In my hand I held a syringe with a fine needle. It contained 0.5 milliliters of clear liquid, to be injected into the eye of my patient, a Chinese woman in her 70s who could barely count my fingers when I held them inches from her face. She had suffered a "vein occlusion" to her retina - a kind of stroke that blocks blood flow in the eye.

In one swift motion, I marked the injection point and shot the drug into the back of her eye. And just like that, my patient received an elixir that could be called a modern medical wonder. About half the patients who get these injections show improvement in their vision, a recent study found.

The injection is part of a class of drugs called VEGF (vascular endothelial growth factor) inhibitors. These therapies target a problem common to many diseases: blood vessels gone wild. In many types of cancer, overgrown blood vessels nourish malignant tumors. Block these feeders and you'll starve the tumor.

Uncontrolled diabetes causes blood vessels to bloom like weeds in the retina. The vessels bleed or scar and eventually cause blindness. But crimp the vessels' growth factor (VEGF) and you can save the eye.

Anti-VEGF therapy has made inroads against colon cancer, lung cancer, breast cancer, diabetic retinopathy, macular degeneration, and now, say new studies released last month, vein occlusions or "strokes to the eye," which affect more than a million people per year, including my patient.

The strategy has far-reaching implications. It shows how bench lab research, delving into the biological underpinnings of disease, can lead to therapeutic success. Years of financial investment and brainpower, with scientists working long hours in the lab, resulted in this feat.

It all started back in the 1960s when the son of a Cleveland rabbi made an interesting observation. Judah Folkman, then a young surgeon doing research for the military on blood substitutes, noticed that tumor cells in a rabbit thyroid gland bathed by these blood substitutes did not grow like normal tumor cells. He surmised that real blood had some component that must enable tumor cells to grow.

Later in his lab at Harvard, he would isolate the first blood vessal-stimulating protein from a tumor. His theory was, if you could tie off the new blood supply, or angiogenesis, of tumors by blocking these factors, you could beat cancer.

As with many revolutionary ideas, his was ridiculed at first. The National Cancer Institute turned down his first grant for anti-angiogenesis work in the 1970s. Said his reviewers: It's common knowledge. The problem is dilated blood vessels, not heavy growth of new ones.

By the 1980s, Folkman and his colleagues had isolated multiple growth factors.

Textbooks slowly acknowledged his research. By the 1990s, all but a few in the field of cancer research were convinced.

In 2004, four years before his death, Folkman saw his dream commercialized. The FDA approved the first anti-VEGF blockbuster, Genentech's Avastin, to treat colorectal cancer after trials showed that it extended patients' lives. Suddenly, dangerous forms of blood vessel growth had an antidote.

Soon after its release, Avastin found a successful application in my field. A Miami ophthalmologist wondered why not inject it into the eye to combat the dreaded macular degeneration. This disease, which causes blood vessals to cloud the retina, had few treatments. Studies soon showed that the VEGF inhibitor could slow visual loss and in some cases restore some vision.

Now the wonder drug isn't without controversy. Genentech created an eye drug similar to Avastin called Lucentis that was far more expensive - at least $2,000 per dose compared with under $100 for Avastin - and then made the cheaper version harder for eye doctors to get. The company has since eased its stance but the episode rankled cost-conscious patients and doctors.

Still, at least 1,000 labs are studying angiogenesis. Fifty anti-angiogenesis drugs are under development, including for patients with pancreatic cancer. And 10 angiogenesis inhibitors have been approved.

It's a thrill, as I train, to be a small part of this revolution. Wills Eye, which has the largest retina practice in the country, continues to be a major study site for these drugs.

As for my patient, we'll have to wait a few weeks and check her during a follow-up appointment. She'll probably need multiple injections to keep her disease at bay. And while it may not be a cure, thanks to Folkman and his tenacious network of researchers, we have another potent weapon in the armory against human ailments.

Contact Rachel K. Sobel at rachelkimsobel@gmail.com.