Refractive power of lenses (Diopter)

in StemSocial3 months ago (edited)


First of all my respectful greetings to the entire academic and scientific community of, the field of science has allowed us as humanity to analyze, and thus, to know everything about our environment, and in this way we have learned about essential phenomena for our existence as is the case of light.

My dear readers, each one of us can be witnesses of the great importance of the phenomenon of light because through it we can observe everything around us, and this is because the light rays that are emitted in our environment reach our retina, where the objects or bodies that emit these light rays are projected.


Each ray of light travels through any space-time of our vast universe, and this using some material or elastic medium such as air, but even light also manages to travel through the vacuum, sometimes many of these light rays manage to penetrate our complex ocular system until they reach our retina, where each of the images they carry are projected.

Due to this remarkable aspect we can say that man has taken great interest in knowing more and more about light and relate to all those intrinsic phenomena during its propagation, it is no secret that these learnings have allowed us to design vital optical systems artificially such as lenses and prisms, which are able to refract the light rays passing through them.

As it has been expressed, each body or object emits a set of luminous rays and these go in all possible directions, that is why when we place ourselves in different positions we can observe different parts of the body or object visualized, since the luminous rays that manage to enter the interior of our ocular system come from that specific part that we are observing, and at the same time the well-known phenomenon of refraction is developed, and thanks to this phenomenon makes these rays converge in a focal point where the images are originated.

Therefore, refraction makes the luminous rays bend and converge as much as possible in the same point which we call focal point, and this action can be performed both by an artificial or natural lens which is part of our ocular system, and that is what we are talking about in a general way in relation to an essential characteristic of lenses of any nature such as diopter.

Therefore, when referring to both convergent and divergent lenses, we must highlight their refractive capacity, that is, how powerful they are at the time of bending or refracting light rays when they pass through them, this refractive capacity is measured in diopter, then, we will know how to calculate this value of diopter, and also how it influences the propagation of light rays.


Every scientific knowledge through time man has put into practice through the field of technology, this aspect has undoubtedly revolutionized our modernity at very high speed, and of course, we are all reliable witnesses of the above, and among these scientific-technological contributions we find the design of both convergent and divergent lenses.

The truth my dear readers is that when it comes to the treatment of any set of luminous rays, the lenses play a fundamental role since each of them fulfill certain functions at the time of providing quality in the formation of any type of image, for example, in artificial optical instruments such as the compound microscope, telescopes, binoculars or binoculars, sextants, projectors, periscopes, among others, and this is also transferred to our complex ocular system.

In relation to the importance of the lenses described above in terms of image formation, it is necessary to relate to an important characteristic of the lenses as is the diopter, this aspect allows us to know the refractive power of a particular lens either artificial or natural (in the case of our eyes), in short, to know how much can bend or refract a lens to a light beam at the time of impact on it.

The above characteristic is what is known in the world of optics as the refractive power of a lens, in simpler terms we can say that the diopter is the unit that represents the power of the lens in relation to its ability to refract or bend light rays.

It is important to express that the value of the diopter is not more than the inverse of the focal length expressed in meters, let's keep in mind my friends readers that the focal length is the one that we measure from the center of an optical system (lenses, mirrors and prism) to the focal point, and the latter, as expressed, is that place where the light rays that carry a certain image meet or converge.

We must emphasize then that the quality of an image will depend on the greater proximity between the concurrence or convergence of these luminous rays, since this action is what generates the images and the refractive power of the lenses can have a significant impact on this action.

Now it is important that we can learn more about diopters, and also, how to know when a lens is more powerful than another at the time of refracting certain light rays, for this it is important to visualize the following figure 1.


Figure 1. Determination of the refractive power Determination of the refractive power of two converging lenses (diopters) of two converging lenses

As you could see my dear readers in the previous figure 1, we have two convergent lenses, and the same, clearly refract the light rays components of a particular beam of light, in the two lenses both the upper (a) and lower (b), we see how the light rays through these lenses converge in the same place (or as close as possible) which is called focal point.

Therefore, we see how the focal point one is closer to a lens than the other, this allows us to know at a glance which of them has greater refractive power, for this case is the convergent lens (a) as it manages to bend the light rays to a shorter focal length than the lens (b), and also, to observe the calculation of the amount of diopter corroborates our visual assessment, since the convergent lens (a) has 10 D and the convergent lens (b) has (5D).

In order to expand the concept of diopter, we can express that the diopter scale is comprised of steps of 0. 25 diopters, and this feature can become either positive or negative, such aspect will always depend on the type of lens with which you want to refract the light or light rays, that is, if these lenses are convergent (positive) or divergent (negative), so it is important to observe the refraction of light rays through a divergent lens, and thus the diopters will be negative, and this can be seen in the following figure 2.


Figure 2. Determination of the refractive power of a diverging lens (negative diopters)

All this refractive knowledge can be transferred to our natural optical systems (eyes), where we find natural lenses such as the cornea and the crystalline lens, and its action can cause a lower or higher refraction of the light rays that fall in parallel in our eyes, and thus, in the quality in the process of formation of images on the retina, and so some ametropias or refractive vices are developed, of which in future installments we will be deepening in this regard.


Our existence is undoubtedly deeply linked to everything that surrounds us, and of course, there are different phenomena that develop every moment we breathe, and light is one of these vital phenomena, which is why we should always learn as much as possible about it, because thanks to light we can observe our environment as it is or as close as possible to it.

In this opportunity we related to the refractive power of the artificial lenses either convergent or divergent type represented in diopters and this we could see in figures 1 and 2, where, this value can be either positive or negative, this will depend on the type of lens, ie convergent or divergent respectively, in future installments we will continue relating to the refractive power of the lenses and their impact on the generation of images.

Until another time my valued readers, especially the members of the great #stemsocial community, for which I highly recommend being part of this beautiful project, as it highlights the wonderful work of academia and the great work of the entire field of science.

Note: All images were created using the Power Point application and the animated gif was created using the PhotoScape application.

Bibliographic References

[1]What’s a Diopter, and Why Do I Care Anyway.



So rays travels through air?

Wow, a good one from you sir on your topic "power of lenses".

Hi @ezeemmanuel.

Light is an electromagnetic phenomenon that can travel through material mediums such as air and even vacuum. Thanks for your visit and important comment. Greetings.

You are welcome my honourable

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 3 months ago Reveal Comment