Contact Lenses and Observing

[kerrylewis]

There are a few threads on this subject, or similar, and I've read  a few but none seem to answer my specific query. I also know that we have some friendly opticians on the forum 

I have worn glasses for years. i have astigmatism in both eyes but one (the left) is better than the other. I also need help with reading so for the last few years I have had varifocal lenses. Expensive but they work well - except for astronomy.

I have never been able to wear glasses with scopes or binoculars even with long eye relief. I can't seem to get used to it somehow. So I use my better eye and then have to put the glasses on to do other things like read the handset or a sky atlas.

This is getting more frustrating and  I also feel that I am not getting the best views through both scopes and bins. I bought a TV Dioptrix a few years back but it only fits my 6mm Radian and I understand that astigmatism  actually has more of an adverse effect with shorter focal length/wider FOV eyepieces.  I have read this on the forum but didn't know it at the time! 

So - the question is would contact lenses be the answer? I understood from some time ago that they would not work for my eyes, but I gather that this might not be the case now. One optician in the town is offering free trials of contact lenses - nit sure if that would apply to me though. 

There is also eye surgery! Not sure if this would work either but is perhaps a bit drastic (and expensive) for this pensioner. 

Any advice gratefully received

Cheers

Kerry 

[Scooot]

Hi Kerry,

I'm the same as you, astigmatism in both eyes, left eye better than the right so I always use my left eye but with a dioptrx. I actually thought it was the longer focal length eyepieces that are more affected by astigmatism. The higher power are less affected because you use more of the centre of the eye and less of the astigmatism region? Hopefully someone will correct me if needed.

I have tried using my contact lenses as well. The trouble is I can't get so precise a prescription with these as with my glasses, and they certainly don't correct my right eye very well. They also have a habit of spinning whilst viewing which causes an airy disc to suddenly appear, presumably because when they spin the astigmatism isn't being corrected. I also then have the problem of having to put on reading glasses to read whilst using the contacts which is a pain to read the charts. So unless I'm viewing with others I prefer the Dioptrx.

[kerrylewis]

Hello Richard

Yes - mistake in my original post: I meant to say that longer focal lengths are more affected - senior moment.

Interesting comments. I see that you have some of the longer focal length TV eyepieces - perhaps that's my answer, lots of expensive Green and Black!

Also you say that the contacts can "spin" and you still wear glasses for reading which is one of the things that I am trying to avoid. I understand that you can get bifocal contacts though.

Kerry

[Scooot]

I only notice the contacts spinning when observing through the scope. I understand they're weighted to hold them on the eye on the correct axis for the astigmatism. They'll fall back again but it's still a bit annoying when it happens, but not having the exact prescription is more annoying. Mine falls in between the standard ones. I suppose it's possible to get custom contacts but I only wear mine occasionally, at weekends sometimes, or on hikes or playing golf etc so it's not really worth it for me.

I'm lucky in that I can normally read (with my left eye) without glasses, but if I wear the contact lenses I'd then have to wear reading glasses to read. So using the dioptrx I can get away with no glasses whilst observing as I can read without them but if I look up at the sky or through the finder I have to put them on again.

If you can get bifocal lenses that might be the answer but they'd need to remain steady on your eye whilst observing. I'm not sure why mine spin sometimes, might be the night air making my eyes water a bit, could just be me and doesn't affect anyone else. I suppose the only way is to try some. I'm sure your optician would give you some trial ones.

The dioptrx work well with all the Delos with the eyeguard up. Not quite so well with the Nagler on which I have to have the eyeguard down, and even then I need to press my eye tight against the eyepiece to get the whole field. However I'm going to get another dioptrx shortly to save switching between eyepieces so much.

[Moonshane]

I wear contacts 24/7 for a month and then replace

whilst I don't have any major astigmatism I love and recommend them highly.

[Special K]

I can sympathize with your situation, Kerry, as I have astigmatism in my dominant eye, am nearsighted, and have increasing difficulty with reading. I don't wear contacts so won't be able to offer any helpful info, other than to agree that observing without eyeglasses is more comfortable for me as well. If I were to wear a contact lens to correct my eyes then I wouldn't be able to read without reading glasses. Therefore, I go naked eye at the EP, keep a pair of prescription glasses on my person for using the finder etc, and also some reading glasses for the charts. Pain in the neck: yes! I suppose I've got used to all this fiddling around. If a contact lens solution looks plausible for you then maybe that's the best way to go.

[Polar Bear]

If you can get a free trial then make use of it and try them. Everyone is different when it comes to eyes and there are so many variables.

I am shortsighted and using contact lenses works for me at the eyepiece, however with contact lenses in my near focus is about 4 feet so I cannot read a star atlas or any apps on my ipad or phone. 

I thought every pair of binoculars I bought for years was out of collimation only to find out I had astigmatism.  The hours I wasted trying to correct them....

I can see fine at the EP but cannot even see a star without my glasses so this becomes a real pain as I do use goto. Give the contacts a go, you have nothing to lose. 

[kerrylewis]

I am going ahead with the trial. I have had a fresh eye test and some lenses will be ordered. Unfortunately the terms of the free trial are only to try them out for 15-20 mins close to the shop. However I can take my binoculars to try with them (I assume!) and most contact lenses are on monthly deal anyway and if it doesn't work out I can always revert to specs. So I have an appointment in a couple of weeks with the contacts specialist and I will see how it goes. Thanks for the input so far; I will report on progress. 

Kerry 

[Mr Flibble]

When you're with the contacts specialist make sure you put in and remove the contacts at least twice so that when you try it for the first time on your own you won't have any issues.

