Diabetic Retinopathy 101

8/10/2019 Diabetic Retinopathy 101

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DIABETIC RETINOPATHY 101

Tomasz Wiraszka, MD PGY-4


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Prevalence

Variable between publications, probably less than 40%.

More common in type I DM

Sight-threatening diabetic retinopathy in 10% patients

Proliferative diabetic retinopathy (PDR): 5-10% of patients with diabetes.

Type 1 DM: Incidence of PDR of 60% after 30 years of diabetes.

Risk factors:

Duration of diabetes

If diagnosed before 30 yoa:

10 year incidence of retinopathy: 50%

30 year incidence: 90%

Poor control

Early control important

Type 1 diabetics benefit more from tight control than type 2

Raised HbA1c correlates with increased risk of PDR

PregnancyGreater risk of progression of DR if:

Poorly controlled at baseline or too aggressively controlled in

early pregnancy

Pre-eclampsia

Fluid imbalance

Hypertension

Very prevalent among DM II patients Goal 140/80 (less if indicated by cardiovascular/stroke risk

factors)

BACKGROU

ND


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Microangiopathy, possible direct effect on retinal cells as well.

Mechanism of toxicity: intracellular sorbitol, oxidative stress, advanced glycation end products, hyperactivity of several PK-C isoforms

Capillary damage: pericytes and vascular smooth muscle lost, endothelial proliferation, basement membrane thickenining.

Neovascularization: Formation of pre-retinal and intra-retinal neovascular complexes, intra-retinal shunt formation (IRMA)

Background/Non-proliferative Diabetic Retinopathy (BDR/NPDR)

Signs: Microaneurysms, dot-blot hemorrhages, exudates

Diabetic maculopathy

Changes affecting macula, with significant visual impact, e.g.

edema, ischemia

Proliferative diabetic retinopathy

Presence of neovascular lesions within 1 dd of disc and/or lesions

elsewhere

Advanced diabetic diseaseTractional detachment, perisistent vitreous hemorrhage,

neovascular glaucoma

BACKGROU

ND

Pathogenesis

Classification


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MA/EXUD

ATES

Exudates - hardLesions in BDR

Microaneurysms

Exudates-soft (aka cotton-wool spots)


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DIABETICH

EMORRHAGES-NPDR

Bloody diabetes- NPDR

0

20

40

60

80

100

120

140

160

180

1st Qtr 2nd Qtr 3rd Qtr 4th Qtr

East West North


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MACULAR

ISCHEMIA

Macular ischemia

Signs:

Can be relatively mild-appearing fundus exam with decreased

visual acuity or fulminant.

Cotton wool spots: Superficial, fluffy, obscure underlying vessels.

Seen only in posterior retina.

Venous changes: Diffuse dilation and turtuosity, looping, beading.

IRMA: arteriolar-venular direct communication bypassing capillary

bed. Often adjacent to area of hypo-perfusion.

On IVFA:

Capillary non-perfusion at fovea,

Enlargement of foveal avascular zone (FAZ),

Additional areas of nonperfusion

(Posterior pole and peripheral)

ManifestationsFundus exam

IVFA


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CSME

Criteria for Clinically significant Macular Edema

Defined in ETDRS study as:

Retinal thickening within 500 microns

of center of macula

Exudate (hard)within 500 microns of

center of macula, if associated with

adjacent thickening (thickening doesnt

have to be within 500 microns of

center, though)

Retinal thickeningone disc area orlarger, any part of which is within one

discdiameter of center of macula IVFA


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ABBREVIAT

EDETDRSCLASSIFICATION

Very MildMicroaneurysms only F/U in 12 mos

MildAny combination of: microaneurysms, retinal

hemorrhages, exudates, cotton wool spots up to level

of moderate NPDR. NO IRMA or BEADING

F/U in 6-12 months

ModerateSevere hemorrhages in 1-3 quadrants or mild IRMASignificant beading in no more than 1 quadrant

