Hyperopia (farsightedness)

Japanese: 遠視 - えんし（英語表記）Hyperopia (farsightedness)

What is the disease?

The light that enters the eye cornea ( Hide )・Crystalline crystalline lens ( Invitation ) Passing through, retina ( Also well ) In normal vision, the light is focused on the retina, but in hyperopia, the depth of the eye ( Eye axis ( Hard work ) ) is often short, so the focus is behind the retina (Figure 72).

Hyperopia is often mistaken for "good eyes that can see far away," but in terms of the refractive state of the eye, it is actually unable to focus on either far or near objects. However, the eye has a function called "accommodation" that increases the thickness of the crystalline lens, which acts as a lens, and shifts the position where the image is formed, so when we are young, we can see both far and near (Figure 73).

However, as the ability to "accommodate" weakens with age, it becomes gradually harder to focus and it becomes more difficult to see things up close, which requires more "accommodation." People with hyperopia have more accommodative power than people with normal vision or myopia, which is why people often say, "I had good eyesight when I was young, so I developed presbyopia early."

The approximate incidence of hyperopia is 100% in newborns, 60-70% in toddlers, 50% in elementary school students, 20% in junior high school students, and 15% in high school students, and then gradually decreases. In elderly people, hyperopia can return to myopia or hyperopia due to age-related changes in the crystalline lens.

How symptoms manifest

With farsightedness, the eyes have to constantly "adjust" when looking, which can lead to: 1) eye fatigue Eye strain ( Cancer Discovery ) ), 2) headaches and eye pain, and 3) lack of concentration. In children, the tendency for the eyes to move together is strong when adjusting the vision. Esotropia ( Notice ) This is called accommodative esotropia.

The type of hyperopia that requires the most attention is severe hyperopia in children. When hyperopia becomes severe, it becomes difficult to focus even with adjustments, so vision does not develop and, if left untreated, it can lead to amblyopia.

Treatment methods

Farsightedness can be corrected with glasses or contact lenses. People who work long hours at close range, such as in an office or computer, are particularly susceptible to eye strain caused by accommodation, so wearing glasses for close-up work can help alleviate symptoms, regardless of age.

Children with accommodative esotropia can have their esotropia treated with appropriate eyeglasses. Amblyopia ( Pole ) Even in children with severe hyperopia, who may develop glaucoma, the development of vision can be promoted by showing them clearly focused images through the early wearing of appropriate glasses.

Sayuri Ninomiya

Figure 72 Hyperopia
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Figure 72 Hyperopia

Figure 73. Focus adjustment
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Figure 73. Focus adjustment

Source: Houken “Sixth Edition Family Medicine Encyclopedia” Information about the Sixth Edition Family Medicine Encyclopedia

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