To perform quantitative assessments, GSA-stained sections were
examined at ×400 with an (Axioskop; Carl Zeiss, Thornwood, NY)
microscope with the observer masked to treatment group. Images were
digitized using a three CCD color video camera and a frame grabber.
GSA-stained blood vessels were delineated and the area in the
subretinal space measured by computer with image analysis software
(Image-Pro Plus software; Media Cybernetics, Silver Spring, MD). For
each CNV lesion, area measurements were made for all sections on which
some of the lesion appeared and added together to give the integrated
area measurement. Only CNV lesions in which good sections were obtained
through the entire extent of CNV, so that a valid area measurement
could be made on each, were included in the analysis. Lesions were
excluded based solely on the inability to obtain an accurate
measurement because of poor quality of some sections from that
particular CNV lesion with the observer masked with regard to treatment
group, so that there was no possibility of a bias with regard to lesion
exclusion. After unmasking, it was found that precise measurements had
been obtained on the following number of lesions in each treatment
group: 52 controls, 56 PTK787, 52 CGP 53716, and 52 genistein. There
were 60 CNV lesions in each group, and therefore there were 4 that were
unmeasurable in the PTK787 group and 8 in each of the other three
groups.