New Posts New Posts RSS Feed - Astigmatism (sp???) and Scopes
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Check GunBroker.com for SWFA's No Reserve and No Minimum bid firearm auctions.

Astigmatism (sp???) and Scopes

 Post Reply Post Reply   Topic Search Topic Search  Topic Options Topic Options Page  1 2>
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 00:43
mlv2k5 View Drop Down
Optics Journeyman
Optics Journeyman
Avatar

Joined: September/18/2008
Status: Offline
Points: 300
So, I have been doing a lot of comparisions between my various riflescopes lately, both in low light as well as during the day. The results I have found have been both startling and a little unsettling. First let me say that I have always believed that you get what you pay for, and that tends to hold true for optics. With that said, when I went to put a scope on my Sako 75 in .270 which I purchased last year I was looking for a very high quality scope. I ended up picking up a Kahles 4x12x52 CL with the MultiZero system. Anyhow, the optics are very good and I don't have any complaints about them. But, out of pure curiousity I decided to test this pretty high-end scope against my other cheapys. The two I compared it to were a Nikon Prostaff 3x9x40, and an old Tasco 4x32. All comparisons were done on 4x since that was the only power they could all be adjusted to, then in the low light test, I also compared the two variables at 6x. First I simply looked through them during daylight and tried to observe clarity, and brightness. The Kahles seemed brighter, and clearer, especially when looking at far away objects. But the difference was not as significant as I expected. Next I tested them in low light for clarity, brightness and resolution by attempting to observe bolded black letters which I had drawn out and tacked up against a white garage door about 30 yards away. As the light began to fade I would intermittantly check them against one another to see which "faded out" first. To my surprise they all seemed very close in low light performance. The tasco actually seemed to outperfom the Prostaff until it became very dark and the 4x magnification was not enough to resolve the various letters. The Kahles did seem a bit clearer and brighter than the Nikon, but not enough to reflect the vast difference in the MSRP pricetags in my opinion. The results were that by the time total darkness fell the Kahles only slightly outperformed the Nikon by being able to hazily resolve the largest letters on 4x power. As a cranked up the magnification on both the letters became more visible although the image quality seemed to suffer some particularly with the Nikon. My final result was that the Kahles was indeed the superior scope as was expected, but if you had let me look through both without telling me who made them, I would have assumed the Kahles was probably only a couple hundred dollars more expensive if that gives you any idea of the level of superiority in reference to clarity and brightness. Now, I have obviously contemplated a variety of options to explain this, becasuse I have heard many people rave about the excellent optics of the Kahles Cl line. One thing I have come up with is that the apparent similarity could me my fault. I have mild astigmatism in both eyes, and although corrected by my contacts, I suppose it could be possible that it might be interfereing with scopes. However I do not have any problems with my visual clarity etc, and with contacts I have at least 20/20 vision (I think it might actually be better in my non-shooting eye). Does anyone know if this could have an effect on optical clarity even if my vision is corrected. Or maybe there is something I am not doing to fully take advantage of my optics. I just can't believe that the fairly marginal difference in optical quality I observed is the extent of what so many people talk up with regard to the various high-end european optics such as Kahless, Zeiss, and Swarovski...Sad
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 04:24
skilly1979 View Drop Down
Optics Apprentice
Optics Apprentice
Avatar

Joined: February/18/2008
Status: Offline
Points: 84
its not your eyes. most scopes of margin medium prices with high end priced scopes when looking in daylight seem pretty close optically until you place little letters 100 yds away and try to make out how visible they are,then the higher end ones will shine and especially at low light. for example my slll 8-32-56 that i compared against nightforce, swaro, zeiss, etc.   there is very little difference in optical clarity between the two. yea they might be a little brighter but they are not optically way better just a little better. but now the slll had a little better optics than the nxs we compared it to. but for price is the swaro and zeiss can you see $2000 worth of difference (HELL NO ABSOLUTELY NOT!) its just the way it is in optics.Now many scopes may have a little warmer view verses a less warmer view you as in color wise, some bring out the true colors while others dont as well.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 06:42
jetwrnch View Drop Down
Optics Apprentice
Optics Apprentice
Avatar

