I had a cataract removed at 28. Cataract removal involved implanting a fixed focus perspex lens to replace the damaged natural lens, leaving me with completely fixed focus in the affected eye. As a result, I developed quite an interest in multifocals (bifocals, trifocals and progressive lenses).
One day I was discussing their relative merits with an optometrist friend, who told me that someone had done some careful research about multifocal lens type preferences. They apparently took a large group of first time multifocal users and randomly allocated half each to bifocals and to progressive lenses. Then, after six weeks, they reversed the allocations, so that those who started with bifocals got to experience progressives and vice versa.
And the result? He said that they overwhelmingly preferred whichever they had experienced first!
In addition to having had a cataract removed, I also have strabismus; my eyes do not converge correctly and I can choose which to see, while retaining normal peripheral vision in the other. It's quite seamless and doesn't bother me in the slightest; I can swap my attention between eyes at will and in mid-task, but I can no longer see 3d effects which depend on stereopsis (slightly different images to each eye).
Furthermore, for various reasons related to my complicated optical history, I tend to use each eye for different sorts of tasks, and the base script (for distance vision) for each eye is quite different. So I find bifocal or trifocal lenses best for one eye and progressives for the other.
Why?
My right eye has a base script of about -4 spherical (quite short sighted) with very little cyl (astigmatism), and I find that a progressive lens works well for that eye. It's also the eye I favour for very close detail work, by simply removing my specs entirely.
My left eye, which has had a fixed focus lens implant, has about -2.5 cyl (cylindrical, eg: astigmatism) as a result of the inexperience of the surgeon who was learning on me. I've found that a progressive lens overlaid on a script with a lot of cyl has quite poor characteristics, with a very narrow strip down the centre which works well. After years of unsatisfactory progressive lenses, I got a pair of "single vision" glasses for using a computer and realised I could read with my dominant left eye again; to my great relief. Since then, I've had only bifocals and trifocals for that eye and I've been very happy with them. Meanwhile, my right eye, which retains some accommodation (ability to change focus; I'm 52 now, and my right eye is aging normally) continues with progressives which work seamlessly for me.
The main issue I see with progressives is the quality of vision, and the width of the band down the middle of the lens which gives an acceptable result.
Discuss this issue with your optometrist; different brands of lens use different algorithms, while large cylindrical components, used to treat astigmatism, can also seriously affect useability.
Also, for reference, for my left, fixed focus eye, I find a +1.5 correction suits reading a computer screen which is at arms length away, and +2.5 is suitable for reading books and close up work. Since trifocals are only available with evenly spaced steps, I end up with 0/+1.25/+2.5 for "outside" specs, while using +1.5/+2.5 bifocals for indoor/computer/dinner table specs.
Presumably you are simply over 45 and have some residual accommodation, but even so, have a think about what distances particularly matter to you, eg: for instrument panels, using a laptop, etc. Seriously consider dedicated specs for different tasks. Apparently lenses with reading sections at the top for reading overhead instruments are possible, for example.
One last thought; those people who had laser surgery when they were 30 to cure their myopia (short/near sightedness) and rid themselves of glasses? At 45 they suddenly discover they need to buy and carry reading glasses, while untreated myopes simply take their specs off to see close up detail.
Last edited by nonsense; 11th May 2015 at 13:37.