Myopia is near-sightedness. It is a fairly common medical condition, and in recent years it has been appearing with increasing frequency in industrialized nations. It is not lethal, except to the extent it may be increasing the number of motor vehicle accidents on our perpetually crowded roads. It is not truly disabling, except for those individuals who develop crippling headaches in association with their compromised vision and those who need exceedingly clear and precise vision for their work. Myopia is treatable, although the surgical treatments are costly and carry some risk. What remains unanswered by those who treat this condition and for those burdened with this condition is why it is appearing more frequently in the general population than it did years ago.
In most cases, near-sightedness develops because the distance between the lens of the eye and the image perceiving tissue, the retina, is slightly greater than is optimal. The human eye is designed to see objects a few or more feet away from the face with the least effort. This means that light from remote scenes passing through the cornea, the transparent ‘windshield’ of the eye, and the lens, the ultimate focusing device in the eye, will land in focus on the retina with little or no adjustment of the lens. The lens has muscles around it that adjust the curvature, and therefore the focus, of the lens. [If this is giving you a headache, relax and read on].
People who are near-sighted generally have a structural defect that leaves remote objects out of focus and very near objects in focus. Glasses or surgical adjustments to the cornea can usually compensate for this problem. As with any medical condition, prevention is preferable to treatment. Prevention is only feasible when a cause is known.
There are many reasons for problems to develop in the human nervous system. The eyes are part of the nervous system and are developmentally and structurally part of the brain. Brain development and final structure may be affected by diseases, such as viral or bacterial infections, acquired by the affected individual’s mother during pregnancy. Mumps can cause congenital deafness. Zika virus infections may limit brain formation in a fetus and produce microcephaly [small brain] or anencephaly [virtual absence of brain structures responsible for thinking]. Alternatively, malnutrition and environmental poisons (e.g., lead) may affect the normal growth and development of nervous system structures. Genetic causes of eye and brain problems are being identified with greater frequency every year, but none of these causes of nervous system disturbance has been linked to the evolving myopia epidemic. Of course, the fundamental problem may quite literally be right in front of our eyes. If you are reading this material on a computer or on a cell phone, you may be staring at the source of the problem.
Over the past few decades, children have relied upon cellphones and computers for many of their activities throughout the day. Children in industrialized countries are spending much of the day staring at computer and phone screens that are barely an arm’s length away from their faces. The developing nervous system tries to adjust to challenges its environment imposes. If it is burdened much of the day with resolving images that are 20 inches, rather than 20 feet, away, it may undergo changes in the visual equipment, including the eyes, that make this feasible.
What is obvious may not be what is accurate. This has been a recurrent theme in medicine for centuries. One notable, but unfortunate, case involved Dr. John Hunter, a distinguished English surgeon whose patients included King George III. In 1767, Dr. Hunter decided to determine whether gonorrhea and syphilis were different manifestations of the same disease or two distinct venereal infections. He took discharge from the penis of a man with typical symptoms of gonorrhea and rubbed the discharge into puncture wounds he made on his own penis. [Yes, doctors did weird things even back then.] Within days he developed unambiguous signs of gonorrhea and shortly thereafter exhibited the disfiguring skin lesions, called gummas, of syphilis. He concluded these two diseases were obviously just two stages of one disease. His logic was unassailable. His conclusion was wrong. The man he got pus from had both gonorrhea and syphilis, two very different diseases. [And the good doctor died from the syphilis he gave himself.]
Myopia may be a consequence of any one of dozens of recent environmental changes. The international spread of cellphone use is an attractive explanation for our increasingly myopic population, but perhaps the inciting agent is a virus spreading undetected amongst us because it does not kill or otherwise disable. Perhaps it is one of the innumerable agents routinely added to our food and beverages. Perhaps it is a toxin accumulating in our ever more polluted air and oceans. What is more likely than not is that this problem is, like John Hunter’s venereal diseases, self-inflicted.
Dr. Lechtenberg is an Easton resident who graduated from Tufts University and Tufts Medical School in Massachusetts and subsequently trained at The Mount Sinai Hospital and Columbia-Presbyterian Medical Center in Manhattan. He worked as a neurologist at several New York Hospitals, including Kings County and The Long Island College Hospital, while maintaining a private practice, teaching at SUNY Downstate Medical School, and publishing 15 books on a variety of medical topics. He worked in drug development in the U.S., as well as in England, Germany, and France.
