Diabetes and the Eye

1. Diabetes and the Eye Kelli Shaon, O.D.

2. Diabetes Mellitus Facts • DM has been estimated to affect ~19 million Americans • 5 millions of those individuals don’t know they have DM • There are known risk factors for the development of DM: • Obesity (>120% desirable body weight) • 1st degree relative with diabetes • Member of high-risk ethnic population (African American, Hispanic, Native American) • Diabetic retinopathy is the leading cause of blindness in 20 to 74-year-old population • Accounts for ~12% of all new cases of blindness each year

3. Diabetes Mellitus • Types: • Type I (aka. IDDM - “insulin dependent diabetes mellitus) = 10% • Usually found in younger patients, most commonly in patients less than 30 years of age • Type II (aka. NIDDM - “non-insulin dependent diabetes mellitus) = 90% • Most common form - Usually found in older patients, but has become more prevalent in younger individuals as well

4. Blood glucose levels & Testing • Fasting blood glucose testing: • Diagnosis of DM if blood glucose levels of >126mg/dl on two occasions • Pre-diabetes or “impaired fasting glucose” (IFG) – glucose levels 100-125 mg/dl • HbA1c: average of blood glucose levels over ~3 months • On a scale of 4.0-14.0+% • Strongest predictor to if a patient will develop ocular complications due to diabetes, because it is the most accurate measurement of the patient’s blood sugar

5. AOA Clinical Care Guidelines: Standards for Glucose Control • Fasting glucose: • Non-diabetic: <100 mg/dl • Diabetic goals: 80-120 mg/dl • Glycosylated hemoglobin (HbA1c): • Non-diabetic: <6% • Diabetic goals: <7%

6. Important questions to ask • Type of DM or do they control their diabetes with pills, insulin, or a combination of both • Medications? Compliance with meds? • Average blood sugar? and/or Blood sugar that morning? Do they know their last HbA1c? - - Try to get a feel for BS control • How long have they been diabetic? • Any previous systemic or ocular complications due to diabetes? - - This will help tell if there is a increased risk of ocular complications

7. Can you convert? • Every 1% change in HbA1c is equal to 30 mg/dl from average HbA1c 7% = 150 mg/dl • 6% = 120 mg/dl • 8% = 180 mg/dl • Conversion  • Average BG levels = (HbA1c - 2) x 30 • Example: Avg BG = (9.5% - 2) x 30 = 225 mg/dl • HbA1c = (BG levels/30) + 2 • Example: HbA1c = (210/30) +2 = 9.0%

8. Duration of DM and the Presence of Ocular Complications in Type I • 5 years – possible ocular manifestations, depending on BS control • >10 years – 60% will have some retinopathy • >15 years – virtually all patients will have some degree of retinopathy (25% proliferative) • >20 years – 50% proliferative retinopathy

9. Duration of DM and the Presence of Ocular Complications in Type II • At diagnosis – 20% have retinopathy • >4 years – 4% progress to proliferative retinopathy • >15 years – 60-80% have retinopathy up to 20% have proliferative retinopathy • Bottom line for Type I or Type II - *** the longer they have the disease the more likely they will have ocular manifestations***

10. Ocular Complications • Functional: • Tritan color vision deficiencies • Refractive error changes • Myopic shifts are more common if BS has been elevated; this is due to sugar being trapped in the lens causing it to swell • Hyperopic shift can be may occur once BS control begins to normalize (if previous myopic shift) or if macular swelling is present • Accommodative dysfunction

11. Ocular Complications • EOM anomalies: • Neuropathies may involve the third, fourth, or sixth cranial nerves • Isolated CN 6 – most common • Pupils: • Sluggish reflexes &/or small changes in light and dark pupils diameter measurement • Adie’s pupil can also occur • Conjunctiva: • Bulbar conjunctiva microaneurysms • Tear film: • Deficiencies resulting in dry eye

12. Ocular Complications • Cornea: • Decreased corneal sensitivity • Reduced corneal wound healing • Basement membrane abnormalities resulting in an increase in abrasions and RCE • Endothelium cell changes

13. Ocular Complications • Iris: • Depigmentation • Neovascularization (rubeosis iridis) • Neovascular glaucoma • Lens: • Increased risk of cataracts & may be noted at younger ages

14. Ocular Complications • Vitreous: • Hemorrhages • Retina: • Retinopathy (nonproliferative/proliferative) • Macular edema • Optic Nerve: • Papillopathy – optic disc swelling secondary to DM • Higher incidence of Open angle glaucoma

15. Neovascularization (rubeosis iridis)

16. Neovascular glaucoma

17. Preretinal &Vitreous Hemorrhage • Top picture: Preretinal hemorrhage (Boat hemorrhage) that has settled inferiorly due to gravity • Bottom picture: Partial Vitreous hemorrhage, that is only blocking a portion of the underlying retina

18. Diabetic Retinopathy • Most common associated ocular sign seen in diabetic patients • It is important to know how classify the different stages of DR because it determines when you will follow-up with patients • Diabetes causes occlusion and leakage of retinal microvasculature • Retinal tissue has the highest metabolic activity, by weight, when compared to other tissues – therefore most O2 consumption

