Can you also see this kind of "little flying insect"?

When you put down your phone, stretch your cervical spine, and look up at the blue sky and white clouds, what kind of picture do you see?

Image source: Nitu.com

Do you see these little curved white lines or black dots floating around like little flies? Are we all the chosen ones who can see cells directly without a microscope? !

In fact, this is not a special ability. Many people have it - floaters .

01 Where do “little flying insects” come from?

In fact, those flying things are not small insects, but cloudy substances in the vitreous body of the eye.

The vitreous body is located in the center of the eye and fills most of the space inside the eye. It is not real glass, but it is pure and transparent, hence the name. More than 98% of the vitreous body is water, and the remaining 2% is mainly collagen and hyaluronic acid . Don't underestimate this 2%, it can firmly lock the 98% of water.

Collagen builds a three-dimensional grid with a lot of hyaluronic acid attached to it. Hyaluronic acid - or perhaps you prefer to call it "hyaluronic acid" - has excellent water-collecting and moisturizing capabilities, which also makes it infinitely shining in the field of cosmetics and medical beauty.

The strong grid structure composed of collagen and hyaluronic acid allows the vitreous body, which is full of water, to change from liquid to gel. Just like jelly, duang~duang~.

Image source: NetEase Unfortunately, the vitreous body is not easy to regenerate.

Starting from the age of 4 , due to the gradual depletion of hyaluronic acid, water and collagen will gradually separate, the reticular structure will collapse , and the gel form of the vitreous will gradually liquefy.

Transition between the gel state and the liquefied state of the vitreous body Source: Tencent Medical Dictionary

About 20% of the volume of the vitreous body of adolescents will liquefy, while it can reach more than 50% in the elderly. This is an inevitable "breakup" between water and collagen, which is determined by time.

When the vitreous body liquefies, opaque proteins or other impurities often precipitate out - turbid substances that are either thread-like, flocculent, or have small black spots, which is what we often call vitreous opacities .

Vitreous opacities and floaters

Image source: Tencent Medical Dictionary These turbid substances are scattered throughout the vitreous body. When the external light is bright, such as when looking at the sky or a white wall, they will cast a tiny shadow on the retina of our fundus, which looks like small flying insects of various shapes. This is the cause of floaters.

02Who will have floaters?

In fact, most cases of floaters, or clouding of the vitreous, are normal. They develop slowly, do not affect vision, and are particularly common in two groups of people:

One category is middle-aged and elderly people . With age, vitreous liquefaction and opacity will gradually become obvious. The other category is myopic people . Due to the elongation of the eye axis and the collapse of collagen fibers, vitreous opacities will occur more frequently and earlier than normal people. Moreover, the higher the degree, the more severe the vitreous liquefaction will tend to be.

Image source: sohu.com However, some special types of floaters are "pests" that require our high attention.

1. The number of floaters suddenly increases and becomes larger in a short period of time;

2. The floaters occupy too large an area, and even block your view of things;

3. Floaters are accompanied by frequent flashes of light;

4. Floaters affect vision.

These situations indicate that pathological turbidity has occurred in the vitreous body (such as the mixing of "bad bugs" such as pigment cells and blood), which may mean the occurrence of diseases such as vitreous hemorrhage or retinal tears , and you need to go to the hospital immediately for medical treatment.

Vitreous hemorrhage and visual obstruction Source: Tencent Medical Dictionary

03Can floaters be treated?

Generally speaking, physiological floaters do not require treatment , and there is currently no specific medicine to treat them. Some invasive surgeries or lasers may have certain therapeutic effects, but they often do more harm than good and have not actually been widely used.

Instead of excessive intervention, what we need to do is to maintain eye hygiene and avoid eye fatigue; have regular physical examinations and do a good job in myopia prevention and control.

Image source: The Paper

In clinical work, we often find that some patients who have undergone eye surgery (especially cataract surgery or myopia surgery) will tell their doctors that their floaters have worsened after surgery. In fact, these floaters are still there and have not changed. It's just that their visual quality has been greatly improved, so they pay more attention and carefully observe every detail of this colorful world.

The next time you notice these "little flies" floating around, you will know that they will not affect anything and will not fly out to bite you. Try not to look at them deliberately and learn to coexist with them.

Of course, except when you are slacking off.

Author: Shu Lian, resident physician at the Eye, Ear, Nose and Throat Hospital of Fudan University Editor: rain