Any opticians out there ....

[OneEyedSam]

As my avatar might suggest, I can only see through one eye. Ive lived with this most of my life and day to day it isnt something I think or worry about.

I have started to notice that my naked eye vision isnt as good as other peoples and wonder if thats just that I just happen to have poor night vision, or whether "normal" people have an advantage over me because they are collecting 2 eyes worth of light.

On the plus side, i dont have to squint when looking through an eyepiece, which I hear can affect viewing, so its not all bad

Does anybody know ?

[ronin]

Could be showing long or short sightedness, astigmatism, possibly cataracts and hopefully nothing worse.

Answer: Go get it checked at a good opticians.

Asking here is really no use at all is it ?

[OneEyedSam]

oh, should have mentioned - my "good" eye has 20/20 vision

[OneEyedSam]

Ronin - it gets checked regularly by a consultant opthalmologist at Addenbrookes

[OneEyedSam]

just edited my post ... the issue isnt my eyesight degrading, more that I have noticed that other people seem in general to have better night vision than me

[stargazerslivingroom]

I do like your glass half full attitude, Sam.

Don't think I'll fret about squinting after reading your post...Fair play chap.

Steve

[acey]

Two eyes do have an advantage over one. The standard factor for judging the superior performance of binocular (two-eyed) vision over monocular vision is root-2, i.e. about 1.4. In other words a two-eye person is expected to have a threshold about 1.4 times better than with one eye, which works out at about 0.4 mag fainter. Similarly, looking through binoculars should give a limiting mag about 0.4 fainter than a refractor of equal aperture (all other things being equal - though binoculars lose light in their prisms).

When we look through a telescope we lose whatever two-eyed advantage we have. A binoviewer splits the available light between two eyes, so each one gets a dimmer image, and the effect cancels out. Some people perceive a 3d effect on objects such as the moon, which must be a function of the way the visual system works (it can't be genuine 3d).

Your night vision should only be poorer for naked-eye viewing. Try seeing what your limit is for stars seen through a telescope, and compare with other people viewing with you (with the same scope). You may find that with monocular vision you're no poorer than them. Though another factor is age: our ability to see faint targets gets poorer with age, and the effect begins to accelerate in middle age and beyond. Mine has certainly deteriorated over the years - just one of those things.

[Cath]

Yes two eyes are better than one, especially as it gives you twice the aperture size and parallax abilities.

The brain is a remarkable data figuring out machine. The more data input it has the better it does really.

[OneEyedSam]

Thanks for the input

 Try seeing what your limit is for stars seen through a telescope, and compare with other people viewing with you (with the same scope). You may find that with monocular vision you're no poorer than them.

i think through the EP I am as good as the next man, pretty sure about that

The brain is a remarkable data figuring out machine. The more data input it has the better it does really.

Oh yes, I know about this one...my right eye had very poor sight, light and shade. When I had it removed, I expected that it would be dark on the right hand side as I would be losing that vision.  BUT, turns out I can still "see" beyond my nose where I should not be able to see.  It sounds like witchcraft, but its my brain acting as a sort of video recorder and building up an image.  I occasionally  get caught out by moving objects though.

[Peter Drew]

On a similar tack, with a bit of practice, you can fool your brain into thinking that you are using both eyes to look through the same single eyepiece by trying to look  with both eyes at the image presented to the eye actually in use rather than staring blankly ahead with the other. It's a bit like going slightly cross-eyed and you can't comfotably hold it for long but for me at least, it gives an enhanced planetary view.    

[JamesF]

On a similar tack, with a bit of practice, you can fool your brain into thinking that you are using both eyes to look through the same single eyepiece by trying to look  with both eyes at the image presented to the eye actually in use rather than staring blankly ahead with the other. It's a bit like going slightly cross-eyed and you can't comfotably hold it for long but for me at least, it gives an enhanced planetary view.    

Sounds a bit like trying to see those stereoscopic images that were all the rage *ahem* years ago.

James