Joined: July/03/2006
Location: Knoxville, TN
Status: Offline
Points: 294
I had similar results when comparing a 4x Pro Staff, Elite 4200, 2.5-8 Zeiss conquest, and a 40 year old K2.5 El Paso Weaver. These were tested at 4x and 2.5x. I was a little disapointed that the difference wasn't greater. Where I did notice a difference was in contrast. Try that same comparison with a brown jacket in wooded area. In reality though the spread may not be all that great at close range. I'm coming to the conclusion that with limited funds the big money is better spent on binoculars as these are what you should be glassing with, not scopes. Use the binos to locate and evaluate game. My monetary order of priority is binos, scope, then rifle. Whatever's left over is for food and shelter. Smile
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 08:09
silver View Drop Down
Optics Master
Optics Master


Joined: November/04/2005
Location: United States
Status: Offline
Points: 2291
Some where between two and twelve sentences make up a paragraph.  While the rules say you may have more sentences, it gets into an abstract (rambling)  thought that is unclear and harder to understand.  Long paragraphs show a certian loss of focus and are the tools of a "troubled" writer. 
 
I expect people to pay by the word.  Shop rate is 40$ per hour to fix such. The opening post really needs to be edited for legablity. 
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 08:21
300S&W View Drop Down
Optics God
Optics God
Avatar

Joined: January/27/2008
Location: Burlington,WV
Status: Offline
Points: 10592
    Thunbs Up    GOOD read,m!
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 09:19
safariarms man View Drop Down
Optics Apprentice
Optics Apprentice
Avatar
Dolphin Overton

Joined: June/28/2009
Location: K67BB
Status: Offline
Points: 111
Originally posted by mlv2k5 mlv2k5 wrote:

So, I have been doing a lot of comparisons between my various rifle scopes lately, both in low light as well as during the day. The results I have found have been both startling and a little unsettling. First let me say that I have always believed that you get what you pay for, and that tends to hold true for optics. With that said, when I went to put a scope on my Sako 75 in .270 which I purchased last year I was looking for a very high quality scope. I ended up picking up a Kahles 4x12x52 CL with the MultiZero system. Anyhow, the optics are very good and I don't have any complaints about them. But, out of pure curiosity I decided to test this pretty high-end scope against my other cheapies. The two I compared it to were a Nikon Prostaff 3x9x40, and an old Tasco 4x32. All comparisons were done on 4x since that was the only power they could all be adjusted to, then in the low light test, I also compared the two variables at 6x. First I simply looked through them during daylight and tried to observe clarity, and brightness. The Kahles seemed brighter, and clearer, especially when looking at far away objects. But the difference was not as significant as I expected. Next I tested them in low light for clarity, brightness and resolution by attempting to observe bolded black letters which I had drawn out and tacked up against a white garage door about 30 yards away. As the light began to fade I would intermittently check them against one another to see which "faded out" first. To my surprise they all seemed very close in low light performance. The tasco actually seemed to outperform the Prostaff until it became very dark and the 4x magnification was not enough to resolve the various letters. The Kahles did seem a bit clearer and brighter than the Nikon, but not enough to reflect the vast difference in the MSRP price tags in my opinion. The results were that by the time total darkness fell the Kahles only slightly outperformed the Nikon by being able to hazily resolve the largest letters on 4x power. As a cranked up the magnification on both the letters became more visible although the image quality seemed to suffer some particularly with the Nikon. My final result was that the Kahles was indeed the superior scope as was expected, but if you had let me look through both without telling me who made them, I would have assumed the Kahles was probably only a couple hundred dollars more expensive if that gives you any idea of the level of superiority in reference to clarity and brightness. Now, I have obviously contemplated a variety of options to explain this, because I have heard many people rave about the excellent optics of the Kahles Cl line. One thing I have come up with is that the apparent similarity could me my fault. I have mild astigmatism in both eyes, and although corrected by my contacts, I suppose it could be possible that it might be interfering with scopes. However I do not have any problems with my visual clarity etc, and with contacts I have at least 20/20 vision (I think it might actually be better in my non-shooting eye). Does anyone know if this could have an effect on optical clarity even if my vision is corrected. Or maybe there is something I am not doing to fully take advantage of my optics. I just can't believe that the fairly marginal difference in optical quality I observed is the extent of what so many people talk up with regard to the various high-end european optics such as Kahless, Zeiss, and Swarovski...Sad
I think your experience is not unusual.  However, if you scoped out to further distances and had a Tasco at a higher power you would have seen vast differences in the Kahles and the others.  Now whether the differences are worth the cost differences are up to you.  In scopes I believe there is a law of rapid diminishing return once you get to a 300 to 400 dollar price range of a good manufacturer, ie Nikon, Bushnell etc..  I own a Kahles that was purchased for 599, a CL 2.5x10 I believe, I would have to look at it, but it is one of my favorites, but I did not pay the MSRP, nor would have I ever done that, because I did not think it was worth that.  But, at 599, I thought it was worth the extra cash.  Those are decisions only you can and other purchasers have to make.  That is why I always say, check out the scopes you are considering to purchase, you may find that you do not want to part with that extra 500 dollars just for a high end name.  But, that is each individual's decision.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 10:05
Dale Clifford View Drop Down
Optics Jedi Knight
Optics Jedi Knight


