NVG - eye surgery for ageing eyes...
 

Hello All,

Am getting to that age where I need to wear glasses for my night flying.

This is complicated further by the fact that my job requires me use night vision goggles.

I have heard that presbyopia doesn't really have a long term l@ser surgery solution, but I love to get just another 5 years of flying without faffing around with glasses.

I'd really appreciate any advice or to hear of anyone's experiences.

Thanks

Bomber - what do you need the glasses to see? Is it through the NVG or under the NVG for the cockpit instruments, document or map reading?

My distance vision is good so I am fine looking through the goggles using the dioptre adjustment at the rear but I take a pair of glasses or sometime pince-nez for reading a map or looking at close instruments, switches etc.

I know plenty of people who fly on NVG wearing glasses and it doesn't seem to be a problem.

The biggest NVG/glasses problem I had (several times) was sitting on the buggers (glasses) as I got ready. For some inexplicable reason I would put my glasses on my seat as I stood outside and put my helmet/goggles on - yes I know we should learn a lesson from our mistakes but in a 1000hr + NVG career I never did and usually never thought about my glasses until I was strapped in on top of them!

May I suggest you talk to Dr Julian Stevens not saying he will give you a perfect fix but he is the Leading specialist in Eye Corrective surgery and is used by Military Fast Jet & Special forces types UK and US and has pioneered some of the new technology used for Eye Surgery.
I had my eyes lazered last year and it has kept on getting better.

Julian Stevens | Consultant Ophthalmic Surgeon at Moorfields Eye Hospital

I had obviously missed something and didn't know EASA Part Med now permits laser eye surgery for presbyopia. At a practical level, what's the length of time between having it done and regaining the Class One?

HS

I flew many hours on NVGs wearing glasses. It wasn't a problem.

That's my understanding as well, because the problem isn't caused by an inherent defect in the eye's lens. Presbyopia is long-sightedness caused by loss of elasticity of the lens of the eye, occurring typically in middle and old age. Surgery could correct at the time of surgery, but the elasticity of the lens could then deteriorate further with time.

Thanks for the responses.

Crab - My distance vision is fine, and I look through the tubes with the naked eye, but have the smallest glasses I can find perched on the end of my nose for viewing the instrument panel. This leaves a gap (between the goggles and the spectacles) out to the right to use an external white light reference for winching, etc. However, I'd rather not have the glasses getting in the way of my below goggle view through the chin bubble for helipad style departures etc.

Mighty Gem - I have heard the surgery won't provide a permanent solution to my presbyopia, but I'd be prepared to undergo treatment if it were able to give me, say, another 5 years of goggle flying without needing specs.

Thanks again

Bomber - you could try pince-nez- I use NooZ - they can be pushed flat when you don't need them and you don't have the problem of spectacle arms fitting in your helmet. This gives much more vision under goggs for winching etc.

Thanks for the link. I use an almost identical product https://www.thinoptics.com/headline-reading-glasses

I'd just like to explore whether I can surgically avoid having to use them for 5 years, then revert to wearing reading glasses once the surgically delayed presbyopia kicks in again, after I have given up goggle flying.

There are no good solutions for presbyopia where refractive surgery is concerned. Your only choices are multifocal correction and monovision. Both really screw with your depth perception. You can try both by going to your eye doc and asking for contact lenses that do the same things.

Indeed, I've tried both myself. Monovision wasn't bad. I put the near vision lens in my non-dominant eye. It was fine for day to day stuff, and for driving, but it was not at all optimal for flying. And it will not meet the FAA medical standards, you'd have to request a waiver. I also tried multifocal contact lenses. The multifocal approach requires a lot of "brain training". I stuck with it for a few weeks but just couldn't make it work, not even for day to day, ground based stuff. It was so bad I never tried it in the air at all.

I've also tried progressive lenses. Again, I did not care for them, although I can understand how some might prefer that, especially with the FAA requirement for older pilots to demonstrate visual acuity at both 16 and 32 inches distance.

For flying I still very much prefer a set of plain old bifocals with a line set a little lower than what might be normal. I can easily meet the FAA requirement for 20/40 at 16 inches using the lower section, and 32 inches with the upper section. I've got bifocal sunglasses, too. They are the cat's meow and I wear them for everything, not just flying.

