Memory woes? Check your eyes

Can't recall a name? Keep drawing a blank on where you put the keys? Is it getting more difficult by the year to get a decent night's sleep?

Such common symptoms of aging, or at least the degrees to which we must suffer them, have been chalked up to obesity, high cholesterol, and a few other factors by scores of correlative studies and medical experts.

Now you can blame it on the eyes.

As eyes age gradually the lens yellows and pupil narrows, disrupting the body's circadian rhythms, controlled by the body's internal clock. The body's 24-hour clock is not dependent on environmental cues, but depends instead on internal, biochemical changes which affect physical, mental, and behavioral aspects. Even microbes and plants have these biochemical rhythms. The study of circadian rhythms is called chronobiology.

Getting back to eyes, doctors at the University of Kansas School of Medicine found that the role of light in aging is bigger than once realized, and that the eyes have a bigger role in circadian rhythms. Photoreceptive cells in the retina (more than the previously known rods and cones) absorb sunlight and transmit messages to the part of the brain which governs the internal clock and initiates the release of the hormone melatonin in the evening and cortisol in the morning. Improper levels of melatonin and cortisol have been linked to many health problems.

As eyes age, less light gets through to the retina. Resulting biochemical problems aren't restricted to the aging population; shift workers and others whose rhythms are out of sync also tend more to have problems with insomnia, cancer, and heart disease. Another unexpected question raised by the new research involves the levels of blue light, which is filtered by the eye's aging lens.

Blue light is found in most electronic gadgets and energy-efficient light bulbs. This adds to the general concern over significant eye strain added by society's ever-increasing use of computers, phone screens, and tablets.

Wish I'd never let go of that typewriter.

In a study published in The British Journal of Ophthalmology, scientists estimated that by age 45, the photoreceptors of the average adult receive only half of the light needed to fully stimulate the circadian system. By age 55, it dips to 37 percent, and by age 75, to a mere 17 percent. European studies concluded similarly; one compared a group of women in their 20s to women in their 50s, finding the amount of light which caused the younger women to feel more alert, awake, happy and with better memory retention had no effect at all on the older group.

So if we need more light, what's wrong with getting it from all the gadgets? Different intensity and different part of the light spectrum. Old-fashioned sunlight is what the body needs, say the Kansas Medical School researchers, who installed skylights in their offices after concluding their research.

Is it summer yet?

Sholeh Patrick is something of a confessed Luddite and a columnist for the Hagadone News Network. Contact her at [email protected].