Occupational Lenses

[Robin]

You only had to ask :)

I suspect some may deny it because our eyes/brains often settle for out-of-focus images without telling us.

[Tim+]

Eh? No different from a conventional camera. I think you need to hang out with better informed people. ;-)

Tim

[Bob Eager]

I use bifocals. Arranged so that the demarcation point is just above teh dashboard.

[Chris Green]

Exactly my thought.

It is obvious when you realise you can read small print in bright sunlight whereas you don't have a hope in dimmer light. It's simply because the iris has stopped down and the increased depth of field means that closer things are in focus.

[Bing AI]

Occupational lenses are a type of multifocal lens that can be used for a person’s occupation or lifestyle. They are designed for close to intermediate tasks such as reading, writing and screen-work. These lenses can be either ‘office’ or ‘computer’ varifocal lenses which differ in their focal capacities. Some occupational lenses come with anti-glare coating or blue-shield coating (ideal for computer use and to help with migraines and severe headaches at work).

[Jonathan Ward]

Having just had cataract surgery and having good long-distance vision for the first time in over 50 years, these are wonderful. Post surgery I have to have reading glasses for the first time in my life. They were prescribed by Specsavers, who call them super readind glasses. They are varifocal with a close-up reading range and the top half go up to two metres, theoretically but in fact go further. I am able to use them inside all the time without having to take on and off a pair of traditional reading glasses. Truly wonderful, Jonathan

[Rod Speed]

I do too.

[Joe]

Basic optics. It works the same for eyes as for cameras and other optical instruments. The smaller the aperture, the less curved is the part of the lens which is in use, so the less focussing there will be. Or to look at it another way, the more parallel will be the light rays passing through the aperture.

[Rod Speed]

Yep, I knew that back in school with pinhole cameras.

[Peter Johnson]

Being diagnosed with early-onset cataracts and advised that their development will be slowed by the use of sun glasses in bright light, I have a pair of varifocals with transitions

that I use for everything. They are sometimes a bit slow to react when I move from outside to inside though.

[Tim+]

Sluggishness seems to be a common theme with reactive lenses. Most folk I know who’ve tried them find there slow time to “recover” irritating.

Tim

[Tim+]

FFS, THEIR! ;-)

Tim

[Colin Bignell]

I have transitions, but I also wear a broad brimmed hat whenever outdoors.

[RDS]

Advised by who? Glasses Direct?

[Bob Henson]

+1

[Spike]

Shop around/check out something called CAN-C eye drops, available on Amazon and doubtless other outlets.

These are a 1% solution of n-acetyl-carnosine, which is converted in the anterior chamber of the eye to L-carnosine. The latter is not absorbed by the eye so are ineffective in the form of drops. However, it has the ability to dissolve immature cataract, although has no effect on mature cataract. The original paper on this was published circa 1936. You can also get L-carnosine as a dietary supplement.

If you fancy way out instead of science, try alcohol-free eye drops of cineraria maritima such as Schwabe Cineraria Maritima Eye Drops 10ml ( non-alcoholic), also available on Amazon.

[Joe]

According to my wife, who has used glasses for sixty years, the early reactive lenses were quicker to clear. She noticed the difference when getting new glasses once, and they haven't improved since, so it isn't her perception.

Possibly the original type used a now-forbidden chemical, or the current methods of glass processing don't allow the original material to be used.

[Andy Burns]

I've seen those being recommended, but the clinical studies show "inconclusive results", so beware of buying expensive snake-oil.

e.g. Royal College of Ophthalmologists ...

"The evidence for the effectiveness of N-acetyl carnosine eye drops is based on experience on a small number of cases carried out by a Russian research team [Babizhayev]. To date, the research has not been corroborated and the results replicated by others. The long-term effect is unknown. Unfortunately, the evidence to date does not support the 'promising potential' of this drug in cataract reversal. More robust data from well conducted clinical trials on adequate sample sizes will be required to support these claims of efficacy. Furthermore, we do not feel the evidence base for the safety is in any way sufficient to recommend its use in the short term. More research is needed."

[Robin]

I'd recommend anyone interested to also glance at the Wikipedia page on the subject and perhaps also at the [Gold standard] Cochrane review cited there.

[Bob Henson]

If either worked, they would be in regular use in ophthalmology. They aren't, so they don't.