<p>A course of verteporfin therapy is a two-step process requiring administration of both drug and light. The first step is the intravenous infusion of Verteporfin. The second step is the activation of Verteporfin with light from a nonthermal diode laser. The physician should reevaluate the patient 3 months after treatment and if choroidal neovascular leakage is detected on&nbsp;fluorescein angiography, therapy may be repeated.<br />
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<strong>Lesion Size Determination</strong>: The greatest linear dimension (GLD) of the&nbsp;lesion&nbsp;should be estimated by fluorescein&nbsp;angiography&nbsp;and color fundus photography. All classic and occult CNV, blood and/or blocked fluorescence, and any serous detachments of the&nbsp;retinal pigment epithelium should be included for this measurement. Fundus cameras with magnification within the range of 2.4-2.6X are recommended. The GLD of the lesion on the fluorescein angiogram must be corrected for the magnification of the fundus camera to obtain the GLD of the lesion on the&nbsp;retina.<br />
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<strong>Spot Size Determination</strong>: The treatment spot size should be 1000 microns larger than the GLD of the lesion on the retina to allow a 500 micron border, ensuring full coverage of the lesion. The maximum spot size used in the clinical trials was 6400 microns.<br />
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The&nbsp;nasal&nbsp;edge of the treatment spot must be positioned at least 200 microns from the temporal edge of the&nbsp;optic disc, even if this will result in lack of photoactivation of CNV within 200 microns of the&nbsp;optic nerve.</p>