Near-sightedness (myopia)
Have you ever felt it is harder for you to recognise people or objects located at a certain distance away or that you see them less clearly? And that, on the other hand, if you read a book, your vision does not cause you any problems?
If so, we recommend that you visit an ophthalmologist for a check-up as soon as possible and take an eye test there, as you may be near-sighted.
What is near-sightedness?
The term near-sightedness (known by the medical term myopia) is used to refer to the congenital or acquired refractive error of one or both eyes. Near-sighted people see more distant objects as indistinct and blurry, but recognise nearby objects without any effort.
Near-sightedness can be compensated for or corrected relatively easily by wearing glasses or contact lenses and rarely requires an operation. Near-sightedness is measured in dioptres.
Symptoms
People with near-sightedness therefore often encounter the following difficulties in their everyday lives:
Faces and people, for example on the opposite side of the road, are not recognised until later, and it is difficult to read street names or display panels. At school, at university or in the context of advanced training, it is no longer possible to read or decipher texts projected onto the board or wall correctly. In the outdoors, near-sighted people recognise trees very well, but no longer their individual leaves or branches. In many cases, the first signs of near-sightedness are noticeable by the fact that the text on billboards, road signs or car number plates a greater distance away is much harder to read than is the case for ‘normal-sighted people’.
A typical characteristic of near-sightedness is also the squinting of the eyes when looking into the distance. This squeezing of the eyelids reduces the size of the pupil, which in turn increases the depth of field, which at that moment can minimally improve vision. By squeezing the eyelids, an attempt is made to compensate for the lack of vision; however, this usually only succeeds rarely or has no noticeable success. The resulting ‘blind face’ (derived from the Greek word ‘myops’) also gave near-sightedness its medical term: myopia.
Causes
There are basically two medically recognised causes of myopia:
Either the eyeball is too long (known as axial myopia) or the refractive value of the eye lens is too high (known as refractive myopia). For some people, both are true. The consequences for the eye – and therefore for vision – are the same in both cases: the eye cannot focus properly, the seen images are only perceived blurred as or distorted. The latter happens because the light rays coming from a distance converge before they reach the retina in short-sighted people. In ‘normal-sighted’ people, on the other hand, rays of light converge precisely on the retina, resulting in a sharp image.
Other causes
It is interesting to know that near-sightedness is often inherited. If both parents are near-sighted, the risk of their children also becoming near-sighted is 60%. General living conditions also have a further influence on the deterioration of vision: excessive close-up work promotes the development of myopia. This includes not only reading books and newspapers, but also intensive use of smartphones and tablets.
Conversely, relevant studies show that children become less near-sighted the longer they spend outdoors during the day. This is because the ‘happiness hormone’ dopamine, which – stimulated by daylight – is increasingly released from the retina, also has a positive effect on vision.
Diagnosis
An ophthalmologist’s diagnosis of myopia is generally quick, uncomplicated and pain-free: an eye test is used to examine how well the eyes can see into the distance (= far-distance vision) or close by (= near-distance vision).
Patients have to recognise and describe letters or characters of different sizes that are projected onto a further-away wall with one eye. This makes it easy to determine whether a person is near-sighted and, if so, how severe it is.
Treatments
As a general rule: near-sightedness cannot be cured.
However, existing myopia can be easily compensated for and corrected by wearing a suitable visual aid in the form of glasses or contact lenses.
It is now known that wearing night lenses can stop near-sightedness in adolescence.
The elimination of near-sightedness using laser eye treatment is becoming increasingly important and popular.
If near-sightedness is compensated for with the help of glasses or contact lenses, diverging lenses with a negative refractive value (the unit of measure of refractive value: dioptre, abbreviated dpt) are used. These lenses (also known as minus lenses) shift the point at which distant objects form a sharp image, so that it is again directly projected on the retina. Minus lenses are slightly thicker at the edge than in the middle (= concave), but thanks to modern technology, they can now be polished very thinly.
Severely near-sighted people should have their eyes examined once a year. From a lens thickness of -6 dpt, your risk of serious eye diseases such as cataracts, glaucoma or even retinal detachment increases considerably.
Aftercare
If you have been diagnosed with near-sightedness, it is important and essential that you consult your ophthalmologist at regular intervals and have your eyes examined. The ophthalmologist needs to check whether your near-sightedness has remained the same or whether your vision has deteriorated further and therefore it is necessary to adjust your glasses and/or contact lenses to the corresponding dioptre value.
Talk to your ophthalmologist – he or she will tell you how often or at what intervals you should see him or her.
FAQs
What is the difference between near-sightedness and far-sightedness?
People with near-sightedness have good vision close by and out-of-focus in the distance, whereas those with far-sightedness usually have good vision both at a distance and close by. However, for this ‘good near-distance vision’, they have to put a lot of strain on their inner eye muscles, which tires them over the long term. In cases of severe far-sightedness (known by the medical term hyperopia), sharp vision in the near-distance is no longer possible without aids.
If someone finds it difficult to see both near and far objects in sharp focus, then varifocal glasses may be the tool of choice: Thanks to their two fields of vision, they can correct several visual disturbances at the same time and even corneal irregularity. Without these glasses, affected persons would otherwise have to constantly switch between reading glasses and standard glasses. And because the transition between the two fields of vision of varifocal glasses is gradual, you can also see sharply and clearly in the middle distances.
What about near-sightedness in children?
By the end of nursery years, most children are still normal-sighted or slightly far-sighted. Short-sightedness in children often only occurs after starting school (= school-age myopia), usually becoming noticeable between the ages of 8 and 15. The sooner it starts, the higher the values that are usually reached. Beyond the age of 20, near-sightedness usually progresses much more slowly; at the age of 30, it usually stops progressing completely.
What happens if a near-sighted adult does not want to wear glasses or contact lenses?
Although choosing not to wear glasses (or contact lenses) is not fundamentally harmful for adult eyes, it is sometimes quite exhausting. This can result in unpleasant accompanying symptoms such as head and neck pain, burning eyes, double vision or watery eyes. As an alternative, laser eye treatment could be used to correct the refractive error so that someone no longer has to wear glasses or contact lenses afterwards.
