Eye Ache

I received several queries on my statement last week that “Technically, long sighted people may also have difficulty seeing distance and near clearly especially if well above the age of forty!” Some thought I had made a mistake. “Isn’t it a well known fact that long-sighted people can see distance clearly and have problems only with near?” asked John, a law student.

“It is very simple” I said. “For an object at a distance to be seen clearly, the rays of light from that object must fall on the retina (the inner photographic coat of the eye). In a short-sighted person, the rays fall short of the retina (anteriorly) and behind the retina (posteriorly) in a long-sighted person. So in both cases the image of a far object is blurred.”

“How then can a long-sighted person see distance clearly?” he asked again? “There is what is called “accommodation.” This is an active process causing an alteration in the shape of the natural lens inside the eye thereby making it possible for rays of light falling behind the retina to be focused on the retina. A long-sighted person employing his accommodation will bring the rays of light which is behind the retina to focus on the retina and the object is thus seen clearly.”

“Now imagine the same process happening to the rays of light in front of the eye in a short-sighted person. The rays of light will move farther away in front of the retina and the vision becomes more blurred. So, the short-sighted person learns that using his accommodation makes his vision worse and and as a rule avoids using it. The long-sighted person benefits from it and uses it regularly.

“Young people have tremendous amount of accommodation in reserve and they may use it successfully for clarity of distance vision. Their reserve may also provide the additional effort needed for reading and other tasks at near.

“Unfortunately, the more above 40 years you are, the lower your ability to accommodate and therefore distance vision tends to be blurred in the long-sighted patients well above the age of forty.

But accommodation is not supposed to be used for distant vision. It is meant for near work such as reading, sewing etc.” “Therefore the long-sighted person gets tired using his accommodation for a distance when he shouldn’t. When he has to do close work such as reading, the muscles of accommodation are already tired and they relax off and on to take a rest leading to intermittent blurring of near vision. It is like you are running when you are supposed to be sitting down. When you are now supposed to be running, you are already tired and out!”

“The constant and unconscious attempts by the long-sighted person to see clearly at distance and near result in eye strain and subsequent eye ache. This eye ache may be quite intense and tends to occur towards the close of the day. Usually there are no visible signs in the eye. It is persistent and will not go away until appropriate glasses are prescribed.” Since accommodation diminishes with age, it is therefore obvious that there is need for a change of glasses to take care of the increasing loss of accommodation which occurs with age.”

“Are there any other causes of eye ache?” asked John again. “Yes. Most are due to fatigue caused by tiredness, concentrated gaze (at a computer or television screen) in the near or intermediate distance even in those without any need for glasses. Excessive intake of alcohol and drinks containing stimulants, such as caffeine, can lead to impairment of accommodation and eye ache.

Eye ache is best resolved by discontinuing whatever activity you are engaged in and resting your eyes for between five and 10 minutes every hour; looking away into the distance at a non specific point, or by closing the eyes for five minutes every hour to rest them. Sleep, no matter how short, is also useful. Basically part of your body is tired, do what you would do normally if you were feeling tired.