Asthenopia and Dry Eye

 1. What is asthenopia?

I am sure that most people have heard the term "asthenopia," but do you know what particular symptoms this condition entails?

So-called "eye strain" refers to fatigue of the eyes that can be remedied by taking a short rest or nap. If this becomes serious, the result will be "asthenopia," a condition that may cause symptoms such as pain in the eyes, hyperemia, blurred vision or impaired vision. In addition, other non-ocular symptoms may occur including headaches, stiffness in the neck and shoulders, stomach pain, changes in appetite and constipation. If the condition worsens further, adverse psychological effects may manifest themselves, developing, in some cases, into symptoms such as irritability, insecurity and depression. Although the terms "eye strain" and "asthenopia" may not conjure up images of serious illnesses, these conditions can give rise to all kinds of symptoms such as those listed above.

Some of this may strike a chord in people who sit in front of computers for hours at a time.

 2. Dry eye is one cause of asthenopia

One of the causes of asthenopia is so-called "dry eye.  In technical jargon, dry eye is "damage to the eyes caused by abnormalities in lachrymal secretion." In layman's terms, the condition is known as "dry eye," but what effects does a shortage of tears have on the eye? It is known that normally, 2 - 3ml of tears are secreted every day. Tears serve the following essential purposes:

  • Protection and prevention of drying of the surface of the eye
  • Supply of nutrition to the cornea (black iris)
  • Prevention of penetration of germs, dust and other substances

Tears are secreted from the lachrymal glands by the mechanism of blinking. However, when continually staring at a computer screen or watching television for prolonged periods of time, the number of times a person blinks decreases by about one quarter. In other words, the quantity of tears steadily decreases, with the result that the surface of the eye rapidly becomes dry.

 3. Important roles of tears

The 3-layer lachrymal film that covers the surface of the eye comprises an oil layer, a water layer and a mucin layer. The water layer accounts for 98% of this layer and is sandwiched between the oil and mucin layers. The lachrymal film is more than 7 microns thick. In the same way as a droplet of oil dropped into a cup, the oil layer forms a thin film to prevent heating of tears. The mucin layer fulfills the role of glue that adheres to the surface of the eye to prevent tears from running out of the eye. 

Worsening of the dry eye condition may result in pain in the eyes, inability to open the eyes and may lead to a condition known as recidivist detachment of the corneal epithelium. This is a frightening condition that may result in detachment of the dry cornea. 

However, dry eye is a condition that is difficult to spot by the sufferer him/herself. Since people wearing contact lenses in particular will not experience any accompanying pain, it often takes some time before subjective symptoms arise and prompt a visit to a hospital. People who find that their eyes easily become tired, or constantly suffer from symptoms such as a feeling of grittiness, heaviness or dryness in their eyes would be well advised to make an early visit to a hospital for a checkup.

Let's start taking good care of our eyes before these essential organs suffer damage.

 4. What can you do yourself to maintain healthy eyes?

Asthenopia and dry eye can both be avoided by exercising a little care on a daily basis.

Avoid continuous use of computers for prolonged periods of time. Take a 10-minute break every hour.

Engaging in prolonged work on a computer, delicate tasks or driving can cause dry eye by reducing the number of times you blink. Let's remember to take a 10-minute break every hour to close our eyes and relax, or do some moderate exercise.

Use of eye pillows and eye packs

Eye pillows have recently become commercially available and are in wide use. These pillows contain substances such as herbs and effectively promote relaxation. Eye packs can be easily applied at home. Have a warm and cold towel on hand and place the warm towel over the eyes for about 3 minutes. Next apply the cold towel for about 3 minutes. You will find that this really refreshes the eyes.

Try pressure point massages

This will improve blood circulation in and around the eyes.  Pressure points are located in areas such as the web between the thumb and forefinger, the temples, the back corners of the eyes and the middle of the eyebrows. Let's get into the habit of pressure point massages about twice a day, once during the day and once at night.

Use of eye drops and supplements

During regular breaks, try refreshing your eyes by using eye drops to prevent dry eye, or alleviate asthenopia, for example. These are all simple measures that can be carried out at home or at work. Let's remember to keep up these preventative measures so that we can enjoy the benefits of optimum eye health both in our private and professional lives.