NON-PROLIFERATIVE DIABETIC RETINOPATHY

MOHAN PHANEENDRA AKANAFinal M.B.B.S Part-1

7th SEMESTERNOV 11,2015

What is the Retina?• The retina is a multilayered, light sensitive neural

tissue lining the inner eye ball. Light is focused onto the retina and then transmitted to the brain through the optic nerve.

• The macula is a highly sensitive area in the center of the retina, responsible for central vision. The macula is needed for reading, recognizing faces and executing other activities that require fine, sharp vision.

Retina

RETINA

Diabetic Retinopathy (DR)Definition

• Progressive dysfunction of the retinal blood vessels caused by chronic hyperglycemia.

• DR can be a complication of diabetes type 1 or diabetes type 2.

• Initially, DR is asymptomatic, if not treated though it can cause low vision and blindness.

Healthy Retina

Diabetic Retinopathy

Diabetic retinopathy symptomsDiabetic retinopathy is asymptomatic in early stages of the diseaseAs the disease progresses symptoms may include• Blurred vision• Floaters• Fluctuating vision• Distorted vision • Dark areas in the vision• Poor night vision• Impaired color vision• Partial or total loss of vision

Risk factors

• Duration of diabetes • Poor Blood Sugar control• HTN• Hyperlipidemia

How diabetes cause vision loss Mechanism of VISION LOSS

Preclinical changes

Macular edema

Proliferative DR

Diabetes Background

DR

Clinical significant

macular edema

Vitreous hemorrhage

and/or Retinal detachment and/or

neovascular glaucoma

Preproliferative DR

Vision loss

Pathophysiology

Diabetic Retinopathy is a microvasculopathy that causes:• Retinal capillary (microvascular) occlusion • Retinal capillary (microvascular) leakage

Microvascular OcclusionMicrovascular occlusion is caused by:• Thickening of capillary basement membranes• Abnormal proliferation of capillary endothelium• Abnormalities in platelet function (Increased

adhesion)• Increased blood viscosity• Defective fibrinolysis

Cotton – wool spots

Neovascularization

Ischemia

Neovascular glaucoma

Microvascular Occlusion

Fibrovascular bandsVitreous hemorrhage

Increased VEFG

Tractional retinal detachment

Infarction

Microvascular leakageMicrovascular leakage is caused by:• Impairment of endothelial tight junctions• Loss of pericytes• Weakening of capillary walls• Elevated levels of vascular endothelial growth

factor (VEGF)

Edema Retinal hemorrhageHard exudates

Microvascular Leakage

Ophthalmic features of non-proliferative diabetic

retinopathy• Microaneurysms(inner nuclear)• Retinal hemorrhages(dot and blot)• Oedema(macular)• Hard (retnal lipid)exudates• Cotton-wool spots(nerve fiber layer)• Venous abnormalities• Intraretinal microvacular abnormalities• Dark-blot hemorrhages

HyperglycemiaDamage to retinal capillaries

Weakens capillary walls

Small outpouchings leaky,fluid seep into retinaof vessel lumen

fluid deposition under macula

rupture Macular edema

hemorrhage Resolution of fluid lakes

Sediments of lipid byproducts

Glucose galactose Sorbitol galacitol

Can’t diffuse out of the cells(lens epithelial,pericytes,schwann cells)

Incr. intracellular conc.Inc. osmotic forcesWater diffuse into cellElectrolyte imbalanceDamage to pericytes on vessel wallloss of contraction & relaxation of

vessel wallCotton wool spots

Associate features:

• Vitreous hemorrhage• Retinal detachment• Neovascular glaucoma• Premature cataract• Cranial nerve palsies

ETDRS study classification:• Mild NPDR• Moderate NPDR• Severe NPDR• Very severe NPDR

Findings Obsd

International Clinical Diabetic Retinopathy Disease Severity Scale

Proposed Disease Severity Level Findings Observable upon Dilated Ophthalmoscopy

No apparent retinopathy No abnormalities

Mild nonproliferative diabetic retinopathy Microaneurysms only

Moderate nonproliferative diabetic retinopathy More than just microaneurysms but less than severe NPDR

Severe nonproliferative diabetic retinopathyAny of the following: More than 20 intraretinal hemorrhages in each of four quadrants Definite venous beading in two or more quadrants Prominent IRMA in one or more quadrants and no signs of proliferative retinopathy.