After you've done it a few times and got the knack it becomes a doddle.

They really do make observing so much easier and comfortable.

[clarkpm4242]

Hi there

I am very short-sighted (no jokes) -11 and 2 dioptres of astigmatism.  This is what works for me, plus a few comments...

- using thin, high refractive index glass long distance specs

- using eyepieces with an eye relief of 15+mm e.g. Delos

- trying to remember to fold down eye cup if required

- a unit power RDF or Telrad (with specs)

- a tablet with planetarium program of choice (Sky Safari), zooming in an config. can make it bigger (night mode & screen filters retain dark adaptation)

- DO NOT have surgery

- a short trial of contacts without fully dark adapted eyes (wide pupil) will not give you an accurate feel for there good/bad points

- DO NOT have surgery

- varifocals will not work owing to varying correction and scope/eye positions

- DO NOT have surgery

There are still occasions of frustration however, using familiar specs that stay on all the time gives you a good base to observe from.

Hope this helps, others may have differing opinions...

...good luck.

Cheers

Paul

[Yearofthegoat]

I am short-sighted (5.75) and have astigmatism. I wear glasses a far bit and contact lenses for sport, walking etc. I also use microscopes a fair amount and found that with those, the lenses were okay and the glasses were marginally worse, such that sometimes I took them right off and just used my bare eyes.

I've recently become unable to read close up with my contact lenses on and my optician has suggested getting some +1 reading glasses, which is a pain but sort of makes sense if I'm doing something which otherwise needs me to wear contacts.

Post above is correct - don't have surgery.  There isn't the long-term data available yet and it could well cause you more problems than it solves.

I find my contact lenses do move a bit but a blink puts them back in the correct orientation and on balance they're fine with microscope/telescope/camera.  I'm surprised the trial is only 'within a short distance of the shop'! I use Vision Express and they let me take lenses away for a week to try, I then go back and they put a 'proper' order in.  As has been mentioned above, how can you test them fully (e.g. in the middle of the night with your scope) like that?

Anyway, hope you get it sorted as it is annoying when your vision isn't as good as you'd like.

[kerrylewis]

Well, I've had the contacts for 5 days now and have  been gradually increasing the time wearing them. I've not yet used them properly with a scope yet but through binoculars I think the view is sharper with less flare on bright objects. Hoping to have a full trial with the scope tomorrow evening and will report further.  

[Jonimac25]

I have astigmatism in both eyes and wear contact lenses. I originally started wearing them solely for astronomy use but after no time at all I was wearing them all the time, they are great! I go for the daily throw away ones, they can be a bit more expensive but I don't have all the messing about with solutions and whatnot. They don't take long to get used to wearing them, and I would recommend them to anyone!

[Merlin]

An alternative to contacts that I prefer is to file down a spare specs lens, so that it can fit inside the rubber eyeshields of eyepieces.

I filed down two lenses to fit the WO binoviewer.

[Hals]

Contact lens wearer for twenty-years and I've never had a problem with them either using bins or a 'scope.

[Moonshane]

I literally wear mine 24\7 for a month then take them out and put a new pair in. like laser surgery without the laser or the surgery.

[RichieP]

I use contacts at the scope with no issues (as long as they are clean!). Main thing to remember is to keep blinking on a regular basis because they can dry out pretty quickly.

[Tommohawk]

Hi. Slightly late comment but I am hospital optometrist and erstwhile contact lens optician.... am also astigmatic (-2.00 each eye) and myopic(-2.50 ish) , and presbyopic ( ie need separate reading glasses/varifacals cos old bloke) so know the terrain.

I sympathise with your problem - occasionally I use binoculars and have the same issues.  A few comments.

Contact lenses (CLs) should sort your distance vision same as distance glasses - assuming the lens stabilises properly. Toric contact lenses (ie correct astigmatism) do have "weights" so are prone to rotate if you stand on your head, but the thing that stabilises mostly is the blinking action. So dont stop blinking.

If your contacts are both set for distance, you'll need simple readers over the top for near; off-the-peg chaps should do. About +2.00 or +2.50 if youre over 60.

You could have one CL set for distance and the other for near. Its not ideal, cos only using one eye at a time, but it can work. Not great for driving, but OK for monocular scope use. You could use the distance eye with the scope, and the near eye for chart/whatever.

There are various bifocal/varifocal contact lenses - the optical performance is typically errr.... variable. (Usually somewhere between poor and awful)

One apporach is, throw away all your eyepieces and use a camera / laptop. I'm sort of joking, but TBH thats what I mostly do. I'm a bit surprised this approach isn't more popular - you can do intermittent longer exposure shots (depending on your guiding set up) for DSOs, and view in comfort with both eyes open.

Let us know how you get on.

Regards

[kerrylewis]

Thanks for your comments Tommo.

I've got the distance on one eye and reading on the other set up. The distance works well but the reading is not good enough and I think I will need additional glasses. It should be good enough to read the mount handset though and that will be an improvement in not having to take glasses on and off. I've not yet tried observing and quick tests with the binoculars didn't really show up a dramatic difference.

So, my next appointment is Tuesday and if I can keep the present lenses but add corrective glasses for reading I think it'll work out.

[Tommohawk]

OK Kerry. Remember if you have monovision (one far other near) and using binoculars you'll need to offset one of the eyepieces - otherwise youll only be using one eye properly. Should be within adjustment range.

Readers over the top should work OK - obviously the eye thats set for near shouldnt need much if any correction.

Good luck - be interested to see how it works out. Forgetting scope/astro stuff, how is it for everything else?