When we are young, the lens inside the eye is soft and flexible. To change focus from near to distance and back again, the muscles surrounding the natural lens contract and relax changing the optical power of the lens. This ability of the lens to change its shape and focus is called accommodation.
Around the age of 40, a condition known as presbyopia develops when we lose the ability to change the shape of the lens inside the eye. As this occurs, we become more and more dependent on reading glasses to see close objects.
Benjamin Franklin invented a way to correct this condition with bifocal lenses back in 1784. Today, progressive lenses are available. These lenses have the appearance of single vision lenses while providing you with a full range of vision from near, intermediate, and distance.
Progressive lenses are created with a gradient of power starting with the patient’s distance prescription at the top of the lens, a stronger intermediate power in the middle of the lens, and the strongest near power at the bottom of the lens.
This seamless gradient of power zones allows patients to easily shift their focus from distance, intermediate, and near without the visual interference of lined bifocal or trifocal lenses.
If you experienced trouble in the past choosing a frame that would accommodate a progressive lens, there are now many progressive lens designs available for virtually any style of frame.