Some tips about progressive bifocals. I'll try to keep this in non-technical terms...
1. Not all progressive lenses are created equal. There is some difference in lens design. Even the major manufacturers, such as Varilux and Sola, will have more than one progressive lens design that they offer. Talk with your optician before you purchase.
What differs about progressive lens design? In simple terms, the manufacturer can vary how the "blend" works, and can vary the horizontal size of the clear zone of near vision. Progressives need to have a blend zone where the distant and near lens prescriptions are blending together - if you are looking through that blend zone, you're going to have distorted vision. When I purchase a progressive, I prefer a lens with a wider (horizontal) zone of clear vision for reading. That makes reading more comfortable for me. (If you talk with your optician, they may refer to the "corridor" - that's the area in your lens where the lens power is progressively increasing to gradually give you improved vision for tasks that are closer and closer to you.)
2. To use a progressive for reading, expect that you will need to move your head somewhat while you read across the page (rather than just scanning your eyes across the page). If you can learn to move your head, your eyes will avoid looking through what I'm calling the blend zone (which will distort your vision or make you swim).
3. Currently, teeny-tiny lens frames are very fashionable. But to create a progressive, the optician will need enough vertical height in the lens so that there is sufficient room to get the progressively increasing power in. So avoid lens frames that have only a very small vertical height to the lens - you need enough vertical dimension in your lens to fit the progressive add in comfortably. Also, if you have enough vertical dimension to your lens, you can ask the optician to start the progressive add perhaps 1-1.5 mm lower than he otherwise might. That's very important to me when I purchase a progressive. If the progressive add starts up too high, I find that it is so close to my zone of clear distance vision that I am blurred for distance if I look down even the slightest bit.
Hope I didn't confuse everyone too much...
I hated my first progressive, and I had trouble with my second. But I just love my 3rd pair. I currently wear a SolaMax lens, which I find gives me a wider and more comfortable zone of undistorted reading vision than my previous glasses. You should be able to decide on the best choice for yourself after some discussion with your optician.
