What is the difference between SV lenses and Bifocal Lenses

Difference between single vision lenses and Bifocal Lenses

What is the difference between SV lenses and Bifocal Lenses

Single vision lenses

Lens type

Single vision lenses optically correct only one type of vision, sometimes known as “monofocal” lenses because the lens power is constant throughout the lens.

Vision correction 

A single vision lens is made exclusively for one sort of vision correction; it can offer considerably sharper, clearer vision at a particular distance that is suitable for your needs. They cannot, however, be used to improve your vision for both, (near and far distances)

Problems solved by single vision lenses:

  • Astigmatism
  • Hyperopia
  • Myopia
  • Presbyopia (only to correct the near vision)

 

Advantages of SV lenses:

Single vision lenses may raise your overall level of living since they provide higher visual clarity and quality. Additionally, they help to lessen headaches, weariness, and visual fatigue. Single vision lenses help you protect your eyes from harmful rays like UV and blue rays produced by all digital screens (laptops, tablets, and phones).

 

Bifocal lenses

Lens type

A bifocal lens is a type of lens that has two powers and corrects your vision for two focal lengths, improving your eyesight in the distance and near vision (reading).

Vision correction 

Bifocal lenses have two parts: the top half is for distant vision, and the lower is for close-up vision. Bifocals meet both your demands for distance and near vision, in contrast to single vision lenses.

Problems solved by the bifocal lens 

  • Bifocal lenses to correct both presbyopia and myopia.
  • Children who have trouble focusing in class and have eye fatigue from spending so much time reading and writing are sometimes given bifocal lenses to wear.

Advantages of bifocal lenses

Bifocals‘ key selling point is that you can see clearly both close up and far away, and you won’t have to worry about taking your glasses off every time you switch between reading and going outside.

Disadvantages of bifocal lenses

  • Distracting bifocal line: The extreme contrast between the two prescription kinds often annoys and distracts consumers. 
  • One more disadvantage is that BF does not help in the intermediate distances like working on the computer.

 

References:

  • Fedtke, C., Bakaraju, R. C., Ehrmann, K., Chung, J., Thomas, V., & Holden, B. A. (2016). Visual performance of single vision and multifocal contact lenses in non-presbyopic myopic eyes. Contact Lens and Anterior Eye, 39(1), 38-46.
  • Fulk, G. W., Cyert, L. A., & Parker, D. E. (2000). A randomized trial of the effect of single-vision vs. bifocal lenses on myopia progression in children with esophoria. Optometry and Vision Science, 77(8), 395-401. 

 

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