Most Common Ophthalmologic Complications in Uncontrolled Diabetes
Diabetic retinopathy is the most frequent cause of new cases of blindness among adults aged 20-74 years in developed countries, while glaucoma, cataracts, and other eye disorders occur earlier and more frequently in people with diabetes. 1
Primary Ophthalmologic Complications
1. Diabetic Retinopathy
Diabetic retinopathy is a highly specific vascular complication of both type 1 and type 2 diabetes, with prevalence strongly related to:
- Duration of diabetes
- Level of glycemic control
- Presence of other risk factors 1
Progression of diabetic retinopathy follows a predictable pattern:
- Non-proliferative diabetic retinopathy (NPDR) - characterized by microaneurysms, hemorrhages, and cotton wool spots
- Proliferative diabetic retinopathy (PDR) - characterized by neovascularization, which can lead to vitreous hemorrhage and retinal detachment
- Diabetic macular edema (DME) - can occur at any stage and is the leading cause of vision loss in diabetic patients 2
2. Cataracts
- Occur earlier and more frequently in people with diabetes 1
- Chronic hyperglycemia contributes to cataract formation through:
- Oxidative stress pathways
- Non-enzymatic glycation of lens proteins 3
- Some diabetes medications like pioglitazone may increase cataract risk 3
3. Glaucoma
- Higher prevalence in diabetic patients compared to non-diabetic individuals 1, 4
- Both open-angle and neovascular glaucoma can occur
- Neovascular glaucoma specifically can develop as a complication of severe proliferative diabetic retinopathy 4
4. Diabetic Papillopathy
- Swelling of the optic disc that can occur in diabetic patients 1
- May be associated with sudden changes in glycemic control
5. Ocular Surface Disorders
- Dry eye syndrome
- Recurrent corneal erosions
- Persistent epithelial defects
- Impaired corneal sensitivity 4, 5
Risk Factors for Progression
Several factors increase the risk of developing or worsening diabetic eye complications:
- Chronic hyperglycemia 1
- Duration of diabetes 1
- Hypertension 1
- Diabetic kidney disease/nephropathy 1
- Dyslipidemia 1
- Pregnancy (can cause rapid progression of retinopathy) 1
- Poor glycemic control at conception 1
Screening and Prevention
Early detection is critical as patients with proliferative diabetic retinopathy or macular edema may be asymptomatic until significant damage has occurred:
- Type 1 diabetes: Initial comprehensive eye exam within 5 years of diagnosis, then annually 1
- Type 2 diabetes: Initial comprehensive eye exam at time of diagnosis, then annually 1
- If no retinopathy is present and diabetes is well-controlled, screening every 1-2 years may be considered 1
- More frequent examinations are needed if retinopathy is progressing 1
Treatment Approaches
For Diabetic Retinopathy:
- Panretinal laser photocoagulation - reduces risk of severe vision loss from PDR from 15.9% to 6.4% in treated eyes 1
- Anti-VEGF injections (e.g., ranibizumab) - indicated for:
- Focal laser photocoagulation - beneficial for macular edema 1
For Other Complications:
- Cataract surgery when visually significant
- Glaucoma management with medications, laser, or surgery
- Ocular surface disorders treated with lubricants and other therapies
Important Clinical Considerations
- Diabetic retinopathy is now recognized as an inflammatory, neuro-vascular complication with neuronal injury/dysfunction preceding clinical microvascular damage 6
- Pregnancy can cause rapid progression of diabetic retinopathy - women with pre-existing diabetes should have eye exams before or during first trimester and be monitored throughout pregnancy 1
- The presence of retinopathy is not a contraindication to aspirin therapy for cardioprotection 1
- Artificial intelligence systems for screening are emerging but should not replace comprehensive eye exams for patients with known retinopathy 1
Intensive diabetes management with near-normoglycemia has been shown to prevent and/or delay the onset and progression of diabetic retinopathy and potentially improve visual function 1.