zone

Answer 5

0,5 mm (500um)

Question 6

Name the each part of the following diagram with its corresponding dimensions.

Answer 6

umbo: central area

Foveola: 350um

FAZ: 0,5mm

Fovea: 1,5mm

Parafovea: the next 0,5mm

Perifovea: the next 1,5mm

Question 7

At which depth are the mayor retinal vessels located?

Answer 7

In the nerve fiber layer.

Question 8

How many ciliary arteries supply the eye, aprox.

Answer 8

• The ophtalmic artery divide into medial and lateral posterior ciliary arteries.
• Each is divided into one long posterior ciliary artery and 5-10 short posterior ciliary arteries.
• 7 anterior ciliary arteries travel along side the rectus muscles and form the major circle of the iris and anastomose with the LPCA to vascularize the anterior coriocapilaris.

Question 9

Where are the muller cell’s nuclei located?

Answer 9

In the inner nuclear layer.

Question 10

Name the main two components of the hemato-ocular barrier.

Answer 10

Inner retinal barrier: capilary endothelium (tight junctions)

Outer Retinal Barrier: RPE

Question 11

Does the bruch’s membrane constitutes an actual barrier between the retina and choroid?

Answer 11

It does provide structural support, but due to its porous nature it probably plays a minimal role in substance movement regulation.

Question 12

Name the layers of the bruch membrane

Answer 12

According to this text, two collagen layers surrounding a central elastic layer.

The RPE basement membrane, and the choriocapilaris endothelium basement membrane are not included as part of this structure as it is in other texts.

Question 13

Name the fluorescein excitation and emission wave lenghts

Answer 13

Excitation:aprox 490nm

Emission: aprox 520 nm

Question 14

Are the ocular capillaries permeable to fluorescein?

Answer 14

Yes, with the exception of those at the retina.

Question 15

After injected into a cubital vein, when does the choroidal filling starts?

Answer 15

10-15sec latter.

Question 16

Between the retinal capillaries, and the cilioretinal artery, which one fills sooner with fluorescein?

Answer 16

The cilioretinal artery fills earlier since it is provided by the choroidal circulation.

Question 17

How are fluorescein and Indocyanine Green Excreted?

Answer 17

Fluorescein: Liver and Kidney

ICG: Just Liver.

Question 18

Name ICG Absorption and emission wavelengths

Answer 18

805nm and 835nm, respectively.

Question 19

Name the reasons why ICG works better for choroidal visualization than FA.

Answer 19

1- it is a larger molecule.

2- the main reason is that it is greatly protein-bound.