ABSTRACT
BACKGROUND: The presence of vessels has a negative influence on corneal transplant survival. Closure of such vessels prior to transplantation may improve the transplant results, and this might be achieved by irradiating the vessels with argon laser light after intravenous administration of a photosensitizer, e.g. bacteriochlorin a (BCA). A suture-induced corneal neovascularization model in rats was set up to test this hypothesis. METHODS: Suture-induced vessels in the cornea of male Wistar rats were irradiated with argon laser light after intravenous administration of BCA. We applied irradiation of varying energy levels and duration and assessed the changes in the vessels by slit-lamp examination, fluorescein angiography and histology. RESULTS: Suture-induced corneal vessels in the rat could be used effectively to study photothrombosis therapy. Intravenous administration of BCA prior to irradiation (lambda = 514.5 nm) of the corneal vessels led to vessel closure at lower energy levels and of longer duration than occurred with laser treatment alone. CONCLUSIONS: Suture-induced corneal neovascularization in the rat can be used as a model to study the efficacy of photothrombosis therapy. BCA can be used to enhance the rate and duration of vessel closure.
Subject(s)
Corneal Neovascularization/drug therapy , Laser Coagulation , Photochemotherapy , Photosensitizing Agents/therapeutic use , Porphyrins/therapeutic use , Animals , Cornea/blood supply , Cornea/drug effects , Cornea/pathology , Corneal Neovascularization/pathology , Disease Models, Animal , Fluorescein Angiography , Injections, Intravenous , Male , Photosensitizing Agents/administration & dosage , Porphyrins/administration & dosage , Rats , Rats, Wistar , Regression AnalysisABSTRACT
The B-mode images of 32 patients affected with a malignant melanoma of the choroid were studied, in particular with respect to choroidal excavation. The degree of visibility of choroidal excavation at the B-scan was compared with the thickness of the choroid, scleral invasion, vascularisation, retinal detachment and the reflectivity of the tumour. None of these histological and echographical features appeared to be significantly related to the degree of the visibility of choroidal excavation. Also the condition of the choroid was studied. At examination of all the histological sections no choroid was found between tumour and sclera. This implies that choroidal excavation should be visible at echograms in every case instead of only in 75% of the cases as was found for our series.
