Author Topic: How can you need glasses for both far vision and close up?  (Read 5100 times)

Kim

  • Timelord
    • Fediverse
Re: How can you need glasses for both far vision and close up?
« Reply #25 on: 29 May, 2023, 12:31:53 pm »
How do the lenses compare to jibbling the monitor gamma, which seems like a much cheaper and less annoying solution?

Re: How can you need glasses for both far vision and close up?
« Reply #26 on: 29 May, 2023, 01:30:55 pm »
The blue filter lenses I uses are tinged slightly yellow.

They make a huge difference for computer use, and preventing 'artifacts' when driving at night.

Won't have glasses without them now.

Sorry to be dense, what do you mean by artifacts.

Re: How can you need glasses for both far vision and close up?
« Reply #27 on: 29 May, 2023, 01:33:10 pm »
I'm looking into the cost of fl41 tinted glasses,  great for fluorescent lights but my need is migraine photosensitivity. The wavelength they filter out is in the blue but a very narrow range which has links as a trigger for migraines in some ppl. April/ may is the time I get a cluster of attacks usually. It corresponds with brighter days and still lowish sun angles which gets be badly. I plan for next year to have a pair b or two.

PS fl41 tints vary by suppliers. Similar for other specialist tints. It comes down to quality. Not all fl41 tints are filtering out the right wavelength of light efficiently.  It is supposed to be a slightly pinkish brown,  but can be orange to purple!

barakta

  • Bastard lovechild of Yomiko Readman and Johnny 5
Re: How can you need glasses for both far vision and close up?
« Reply #28 on: 29 May, 2023, 10:29:40 pm »
As a fellow migraineur and someone who works with people who experience 'visual stress' (that what they use coloured overlays and lenses for to help reading etc).

The research evidence for much of this is limited. Many of the proprietary options like the FL41s, the green equivalents and Mears-Irlen lenses have no decent data. Intuitive colourimetry (which many UK opticians offer) is better but incomplete in terms of research - much carried out by a guy called Arnold Wilkins. His data/papers have been peer reviewed but we need a lot more research to separate out the different groups who can benefit from the lenses as I don't think our issues are all the same.

I have the Colourimeter tinted lenses having tried very pale blue ones at random from a dodgy optometrist (the quackery was considerable) which didn't help. I have a dark blue/turquoise/green combo colour and it is honestly the only thing that helps with my light flicker/brightness/colour-temp sensitivity and migraines (which are linked). So worth it I pay over £400 a pair for the glasses (basic frames £350+ for lenses) on top of a clear lensed pair.

I looked at FL41s but felt it was a corporate scam without any evidence behind it but I haven't looked seriously in the 6 years since I last looked.

Re: How can you need glasses for both far vision and close up?
« Reply #29 on: 30 May, 2023, 07:23:48 am »
The blue filter lenses I uses are tinged slightly yellow.

They make a huge difference for computer use, and preventing 'artifacts' when driving at night.

Won't have glasses without them now.

Sorry to be dense, what do you mean by artifacts.

Bright distortions, often 'spikes' coming off the edges and corners of objects.
<i>Marmite slave</i>

Re: How can you need glasses for both far vision and close up?
« Reply #30 on: 30 May, 2023, 09:19:09 am »
The blue filter lenses I uses are tinged slightly yellow.

They make a huge difference for computer use, and preventing 'artifacts' when driving at night.

Won't have glasses without them now.

Sorry to be dense, what do you mean by artifacts.

Bright distortions, often 'spikes' coming off the edges and corners of objects.
It is the anti-reflective coating that prevents that. Not the blue filter.

Re: How can you need glasses for both far vision and close up?
« Reply #31 on: 30 May, 2023, 10:53:03 am »
The blue filter lenses I uses are tinged slightly yellow.

They make a huge difference for computer use, and preventing 'artifacts' when driving at night.

Won't have glasses without them now.

Sorry to be dense, what do you mean by artifacts.

Bright distortions, often 'spikes' coming off the edges and corners of objects.
It is the anti-reflective coating that prevents that. Not the blue filter.

No, these aren't artifacts caused by internal refraction, they are visual artifacts that I get from bright point sources. I get them without glasses on.

Anti-reflective coating is also very useful and I wouldn't be without it.
<i>Marmite slave</i>

Re: How can you need glasses for both far vision and close up?
« Reply #32 on: 30 May, 2023, 01:19:21 pm »
The blue filter lenses I uses are tinged slightly yellow.

They make a huge difference for computer use, and preventing 'artifacts' when driving at night.