FWIW I recently had full replacement lens surgery and was flying within 2 weeks. My right eye is now 20/15. Caveat FAA land.

Watch at your peril:

The UK CAA mandate a minimum of 6 weeks before flying, after cataract replacement surgery.

Hi,
glasses are a pain in the a....
always some dust on it which irritates, you need to wear a cap to prevent rain and drizzle on them and the distance between eye and NVG needs to be increased - so the field of view decreases :-(
Also you need spare glasses, if they are added in your medical.
I use progressive glasses and started early with them, cause it takes time to get accustomed to. With less dioptrien it´s easier than starting later with more dioptrien.
Biggest problem for me was, that while wearing NVG part of the correction got covered - so the checklist on the lap was sharp, but viewing cross the cockpit to the moving map i.e. got somewhat blurry.
I adopted in that way, that I now have the NVG screwed as high as possible, just using the lower 2/3rds of the googles looking outside, while having the lower part of my glasses free, which allows me to use all of the progressive part. (High end progressive glasses - the cheaper ones have narrower areas to look through)
Tip for cleaning, especially if you get coated glasses - stay away from the pre soaked cleaning packs you can buy - they ruin the coating.
Just some (non remoistening) soap (litte) with warm running water for cleaning will do. Dry with kitchen paper towels (without print) ;-)

FB - I think its an urban myth that moving the NVG away from your eyes reduces the FOV - you only have about 40 deg FOV anyway and you are focussing your eyes on the screen inside the tube not what comes in at the far end of it.
I fly with mine quite far forward so that vision under them isn't impaired.

Not sure if you need to flip/flop between NVD and unaided flight, but that was the most annoying aspect of using NVD and �� specs. Particularly if you need bifocal for distance and reading, but then couldn’t read the overhead panel switches!

FB - never had that problem - always set mine up further away than the standard 1 inch eye relief distance and can always see the full screen.:ok:

Yes, probably right about different setups - I don't wear glasses to look through the goggles and we set ours up on a Hoffman box before use, wearing the helmet so you can experiment with eye relief and focussing settings.:ok:

Hi crab,
glasses are the problem with aging eyes ...
What is a Hoffmann Box? Never heard of before.
Can you give some more information please?

I adjust my googles on the way to the helicopter with some fine tuning in the cruise.

Bye the way, I designed and 3D printed covers for the lenses, which are easier to use then the ones delivered with the NVG 😏


https://cimg0.ibsrv.net/gimg/pprune....840ea5a78.jpeg
Cover for NVG - 3D printed

Immediately after retiring, I had presbyopic lens exchange and I kick myself for waiting. From bifocals to 20/30 vision. I also had some cataract development, now I see colors better.

FB - a Hoffman Box is something that hangs on the wall and is used to check the setup of NVG - you use it in a darkened room and it has a very low light illuminated series of graduated circles and a series of Snellen charts in it.

The Snellen charts are a series of vertical and horizontal lines at different thicknesses that correspond to visual acuity - ones for 20/20, 20/25, 20/30, 20/35 etc up to about 20/50 I think (6/6, 6/9, 6/12 etc for Europe).

On a good pair of goggles, correctly adjusted, you should see 20/35 clearly.

The circles go from light to dark shading in sectors and the more sectors you can discern, the better the goggles.

I will take some photos tomorrow at work and post them.

Using the Hoffman Box sets a base level by which you can assess poor tubes and note excessive scintillation, honeycombing and black spots.

Can I check something with you Shy?
I have worn specs for over 40 years and contacts for some 30, I looked into lens surgery about twelve months ago and even went to a full blown eye hospital explaining that I wanted to start flying again, after several visits the surgeon told me under no circumstances would they perform the operation as CAA regulations would not allow me to fly once it was done.
I wear multi focal contact lenses and as these cannot be worn I have had to buy varifoca glasses.
My AME at the time told me a BA pilot had had the surgery done and that my surgeon wasn't up to speed.

In the end I have stuck with the varifocals, but I would love to have the surgery if it would mean I can fly without specs or contacts! The CAA and other bodies across the globe would need to be in agreement of course, but if you know this is possible I'd love to hear back from you or anybody else that knows about this.

