Farsightedness (hypermetropia): causes, vision testing and correction in Tashkent

What happens to focus?

For a person to see clearly, the image must be collected exactly on the retina. With farsightedness, the optical system of the eye refracts light weaker than necessary for its length, and the focal point moves beyond the retina. The reason is almost always anatomical: the anteroposterior axis of the eye is shorter than the average, sometimes by only one or two millimeters, but for optics this is a lot. Less commonly, it is a matter of weak curvature of the cornea or the characteristics of the lens. In order to still see sharply, the eye tenses the ciliary muscle and makes the lens more convex - this mechanism is called accommodation. This is why a young man with a plus of up to two or three diopters is often completely unaware of his peculiarity: he pays for good vision with constant muscle tension, and not with a blurry picture.

• Weak hypermetropia - up to approximately +2.0 diopters; at a young age it is often completely hidden by accommodation
• Average - from +2.0 to +5.0 diopters; Close work gets tiring already at 20-30 years old
• High - above +5.0 diopters; vision suffers both near and far, glasses are constantly needed
• The obvious part of hypermetropia is what is visible during a routine vision test.
• The hidden, latent part is dioptres, which are compensated by a tense muscle; they are discovered only after drops

Farsightedness and presbyopia are not the same thing

The word “farsightedness” in everyday life is applied to two different conditions at once, and this gives rise to endless confusion. Hypermetropia is a congenital feature of the structure of the eye: it is short, and this value is generally stable throughout life. Presbyopia is an age-related hardening of the lens: it loses elasticity and stops changing shape, so focusing at close range becomes weaker. Presbyopia develops in absolutely everyone after 40-45 years, including myopic people and those who have had perfect vision all their lives.

• Hypermetropia is present from birth; Presbyopia appears after 40 years of age and increases until approximately 60-65 years of age, and then stabilizes
• With hypermetropia, the problem is the length of the eye; with presbyopia, the problem is the stiffness of the lens.
• A farsighted person encounters presbyopia earlier, sometimes already at the age of 38-40: his accommodation reserve has been spent all his life on compensating for the plus
• A nearsighted person notices presbyopia later, and with a slight disadvantage he can read by simply removing his glasses
• With hyperopia, glasses for distance and near are different in strength; with isolated presbyopia, glasses are needed only for close distances

Farsightedness in children: when plus is the norm

Almost all children are born farsighted, and this is physiological. A newborn has a short eyeball, the reserve is approximately +2.0 to +3.5 diopters. As the eye grows, it lengthens, and by the age of 6-8 years, hypermetropia usually decreases to small amounts - this process is called emmetropization. Therefore, the entry “+1.5 diopters” in the chart of a five-year-old child most often does not mean a disease, but a normal stage of development that simply needs to be observed. The problem begins when the plus is significantly higher than the age norm, differs greatly in two eyes, or is accompanied by strabismus.

This leads to an important practical conclusion for parents: the number on the form by itself does not solve anything. The same result “+2.0 diopters” in a three-year-old child is a variant of the norm, but in a nine-year-old child this is already a reason for correction. The doctor looks at three things at once: whether the refraction is age-appropriate, what the visual acuity of each eye is, and whether the eye is abnormal. Only the combination of these data determines whether glasses are needed, and that is why the decision cannot be made on one line from an automatic instrument in the optics.

• Plus, it is noticeably higher than the age norm - the child has to constantly overstrain accommodation, and the brain gets used to the unclear image
• The difference between the eyes is more than 1.0-1.5 diopters: the brain begins to suppress the image from the weaker eye
• Convergent strabismus - with farsightedness, excessive stress of accommodation causes the eyes to move inward
• Visual acuity does not improve even with correctly selected glasses - this is amblyopia
• Complaints of headache, refusal to draw, books and small games, habit of bending low to the page

How does it feel in adults?

In adults, farsightedness rarely appears as just a blurry picture. Much more often, this is a set of complaints that a person attributes to fatigue, screens, lack of sleep or blood pressure. The key sign is that discomfort increases towards the end of the day and after close work, and after a weekend or vacation it becomes noticeably easier. Doctors call this complex accommodative asthenopia.

• Headache in the forehead and brow ridges after reading, documents, needlework, telephone
• Rapid eye fatigue, feeling of sand, burning, desire to rub the eyes
• The text blurs after 10-20 minutes of reading, the letters begin to merge
• The habit of moving a book or phone further away and enlarging the font
• Redness of the eyes and eyelid margins, sometimes recurring styes and blepharitis
• Deterioration of vision in poor lighting and at the end of the working day
• After 40 years - gradual deterioration of vision and distance vision too

There is another scenario that often leads astray. Constant overstrain of accommodation leads to its spasm: the muscle ceases to fully relax, and distance vision temporarily deteriorates. A person comes to the doctor with a complaint of “sudden myopia”, receives minus glasses, and from them it only gets worse. The correct answer here is given by a study with drops: it shows that behind the imaginary minus there is an uncorrected plus. That is why, when blurriness first appears in young people, one cannot limit oneself to the readings of an automatic device.

Examination: why drops are needed

1. Визометрия — проверка остроты зрения вдаль и вблизи, с коррекцией и без неё.
2. Авторефрактометрия — прибор быстро оценивает рефракцию, но у молодых пациентов почти всегда занижает истинный плюс.
3. Рефрактометрия в условиях циклоплегии: капли временно выключают аккомодацию и показывают настоящую рефракцию. Детям и подросткам этот этап обязателен, взрослым до 35-40 лет он тоже часто нужен.
4. Подбор очковой коррекции с проверкой переносимости: при высокой гиперметропии полную силу иногда дают не сразу.
5. Осмотр глазного дна с расширенным зрачком — оценка диска зрительного нерва и сетчатки.
6. Измерение внутриглазного давления и оценка передней камеры, особенно при высокой гиперметропии и после 40 лет.
7. Кератометрия, биометрия и топография роговицы — при планировании лазерной коррекции или замены хрусталика.

Correction and the main myth about glasses

The goal of correction for farsightedness is not to “make the eye work,” but, on the contrary, to remove excess load from it. The plus lens takes on that part of the work that the ciliary muscle would otherwise do, and the tension goes away along with the headache.

• Glasses are the basic method. With a small plus, adults are sometimes prescribed glasses only for near vision; with a larger benefit, they are prescribed glasses for constant wear. After 40-45 years, progressive or bifocal lenses are convenient.
• Contact lenses - suitable for any degree, provide a wider field of vision without distortion at the edges; There are multifocal options for near work.
• Laser correction - for hyperopia, it is performed, usually approximately up to +4.0-+5.0 diopters, with stable refraction, usually from the age of 18 and only after a complete examination of the cornea.
• Replacing your own lens with an artificial one is discussed after 45-50 years, especially with high hypermetropia and incipient cataracts; Modern lens models can simultaneously solve the problem of near vision.
• For children, only glasses or contact lenses: laser correction is not performed in childhood, because the eye continues to grow.

Now about the most persistent myth. The statement “glasses spoil vision” is not confirmed by anything other than a subjective feeling. It arises due to a simple effect: a person, accustomed to a clear picture, takes off his glasses and acutely notices the blur to which he had previously become accustomed. The refraction itself does not change - the optics of the eye does not depend on whether you wear glasses or not. In children, everything is exactly the opposite: refusal of glasses with significant farsightedness leads to amblyopia and strabismus, and it is extremely difficult to correct amblyopia after 8-9 years. Gymnastics instead of glasses, hardware courses instead of correction and blueberry supplements do not work in the same way: they do not change the length of the eyeball.