Patients facing blindness see results from revolutionary gene therapy: Part 2

Monroe Le, 6, and Heather Hodlin, 25, each underwent the first FDA-approved live gene therapy. They experienced very different paths to recovery but their lives have been changed forever.
7:14 | 07/11/19

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Transcript for Patients facing blindness see results from revolutionary gene therapy: Part 2
Reporter: Heather is scared. Over the course of the next few days her life is going to change for better or for worse. It was the longest night ever. Reporter: The 25-year-old is recovering from surgery, to see if the first-everybody approved live gene therapy can restore her eyesight. Now we're going to check your vision. I was really nervous when we took the patch off that day. It's just really scary. And when I couldn't see the nurse's hand going back and forth, I kind of panicked. Do you see my hand moving here? Did I really try to fix my eyes and make them worse now? Hey, Heather. Is this backfiring? So let me have a look. Very blurry. Very blurry. Look straight. Up and left here. Oh, that hurts. Excellent. Looks perfect. All the medicine's absorbed. Okay. You do have an air bubble. And that's what causes the blurriness? Yes. The optics of the air is very poor, that's why it's so blurry. Reporter: Dr. Miguel is not alarmed. He says the air bubble is normal and the day after surgery is always rough. But by the end of that first week she was reconsidering whether to have the second operation at all. To fix her other eye. I still can't see the same as before surgery, like my vision is still worse. Reporter: But she decided it was worth the risk. Leather, this. Is Dr. Miguel. I know you're just warking up. Everything looks so perfect, all right? Just like the other eye. We'll let you relax and I'll see you tomorrow morning. Great. Reporter: Nearly all the major improvements will happen in the first month after both surgeries. He likes it! Reporter: And Monroe's progress has been incredible. I can see the stars! What, baby? Ki I can see the stars! Reporter: After surgery, I imagine it's pretty shocking. She's a whole new girl. Reporter: Born again? Born again. Reporter: Does she realize it? Oh, 100%. What do you see? Stars in the sky! Reporter: The treatment, opening up a whole new world for the little girl, a world she'd never seen before. Where do you want to go? Okay, show me the way, babe. Which one is your favorite princess? Um, belle. Yes, come on. Reporter: In fact, on this day, Monroe has gone to transform into a princess. Reporter: The wonders never cease for the 6-year-old fan. Princesses never been on this ride. Those are different. Those are always the same, honey. You just couldn't see them before. Everything was worth it. My baby could see. Reporter: Every minute, every dollar? Everything. Reporter: All worth it? 100%. Reporter: Almost two months after surgery, Heather was still struggling to really see the impacts. The recovery process is much harder for me than I expected. My peripheral has improved a Reporter: What can you see right now? We decided to test out Heather's eyes in the dark. One of her dreams was to walk on the beach at night. Can you turn off the light completely? Just give my eyes a second. Just let them adjust a little. I see that light, it looks like it's glowing almost, like there's reflection on the bottom? What's over this way? I'm not sure if there's something. Reporter: Those are two white lines of the waves. Holy moly. I see those a lot. I see a glare. Is that from the moon? Reporter: Yes. This is crazy. Oh, I hear the water coming. Reporter: Back up a little bit. Can you see it right there below us? I do, it's like right that. I do see that. And there's a little second one coming. Reporter: Yes, that's awesome. Is one of your dreams to see the stars? Oh, yes, definitely. It's always been a dream of mine. Just kind of waiting because I'm afraid I won't be able to. Reporter: Now she will get that chance. So I set up two telescopes. Reporter: Thanks to amateur astronomer John Isaacs who set up some telescopes for us. He decides to start with the moon. If Heather can't see something that large through a scope she will never be able to see a Oh, I see it. The defined shape. It's amazing. Reporter: Now the real moment of truth. John repositions to look at Sirius. The brightest star in the sky. If you have 20/20 vision you clearly see the star here in our video with the naked eye. For Heather, her only hope is through this telescope, after 25 years of waiting. So are you seeing it yet? Find gray spot again. Oh, I see it! You do? Are you okay? I see it. I can't even talk. It doesn't seem real. I can't believe I'm seeing a star for the first time ever. Oh, my god. It's amazing. Okay. Thank you. Yeah. Reporter: We'll be right back. What about him? Let's do it.

This transcript has been automatically generated and may not be 100% accurate.

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