Can semaglutide (glucagon-like peptide-1 receptor agonist) affect eyesight?

Semaglutide and Its Effects on Eyesight

Yes, semaglutide can affect eyesight, particularly in patients with pre-existing diabetic retinopathy, where it may cause worsening of retinopathy complications due to rapid blood glucose reduction. 1, 2

Mechanism and Risk

Semaglutide's impact on vision occurs through several mechanisms:

1. Rapid glycemic improvement: When semaglutide rapidly lowers blood glucose levels, it can paradoxically worsen diabetic retinopathy in the short term 2

2. Increased risk in specific populations:

   • In clinical trials, semaglutide showed a higher rate of diabetic retinopathy complications (3.0%) compared to placebo (1.8%) 1
   • The absolute risk increase was significantly higher in patients with pre-existing diabetic retinopathy (8.2% with semaglutide vs. 5.2% with placebo) 1
   • Patients without known history of diabetic retinopathy had much lower risk (0.7% with semaglutide vs. 0.4% with placebo) 1

3. Risk factors for vision complications:

   • Pre-existing diabetic retinopathy 3, 1
   • Rapid A1C reduction 3, 2
   • Longer duration of diabetes 3
   • Age ≥60 years and diabetes duration ≥10 years 4

Clinical Management Recommendations

Before Starting Semaglutide

• Baseline eye examination: Perform a dilated comprehensive eye exam before initiating semaglutide, especially in patients with diabetes 3, 2
• Risk assessment: Evaluate for pre-existing retinopathy, as this significantly increases risk 1

During Semaglutide Treatment

• Monitoring: Patients with history of diabetic retinopathy should be closely monitored for progression of retinopathy 1
• Titration strategy: Consider slower titration of semaglutide in patients with established retinopathy to minimize rapid glucose reduction 3
• Regular eye exams:
  • For patients with type 1 diabetes: within 5 years after diabetes onset 2
  • For patients with type 2 diabetes: at the time of diagnosis 2
  • If retinopathy is present: at least annual examinations 2

Special Considerations

• Non-arteritic anterior ischemic optic neuropathy (NAION): Some studies suggest increased risk of NAION with semaglutide, particularly in patients with crowded optic discs 5
• Potential benefits: Interestingly, some research suggests semaglutide may have direct beneficial effects on retinal neuroinflammation and vascular leakage independent of its glucose-lowering effects 6, with one case report even showing resolution of proliferative diabetic retinopathy 7

Clinical Decision Algorithm

1. Assess baseline risk:

   • Does the patient have pre-existing diabetic retinopathy? (Higher risk)
   • Does the patient have long-standing poor glycemic control? (Higher risk)
   • Is the patient ≥60 years with diabetes duration ≥10 years? (Higher risk)

2. If high risk:

   • Ensure comprehensive eye examination before starting semaglutide
   • Consider slower titration schedule
   • Schedule more frequent eye examinations (more than annually)
   • Discuss risk-benefit with patient

3. If low risk:

   • Follow standard eye examination schedule (annually or every 1-2 years if no retinopathy)
   • Use standard titration schedule
   • Educate about potential vision symptoms to report

4. For all patients:

   • Advise to report any vision changes immediately
   • Continue regular eye examinations as recommended for diabetic patients

Common Pitfalls to Avoid

1. Failing to assess retinopathy status before initiating semaglutide
2. Rapid titration in patients with pre-existing retinopathy
3. Ignoring vision complaints in patients recently started on semaglutide
4. Attributing all vision changes to semaglutide without proper ophthalmologic evaluation
5. Discontinuing beneficial therapy without proper risk-benefit assessment

The long-term effects of semaglutide on diabetic retinopathy complications have not been fully studied 1, so continued vigilance and appropriate monitoring are essential for patients on this medication.