Cotton wool spots commonly seen

F/U in 6 months

PDR in up to 26%, High-risk PDR in up to

8% within 1 year

Severe

The 4-2-1 rule

Severe hemorrhages in all 4 quadrantsSignificant beading in 2+ quadrants

Moderate IRMA in 1 or more quadrants

F/U in 4 months

PDR in up to 50%, High-risk PDR in up to

15% within 1 year

Very Severe

Two or more criteria for severe

F/U in 2-3 months

High-risk PDR in up to 45% within 1 year


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PROLIFERA

TIVEDIABETICRETINOPATHY

PDR

NVD/NVE

Sequelae

Advanced Diabetic Eye Disease

Hemorrhages (preretinal, intravitreal)

Use B-scan if necessary to rule outunderlying detachment

Tractional detachment/retinoschisis

Rubeosis iridis/NVIWith severe ischemia


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PDRCLASS

IFICATION

Mild- ModerateNVD or NVE, extent insufficient to meet high risk

criteria

Consider treatment on individual basis. If

not treating, F/U 2 months

High risk PDRNVD greater than 1/3 disc areaAny NVD with vitreous or preretinal hemorrhage

NVE greater than disc area with vitreous

hemorrhage (may be obscuring NVE/NVD)

Treatment immediately if possible


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LASERS

CSME

All eyes with CSME should be considered for laser regardless of

visual acuity

TREATMENT reduces risk of visual loss by 50%

Pre-treatment IVFA :

Leaking microaneurysms

Ischemia

Focal laser:

Indication:

Treat microaneurysms and IRMA in center of exudate rings

located 500-3000 microns from center of macula.

**May go up to 300 microns from center of macula in special

cases

Spot size: 50-100 microns

Time: 100 ms

Power: sufficient for GENTLE whitening or darkening of lesion

Grid laser:

For diffuse retinal thickening over 500 microns from center of

macula and 500 microns from temporal margin of disc

Spot size: 100 microns

Time: 100 ms

Power: sufficient for GENTLE whitening, lighter if treating ischemic

area


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HIGHRISK

PDR

High risk PDR

DRS study:

Mild NVD with hemorrhage has 26% risk of visual loss, reduced

to 4% with treatment

Severe NVD without hemorrhage has 26% risk of visual loss,

reduced to 9% with treatment

Severe NVD with hemorrhage has a 37% risk of visual loss,

reduced to 20% with treatment

Severe NVE with hemorrhage has a 30% risk of visual loss,

reduced to 7% with treatment.

Treatment aims to induce involution of abnormal new vessels and

thereby prevents vision loss.

** If CSME present, treat CSME before or at same time as doingPRP, because PRP can exacerbate CSME. Also, do minimum

effectie amount of PRP.

Risks:

Decreased night vision, loss of peripheral vision, possibility of

accidental foveal burns, macular edema.

Parameters:

Spot size: 100-300 microns with Pan-fundus lens (e.g.Superquad)

Time:50- 100 ms

Power: Aim for light intensity burn

Dosage: 1500-2000 spots in one or more sessions

Appropriate intensity burns

Effect of PRP on neovascular lesions


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ADVANCED

DIABETICRETIN

OPATHY

Surgery

Vitrectomy in diabetic eyes:

Indications:

Severe persistent vitreous hemorrhage precluding laser

- If no NVI, consider within 3 months of hemorrhage in type IDM, or with bilateral VH.

Progressive Tractional RD

- Treat urgently if affecting macula, otherwise may observe

Combined tractional and rhegmatogenous RD

- Treat urgently even if macula spared

Premacular subhyaloid hemorrhage

- Consider vitrectomy if dense

- May stimulate fibrovascular proliferation and consequent

tractional macular epiretinal membranes and retinal

detachments

Anti VEGF

Adjunctive role to PRP

-Can be used pre-op with persistent vitreous hemorrhages

-Does not obviate need for PRP

Outcomes of vitrectomy

About 70% of cases achieve visual improvement

10% get worse

Remainder unchanged

Favorable prognostic factors:

Good Preop visual acuity

Age 40 or less

Absence of pre-op NVI/NVG

Previous PRP to at least fundus


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BCSCHIT-LIST

What Else to read in BCSC RETINA

book??

ETDRS Study (Key definitions and staging)

WESDR Study (epidemiology of DM)

DCCT Study (Type 1 DM)

UKPDS Study (Type 2 DM)

DRS Study (Effectiveness of photocoagulation)

DRVS study (Vitrectomy in eyes with PDR)

Documents

Diabetic Retinopathy 101