Under what circumstances, it is not clear to the eye to see far and far with what power it adds

SPH stands for S:Spherical (power of nearsightedness or farsightedness) C:Cylindrical cylindrical (degree of astigmatism) AXS stands for A:

axls axis (the direction of astigmatism, if there is astigmatism, there is an axis).

1) The imaging principle of the human eye is the same as that of the camera, the lens is equivalent to the convex lens, the retina is equivalent to the film, and different objects near and far are imaged on the retina through the adjustment of the lens

2) When the object gets closer to the eye, the focal length of the lens also becomes smaller; When the object is farther away from the eye, or the focal length of the lens becomes larger; Always make a clear image on the retina

1) The imaging principle of the human eye is the same as that of the camera, the lens is equivalent to the convex lens, the retina is equivalent to the film, and the objects of different distances and distances are imaged on the retina through the adjustment of the lens

2) When the object gets closer to the eye, the focal length of the lens also becomes smaller; When the object is farther away from the eye, the focal length of the lens becomes less important; Always on the retina into a clear image of the coarse open.

Top 10 tips to protect your eyes.

1.Reflections to avoid:

Desks should have side lights to reduce reflections.

Reading distance is moderate:

The standard distance between the book and the eye is 30 cm, sitting on a chair.

The height matches the child's physique.

Sleep is essential:

Sleep should be more than 8 hours a day, and physical fatigue is easy to cause vacation.

Sexual myopia: Sitting posture should be upright.

Sit in a proper position:

Experts believe that Suixin: if the neck has been maintained in a forward bent posture, eyes.

The ball will be in a state of congestion, intraocular pressure.

It will increase in height, and the bulge of the eyeball is easy to create. myopia.

Be well-lit and comfortable:

The desk lamp on the desk, the bulb is 40w-60w, and the fluorescent lamp is used. 20w for.

Suitable. Don't be too far away from the TV:

Keep your eyes at least 3 meters away from the screen, and watch for 30 minutes every 30 minutes.

bell, just take a break.

Often look at the distant mountains and look at the green fields:

Frequent activities in parks or open spaces give the eyes a chance to see far.

Whether it's doing smart lessons, playing computers, or electric toys.

Or watch TV, time not.

It is too long, so it is advisable to take a short break every half hour.

Regular. Vision exams.

Prevention is better than** insurable

Window to the soul. Forever healthy.

Balanced nutrient intake:

Particular attention should be paid to vitamin B (

Embryo rice. Rolled oats.

Yeast....Preservative foods.

Can't eat. The wind passes without a trace, for you to answer, I hope to be able to help you, but also hope that you can, thank you.