Collagen levels associated with the cell layer and media combined of keratocytes in standard and in agarose overlay cultures normalized for DNA content in the cell layer. Keratocytes were cultured in media containing IGF-I, TGF-β, FGF-2, or PDGF and harvested on day 20. IGF-I, TGF-β, and PDGF treated agarose cultures contained significantly less total collagen than standard cultures. FGF-2 cultures contained significantly (p< 0.02) less collagen than the other cultures.