Won't have glasses without them now.

Sorry to be dense, what do you mean by artifacts.

Bright distortions, often 'spikes' coming off the edges and corners of objects.

Sorry if I'm asking alot of questions, is this night or day?  As at night I am having something similar with LED lights so wondering if it is an age thing for me or something else.

Re: How can you need glasses for both far vision and close up?
« Reply #33 on: 30 May, 2023, 01:54:35 pm »
The blue filter lenses I uses are tinged slightly yellow.

They make a huge difference for computer use, and preventing 'artifacts' when driving at night.

Won't have glasses without them now.

Sorry to be dense, what do you mean by artifacts.

Bright distortions, often 'spikes' coming off the edges and corners of objects.

Sorry if I'm asking alot of questions, is this night or day?  As at night I am having something similar with LED lights so wondering if it is an age thing for me or something else.
I only really notice them at night.
<i>Marmite slave</i>

Re: How can you need glasses for both far vision and close up?
« Reply #34 on: 30 May, 2023, 03:38:43 pm »
They're mostly called starbursts and halos and you should mention them to your optician as they can be a sign that something is amiss.

I get them and asked my optician. She diagnosed Pigment Dispersion Syndrome after doing some extra checks because of it. At the eye clinic they were impressed she'd spotted it, as I was in very early stages then.

As per: https://www.allaboutvision.com/symptoms/starburst-lights/

Re: How can you need glasses for both far vision and close up?
« Reply #35 on: 30 May, 2023, 03:59:05 pm »
Reminds me, must be time for my glaucoma checkup.

Last eye test, the pressure was at the top end of normal. My father had glaucoma.
<i>Marmite slave</i>

Re: How can you need glasses for both far vision and close up?
« Reply #36 on: 30 May, 2023, 04:31:46 pm »
As a fellow migraineur and someone who works with people who experience 'visual stress' (that what they use coloured overlays and lenses for to help reading etc).

The research evidence for much of this is limited. Many of the proprietary options like the FL41s, the green equivalents and Mears-Irlen lenses have no decent data. Intuitive colourimetry (which many UK opticians offer) is better but incomplete in terms of research - much carried out by a guy called Arnold Wilkins. His data/papers have been peer reviewed but we need a lot more research to separate out the different groups who can benefit from the lenses as I don't think our issues are all the same.

I have the Colourimeter tinted lenses having tried very pale blue ones at random from a dodgy optometrist (the quackery was considerable) which didn't help. I have a dark blue/turquoise/green combo colour and it is honestly the only thing that helps with my light flicker/brightness/colour-temp sensitivity and migraines (which are linked). So worth it I pay over £400 a pair for the glasses (basic frames £350+ for lenses) on top of a clear lensed pair.

I looked at FL41s but felt it was a corporate scam without any evidence behind it but I haven't looked seriously in the 6 years since I last looked.

Last time I looked there was research from Birmingham,  utah and the utah guy's old institution in NY where he worked before utah.i think it's utah, might be another, similar state's university. Aiui it started as a pet, side project in Cambridge then picked up by someone in Birmingham before a US based  specialist took it on and fine tuned the filter frequency of FL41. I think the Birmingham and the utah based academics are responsible for most of the fl41 research.

Aiui fl41, as the first of these filters to be developed, suffered from commercialisation and a wide variety of products using the fl41 code. You'll see that in the wide variety of colours masquerading add fl41. Many little more than tints without any science behind them.

As a migraine sufferers from early teenaged years I once got recommended tinted lenses for migraine sufferers. They were simply a basic blue tint and did nothing for my migraine. Still the opticians got their extra twenty quid.

Most opticians do not offer anything like these health based calorimetry or filter lenses for medical conditions. Certainly not the big chains. As one worker at one chain told me,  they're a simply colour tint and out the door merchants  not set up for special filters. Better to try small independents.

HTFB

  • The Monkey and the Plywood Violin
Re: How can you need glasses for both far vision and close up?
« Reply #37 on: 30 May, 2023, 04:49:40 pm »
For the worse sort of migraine I find it best just to go around with one eye shut. 3D vision is painful and exhausting.

I don't think I'm triggered by any particular wavelength of light (or anything else in particular, tbh) but when opticians get the letters equally clear on the red and the green the lens is too strong for blue light. So dusks when everything is blue are just difficult to see in.
Not especially helpful or mature

Re: How can you need glasses for both far vision and close up?
« Reply #38 on: 30 May, 2023, 06:04:13 pm »
The blue filter lenses I uses are tinged slightly yellow.

