Skip to content

Diabetes Health Center

Font Size

Light at Night Protects Diabetics' Eyes

Sleeping With the Lights On Could Prevent Retinopathy
By
WebMD Health News

June 27, 2002 -- An illuminating theory may lead to a simple way to prevent a common cause of blindness among diabetics. Researchers from the U.K. suggest that a condition known as diabetic retinopathy might be avoided by sleeping with the lights on. But they add that more studies are needed to prove that their bright idea can actually save sight.

Some 17 million Americans have diabetes, and roughly a quarter are believed to have some degree of diabetic retinopathy. The condition occurs when tiny blood vessels in the retina -- in the back of the eye -- rupture, but the exact cause of these ruptures is not clearly understood.

In a study published in the June 29 issue of The Lancet, Cardiff University professor Neville Drasdo and colleagues offer direct evidence that diabetic retinopathy is caused by a lack of oxygen, occurring within the inner layers of the retina during darkness. Previous research has shown that oxygen levels in the retina of diabetics fall as the eyes adapt to dark.

The researchers tested the effect of breathing in 100% oxygen -- normal air is 21% oxygen -- on the eyes of seven people with type 2 diabetes and eight people without diabetes. The diabetics had the disease for an average of about seven years. None of the patients had been diagnosed with retinopathy, but they all had evidence of too little oxygen within the retina during darkness.

With high oxygen treatment, the eyes of the diabetic patients returned to normal.

Drasdo tells WebMD that the findings expand on earlier research indicating a link between a lack of oxygen and diabetic retinopathy. He also suggests that it's likely that the lack of oxygen is what is causing the increase in blood vessels in the eye -- thus the retinopathy.

The researchers suggest that sleeping with the lights on could prevent retinopathy in diabetics because light through closed eyelids suppresses the eyes' ability to adapt to the dark. Drasdo says the nighttime light therapy would have to be permanent because it takes up to two decades for retinopathy to develop in diabetics. And he adds that the long-term consequences of this preventive treatment are not known.

"We believe that those consequences, if they exist, will be far outweighed by the benefits, but we don't know that for certain," he says. "So we can't actually recommend that people try this just yet."

While calling the new research "fascinating," retinopathy expert William F. Mieler, MD, of Houston's Baylor College of Medicine, agrees that it is too soon for diabetics to turn on their nightlights. Mieler is a spokesman for the American Academy of Ophthalmology.

"This is just one study with a very small number of patients," he says. "It is possible that (a lack of oxygen) is just one of many factors that trigger the development of retinopathy."

Is This Normal? Get the Facts Fast!

Check Your Blood Sugar Level Now
What type of diabetes do you have?
Your gender:

Get the latest Diabetes newsletter delivered to your inbox!


or
Answer:
Low
0-69
Normal
70-130
High
131+

Your level is currently

If the level is below 70 or you are experiencing symptoms such as shaking, sweating or difficulty thinking, you will need to raise the number immediately. A quick solution is to eat a few pieces of hard candy or 1 tablespoon of sugar or honey. Recheck your numbers again in 15 minutes to see if the number has gone up. If not, repeat the steps above or call your doctor.

People who experience hypoglycemia several times in a week should call their health care provider. It's important to monitor your levels each day so you can make sure your numbers are within the range. If you are pregnant always consult with your health care provider.

Congratulations on taking steps to manage your health.

However, it's important to continue to track your numbers so that you can make lifestyle changes if needed. If you are pregnant always consult with your physician.

Your level is high if this reading was taken before eating. Aim for 70-130 before meals and less than 180 two hours after meals.

Even if your number is high, it's not too late for you to take control of your health and lower your blood sugar.

One of the first steps is to monitor your levels each day. If you are pregnant always consult with your physician.

Did You Know Your Lifestyle Choices
Affect Your Blood Sugar?

Use the Blood Glucose Tracker to monitor
how well you manage your blood sugar over time.

Get Started

This tool is not intended for women who are pregnant.

Start Over

Step:  of 

Today on WebMD

Diabetic tools
Symptoms, diagnosis, treatment, and more.
woman flexing muscles
10 strength training exercises.
 
Blood sugar test
12 practical tips.
Tom Hanks
Stars living with type 1 or type 2.
 
Woman serving fast food from window
Video
Can Vinegar Treat Diabetes
Video
 
Middle aged person
Tool
are battery operated toothbrushes really better
Video
 

Prediabetes How to Prevent Type 2 Diabetes
Article
type 2 diabetes
Slideshow
 
food fitness planner
Tool
Are You at Risk for Dupuytrens Contracture
Article