Cataract
Sooner or later many pilots eyes will develop cataracts and need surgical treatment. However, this is not straightforward and CAA rules prohibit many currently available types of lens implants (IOLs)
I have been trying to make sense of this important and complex topic. Although I am not an expert, I have tried to set out the current position as follows. Input from others would be much appreciated.
Cataract is cloudiness that develops in the eye's lens. It can be treated by surgical removal and replacement with an artificial lens known as an IOL (Intraocular Lens).
There are three basic types of IOL: Monofocal, Mulitfocal and Accommodative.
Monofocals (the only kind provided by the NHS) are simple lenses of single focal length that must be augmented by spectacles to provide a sharp image over the full depth of visual field. Their use is not recommended by the CAA.
Multifocals are (in layman's terms) something like varifocal specs that are implanted and can provide (at least) two foci. For some individuals this can provide spectacle-free vision, although some 'downsides' are known to exist. These can include a lack of sharpness at some visual distances and disturbances such as a 'halo' effect. There are others too. Their use is specifically forbidden by the CAA for pilots.
Accommodatives aim to provide continuously adjustable focus by bending and/or moving the lens along the visual axis. However, they seem to work much better for some individuals than for others, and it is said, can produce spec-free vision. The CAA approves their use. Unfortunately, it seems that many of the currently available Accommodative IOLs don't work as well as had been hoped. Indeed, the Bauch+Lomb 'Crystalens' Accommodative Lens appears to have been withdrawn by it's manufacturer.
This leaves any pilot who wants spectacle-free vision, following cataract surgery in a bit of a jam. I have tried to get further guidance from the CAA but they haven't proved too helpful so far. I have asked for a meeting with a CAA registered 'Consultant Aviation Opthalmology Advisor'.
There is a glimpse of a hope for the future. Developments in design of both Multifocal and Accommodative lenses seem to be addressing shortcomings of existing IOLs. They are starting to become available now but as yet guidance from the CAA has not been updated to allow their use. It seems that the FAA do now allow use of modern Multifocals if the resultant visual performance meets existing requirements.
How many of us in the pilot community are affected? Perhaps if enough of us register our concern the CAA will feel moved to help.