Why do we see colour with our eyes closed?

When we close our eyes, and drift towards sleep, mysterious patterns and blobs bedazzle the back of our eyelid. This is not an illusion but a real show of lights. It comes from under our own eye and appears as a geometric pattern as well as random spots of colour. When we rub our eyes, the lights suddenly intensify and bursts of bright colour appear all across our field of vision. A few seconds later, the colour settles down again. This phenomenon is known as phosphenes.

This is similar to fire fluids and to the glow of deep sea creatures. The cells within our eye emit biophotons or biologically produced light particles.

According to Istavan Bokkon, a Hungarian micro-scientist, who works at Vision Research Institute in Lowell, Massachusetts, “We see biophotonic light inside our eye in the same way we see photons from external light.” Biophotons exist in eye because atoms of the body constantly emit and absorb tiny particles of light or photons. This photon exchange is just part of a normal cellular function.

Our eye cannot tell the difference between photons from outside light and the biophotons emitted by our own atoms. It simply relays these light signals by the optic nerves to the brain which will then decide if it accurately represents the real world. The eye actually produces far more biophotons than we end up seeing as phosphenes. But, they are generally absorbed locally, says Istavan.

Inside the retina, millions of tiny cells called rod and cones collect light and convert it into electric signals. These signals travel through the optic nerves to a part of the brain called ‘visual cortex’. Here the brain reconstructs an image using the information received from the eye.

According to Istavan, any type of pressure on the eye can cause them to emit an
“excess biophoton.” Sneezing hard, getting whacked in the head and standing up too fast (causes a drop in blood pressure) are also ways to trigger phosphenes.

Only people who are blind by birth can never see phosphenes. But, people who lose their vision at a subsequent stage due to illness or injury usually do not lose all visual functions since phosphenes can originate in different parts of the visual system.

Theoretically, all blind people who could previously see can retain the ability to see phosphenes, explains the scientist.

Researchers are studying the ways to trigger phosphenes on blind patients to try and figure out ways to potentially restore their vision. This could prove helpful for visually-challenged people and enable them to see real images.
K S Someshwara

Weight gain possibly tied to later bedtimes

There may be a link between later bedtimes and weight gain, new research suggests. Researchers studied 3,342 adolescents starting in 1996, following them through 2009. At three points over the years, all reported their normal bedtimes, as well as information on fast food consumption, exercise and television time. The scientists calculated body mass index (BMI) at each interview.

After controlling for age, sex, race, ethnicity and socioeconomic status, the
researchers found that each hour later bedtime during the school or workweek was associated with about a two-point increase in BMI. The effect was apparent even among people who had a full eight hours of sleep, and neither TV time nor exercise contributed to the effect. But fast food consumption did.

The study, in the October issue of Sleep, raises questions, said the lead author,
Lauren D Asarnow, a graduate student at the University of California, Berkeley.“First, what is driving this relationship?” she said. “Is it metabolic changes that happen when you stay up late? And second, if we change sleep patterns, can we change eating behaviour and the course of weight change?”

The scientists acknowledge that their study had limitations. Their sleep data
depended on self-reports, and they did not have complete diet information or data on waist circumference.
Nicholas Bakalar