The word 'pandemic' has taken on a special meaning in recent months. But, beyond the omnipresent covid-19, in our environment, other pandemics are being generated, much more silently, that devastate us without our often being aware of it. This is the case of myopia: according to the results of a report published by the Holden Vision Institute Brien, one of the most prestigious ophthalmological institutions in the United States, half of the world's population, about 5 billion people could become myopia in 2050. It is not surprising, therefore, that visual health professionals are already beginning to speak of it as one of the pandemics of the 21st century. A pandemic that, in addition, seems to be affecting young people to a greater extent, as has been confirmed among the youth of China, Singapore and other Asian countries.
Now, do we know what myopia really is? "It is a refractive defect that causes the eye not to be able to focus on distant objects," explains Dr. Nabil Ragaei Kamel, head of the Ophthalmology Service at the Quirónsalud San José Hospital. As a consequence, he adds, “distant vision is blurred, while maintaining the near vision. For this reason, the myopic is also defined as 'short-sighted'.
This difficulty in focusing on distant objects is the key, and it gives us a clue to understand why there are more and more cases of myopia. Let's think that human vision is not designed for short distances (our ancestors looked far away to hunt and to distinguish the fruits on the trees), but in recent decades we have begun to force short vision: we passed many hours a day at a computer and, what is more worrying, more and more time in front of the small screen of a mobile.
Myopia advances because, basically, our eyes are not prepared for the visual needs that we currently require in near vision. “The most recent studies – underlines the specialist – lead us to think that the use of mobile phones and tablets from a very young age, as well as the increase in academic demand at an early age, could cause an increase in myopia”. Not only do our eyes have to be making constant accommodative efforts to see up close, but also fewer and fewer outdoor activities are being enjoyed. “Especially now, given the extraordinary situation we are experiencing due to the appearance of covid-19, the use of mobile devices and screens has increased even more. They are used for study, work and entertainment ”.
Until recently, when faced with a myopic subject, most of the guidelines were limited to a tight optical correction: glasses, contact lenses, refractive surgery … monitor the progression in time, but without being able to do anything to slow it down. But the situation has changed, explains the specialist: “Given the current data on the incidence and progression of myopia in our young people (and the greater risks of pathology associated with myopia depending on the increasing number of diopters), more and more studies and research in search of therapeutic possibilities that, in addition to correcting the refractive defect, also slow its progression ”.
In this sense, research shows the importance of the environment. “It seems that not only genetic inheritance influences the development of myopia, but also environmental conditions. It has been seen how up to six out of 10 children whose parents are myopic will develop myopia if they do not perform five minimum hours of outdoor activities”, Says the specialist. Although the cause why this happens is not yet clearly established, everything seems to indicate that there is a direct relationship with exposure to sunlight, although it could also be due to the fact that in an outdoor environment we need less accommodative effort so that the eye can focus well. The specialist's recommendation is that children do at least 15 hours of outdoor activities a week.
Another measure that is being investigated is the use of atropine drops. Studies with high scientific evidence show that the use of atropine (anticholinergic drug for topical ocular application) controls the progression of myopia. “Ophthalmologists use this drug, or some of its derivatives, to dilate the pupil and see the fundus of our patients, as well as to objectify real refractive errors. The problem is that, at the usual doses, they impede near vision and represent a disabling discomfort in the vision ”. However, it has been proven that atropine, at doses up to 100 times lower than that used in consultation, is effective in controlling the progression of myopia and does not generate these uncomfortable adverse effects.
The potential rebound effect after discontinuation over time is unclear, but it appears that at such low concentrations the potential for rebound in increased myopia seems irrelevant. "In any case, It is a treatment that must be prescribed and monitored by an ophthalmologist”.
There are two other measures that Dr. Ragaei highlights:
- First, the orthokeratology (Ortho-K). "It consists of wearing rigid gas-permeable contact lenses at night. A double effect is pursued: on the one hand, its technology induces a corneal molding during sleep that makes it possible for the patient to remove the lens when they get up. see well without glasses or contact lenses for at least the next 12-15 hours (based on previous graduation). On the other hand, it can make myopia progress between 40% and 50% less than if conventional glasses or contact lenses are used. "That is, if what is expected in a specific case was that myopia increased by around one diopter per year, it could be achieved that it only increased 0.50 diopters in the same period.
- Another option are peripheral blur soft contact lenses. “There are already several published studies that state that, using this type of lens, the progression of myopia was 59% less than in the control group that did not use them. Also, these contact lenses are approved by the American Drug Agency (FDA) for their use in controlling the progression of myopia”. To achieve this effect, these lenses must be worn daily for at least 10 hours.
The advantages of surgery
However, if we want to end myopia definitively, the best option is surgical, that is, correct it using refractive surgery or Lasik technique. “Laser surgery,” explains Dr. Ragaei, “modifies the shape of the cornea to restore correct vision to the patient. Eliminate the use of glasses and contact lenses permanently ”.
The technique consists of intervene on the stroma, one of the layers of the cornea. “We create in it something similar to a pocket, as if it were an envelope. This 'pocket' can be done in two ways: with a microkeratome or with a femtosecond laser; We thus expose the stroma, where the excimer laser 'evaporates' the tissue. The amount of tissue evaporated will depend on the number of diopters, and the location of the tissue will depend on whether we are myopic, hyperopic or have astigmatism ”.
It is a procedure that is performed under topical anesthesia and lasts approximately 10 minutes. In the afternoon, the patient should be at home with his eyes closed so that the 'pocket' made remains in position. Although in the first hours a sensation of grit or dry eye may be noticed, the main advantage of this technique is that the next day the patient can lead a practically normal life, with a vision close to 100%. After surgery, a treatment with antibiotics and anti-inflammatories is necessary for a week. “It is very important to follow the protocol explained in consultation to the letter, since the most serious complication in any surgery is infection. In addition, the patient must also use artificial tears and sunglasses to avoid dryness, which is typical of this procedure ”. Finally, full recovery will come in three months.
In short, it is proven that myopia is a global health problem that we must tackle; Fortunately, thanks to the advances of professionals, we now have tools that a few years ago were unthinkable and that, in the hands of highly specialized personnel, they can help alleviate it.
* El Confidencial, in collaboration with Quirónsalud, presents a series of articles with practical information, advice and recommendations for practicing sports that improve our health and well-being. If you have any questions about this topic or want more information, you can contact the Quirónsalud San José Hospital.