Figure 5. The effect of all-trans-retinoic acid (RA) on the morphology of cultured human scleral fibroblasts (HSFs) visualized with an inverted phase contrast microscope. A: In untreated control HSFs, cells spread on collagen I-coated standard plates and displayed many protrusions. B: After incubation with RA (10⁻⁷ M) for 48 h, the shape of the cells changed. The original magnification was 400× and the scale bar=20 μm.