Background: To report the histopathological findings after photodynamic therapy (PDT) in eyes obtained postmortem with choroidal neovascularisation (CNV) secondary to age-related macular degeneration (AMD).
Methods: Two eyes were obtained postmortem from two patients with CNV secondary to AMD. Both of the patients had been treated with PDT. Serial sections through the posterior poles were obtained and stained with haematoxylin-eosin, periodic acid-Schiff, Masson trichrome or phosphotungstic acid haematoxylin (PTAH). Two-dimensional reconstructions were prepared and compared with fluorescein angiograms.
Results: The interval between PDT and death was 3 months and 17 months in each patient, respectively. Light-microscopic examination showed that CNV enveloped with retinal pigment epithelium (RPE) in both eyes. The average size of the CNV was 550×280 µm. One eye had combined (subRPE/subretinal) growth pattern CNV, and the other eye had both type I (subRPE) and combined growth pattern CNV. All specimens contained fibrous proliferation and patent vascular channels within the CNV, and there was no thrombus formation within the vascular channels. No apparent abnormalities in the choroid were observed by light microscopy.
Conclusions: Although involution with fibrous tissue proliferation occurred, PDT did not result in permanent occlusion of the vascular channels in the CNV. Our findings indicate that PDT may accelerate involution of CNV, thus limiting its size and preserving photoreceptors.
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Presented in part at the 2005 annual meeting of the Association for Research in Vision and Ophthalmology at Fort Lauderdale, Florida.
Competing interests: None.
Funding: HEG is a recipient of the Research to Prevent Blindness Senior Scientific Investigator award. This study was supported by a grant from QLT, Vancouver, BC, Canada. The sponsors participated in the study design, in the collection and in the decision to submit the paper for publication.
age-related macular degeneration
phosphotungstic acid haematoxylin
retinal pigment epithelium