Diabetic Retinopathy

Question 1

NPDR definition

Answer 1

intraretinal vascular changes, no development of extraretinal fibrovascular tissue. Used to be known as NPDR

Question 2

PDR

Answer 2

presence of retinal neovascularization from diabetes induced ischemia. Characterized as early PDR or PDR with high risk characteristics (HRC)

Question 3

DME

Answer 3

caused by abnormal vascular permeability

Question 4

Factors that lead to diabetic damage

Answer 4

1. endothelial damage
2. pericyte loss
   this happens from exposure to hyperglycemia leads to:
   -increased inflammatory oxidative stress
   -advanced glycation end products, and protein kinase c pathways

BM thickening and pericyte loss lead to:
Capillary occlusion and retinal nonperfusion

Question 5

Consequences of endothelial barrier decompensation

Answer 5

retinal edema (serum leakage)

Question 6

Recommended Diabetes follow up

Answer 6

Type 1 DM: 5 years after dx
Type 2 DM: immediately upon diagnosis
Pregnant with either DM: soon after conception and early in first trimester. FU every 1-3 months if severe NPDR or worse

Question 7

What did the Diabetes control and complications trial (DCCT) and UK prospective diabetes study (UKPDS) show?

Answer 7

Intensive glycemic control was associated with:

• reduced risk of new onset retinopathy
• reduced progression of existing retinopathy

DCCT looked at type 1, UKPDS looked at type 2

Question 8

What is metabolic memory

Answer 8

in the DCCT, patients who had intensive glycemic control in the beginning had decreased onset, progression, and need for surgery even 20 years after the study ended and the HbA1c levels converged.

Question 9

What A1c is recommended based on DCCT and UKPDS?

Answer 9

less than 7

Question 10

What did the ACCORD and ACCORDION study show?

Answer 10

A1c levels less than 6 slowed DR progresison even more in T2DM, but increased mortality

Question 11

What other factors are associated with DR

Answer 11

• HTN
• severe carotid artery occlusive disease (part of ocular ischemic syndrome)
• Advanced diabetic nephropathy
• Anemia
• cholesterolemia

Question 12

How does DR lead to vision loss?

Answer 12

capillary leakage (DME)

• capillary occlusion (macular ischemia)
• sequelae from retinal ischemia (neo, vit heme, TRD, NVG)

Question 13

What to do in DM patients who need CE/IOL

Answer 13

If DME, give anti-vegf

If severe NPDR or PDR, consider scatter PRP before cat removal.

Question 14

NPDR damage

Answer 14

Dmg stays within ILM:

• MAs
• intraretinal hemorrhage
• CWS
• venous beading
• IRMA

Question 15

Criteria for Severe NPDR

Answer 15

4-2-1 rule:

• 4 areas of MAs
• 2 areas of venous beading
• 1 area of IRMA

Question 16

Severe NPDR vs Very severe NPDR

Answer 16

severe NPDR has 1/3 of 4-2-1 rule. Severe npdr has a 15% risk of progression to PDR in 1 year and 60% in 3 years.

Very severe has 2-3/3. Has a 45% risk of progression in 1 year

Question 17

Signs of macular ischemia

Answer 17

FAZ appears irregular on FA or OCTA and enlarges as the innermost capillaries become nonperfused

Question 18

Treatment of NPDR

Answer 18

There is no clear treatment mandate for eyes with NPDR wo DME (besides control of glucose, lipids, and HTN)

Anti-vegf, lasers, and steroids have shown NPDR levels

PVDs have been hypothesized to improve outcomes in diabetic eyes bc it takes away the scaffolding for NV

Question 19

Extraretinal fibrovascular proliferation progression

Answer 19

1. New vessels with minimal fibrous tissue cross and extend beyond ILM
2. New vessels get larger and become more fibrous
3. vessels regress, leaving residual fibrovascular tissue that may be tethered in posterior hyaloid

Question 20

high risk PDR

Answer 20

1. NVE w heme
2. NVD w heme
3. NVD that is 1/4-1/3 in size

Question 21

Possible draw back of treatment of PDR

Answer 21

treatment with PRP or anti vegfs may lead to contraction of fibrovascular tissue, and treatment may be followed by increased VR traction, vit heme, TRD, or combined TRD RRD

Question 22

DRCR.net protocol S

Answer 22

Showed that ranibizumab and prp had EQUAL VISUAL OUTCOMES

Rani had benefits of:

• better average vision
• reduction in peripheral visual field loss
• reduced rates of sx
• less DME

Question 23

Anti vegf in PDR

Answer 23

Given before vitrectomy, can help treat NVG

Question 24

Steroids in PDR

Answer 24

reduce PDR related outcomes in DR.

Rates of vit heme, need for prp, rates of NV are reduced when steroids are used for non PDR indications like DME

Question 25

PRP treatment is based on what study?

Answer 25

DRS (looked at if PRP was effective for treating DR)

Question 26

How does PRP help?

Answer 26

1. destroys ischemic retina which produced growth factors
2. Increases o2 tension by:
   - destroying retina which increases diffusion of O2 from choroid through scarring
   - decreases retina, which decreases o2 consumption

Question 27

How did DRS and ETDRS define full PRP?

Answer 27

1200 shots more than 500micrometers separated by 1/2 burn width

Question 28

What are adverse effects of PRP?

Answer 28

1. choroidal detachment
2 decreased night vision
3 color vision
4 contrast sensitivity
5 peripheral vision
6 pupillary dilation
7 increased glare
8 you may hit the long ciliary nerve and vessels which control pupillary accommodation and corneal innervation

Question 29

NVI/NVG

Answer 29

small tufts of NV at the border are relatively common, tx can be withheld in these eyes

Treat when there is contiguous NV of pupil and iris collarette w/wo NVA.

Tx is PRP. IVA can be used to temporize

Question 30

Diabetic retinopathy vitrectomy study

Answer 30

T1DM w severe VH benefitted from earlier vx.

while type 2 didn’t