OBJECTIVE To quantify the effect of intravitreally injected tissue plasminogen activator (TPA) and an expanding gas on freshly formed subretinal hemorrhage (SRH). METHODS Thirteen patients with acute (1 week or less) SRH due to age-related macular degeneration (ARMD) were treated with an intravitreal injection of 50 microg TPA, and 24 hours later, with an expanding gas. Fundus photographs taken before and 24 hours after each injection were digitized and calibrated. Area, geometric center, and shift of the SRH were measured at each time point using NIH image analysis software. Elevation of the SRH was assessed by echography. RESULTS Compared to the preoperative size, SRH enlarged significantly 24 hours after TPA injection (P < 0.001). A significant shift of the geometric center toward the inferior retinal periphery out of the macula was found after gas injection (P < 0.001). Significant horizontal displacement of the SRH was not noted after TPA or gas injection. More elevated subretinal blood clots showed a larger increase in size after TPA injection than flat clots (P < 0.05). CONCLUSIONS Enlargement of SRH in a gravity-dependent manner indicates subretinal liquefaction of the clot after TPA treatment. An intravitreal injection of gas 24 hours later can significantly displace the SRH inferiorly.