Background and Purpose-Central retinal artery occlusion is caused by a platelet-fibrin thrombus or embolic occlusion and is a stroke of the eye. Observational studies suggest that thrombolytics may restore ocular perfusion and visual function. We hypothesized that intravenous tissue-type plasminogen activator (tPA) administered within 24 hours of symptom onset might restore ocular perfusion and visual function. Methods-A placebo-controlled, randomized trial of intravenous tPA versus intravenous saline was performed in patients with clinically defined central retinal artery occlusion within 24 hours of symptom onset. tPA was administered at a total dose of 0.9 mg/kg, with 10% given as a 1-minute bolus and the remainder over 1 hour. An improvement of visual acuity of 3 lines or more was considered significant. Results-Twenty-five percent (2 of 8) of the tPA group experienced the primary outcome at 1 week after tPA versus none of the placebo group. One patient had an intracranial hemorrhage. The visual acuity improvement of these 2 patients was not sustained at 6 months. In both patients, tPA was administered within 6 hours of symptom onset. Conclusions-Although essentially a negative study, it does add to the evidence base of reperfusion in central retinal artery occlusion by showing that the time window for intervention is likely to be Ͻ6 hours. Reocclusion is a potential problem and may require adjuvant anticoagulation. Future studies should concentrate on determining the efficacy of thrombolytics in the Ͻ6-hour time window. Clinical Trial Registration-URL: http://www.anzctr.org.au. Unique identifier: 83102.

Between 1993 and 2013 the number and power of CTOs increased; as indicated in the percentage of firms with CTOs, their increasing presence on boards, their compensation relative to their CEOs, and compensation relative to other highly compensated executives. Firms which pursue an aggressive technology strategy (powerful CTO, high R&D spending) in industries in which technology is a critical contingency have well above normal market adjusted returns while those which pursue that strategy in industries in which technology is not critical have well below normal returns. These results empirically confirm longstanding, untested assumptions in the field of technology management. Moreover, the effect of R&D expenditures on firm performance is contingent on the degree to which technology is a critical contingency in the industry and on the power of the firm's CTO. These findings may explain the mixed results of past studies of the effects of R&D expenditure on firm performance. A model which integrates its own insights with those of earlier work on CTOs, R&D expenditures, firm strategy, and firm power dynamics is presented and supported.