Abstract
Purpose: :
To determine optimal exposure parameters to induce subretinal neovascularization with a pulsed Nd_YAG laser as part of a larger study to evaluate the response of these lesions to a variety of therapeutic interventions.
Methods: :
20ns pulsed laser energy at 1064 nanometers was delivered by a Continuum model 581–10 Nd_YAG laser (Santa Clara, California) to the retina of non–human primates. The progress of these lesions was monitored by fluorescein angiography. A combination SLO/OCT instrument with on–line indocyanine green (ICG) capability (OTI technologies Toronto, Canada) was employed to obtain digital images of these lesions. Additional functional analysis was performed utilizing multi–focal electroretinography. The lesions were studied at various time intervals from one week to three months post exposure.
Results: :
Fluorescein angiography proved to be the most consistent method for observing the the presence or absence of choroidal neovascularization. The combination SLO/OCT permitted confirmation of the presence of these lesions with precise registration of the lesion location within the retina. The laser energy necessary to successfully induce neovascularization was 2.0 millijoules (p<.005 by ANOVA) even though the morphology of these laser lesions initially appeared similar to one another after acute exposure with varying levels of laser energy. Multi–focal electroretinography showed increased P1 amplitudes in the vicinity of these lesions but serial observation of these amplitudes over time did not correlate with the development of subretinal neovascularization.
Conclusions: :
Pulsed Nd_YAG laser is capable of producing subretinal neovascularization in the non–human primate. The parameters necessary to achieve these lesions are important to allow study of the behavior and treatment response of neovascular membranes produced by this class of laser which is currently employed in numerous commercial and laboratory environments. These lasers have been the most common cause of serious laser eye injury from incidental laser exposure in human subjects we have evaluated as we continue to explore this field.
Keywords: choroid: neovascularization • laser • retinal neovascularization