Disorders of the Macula

Question 1

What causes drusen?

Answer 1

Choriocapilaris disease. The capillary lumens narrow creating an area of hypoxia that causes RPE to malfunction and release extracellular material onto Bruch’s membrane.

Question 2

What are the two types of drusen? How are they different?

Answer 2

Hard Drusen: Smaller (Less than 63um) with distinct margins. They are not associated with neovascularization.

Soft Drusen: Larger (more than 63um) with indistinct margins. Soft drusen show an increased risk of neovascularization because nutrients cannot cross the drusen to get to RPE.

Question 3

What is a PED?

Answer 3

PED: Pigment Epithelial Detachment
RPE separates from Bruch’s membrane due to the presence of blood, exudate, drusen, or a neovascular membrane. PED’s can arise idiopathically but also can be due to retinal disease.

Question 4

What are the 4 types of PED?

Answer 4

1. Drusen type
2. Hemorrhage type
3. Serous with fluorescein angiographic evidence of CNVM
4. Serous without fluorescein angiographic evidence of CNVM

Question 5

Which type of PED, Serous with CNVM evidence or Serous without CNVM evidence will show an increase in VA upon laser intervention?

Answer 5

Serous CNVM with evidence of CNVM

Question 6

What causes a CNVM?

Answer 6

Breakdown of Bruch’s membrane leading to choroidal neovascularization growth through the RPE. This is not commonly seen in younger patients because there must be a defect in Bruch’s membrane and that is not common in younger patients.

Question 7

What are the three locations of a CNVM?

Answer 7

Subfoveal: Under the center of the foveal avascular zone
Juxtafoveal: 1-199um from foveal avascular zone
Extrafoveal: 200+um from foveal avascular zone

Question 8

What are the two types of neovascularization that can occur with CNVM?

Answer 8

Classic and Occult
Classic will have well-defined borders which will be present early in the angiogram
Occult has two types
1. Fibrovascular PED, will have well-demarcated or poorly demarcated boundaries with angiography depending on the phase
2. Late leakage or undetermined source LLUS, will always have poorly demarcated boundaries with angiography

Question 9

What are the treatment options for a CNVM?

Answer 9

1. VEGF injections
2. Macugen (6% saw increased VA)
3. Lucentis (40% saw increased VA)
4. Avastin (Same result as Lucentis but cost 50 vs 1500 per dose)