Photodynamic effects on choroidal neovascularization and physiological choroid

Area of Science:

• Ophthalmology
• Vascular Biology
• Medical Imaging

Background:

• Choroidal neovascularization (CNV) poses a significant threat to vision.
• Photodynamic therapy (PDT) is a treatment option for CNV.
• Understanding PDT's effects on CNV vascular integrity is crucial.

Purpose of the Study:

• To evaluate the impact of photodynamic therapy (PDT) on choroidal neovascularization (CNV) and surrounding choroidal perfusion.
• To assess vascular integrity changes post-PDT using indocyanine green angiography (ICG-A).

Main Methods:

• Prospective clinical trial involving patients with subfoveal CNV treated with PDT and verteporfin.
• Continuous indocyanine green angiography (ICG-A) with tomographic sections performed before and at multiple time points after treatment.
• Quantification of vascular changes in CNV and collateral choroid based on lesion size, hyperfluorescence, and recurrence.

Main Results:

• Significant reduction in CNV lesion size and late hyperfluorescence observed.
• Persistence of the choroidal feeding complex noted in 54% of lesions, detectable by ICG-A.
• Choriocapillary occlusion occurred in collateral choroid, with slow recanalization and persistent changes in choroidal filling patterns.

Conclusions:

• Tomographic ICG-A reveals persistent CNV and/or feeder vessels after PDT.
• PDT leads to reduced perfusion in the entire photosensitized area, including normal choroid.
• Repair mechanisms in both neovascular and normal choroidal tissues are slow following PDT.