What does crystal power 22 5 mean?

The difference between trifocal crystals and multifocal crystals and monofocal crystals.

In the traditional cataract intraocular lens, the single focal can only see near or far; Multifocal can see far and near, but lacks intermediate vision; And Zeiss.

The trifocal intraocular lens is a high-end intraocular lens that truly has natural intermediate distance vision, which can obtain excellent near, medium and distance vision, patients do not need to wear glasses when reading after surgery, and do not need to wear glasses when using a computer to work, and its perfect far, middle and near vision is complete, higher light efficiency, less postoperative glare, non-pupil dependence and comfortable all-weather excellent vision, becoming an ideal choice for one-stop solution to cataract, presbyopia and myopia.

According to Chengdu Preh ophthalmology experts, cataract surgery in the past.

Just to solve the problem of "seeing" patients, more and more patients are now pursuing visual quality, especially some who suffer from high myopia at a young age.

of patients. Trifocal intraocular lenses make up for the shortcomings of monofocal and multifocal lenses that cannot adapt to intermediate distance vision, not only to meet the needs of cataract surgery, but also to solve presbyopia.

It is suitable for people with myopia problems and those who are free from the shackles of glasses after cataract surgery, so that they can achieve excellent visual quality after surgery. The procedure takes less than 10 minutes, and it can be said that trifocal intraocular lenses have redefined high-end refractive cataract surgery.

f'is the image focal length, and f is the object focal length. In general, the power of light is expressed as the reciprocal of the focal length of the image square (approximate to think of the refractive index of air as 1).

The focal length of this spotlight is meaningful.

The reciprocal of the focal length of a lens is usually called the lens power.

The power is equal to the difference between the convergence of the image-square beam and the convergence of the object-square beam, which characterizes the ability of the optical system to deflect light. The power of the refractive sphere is often represented by the letter , and the power of the refractive sphere = (n '-n) r = n ' f'= -n f, where n' is the refractive index of the image, n is the refractive index of the object, r is the radius of the sphere, f'is the image focal length, and f is the object focal length. In general, the power of light is expressed as the reciprocal of the focal length of the image square (the refractive index of air is considered to be 1).

The above optical power equation is universal to any optical system.

Power characterizes the ability of an optical system to refract an incident parallel beam. The higher the value, the more the parallel beam folds; At >0, the inflection is convergent; At <0, the inflection is divergent. =0, which corresponds to, is a plane refraction.

At this time, the parallel beam along the axis is still parallel to the axis after refraction, and there is no infraction.

Unit: Diopter – the reciprocal of the focal length in meters.

Power of glasses = diopter power 100.

Defining the length of the focal length f of the lens indicates the refractive power. The shorter the focal length, the greater the refractive power. The reciprocal of the focal length of the lens is usually called the lens power, which is denoted by , i.e.

Formula =1 f If the focal length of a lens is, its power is =1 The power of the spectacle lens is the value of the lens power multiplied by 100. For example, the lens power of a 100-degree original lens is 1m -1, and its focal length is 1m

Focal power is equal to the difference between the convergence of the image-square beam and the convergence of the object-square beam, which characterizes the ability of an optical system to deflect light. The power of the refractive sphere is often represented by the letter , and the power of the refractive sphere = (n '-n) r = n ' f'= -n f, where n' is the refractive index of the image, n is the refractive index of the object, r is the radius of the sphere, f'is the image focal length, and f is the object focal length. In general, the power of light is expressed as the reciprocal of the focal length of the image square (the refractive index of air is considered to be 1).

The above optical power equation is universal to any optical system.

Power (also known as diopter). 1 optical power is the refraction of the parallel light through the lens and the focal point at 1 meter. The focal length is measured in m (meters), and m-1 is the optical power value. Obviously, the optical power is inversely proportional to the focal length.

Defining the length of the focal length f of the lens indicates the refractive power. The shorter the focal length, the greater the refractive power. The reciprocal of the focal length of a lens is usually called the lens power, which is expressed by , i.e. the formula =1 f If the focal length of a lens is, its power is =1 The power of the spectacle lens is the value of the lens power multiplied by 100.

For example, the lens power of a 100-degree original lens is 1m -1, and its focal length is 1m

The length of the focal length f of the lens indicates the size of the refractive power. The shorter the focal length, the greater the refractive power. The reciprocal of the focal length of the lens is usually called the lens power, which is denoted by , i.e.

Formula. =1 f If the focal length of a lens is, its power is =1 The power of the spectacle lens is the value of the lens power multiplied by 100. For example, the lens power of a 100-degree original lens is 1m -1, and its focal length is 1m

The formula is p= n n = f f. Among them, ds - recognition distance dt - detection distance h - object size f - optical and mechanical system focal length n - number of pixels required for recognition or detection of object ruler vertical ant front d0 - pixel size 9Optical power Yu Yu:

The reciprocal of the focal length.

Cylindrical top power is the deviation of the top power of sunglasses.

The nominal top power value of sunglasses should be that the deviation of the lens during the manufacture of the lens or the inconsistency of the lens and the frame may produce a deviation of the top power (i.e., with positive or negative top power), if it exceeds a certain range, the wearer may feel that the vision is distorted, and in severe cases, it will affect the wearer's visual health.

According to the requirements of the national standard for spectacle lenses Part 1: single vision and multifocal lenses, the top power tolerance of the spherical lens is; The cylindrical top power tolerance is .

LensThe relationship between convexity and focal length:

Convex. The more convex the surface, the shorter the focal length, and vice versa. Because the surface of the convex lens is more convex, the more the light is deflected after the convex lens (the more the refracted light is biased towards the main optical axis), the closer the focus is to the convex lens, and the shorter the focal length.

The shape of the lens of the eye is the same as that of a convex lens, so it is easier to understand the changes of the lens than a convex lens. The more convex the lens of the eye, the thicker the convex lens, the thicker the convex lens, the refraction of light.

The more capable. If the refraction ability is strong, it is easier to concentrate the parallel light on the main optical axis to form a focal point, so the focal point formed is closer to the lens and the focal length becomes smaller.

Convex.

Convex lenses are made according to the principle of refraction of light. Convex lenses are thicker lenses with thinner edges. Convex lenses are divided into biconvex, plano-convex and concave-convex (or positive meniscus) and other forms, and convex lenses have the effect of converging rays, so they are also called converging lenses.

Thicker convex lenses are expected to be distant, converging, etc., which is related to the thickness of the lens. Farsightedness.

Glasses are convex lenses.

The focal length of the convex lens and the radius of curvature of the two faces of the convex lens.

Relate. The larger the radius of curvature, the larger the focal length and the smaller the magnification; The smaller the radius of curvature, the smaller the focal length and the greater the magnification. In addition, the focal length of the convex lens is also related to the refractive index of the material.

and the refractive index of the environment in which the convex lens is located.

The above content reference: Encyclopedia - Lens.