Optify Bifocal Blue Cut Reading Glasses for Men & Women Contains Bifocal Lenses With Blue Light Blocking Function.Bifocal lenses are lenses that correct both near-sightedness and farsightedness in a single pair of spectacles. The prescription for farsightedness is located on the lens's top. When you're driving- strolling- or speaking with people- your eye naturally glances through the top of the lens. The bottom of the lens carries a near-sightedness prescription. This section of the lens may cover the whole bottom portion of the lens- or it may be smaller and located in the middle. When reading- working on a computer- or other close-up duties- your eye naturally looks through this area of the lens.Blue Cut Lens Protect your eyes from blu-ray- filter hazardous radiation from computer gaming- video games- phone- or TV- and aid in the reduction of eye strain- blurred vision- headaches- and sleep disruption.