Joined: July/04/2004
Location: United States
Status: Offline
Points: 5087
if you just choose clarity and brightness as the guidelines for judgement, it really does a disservice to the scopes with the higher cost. As an example -- no scope approaches the lower end magnification range , in eye relief , quick focus, and lack of tubbing as the z6, and very few if any approach the zeiss diavaris in off axis target eye alignment, or the clarity at the the very outer edge of the reticle as in their z1000 reticle. None of the middle price or lower comes close to the ball detent clicks of a uso or a nf. could go on but it would just be a rant.
Not saying that the middle priced scopes don't offer a good value- you just have to decide what you want.


Edited by Dale Clifford - August/02/2009 at 10:06
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 10:39
Texas View Drop Down
Optics Apprentice
Optics Apprentice
Avatar

Joined: February/11/2008
Location: Texas, USA
Status: Offline
Points: 211
Good morning all! A few years back in my hunting education, I had the epiphany that the optics budget should go more to uber glass in binoculars and less to high-end scopes. Because of that thought, I scrimped and saved and traded a beloved Super Redhawk to the sample list for a fantastic Leica binocular that I absolutely enjoy everyday, and that work especially well when hunting. For scopes I used Leupold and Redfield. This approach worked really well for a while, but then another epiphany came to me and I upgraded most of the scopes on the rifles I use most.

Why?

As I became more experienced hunting I found I was going/staying out in more and more low-light situations. Also, shots kept getting longer and longer. And, my eyes kept aging older and older - and my uncorrected vision was not good to begin with. What kept happening was game I could see and judge with the Leicas became indistinguishable from other animals (and bushes!) through the scope. I was switching back and forth scope to binocular when I needed to be preparing for the shot and pulling the trigger. I can tell you this cost me more than two or three good trophies.

What now works best for me is well-matched optics. I recommend great binoculars absolutely - but I also recommend at least one "go to" big game rifle with the best scope glass you can get. Save, scrimp or forego multiple rifles if necessary, but your big game rifle scope needs to be matched to your binoculars. Go ahead and get the good binos first, of course. That way if I'm wrong, you are still right and good to go on your next hunt.

Justt be aware that one good optic can lead to another, and another, etc. And its all about the hunt and the trophy.

Just my thinking, YMMV. Good shooting!

Texas
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 11:31
tahqua View Drop Down
MODERATOR
MODERATOR
Avatar
Have You Driven A Ford Lately?

Joined: March/27/2006
Location: Michigan, USA
Status: Offline
Points: 8043
Thanks for your observations, mlv. I wear glasses for far sightedness. Though different than astigmatism, does affect using rifle scopes. I have had to make adjustments when lining up the sweet spot between the scopes and my progressive lenses. Once there, it does not have an effect on the brightness or clarity of the scope.
Where I find my top end scopes make a difference is in longer ranges in low light. This has made a difference in the past. I can see branches and other cover that would have otherwise deflected a shot and possibly injured an animal. I love my Kahles 30mm tubed C models.
I always go back and forth on the question of scope cost. Just the other day I had my 3-9x40 Monarch out in back with one of my 1.1-4x24 Kahles' scopes. I was shouldering the guns for kicks and was looking into the wood piles that are out back at ranges from 100-200 yards. The difference was very large to my eyes. The Kahles is worth the difference to me.

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 12:06
RifleDude View Drop Down
MODERATOR
MODERATOR
Avatar

Joined: October/13/2006
Location: Texas
Status: Offline
Points: 14313

Mlv, much of what you are observing involves the law of diminishing returns.  At some point, it becomes very difficult to say an optic provides improvements in performance directly proportional to the additional $s spent.  While I would expect you'd see pretty significant differences in optical performance between a Tasco and the Kahles, a good, solid midrange scope will provide probably 80% of the optical performance of an alpha class scope.  Squeezing out that last 10% -15% of extra image quality involves design measures that dramatically increases price.

