Diabetic Retinopathy
How is Non-proliferative Diabetic Retinopathy detected?
Via examination of the retina through dilated pupils - slit lamp biomicroscopy - Indirect ophthalmoscopy - Standard seven-field stereoscopic 30-degree fundus photos - Fluorescein angiography(used to tell if the vessels are bleeding, by injecting dye into the vein)
how is Diabetic Retinopathy prevented?
Treatment for diabetic retinopathy can be 90% effective in eradicating severe vision loss (visula acuity less than 5/200) with present treatment strategies
what is the function of VEGF in pathology of Diabetic Retinopathy?
VEGF is a potent permeability factor made by glial cell, RPE, and vascular endothelial cells - Production of VEGF is up regulated with retinal hypoxia leading to *abnormal angiogenesis and increase in vascular permeability*
what is the purpose of a Vitrectomy?
Vitrectomy is the removal of blood, vitreous from the back of the eye, and remove all the membranes off the retina - to remove a vitreous hemorrhage - to prevent a retinal detachment and - if a retinal detachment exists, to reattach the retina
What are the Screening Guidelines for Women who are diagnosed as having diabetes (non-gestation) while in their childbearing years?
*Diabetic retinopathy can progress very quickly during pregnancy (pregnancy can exacerbate diabetic retinopathy)* - Should have a dilated eye exam by ophthalmologist prior to conception - Beginning in the first trimester of pregnancy, they should have a dilated eye exam by ophth. at 3 month intervals
What is the "natural history" of Diabetic Retinopathy
*Gradual closure of retinal microvasculature resulting in retinal ischemia* - and there is a significant associations of narrower retinal arteriolar caliber with incident lower extremity amputations and all causes and stroke mortalities
what are the main causes of vision loss in diabetic retinopathy?
- *Macular edema* (ME) - Macular or nerve Ischemia - Non-Clearing Vitreous Hemorrhage - Neovascular Glaucoma - Tractional Retinal Detachment involving the Macula
what is the early stage of Non-proliferative Diabetic Retinopathy characterized by?
- *Microaneurysm formation* (capillary leak and later become occluded) - Intraretinal hemorrhages (dot-and-blot hemorrhages) - Hard exudates - Cotton-wool spots (infraction of the nerve fiber layer) - Edema - Clinically significant macular edema (CSME) if the center of the macula (fovea) is involved - Non-clinically significant macular edema (NCSME)
what are the symptoms of Diabetic Retinopathy?*will most likely be a question on exam*
- Diabetic retinopathy frequently has *NO* early warning signs As disease progresses it produce the following symptoms - Blurred vision - Vision that becomes better or worse during the day - Specks or floaters in vision - Sudden decrease in vision (vision may not change until diabetic retinopathy becomes severe)
Diabetes can cause what ocular problems?
- Dry eyes - Early cataracts - Increased risk of glaucoma - Increased risk of retinal disease (vascular, retinal detachment ect.)
what is the treatment for Diabetic Retinopathy?
- Laser photocoagulation - Argon laser is standard - Focal laser treatment (photocoagulation) - Scatter or Panretinal Laser Surgery (PRP) - Grid photocoagulation laser - Anti-vascular endothelial growth factor (VEGF) Drug therapy - Antiangiogenic therapy (Kenalog, Retanne) - iv - Protein Kinase C-β Inhibitor (ruboxistaurin)
what drugs function as Anti-vascular endothelial growth factor?
- Lucentis (ranibizumab) - Macugen (pegaptanib)
Diabetes retinopathy can be broken down into what two main categories?
- Non-proliferative diabetic retinopathy (NPDR): pt is not hemorrhaging blood - Proliferative Diabetic Retinopathy (PDR): VEGF causes new blood vessels form that are leaky and fragile, and coughing or sneezing can cause those blood vessels to bleed, which turns into scar tissue whin can cause retinal detachment
why is blood sugar control critical to Diabetic Retinopathy?
- Tight control of blood sugar levels can reduce or retard the development of diabetic retinopathy - But, institution of *tight control of blood sugar levels will NOT reverse existing diabetic retinopathy* AND - A sudden tight control of blood sugar levels can TRIGGER a rapid progression of diabetic retinopathy
what are the three types of retinal detachment?
- Traction: means the retinal is pulled up - Rhegmatogenous: hole in the retina - Combined traction-rhegmatogenous - Serous: fluid behind the retina
what are signs of increasing ischemia?
- Venous abnormalities (bending sausaging) - Intraretinal macular abnormalities (IRMA) - More severe and extensive vascular leakages characterized by retinal hemorrhages and exudation
what are the risk factors for developing Diabetic Retinopathy in Type 1 Diabetics?
- after 5 years 15% suffer from diabetic retinopathy - after 10 years 60% suffer from diabetic retinopathy - after 15 years 80% suffer from diabetic retinopathy - after 15 years 25% suffer from PDT
what is the clinical presentation of Proliferative Diabetic Retinopathy?
- cotton wool spots - exudates - boat shaped hemorrhages (blood between the retina and the hyoid) - NVD
what are the screening guidelines for pt who is diagnosed as having diabetes at age 30 or above?
- dilated eye exam by ophthalmologist immediately after diagnosis of diabetes and at least annual thereafter - Retina examination via ophthalmoscope by their PCP at other intervals
what are the screening guidelines for pt who were diagnosed with diabetes under the age of 30 yrs old?