Proliferative diabetic retinopathy One or both of the following: Neovascularization Vitreous/preretinal hemorrhage

Mild NPDR• Atleast one microaneurysm(Ma)

MILD NONPROLIFERATIVE DIABETIC RETINOPATHY

Microaneurysms

Moderate NPDR• Microaneurysms or intraretinal hemorrhages(Ma/H)

in 2 or 3 quadrants• Soft exudates• Venous beading(VB)• Intraretinal micro vascular abnormalities(IRMA)

defenitely present

Moderate Nonproliferative Diabetic Retinopathy (NPDR)

Hard exudates

Flamed shaped hemorrhages

Microaneurysm

Moderate Nonproliferative Diabetic Retinopathy (NPDR)

Hard exudates

microaneurysm

Severe NPDR• H/Ma(>20) in all 4 quadrants• VB in ≥2 quadrants• IRMA in ≥1 quadrant • No signs of proliferative retinopathy• “4-2-1 rule.”

Severe Nonproliferative Diabetic Retinopathy (NPDR)

Venous beading

Very severe NPDR• Any 2 of the severe NPDR (4 – 2 - 1)

Primary prevention Strict glycemic control Blood pressure control

Secondary prevention Annual eye exams

Tertiary prevention Retinal Laser photocoagulation Vitrectomy

Diabetic Eye DiseaseKey Points

• Treatments exist but work best before vision is lost

RECOMMENDED EYE EXAMINATION SCHEDULEDiabetes Type Recommended

Time of First Examination

Recommended Follow-up*

Type 1 3-5 years after diagnosis

Yearly

Type 2 At time of diagnosis

Yearly

Prior to pregnancy (type 1 or type 2)

Prior to conception and early in the first trimester

No retinopathy to mild moderate NPDR every 3-12 monthsSevere NPDR or worse every 1-3 months.*Abnormal findings may dictate more frequent follow-up examinations

Treatment of NPDR

• No ocular intervention is warrented,until disease reaches the proliferative stage.

• As proliferative stage arouses,the treatment is carried out through various measures like….

1. Pan retinal Laser photocoagulation2. Intra-vitreal anti VEGF injections3. Anti-platelet theraphy4. Anti hypertensive agents5. Anti-angiogenesis agents

DIABETIC RETINOPATHY TREATMENTOnce DR threatens vision treatments can include:

Laser therapy to seal leaking blood vessels (focal laser)

Laser therapy to reduce retinal oxygen demand (scatter laser)

Surgical removal of blood from the eye (vitrectomy)

Pan retinal Laser Photocoagulation

Laser Photocoagulation is recommended for eyes with:• Clinical significant macular edema CSME • High risk Proliferative diabetic retinopathy• Lasers named for active medium• Choice of optimal wavelength depends on

absorption spectrum of target tissues• Used for retinal & choroidal abnormalities• Recent appplications have exploited the

subthreshold effects of laser.

DIABETIC RETINOPATHY TREATMENTNEWER DEVELOPMENTS:

The use of anti-vascular endothelial growth factor antibodies has been shown to be useful in the treatment of DR

Anti-VEGF antibody treatment appears to be useful for both macular edema and proliferative retinopathy

Studies to determine the exact role of anti-VEGF treatment in relation to laser treatment in specific situations are underway.

CONCLUSIONS

Diabetic Retinopathy is preventable through strict glycemic control and annual dilated eye exams by an ophthalmologist.

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