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 12:22
Rancid Coolaid View Drop Down
Optics Jedi Master
Optics Jedi Master
Avatar

Joined: January/19/2005
Location: United States
Status: Offline
Points: 7694
Try evaluating at a longer distance and without a white background (since, in hunting scenarios, you will probably never have a target against a white backdrop.)  Also consider field of view.
A few years back, I was hunting in Mississippi during primitive weapon season with a friend's dad's 45/70 (I know it ain't ideal, it was a short-notice hunt and I had no "primitive weapon.) I zeroed the rifle just under 100 yards at 9X.  First, the turrets were backwards: when it said "up", it meant "down" and the same with the windage: "right" was "left."  Later that day, I had a great 60-yard shot on a beautiful 10-point.  Clean Miss!"  At 60 yards!  I could'a thrown the gun at him and killed the deer.
I took the shot at 3X.  When we got back, I fired at the same target I zeroed, but at 3X, not 9X, nowhere near paper.  At 9X, I was dead nutz.
Internals make a huge part of a scope's quality and bad internals screw things up. Badly.

Price alone does not dictate quality, Counter Sniper scopes can cost $7,000 (though I've never seen one of those.)  Glass is the most subjective part of an optic, but there are marked differences between a BSA and a Swaro.

I recommend you use a darker backdrop and try it further away.  Also consider putting indicators on the ground in 1-foot or 2-foot intervals, so you can appreciate the field of view differences.

One of my favorite scopes is my 4X IOR hunter (on my 45/70 -I bought my own after that miss.  That deer still haunts my dreams, we call him Barnes, "Only one that can kill Barnes is Barnes.")  It is nowhere near my most expensive scope, but it does it's job very, very well.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 13:05
Longhunter View Drop Down
Optics Journeyman
Optics Journeyman
Avatar

Joined: February/02/2006
Status: Offline
Points: 422
+1 for Texas
 
I still remember how frustrating it was to see a deer clearly at near-dark through my old Zeiss 8x30s, and then losing the shot because I couldn't make it out through my Leupold Vari-X III 2.5-7x.
 
It pays to compare your scope to your binoculars.  Good binoculars will win, but the scope should at least be close. 
 
 
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 14:13
Oldtrader3 View Drop Down
Optics Journeyman
Optics Journeyman
Avatar

Joined: May/16/2009
Location: WA (state)
Status: Offline
Points: 445
I have atigmatism and am far-sighted.  I also just had cataract surgery on my right eye two weeks ago.  My vision was 20/200 before surgery with impaired color perception.  Everything has changed now.  All my eyepiece on all scopes settings are now off.  Plus, the new eye lens is still settling in to it's final vision configuration from the operation.
I can sit at a computer now and read without glasses for the first time in 30 years, plus color vision is restored.
 
I am blessed to have relatively high quality optics in all (9) of my scopes.  They range from Bushnell 3000, Redfield Illuminator, Nikon Monarch, Leupold VX-II and VXIII to Kahles AH, Swarovski AV and Zeiss Diavari.
 
The issue for now is whether I can shoot without wearing glasses and be able to go from binoculars to Spotting Scope to rifle scope without having to put on and remove eyeglasses.  I won't know for 3 more weeks until I get a new eyeglass prescription, what I have to work with.  We shall see.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 14:40
safariarms man View Drop Down
Optics Apprentice
Optics Apprentice
Avatar
Dolphin Overton

Joined: June/28/2009
Location: K67BB
Status: Offline
Points: 111
All good advice.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 15:53
mlv2k5 View Drop Down
Optics Journeyman
Optics Journeyman
Avatar

Joined: September/18/2008
Status: Offline
Points: 300
Silver: I apologize for the poor rhetorical structure. If it was an impediment to your ability to understand what I was trying to say that is regrettable. I was typing that post out at around five O'clock in the morning and was very tired. Consequently, I believe my mind was focused on getting the idea out, not grammatical and literary guidelines. Also, I was typing on a Mac- I'm not sure if I even attempted to break the paragraph up because I honestly do not remember, but it would not be the first time a Mac has caused formatting issues for me leading to apparently illegible posts. 
To everyone else who responded thank you for the honest replies regarding "diminishing returns" etc. I knew that the differences between a 2000 dollar scope and a 1000 dollar scope were likely to be slight at best, but I guess I just expected a larger margin between my 139.99 Prostaff and the Kahles. I will have to try setting up some tests that involve wooded areas at greater distances and see what the Kahles can really do. The Kahles was my first truly high-dollar scope, and I love it, but I would like to see it outperform my cheapys a little better. Big Grin

