There is no panacea, or cure all, for the “Curse of the 40’s” but Monovision and Bifocal Contact Lenses are a large step in overcoming this problem without glasses.
Monovision
Think of monovision as essentially the 21st century version of the monocle, but done with contact lenses. One contact lens is prescribed in a power to correct for the distance prescription and the other eye is purposefully under-corrected to allow crisp, clear vision for near tasks. This way one eye is always in focus for any given task.
A main benefit of monovision is that any contact contact lens brand will work for this, including astigmatism correcting or “toric” lenses. We simply adjust the prescribed powers, not the brand itself.
Without question, this takes some getting used to, but over time the brain trains itself to only pay attention to whatever eye it needs to for a given visual task.
Bifocal Contact Lenses
The key to bifocal contact lenses is in the design.
These lenses are bifocals in the name only, and work nothing like a pair of bifocal glasses. Bifocal glasses have different zones within each lens with very different prescriptions for clear vision from distance to near. You simply need to direct your eyes through that section of the lens for clear vision at that whatever distance you want to see. Since a contact lens is so small and always sits at the same place on the cornea, it is not feasibility for a soft lens to move around enough to look through different areas.
Instead, if you look at these lenses under a microscope they have concentric rings just like the rings on a dart board.
Each ring of a bifocal contact lens is designed to focus for a different place: distance, intermediate or computer, and reading (see right). All the vision from all distances is focused by the contact onto the retina in the back of the eye and the retina sends that information to the brain.
What the brain receives is a garbled, distorted mess, but the supercomputer sitting between our ears is able to filter out the distances that it’s not interested in.
This results in you being able to read a menu one moment and then check the score of a ball game on a television the next. This process sounds quite convoluted but it actually works surprisingly well!