Can you tell the difference between "hyperopia" and "hyperopia reserve"? This article tells you the difference!

In outpatient clinics, many parents are very concerned about their children's hyperopia reserves, but they don't know much about "hyperopia". What is the difference between these two concepts that sound very similar?

Hyperopia is defined as a refractive state in which parallel light rays pass through the eye's refractive system and focus behind the retina when the eye is in a relaxed state. Children are generally hyperopic when they are just born. Under normal circumstances, the refractive power is about +2.50~+3.00 D, which is physiological hyperopia, also known as "hyperopia reserve".

As the child grows and develops, the hyperopia gradually decreases and generally develops into emmetropia (refractive power between -0.50 and +0.50 D) at around 12 to 15 years old. This process is called emmetropization.

The range of normal hyperopia reserve varies with age. Under normal circumstances, the hyperopia reserve is about +2.50 D at 3 years old, about +2.00 D at 5 years old, about +1.50 D at 6 years old, and about +1.00 D at 8 years old. If the hyperopia reserve is lower than the normal range, it is very easy to develop into myopia; if the hyperopia reserve exceeds the upper limit of the hyperopia reserve for the corresponding age, you should pay attention to whether the child has hyperopia.

Experts from Hunan Provincial People's Hospital said that unlike myopia, hyperopia requires extra adjustment ability whether looking far or near, and a greater amount of adjustment is required when looking close:

1) When the degree of hyperopia is low and the age is young, the hyperopic person can use his or her extra accommodation ability to focus light on the retina, thereby achieving clear distance and near vision.

However, due to frequent and excessive use of accommodation, hyperopia is prone to visual fatigue. And as people age, the range of accommodation of the human eye will gradually decrease, and the part of hyperopia that was previously compensated by self-accommodation will gradually be exposed, and then more visual problems will appear, such as decreased reading ability, eye pain, headache, etc.

2) If the degree of hyperopia is high and is not properly corrected before the age of 6, it may cause amblyopia. This type of amblyopia can be detected and completely corrected early through examination, and appropriate visual training can achieve good treatment results.

3) Hyperopia without refractive correction can also easily lead to esotropia. In order to obtain clear vision, accommodation is used when looking at far objects, and more accommodation is used when looking at near objects, which then leads to esotropia or internal strabismus. If the internal strabismus persists, strabismic amblyopia will also occur.

Therefore, an appropriate amount of hyperopia refractive power is beneficial to the prevention and control of myopia, while excessive hyperopia refractive power will bring other visual problems.

It should be noted that the measurement of hyperopic reserve and hyperopic refraction needs to be performed under paralysis of the ciliary muscle, which is commonly known as "mydriasis optometry."

The computer or manual optometry results under the pupil are only used as screening judgments and are not enough to reflect the child's true hyperopia reserve and hyperopia level. For children who may have abnormal refractive screening, further diagnosis is required in hospitals and professional optometry institutions before corresponding treatment can be carried out.

Hunan Medical Chat Special Author: Guo Yingzhuo, Eye and Optometry Center, Hunan Provincial People's Hospital

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(Edited by YT)