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 16:33
Rancid Coolaid View Drop Down
Optics Jedi Master
Optics Jedi Master
Avatar

Joined: January/19/2005
Location: United States
Status: Offline
Points: 7694
Actually, the difference between a $1,000 scope and a $2,000 scope can be dramatic; generalities do not serve well here.

I don't think you did a fair comparison. If your test represents how you will use the scopes, you should be disappointed.  As you move into real-world hunting scenarios, I think the Kahles will distinguish itself quite nicely.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 17:17
safariarms man View Drop Down
Optics Apprentice
Optics Apprentice
Avatar
Dolphin Overton

Joined: June/28/2009
Location: K67BB
Status: Offline
Points: 111
Originally posted by mlv2k5 mlv2k5 wrote:

Silver: I apologize for the poor rhetorical structure. If it was an impediment to your ability to understand what I was trying to say that is regrettable. I was typing that post out at around five O'clock in the morning and was very tired. Consequently, I believe my mind was focused on getting the idea out, not grammatical and literary guidelines. Also, I was typing on a Mac- I'm not sure if I even attempted to break the paragraph up because I honestly do not remember, but it would not be the first time a Mac has caused formatting issues for me leading to apparently illegible posts. 
To everyone else who responded thank you for the honest replies regarding "diminishing returns" etc. I knew that the differences between a 2000 dollar scope and a 1000 dollar scope were likely to be slight at best, but I guess I just expected a larger margin between my 139.99 Prostaff and the Kahles. I will have to try setting up some tests that involve wooded areas at greater distances and see what the Kahles can really do. The Kahles was my first truly high-dollar scope, and I love it, but I would like to see it outperform my cheapys a little better. Big Grin
 

Well said.  I thought your post was quite reasonable and I regret that you were given such treatment.  I am new around here and I have to say, that most people are very reasonable, but every now and then some folks seem to get their panties in a wad.


Edited by safariarms man - August/02/2009 at 17:18
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 18:21
Oldtrader3 View Drop Down
Optics Journeyman
Optics Journeyman
Avatar

Joined: May/16/2009
Location: WA (state)
Status: Offline
Points: 445
Astigmatism is limited to a focal plane focus error on a small axis arc of the eyeball.  It can only be corrected by grinding eyeglasses to the correct axis, diopter curvature.  It is too much to expect of the diopter correction ring of your scope to help by correcting your astigmatism, particularly since it can not possibly duplicate the off-axis curvature which is causing the astigmatism.
 
This diopter ring on the scope is intended only to make small corrections for far-sightedness or near-sightedness 


Edited by Oldtrader3 - August/06/2009 at 11:54
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 18:29
tahqua View Drop Down
MODERATOR
MODERATOR
Avatar
Have You Driven A Ford Lately?

Joined: March/27/2006
Location: Michigan, USA
Status: Offline
Points: 8043
I appreciate that explanation, Oldtrader........thanks
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 19:24
300S&W View Drop Down
Optics God
Optics God
Avatar

Joined: January/27/2008
Location: Burlington,WV
Status: Offline
Points: 10592
  WOW!! +10,Oldtrader.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 20:19
mlv2k5 View Drop Down
Optics Journeyman
Optics Journeyman
Avatar

Joined: September/18/2008
Status: Offline
Points: 300
Oldtrader, do you know whether wearing corrective contacts would remedy the issue? My contacts are supposed to correct for the problem and I believe my vision is at least 20/20 with them. However, I seem to remember the optomitrist saying something to the effect that in many cases, contacts can not "fully" correct for astigmatism and that you need eyeglasses to truly eliminate the effects. I always wear my contacts when I go shooting and have never noticed any problems, but I suppose it is possible that a minor detriment to my ability to focus could have a profound effect on a magnified image through a scope. 

