What is the initial treatment for a polypoidal lesion in the fundus?

Management of Polypoidal Lesions in the Fundus

The initial treatment for polypoidal lesions in the fundus is intravitreal anti-VEGF therapy, possibly combined with photodynamic therapy (PDT) depending on lesion characteristics. 1

Diagnostic Approach

Before initiating treatment, proper diagnosis is essential:

• Multimodal imaging is crucial for accurate diagnosis:

  • OCT: Look for mid/hyperreflective signal below flat irregular RPE detachment
  • ICGA: Essential for identifying and localizing polypoidal structures
  • OCT-A: Helpful for detecting neovascular networks
  • FA: To assess leakage patterns

• Key diagnostic findings for polypoidal lesions:

  • Well-demarcated CNV "plaque" with or without polypoidal component on ICGA
  • Up to two-thirds of patients with CSC with CNV can have a polypoidal component 1
  • More common in older patients and those with prolonged disease 2

Treatment Algorithm

First-line Treatment:

1. Intravitreal anti-VEGF injections:

   • Ranibizumab, aflibercept, or bevacizumab
   • Initial loading dose: 3 monthly injections followed by as-needed regimen
   • Re-evaluate every 3 months for evidence of leakage 3

2. Consider combination therapy:

   • Anti-VEGF + PDT is more effective than monotherapy for polypoidal lesions
   • The EVEREST II and PLANET studies found combination therapy beneficial 1
   • Peiretti et al. reported 50% of polypoidal lesions closed after full-fluence PDT monotherapy, compared to 25% with anti-VEGF monotherapy 1

PDT Protocol (when used):

• Verteporfin administration:

  • Dose: 6 mg/m² body surface area
  • Infused intravenously over 10 minutes
  • Light activation begins 15 minutes after start of infusion 3

• Light delivery parameters:

  • Wavelength: 689 nm
  • Light dose: 50 J/cm²
  • Light intensity: 600 mW/cm²
  • Duration: 83 seconds 3

• PDT spot size determination:

  • Treatment spot size should be 1000 microns larger than the greatest linear dimension (GLD) of the lesion 3
  • Position nasal edge at least 200 microns from temporal edge of optic disc 3

Evidence for Treatment Efficacy

• In the MINERVA study, eyes with CNV due to CSC treated with ranibizumab had an improvement in BCVA of 6.6 ETDRS letters at 2 months, compared with only 1.6 letters in the sham group 1

• Aflibercept has shown promising results:

  • In the EPIC study, aflibercept resulted in stabilization of vision, resolution of exudative and hemorrhagic complications, and regression of polyps in 67% of cases 4
  • Particularly effective for polypoidal lesions refractory to ranibizumab 5

• Comparative studies between bevacizumab and ranibizumab show similar efficacy:

  • Similar visual acuity improvement
  • Similar reduction in macular edema
  • Comparable polyp regression rates (20.7-24.2% for bevacizumab vs. 21.2-23.3% for ranibizumab) 6, 7

Follow-up and Monitoring

• Re-evaluate patients every 3 months 3
• If choroidal neovascular leakage is detected on fluorescein angiography, repeat treatment
• Regular OCT monitoring to assess resolution of subretinal fluid
• Repeat ICGA to evaluate polyp regression

Important Considerations

• Silent type 1 CNV may be common in chronic CSC but may not require immediate treatment until active leakage becomes evident 1

• Treatment response indicators:

  • Resolution of subretinal fluid
  • Regression of polypoidal lesions
  • Improvement in visual acuity
  • Reduction in retinal pigment epithelial detachment

• Potential pitfalls:

  • Misdiagnosis as uncomplicated CSC
  • Inadequate imaging leading to missed polypoidal components
  • Undertreatment with anti-VEGF monotherapy when combination therapy may be more effective

By following this evidence-based approach, the management of polypoidal lesions in the fundus can be optimized to improve visual outcomes and prevent disease progression.