19. Hypoxia vs. Edema • Hypoxia – occurs in superficial retina or the post-arteriolar circulation • Flame hemes • Venous beading (VB) • Intraretinal microvascular abnormalities (IRMA) • CWS • Capillary nonperfusion/dropout (visible by FA only) • Edema – occurs in deep retina or the pre-venular circulation • Exudates • Dot- Blot hemes • Microaneurysms (MA)

20. NonProliferative Diabetic Retinopathy

21. Criteria for Grading Non-Proliferative Diabetic Retinopathy • Mild NPDR: • Hemes/MA < than Standard photo 2A • At least 1 MA • One or more of the following • Retinal hemorrhages • Hard exudates • Soft exudates • Moderate NPDR: • Hemes/MA > than Standard photo 2A • Soft exudates and VB may also be present

22. Standard Photograph 2A

23. Criteria for Grading Non-Proliferative Diabetic Retinopathy • Severe NPDR: (4-2-1 Rule) • One or more of the following: • Hemes/MA > Standard photo 2A in all 4 quadrants OR • Venous beading present in at least 2 quadrants OR • IRMA in at least 1 quadrant • Very Severe NPDR: • Two or more of criteria for Severe NPDR

24. Follow-up for NPDR • Mild NPDR • OCPG: Annual DFE • Wills Eye: DFE every 6 months • Moderate NPDR • OCPG: every 6-12 months • Wills Eye: DFE every 2-4 months • Severe NPDR • OCPG: Obtain retina consult in 2-4 wks; f/u 2-3 months • Wills Eye: DFE every 2-4 months • Very Severe NPDR • OCPG: Obtain retina consult within 2 wks • Wills Eye: None mentioned

25. Proliferative Diabetic Retinopathy • Early PDR: • NVE or NVD which does not meet the criteria for High-Risk • High-Risk PDR:*** • One or more of the following • NVD > 1/4 to 1/3 DA • NVD and vitreous hemorrhage (VH)/preretinal hemorrhage (PRH) • NVE > ½ DA and VH/PRH

26. NVE &NVD

27. Management timeline for PDR • Early PDR • Obtain a retinal consult within 2-4 weeks; PRP may be indicated at this stage • High-risk PDR • Obtain a retina consult ASAP (within 24-48 hours); PRP is indicated at this stage • VH/PRH • Obtain retina consult ASAP (24-48 hours); Treat as High-risk PDR; Vitrectomy surgery may be useful in restoring vision • NVI/NVA • NVA refer within 24-48 hours, if NVI only refer 2-4 weeks; PRP may prevent neovascular glaucoma

28. Pan Retinal Photocoagulation (PRP)

29. Clinically Significant Macular Edema (CSME) • Guidelines for diagnosing CSME: • One of more of the following – • Retinal thickening at or within 1/3 DD (500 microns) of center of the macula OR • Hard exudates at or within 1/3 DD (500 microns) of center of the macula if associated with adjacent retinal thickening OR • Retinal thickening 1 DA or larger in size, any portion of which is within 1 DD of center of the macula • May have CSME at any stage of Diabetic Retinopathy

30. CSME

31. Management of CSME • CSME: • Obtain a retina consult within 2 weeks • Focal grid laser treatment is indicated in these patients

32. Macular Edema: Before & After Treatment

33. Important Diabetic Studies • Diabetes Control and Complications Trial (DCCT) • This study proved that intensive blood glucose control (HbA1c = 7.2 % or less) & that lowering blood glucose reduces the risk of eye disease by up to 76%, will reduce renal problems significantly, and 40% less likely to suffer from a cardiovascular event • United Kingdom Prospective Diabetic Studies (UKPDS) • This study also confirms that intensive glucose control (mean HbA1c = 7.0 %) reduces the risk of microvascular complications, including retinopathy, by 25% when compared to conventional control (HbA1c = 7.9%). It also showed tight HTN control decreased the risk of vision loss by 49%, death due to DM by 32%, and death due to stroke by 44%.

34. Important Diabetic Studies • Early Treatment Diabetic Retinopathy Study (ETDRS)*** • Coined the term “clinically significant macular edema” • Proved ASA did not affect the progression of retinopathy & did not increase the risk of vitreous hemorrhage • Scatter PRP: Demonstrated a reduction in severe visual loss for those that had early treatment (especially pts with NIDDM) • Showed PRP should be deferred for mild/moderate NPDR; As it progresses to severe or PDR, laser should be considered • Focal treatment for Macular edema: demonstrated that photocoagulation reduces the risk of moderate vision loss in eyes with ME that involved or threatened the center of the macula

35. Important Diabetic Studies • Diabetic Retinopathy Study (DRS) • Demonstrated that photocoagulation reduces the risk of visual loss by more than 50% when compared to no treatment • Diabetic Retinopathy Vitrectomy Study (DRVS) • Demonstrated that early vitrectomy provided a greater chance of prompt recovery of good visual acuity

36. References: • Care of the patient with Diabetes Mellitus – Optometric Clinical Practice Guideline. American Optometric Association. St. Louis, MO 1998. • Flynn, H. and et al. Diabetes and Ocular Disease: Past, Present, & Future Therapies. The Foundation of the American Academy of Ophthalmolgy. San Francisco, 2000. • General Guidelines for the Management of Diabetic Retinopathy. American Optometric Association. St. Louis, MO. • Kunimoto, D. et al. The Wills Eye Manual. Lippencott Williams & Wilkins. Philadelphia, 2004.