I should mention that the image through my Kahles is very good, and I am in no way saying the scope has poor quality optics. I was simply surprised by how close in performance my other scopes were. I intend to go out tonight and try to do a little low light testing in hunting situations. Hopefully I will have some interesting results to post soon.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 20:24
mlv2k5 View Drop Down
Optics Journeyman
Optics Journeyman
Avatar

Joined: September/18/2008
Status: Offline
Points: 300
Actually, on the note of optics testing...Does anyone have any suggestions for distances and targets to try to resolve that might really highlight the advantages/disadvantages of various scopes? I was thinking I would set up some kind of board with letters or numbers bolded on it, then try to resolve them from around a hundred yards down a power-line cut.

If anyone has already perfomed similar tests with their scopes, I would love to know how they turned out. How did high dollar scopes compare to mid-range stuff? Where were the differences most noticeable etc?
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 22:17
silver View Drop Down
Optics Master
Optics Master


Joined: November/04/2005
Location: United States
Status: Offline
Points: 2291
Astigmatism basically means that the lens of your eye is a bit out of round.  Contacts can correct for more of that now and get better every year.  The problem is that the placement of the contact is more "directional" and requires a more exact placement.
 
Contacts would be better than glasses if they are close to correcting your astigmatism.  That is because the correction lies directly on the eye and is not a focusing plane between the eye and the next focusing plane of glass.
 
Now my old computer has its issues also.  Often the format cuts off about the last 8 letters.  so I have to slide.  When I have fifty lines of un interupted text, then I can't read what is being said.
 
One of local our optomoligist is in my Bible study and offers group discounts for Lasik.  We have EYE U in the our back yard and damn good eye surgeons.  My friend is one of the best in town and is not always out of town watching his kids football games like his old partner.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 22:33
silver View Drop Down
Optics Master
Optics Master


Joined: November/04/2005
Location: United States
Status: Offline
Points: 2291
Originally posted by mlv2k5 mlv2k5 wrote:

Actually, on the note of optics testing...Does anyone have any suggestions for distances and targets to try to resolve that might really highlight the advantages/disadvantages of various scopes? I was thinking I would set up some kind of board with letters or numbers bolded on it, then try to resolve them from around a hundred yards down a power-line cut.
 
 
Try using a brown tarp.  That will give you more of an animal colored back ground.  Then a color wheel chart,  some playing cards, an eye chart made into a stencil, and a GI Joe jeep with some tanerrite for good measure. Start at 50 yards and work back.
 
You could use the eye chart stencil on some paper grocery bags and set them out at known ranges.  A photo grey scale could also be fun.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: August/02/2009 at 22:44
Oldtrader3 View Drop Down
Optics Journeyman
Optics Journeyman
Avatar

Joined: May/16/2009
Location: WA (state)
Status: Offline
Points: 445
I have a new perfectly formed plastic lens in my right eye.  It is as good as the Medical Device Labs can make it.  Astigmatism is an aberation of the cornea of the eye caused by uneven muscle tension which pulls the cornea in a single axis direction, making it oblong or football shaped.  This scatters light into the lens of the eye.  The cornea is directly on top of the lens. 
 
This scattered light does not form a focal point and causes blurry vision.  My surgeon says that she could not correct the astigmatism with cataract surgery, so I will need glasses for corrected distance vision.  This is the same as for the other eye which I had surgery on.  I prefer to wear Armorlite type plastic lenses when I shoot anyhow because the protect my eyes well against a pierced primer or whatever. 
 
Contacts depend on the irregular shape of the cornea to orient the lens.  This works better for some people than for others and doctors don't seem to know why some people have trouble keeping the contact lens oriented.
 Post Reply Post Reply Page  1 2>
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Similar Threads: "Astigmatism (sp???) and Scopes"
Subject Author Forum Replies Last Post
CZ 527 SCOPE/ NO SCOPE? JAMINGRIZZ Rifle Scopes 16
what makes a scope a shogun scope? axaviere Shotgun / BlackPowder Scopes 5
Pentax DCF SP 10x50 DAVE44 Binoculars 0
Tools for LR Shooting with SP's when Sitting Ernie Bishop Shooting 18
Pentax SP 8x43 cropslx Binoculars 4
Pentax DCF SP DAVE44 Binoculars 2
1X optic for astigmatism MMasztal Tactical Scopes 6
Bushnell Elite Spotting scope question? bergbennett Spotting Scopes 1
Cricket Bullpup Scope Mark2Cars Rimfire / Airgun 0
Pentax DCF SP 10x50 vs Monarch rh44mag Binoculars 3


This page was generated in 0.531 seconds.