Ta very much!

https://www.hoffmanengineering.com/t...-focus-system/

FB, this is from their website

I have had new lenses fitted at age 77 and now have perfect eyesight - long and short distance. Talk to Mr Jonathan Luck at the Circle At Bath - actually in Peasdown St John.Costs £5800 and the best money I have ever spent.

Glasses
 

Thanks very much I've just had a look at the site and I'll give them a call this week. Much appreciated Georg1na.

https://cimg6.ibsrv.net/gimg/pprune....23c844219e.jpg
FB - the Snellen charts visible inside the Hoffman Box

As AAKEE says, it is the ability to compare goggles to a standard to know which ones work best that is the one big advantage.

The other big plus is that you can teach people how to set their goggles up properly from the outset. When I was a Squadron Training Officer, I used to pick up pilots goggles that they had 'set up' and check them on the Hoffman box - the number that had used the rear, dioptre adjustments to get a good picture instead of the front adjustments was surprising and they were giving themselves eyestrain trying to get a good focus on an image that wasn't properly focused in the first place.

I know I have mine set up properly if I end up with the sharpest image I can get - usually 20/35 - and the dioptre scales at the back match my eyesight prescription for reading glasses - between +1.0 and +1.5.

The only slight downside is that the Hoffman Box gives you a set up with the focus on infinity which isn't much use for helicopter operations so you still make a real world adjustment once in the cockpit or on dispersal - but you are doing it from a known and correct setting.

On the question of degraded depth perception:

(Apologies, not a rotorhead or NVG user. Not sure about the etiquette here - I didn't think I should spawn a new thread)

I have presbyopia (my reading glasses are +2). My distance vision requires no correction but benefits from slight correction. I wear progressives to fly and they seem to work brilliantly, I have perfect acuity wherever in the field of view I need it. However, my landings are still pretty untidy and I wonder if my depth perception is screwed without me realising it. Is that a known thing? I thought progressives and varifocals were the same thing ? Is there any way to objectively measure depth perception (without causing alarm to the AME!) ? I used to drive with bifocal sunglasses, and I also found they were great. But I now wear the progressives as much as I can on the principal that I should train my brain to handle the input. Wondering now if I should try flying in the bifocal sunglasses and see if that's better - although I am reluctant to sacrifice the marginal improvement in distance acuity.

@double_barrel: assuming you are in the US? My AME measures depth perception with his vision testing machine. There are tests for this. You can go to your local eye doc or eyeglass place and be tested (with your preferred vision correction) without "alarming your AME" ;) That's what I do every year (Class II medical). In fact I've got my yearly eye exam set up to be one month before my medical is due every year. That way my prescription is tip top before I go in to see the AME.

Also, it's a very personal decision what works best for you. Like I wrote above, when presbyopia hit I tried pretty much everything. I went with what worked the best for me, which is plain old bifocals. By making them the right strength (and putting the split of the lens in the right place--I like it a little lower than most) I can see 16" 20/40 with the bottom part, and 32" 20/40 with the top part (and 20/20 distant vision, of course). I'm happy with that and it meets the US Class II requirements for old guys :}

Thanks, I will try that. I also think I will give plain bifocals a try. Maybe that distortion at the edges of the zones with progressives is messing with my ability to judge the last few seconds when landing.

Are you sure, Shy? I wore bi-focals/varifocals for all of my civilian career. My various AMEs never questioned it.

I think you are confusing refractive surgery or lens replacement surgery terminology with eyeglass terminology. If I'm reading things correctly, I think Shy is saying he had lens replacement surgery.

Where refractive or lens replacement surgery is concerned, you can get a single correction or a multifocal correction (example). The multifocal approach requires the brain to do a lot of "image processing" for lack of a better term. This is, obviously, quite a bit different than a bifocal or varifocal (what us Yanks call "progressive") eyeglass lens.

Since they make multifocal contact lenses (this approach doesn't work in eyeglasses), you can experience the multifocal approach for yourself if you get a pair of multifocal contacts. I tried them and hated it with a passion. I even gave it a good three weeks to get used to them. Couldn't do it. Some people can. Don't know anyone that flies with them, and don't know anyone that has had multifocal refractive surgery, either.

Thanks. I thought Shy was referring to glasses.