Histopathologic Findings of Surgically Excised Choroidal Neovascularization Three Days Following Photodynamic Therapy in Age-related Macular Degeneration

Abstract

Abstract: : Purpose: To report the histological findings of surgically excised choroidal neovascularization (CNV) 3 days following photodynamic therapy (PDT) in age-related macular degeneration (AMD). Methods: Four eyes of 4 patients (3 male, 1 female) with CNV underwent surgical membranectomy. All patients had fluorescein angiographic evidence of subfoveal classic CNV secondary to AMD. The visual acuity of the affected eyes varied between 5/200 and 10/200. Before the surgery all patients gave written informed consent for the PDT. Fluorescein angiographies were performed before the PDT and on the day of the surgery. One of the 4 patients had a previous PDT 3 months ago. The extracted specimens were studied by light microscopy. Results: Clinical findings: Three patients had a greyish subretinal lesion with some subretinal hemorrhage at the border. No retinal pigment epithelial detachment was seen. One patient with previous PDT had a thick round subretinal fibrosis and a neurosensory detachment of the retina.Fluorescein angiographic findings: Three patients had classic CNV without any occult components. The patient with previous PDT had a classic CNV and staining of the subretinal fibrosis. Three days after the PDT, all the patients did show non perfusion of the CNV. In 1 patient staining of some large choroidal vessels were seen. Late phase of the fluorescein angiography did show central hyperfluorescence consistent with retinal edema. Histological findings: All CNV-specimens consisted of fibrovascular tissue. Venules and arterioles did show abnormal endothelial lining. In few vessels intraluminal debris was detected. Conclusion: These histological findings suggest the endothelial damage as a possible primary effect of PDT in classic CNV within 3 days. Thrombosis is not necessarily seen in classic CNV shortly after PDT, possible thrombosis has taken place at a deeper level, namely underlying feeding choroid.

Keywords: 308 age-related macular degeneration • 516 photodynamic therapy • 346 choroid: neovascularization