Do you utilize thrombolytic therapy in patients with CRAO?

Yes. The previous trial was negative because patients with CRAO were included after 4.5 hours. There are trials underway in Europe for both tPA and TNK to address that. The retina will irreversibly infarct if the blood flow is not restored within 240 minutes (this is from basic science studies with Rhesus monkeys). There have been based on this number, observational studies published have found that thrombolysis within the first 4 to 4.5 that may help with improving visual acuity (rather than blindness which is often the alternative if nothing is done). The most important thing is that the natural history of CRAO recovery is grave and disabling. Vision is one of the most important senses. So thrombolysis, even if it improves visual acuity by two lines on the Snellen chart, may make a lot of difference in the patient's life.

Yes, we use a 4.5-hour window, though the evidence remains relatively limited. There is an AHA guideline on this topic.