The human eye has no flat surfaces, which means that the more surface areaa lens has, the more light is collected, and it can be directed back to theretina. Because of this reason, spherical lenses are used because they havea continuous 360-degree curvature. The eye is also self-lensing becausethere is a gooey substance between the cornea and the vitreous humor lens.This fluid produces a natural lens.
The function of spherical lenses
Spherical lenses are used in cameras and telescopes to form an image of asubject on the film or sensor.
The spherical lens is placed at a focal length away from the subject tofocus light from the point of origin, such as the sun, onto the camera’sfilm or sensor. This causes one part of the lens to be focused on infinity.In contrast, another part is focused on an object closer than infinity.
The term «spherical» means that all rays coming from any point on thesurface of this lens converge to a single point called it’s center ofcurvature. The fact that it has no other symmetry allows it to have nodistortion when it focuses on light sources.
Advantages of spherical lenses
Spherical lenses have several advantages over other types of lenses. Theyare much easier to produce than different lens types and are often the bestchoice for mass production. They also have a wide field of view, which isexcellent for many applications.
Spherical lenses are available in two types:
- Standard spherical lenses
- Customized spherical lenses
Standard spherical lenses can be obtained from most optical stores andonline shops that provide the service of prescription lens manufacturing.They are manufactured to correct presbyopia, astigmatism, or hyperopia.
Customized spherical lenses are designed specifically for a particularpatient’s eyesight by a qualified optometrist who will then send theprescription to an optical laboratory to manufacture these customizedlenses based on the client’s specific needs. The advantage of this type isthat you get better quality results than standard spherical lenses, whichare mass-produced for all patients.
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Disadvantages of spherical lenses
The major disadvantage of spherical lenses is that they are not suitablefor low-light conditions.
There are many other disadvantages as well:
- The lens cannot provide a realistic view of the world and distortdistances, causing an unnatural sense of depth.
- There is no peripheral vision due to the small size of the lens, and itcan cause headaches or dizziness.
- It may be difficult to see if you have astigmatism because thecurvature in the lens can cause your eyes to feel fatigued afterprolonged use.
Conclusion
In conclusion, spherical lenses have several benefits, including that theyare lightweight and do not distort the wearer’s vision, but also presentseveral disadvantages, such as requiring a prescription for eyeglasses.