DIABETIC RETINOPATHY
INTRODUCTION:DM. either type 1 ( IDDM) or type 2 (NIDDM).
*DR. occurs about 40% in type 1 , and 20% in type 2.
*Common cause of legal blindness between 20-65 years.
RISK FACTORS
1. Duration of DM.
2. Poor metabolic control.3. Pregnancy.
4. Hypertension.
5. Hyperlipideamia.
6. Nephropathy.
7. Obesity.
8. Smoking.
WHY INTENSIVE MC. :
*Delay the onset.*Delay the progression of BDR.
*Delay the progression of PPDR to PDR.
*Reduce macular oedema.
*Reduce the need for laser therapy.
PATHOGENESIS:
*Definition: it is a microangiopathy involves pre capillary arterioles, capillaries , post capillary venules and even large blood vessels.
*Mechanism:
A- Micro vascular occlusion:
1. capillary changes:
-basement membrane thickening.
-endothelial cells damage.
-loss of pericytes.
2.Haematological changes:
- RBCs aggregation.
- increase platelets stickiness.
- decrease O2 transport.
* Both 1 and 2 --- ischemia and hypoxia.
* Compensatory mechanisms include :
- A-V. shunts formation from arterioles to venules and called (IRMA= intraretinal micro vascular abnormalities).
- Neovascularization ---either from retina (PDR) or from iris ( Rubeosis).
B- Micro vascular leakage:
-micro aneurism.
-intra retinal hemorrhage.
-retinal oedema.
-hard exudates.
CLINICAL CLASSIFICATION
A. Background DR.:
*micro aneurism.
*hard exudates.
*retinal oedema.
*hemorrhages--- dot-blot or flame shape .
*Mx.--- good metabolic control.
control risk factors.
annual fundus examination.
B. Pre proliferative DR.:
*cotton-wool spots.
*IRMA.
*venous changes.
*arterial changes.
*retinal hg.
*Mx.---- close observation for PDR.
laser photocoagulation if regular follow up is not possible and if PDR present in the fellow eye.
C- Diabetic Maculopathy:
*focal or diffuse exudates related to macula.
*ischemic Maculopathy.
*mixed.
*treatment---- laser therapy ( grid or focal).
vitrectomy in severe causes.
D- Proliferative DR.:
* Neovascularization around or within the disc(NVD).
* Neovascularization elsewhere in the retina (NVE).
*Mx. ---- panretinal laser photocoagulation (PRP).
ADVANCED DIABETIC E.D.:
*Hemorrhage:
- retinal or preretinal.
- vitreous.
*Tractional retinal detachment.
*Rubeosis iridis.
*Retinal membranes.
*Treatment is pars plana vitrectomy.