- dilated eye exam by ophthalmologist within 5 yrs of diagnosis - if there are NO signs of diabetic retinopathy, pt should have a dilated eye exam by ophthalmologist annually beginning with the 5th year after the the initial diagnosis - If diabetic retinopathy is detected on the initial examination, pt should have annual dilated eye exam by an ophthalmologist - Retina examination via an ophthalmoscope by PCP at other intervals If the PT is diagnosed with type 2 diabetes they need an immediate exam
How is Proliferative Diabetic Retinopathy classifed
- extent and location of neovascularization - absence or presence of preretinal or vitreous hemorrhage
what are the treatment option for Macular Edema?
- focal - IVK - Anti-VEGF
what makes pt's with PDR high risk? (may not be on exam, in powerpoint but not in old video)
- new vessels on or within 1 disc diameter of the optic disc (about 1/4 to 1/3 disc area) with or without vitreous or preretinal hemorrhage - vitreous and/or preretinal hemorrhage accompanied by new vessels either on the optic disc (less than 1/4 disc area) - New neovascularization elsewhere (NVE) equal to or exceeding 1/2 disc - Neovascularization of the iris (NVI) and neovascular glaucoma
laser photocoagulation is advised for???
- pt with high risk NPDR and PDR - pt with CSME - pt with neovascularization of the anterior chamber angle (NVI)
the use of what enzyme may slow the progression of diabetic retinopathy?
Angiotensin-converting enzyme (ACE) - helps to control the blood pressure
What is the pathology involved in Proliferative Diabetic Retinopathy?
As a response to the continued retinal ischemia, new blood vessels (neovascularization) grow over the optic disc (NVD) or elsewhere (NVE) on the retinal surfaces → these fragile new vessels can bleed into the vitreous, and undergo fibrosis and contraction which may cause *traction retinal detachment* - Epiretinal membrane formation (ERM) (membrane behind the retina) - Vitreoretinal traction bands and tractional retinal detachment - Retinal tears and rhegmatogenous retinal detachments
Diabetic Retinopathy is the leading cause of blindness in people aged ___ to ___, it affects ___ % of diabetics who have had diabetes for ___ or more years
Diabetic Retinopathy is the leading cause of blindness in people aged *20 to 75*, it affects *70* % of diabetics who have had diabetes for *10* or more years
After diabetic retinopathy has been diagnosed what is the most important factor in progression?
Hyperglycemia
How do Scatter or Panretinal lasers work? what is the effect of this treatment?
It retards the development and facilitates the regression of new vessels on the optic nerve head, the retinal surface, and/or the anterior chamber angle (NVI) Effect: reduction of ischemia and vascular endothelial growth facor
What is the treatment for NVD and NVE?
Laser - stops the formation of new blood vessels
what is Panretinal Laser surgery? How does it work?
Laser surgery in all areas of the retina, except the macula, where new abnormal blood vessels have grown - can decrease the risk of severe vision loss by about 50% for pt with high risk of developing proliferative diabetic retinopathy (PDR)
What are the risk factors for developing Diabetic Retinopathy in Type 2 Diabetics?
Overall risk factor is how long the pt has been diabetic - after 5 years 40% of those pt taking insulin and 24% of those not taking insulin have diabetic retinopathy - after 20 years 84% of those pt taking insulin and 53% of those not taking insulin have diabetic retinopathy - after 5 years of less, 2% develop proliferative diabetic retinopathy - after 25 years or more 25% develop proliferative diabetic retinopathy
what is the function of Protein Kinase C (esp. isoform β ) in the pathology of Diabetic Retinopathy?
Protein kinase C-β (PKC-β) is activated by chronic hyperglycemia - hyperglycemia lead to increased intracellular diacylglycerol synthesis - Diacylglycerol activates PKC-β and increases the synthesis of VEGF - PKC also plays a role in nephropathy and neurpathy
what is Proliferative diabetic Retinopathy characterized by?
Retinal Neovascularization induced by retinal ischemia and partially by VEGF - Neovascularization at the optic disc (NVD) - New vessel elsewhere in the retina (NVE) - *NVD and NVE bleeding results in vitreous hemorrhage*
when would PDR result in glaucoma
When *neovascularization occurs on the surface of the iris to the trabecular meshwork* (NVI) - this is called *neovascular glaucoma* - prevents the normal outflow of aqueous humor - Presentation would include: hyphema (hemorrhage in the anterior chamber), and Rubeosis Iridis Classification: non-high risk, high risk
Other risk factors for Diabetic retinopathy
age blood pressure clotting factors renal disease
why is early detection of diabetic retinopathy so critical?
for laser surgery treatment of diabetic retinopathy to be most effective, it must be done before a decrease in vision occurs
what is the function of grid photocoagulation laser? what is the effect of this treatment?
its a pattern of burns applied to areas of the edema (leakage) or capillary nonperfusion on fluorescein angiography Effect: reduction of VEGF and/or sealing of leaking microaneurysms
Severe NPDR progresses to what?
proliferative diabetic retinopathy
what is the function of Focal laser treatment? what is the effect of this treatment?
used in the center of the retina to get rid of diabetic macular edema - it can reduce the loss of vision due to macular edema by 50% or more - used to treat leaking microaneurysm to reduce or eliminate macular edema Effect: seals leaking microaneurysms
