Every baseball season, 73-year-old Fred Crittenden plants himself in front of his television in his small one bedroom apartment an hour north of Toronto
"Oh, I love my sports, I am a fan of the Blue Jay's," said Crittenden. I will tell you that they need me to coach them. The games are played in his apartment. He can't see so he doesn't watch them.
"I lost my sight when I was 35 years old."
A condition called retinitis pigmentosa led to the decline of his eyesight. The cells that help us see in dim light and the cells that let us see in brighter light were all lost. He went from perfect vision to total blind in one year.
He said that the last thing he saw was his daughter. She was young at that time. I looked at her when she was in the crib. I could barely see her eyes, her nose, her lips or her chin. It's difficult even to this day.
It took him a long time to come to terms with his sight. He doesn't see anything anymore. He reported that it was total darkness. He manages well. He doesn't need help with things like the 24 hour day/ night cycle.
At night, he listens to sports or books. He sleeps by 11 and wakes up by 6:30. Our clocks are influenced by light.
If you didn't see any light, you would shift your sleep cycle so that you would fall asleep later and later. Every day you look at the sun, you train your clock to be on the 24 hour cycle.
It's something of a mystery. His internal clock marches to the beat of a sunlit world, but he's blind. This is not the case for everyone who is blind. What is happening with him?
The African clawed frog is being studied by a Biologist at the University of Virginia who was in graduate school in the 90's. He thinks the frog is disgusting. The skin is very slimy.
The skin on the frog's body is light-colored and helps it blend in with the water below. A molecule called melanopsin was found by Provencio. It was also in the frog's body. He and his team found it in the eye of a frog.
"I told my colleague that we were the first people in the world to actually view a completely novel sensory system in mammals," Provencio said.
Melanopsin isn't in our equipment. The melanopsin cells are located in a different part of the retina. Michael Do is a neuroscience researcher at Boston Children's Hospital and the Harvard Medical School. The melanopsin cells have arms that overlap with the arms of other melanopsin cells to form a mesh.
The whole mesh is sensitive to light. The sun makes a lot of that light, as well as our phones, tablets, screens and some other indoor lights. Our brains are covered with the melanopsin cells.
Do thinks it's 30 brain regions that are contacted by the cells. The base of the brain is where the master clock is located. The suprachiasmatic nucleus uses light to tell the rest of our body when to sleep and when to wake up. The melanopsin cells help influence a lot of things.
There have been lab experiments where mice had their melanopsin turned off. He says that the mice can sense light, but it's not normal.
If you give them a lab-mouse version of jet lag, they will take a month to adjust to the new time zone. Some people have a harder time adjusting to daylight saving time or a change in time zones than other people.
We found out that Fred has melanopsin cells, even though he has no functioning rods or cones.
There is an important system in the brain and retina that is maintained by some people who are blind. This system of melanopsin cells is the reason why the brain can use light.
It's these cells that wake him up in the morning to make sure he's awake when Sarah calls.
She calls me every now and then to see how I'm doing. She's a good person.
He had a picture of Sarah in his apartment. She smiles in it. He had a photo in his bedroom. On a clear day, a shaft of sunlight would flash through that window and light up Sarah.
This story is part of our periodic science series called "Finding Time", which explores what makes us tick.
There was a live show at the Museum of Science in Boston.
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