Perceiving without seeing
Fred Crittenden, 73, lost his sight to retinitis pigmentosa when he was 35 years old. Today he has no visual perception of light.
Fred Crittenden, 73, lost his sight to retinitis pigmentosa when he was 35 years old. Today he has no visual perception of light.
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 love my Blue Jays,” says Crittenden.
“They need me to coach ’em — they’d be winning, I’ll tell ya.” He listens to the games in his apartment.
“I went blind,” Crittenden recalls, when “I was 35 years young.”
Among other things, these light-detecting cells help his body regulate his sleep cycles.
Among other things, these light-detecting cells help his body regulate his sleep cycles.
“The last thing I saw clearly,” he says, thinking back, “it was my daughter, Sarah. She was 5 years old then. I used to go in at night and just look at her when she ...
...was in the crib. And I could just barely still make her out — her little eyes or her nose or her lips or her chin, that kind of stuff. Even to this day it’s hard.”
Crittenden takes a walk near his home in Sutton West, Ontario.
Crittenden takes a walk near his home in Sutton West, Ontario.
Exposure to light is the crucial driver in modulating circadian rhythms for most people. But other factors, including exercise, temperature and social interaction, can influence your internal clock, too.
Exposure to light is the crucial driver in modulating circadian rhythms for most people. But other factors, including exercise, temperature and social interaction, can influence your internal clock, too.
At night, Crittenden listens to sports or his talking book machine. That may not seem remarkable, except that our circadian clocks are deeply influenced by light.
“The frog is really a disgusting-looking animal,” he chuckles.
“It has very slimy skin.”
“We were looking through the microscope,” Provencio recalls, “and I told my colleague who was with me, ‘We are the ...
...first people in the world to actually view a completely novel sensory system in mammals’ ” — including humans.
“Imagine an octopus with its tentacles reaching out,” says Michael Do, a neurobiologist at Boston Children’s Hospital and the Harvard Medical School.
“The melanopsin cells — their arms reach out and overlap with the arms of other melanopsin cells to form a mesh over the retina.”
The evening light from Crittenden’s window casts a faint glow in his apartment.
The evening light from Crittenden’s window casts a faint glow in his apartment.
For instance, give them a lab-mouse version of jetlag — where one day, you suddenly shift when the lights get turned on and shut ...
...off — and “these mice, instead of taking seven days to reset to the new time zone, they will take a month,” Panda says.
So that’s the mystery we started with, solved: Fred Crittenden has no functioning rods or cones, but, he does have melanopsin cells.
Crittenden spends time with his fiancée Carol Tromba on a Saturday afternoon in December.
Crittenden spends time with his fiancée Carol Tromba on a Saturday afternoon in December.
“She usually calls me every other day, to see how I’m doing and that kind of stuff,” Crittenden says fondly.
This story is part of our periodic science series “Finding Time — a journey through the fourth dimension to learn what makes us tick.”