They make a huge difference for computer use, and preventing 'artifacts' when driving at night.

Won't have glasses without them now.

Sorry to be dense, what do you mean by artifacts.

Bright distortions, often 'spikes' coming off the edges and corners of objects.

Sorry if I'm asking alot of questions, is this night or day?  As at night I am having something similar with LED lights so wondering if it is an age thing for me or something else.
I only really notice them at night.
Had these ever since I was a kid and developed my shortsightedness.  I was warned that the laser surgery might make them worse but really no change. 

fruitcake

  • some kind of fruitcake
Re: How can you need glasses for both far vision and close up?
« Reply #39 on: 07 August, 2023, 03:06:51 pm »
I think astigmatism can cause something like the halo or spikes that have been described. For instance I believe it can turn points of light into lines. It's corrected by cylindrical lenses, notated in the "CYL" column of the prescription. This is added in the prescription part way through the eye test when you're shown the collection of black dots on a white background, and the optometrist asks, 'are the dots clearer with lens number one... or two'. With one of the lenses the dots might look clearer and less 'smeared'.

To the OP, I reckon it's normal to need a different lens (or perhaps no lens) when viewing things closer to you, if you're short-sighted. Rarely, if ever. do short-sighted people actually need their full power distance vision lenses to read a book. They might need a lens but it would ideally be less powerful, typically by a dioptre or two. By the way, this is usually checked at the end of the eye test when you're given a 'book' to read (a book which might in fact be a piece of card) and asked which is the smallest sized text you can read. Then the optometrist holds a hand lens over your trial lenses and says, 'what's the smallest you can read now?' The hand lens is plus 1 dioptre, effectively weakening the prescription. If you express a preference for this, the resulting weakened lens for close-up vision will become a 'reading addition' on your prescription, which might be notated as "ADD".

Those with a mild refractive error (i.e. those who are only slightly short-sighted) may be able to read a book without a lens (i.e. reading without glasses) because in these circumstances the natural lens in the eye is made to work in order to focus the eye. Those who have gone through life able to focus on a book with no lens have been lucky! I could until a few years ago.

If you have very mild myopia (short-sightedness) which needs correcting only in the worst of conditions (e.g. distance vision in low light when your safety is at risk), the power of your reading addition might in fact be larger than the power of your driving glasses, shifting your reading prescription from negative numbers into positive numbers (in the SPH column of the print out they give you). Where this is the case, your distance vision would be corrected by a lens with a negative sphere shape (a lens thicker at its edges than its centre), whilst your near vision would be corrected by a positive sphere (a lens thickest in its centre). Looking into the middle distance in good light might need no specs at all. And those who don't need specs all the time are the even luckier ones!

This last scenario may be what's happening in your case. (Feel free to share your prescription here if you like. Specsavers might have given you a printout of the numbers for SPH, CYL and ADD.)

In either scenario, different specs for driving and reading. If the difference between your near lens and your distance lens is huge, your optician might recommend a set of specs with varifocal lenses.   

Anyway nowt wrong with your eyes, and your optician is doing a good job.

barakta

  • Bastard lovechild of Yomiko Readman and Johnny 5
Re: How can you need glasses for both far vision and close up?
« Reply #40 on: 05 September, 2023, 05:12:03 pm »
Had my overdue eye test last week. My distance hasn't changed much but my reading has and they were considering separate lenses. I'm not able to use varifocals cos I have vestibular (balance) dysfunction and an eye movement impairment.

We thrashed it all out as I use both a clear and specialist tinted pair of glasses and 4 pairs is getting Professor Branestawm numbers of glasses levels of silly cos I need tinted distance spex for things like certain lighting.

We have decided to try just using my distance prescription as I read mainly from screens and can zoom (haven't been able to read substantial print for years thanks to migraine nonsense) as I can still accommodate.

If we do go with a reading pair, I'll just get tinted ones which is only 3 pairs of spex not 4. As 2 pairs cost over £1000 I'm hoping to avoid ~£600 on another tinted pair.

fruitcake

  • some kind of fruitcake
Re: How can you need glasses for both far vision and close up?
« Reply #41 on: 05 September, 2023, 05:16:07 pm »
I have three pairs of glasses, each in a different lurid colour case so I can find the right one quickly... without my glasses on. A friend had a lurid orange case from Specsavers which she hated. I swapped for a navy blue one which I couldn't see against a dark background.

On migraine aura nonsense, I'm looking forward to the day when LED backlit screens become obsolete. Gimme an e-ink display and I'll happily read all day - I even prefer it to white paper due to the reduced contrast.