Pupil Dilation

[RichM63]

Had an interesting experience today.

It was my 5 year appointment with my Opthalmic Surgeon, the usual tests for degeneration, diseases, cataracts, diabetes etc. and of course how bad my vision is now.

Whilst there, in conversation I mentioned that being into very amateur astronomy, dark adapted pupil sizes are of interest especially whan it comes to the purchase of different EPs and their exit pupil sizes compared to what could be useful in the real world.

He kindly gave me a decent lecture about the structure of the eye, how it is different from person to person, the chemical reactions that take place etc. (brought back memories of my Human Biology days).

However I asked him if it was possible for me to make a home brewed test of my pupil dilation under the dark skies in our area without a Moon blazing away. 

No problem say he, "I can do that for you". I quickly explained that I was not interested in eyedrops to give max dilation but wanted to know what my eyes could do in a normal situation.

So he placed my head into a clamp on the back of a machine and then proceeded to run a series of tests under different light sources (I don't know what they all were, very bright, oddly greenish, strobascopic, different hues, a dark light.....)

The end result came as a bit of a surprise.

In these test conditions, my eye can attain 8.4mm within 10 mins.

To say I was surprised is an understatement, age 50+.

I know that in the real world we don't have optimum conditions but still it was nice to have this measured.

And probably explains why I fall over things in daylight.

The good thing is that it would seem that I should not be overly worried about 'exit pupil' sizes because I will never be able to afford an EP of ridiculous outlet.

He also explained that for my best observation of an object I should give it at least 5 mins before I start to get the best out of it. (my eyes) even when I have pre-adapted to the dark.

Sorry for the longish post, but it was a pleasure to get an Opthalmic Surgeon to perform an actual measurement.

As regards normal wandering around, thankfully we agree, I need a new pair of specs'.

Cheers, 

Rich

[ronin]

I am not actually surprised by that.

I have the idea that people measure their dilation but of course need some light to do it, and any light will be a problem.

In effect if you have enough light to make a measurement then the measurement is invalid.

[barkis]

If you are able to see a magnitude 6 star naked eye, then you must be reasonablty satisfied.

I know some people can  detect fainter ones, but I think +6 is not to be sneered at.

See if you are able to reach fainter by some naked eye observing from as dark a site as you are able to find, using pre determined area os the night sky

containing stars below +6.

Of course, using a large aperture richest field  instrument will afford you a better opportunity to seek fainter stars within a known constellation.

I can only think you may be a multiple star system enthusiast or something of that nature, with a desire to locate the fainer companions.

Then again, I could be just blowing hot air :grin:.

Good luck anyway. eyesight is a very precious sense, and life can become difficult to some degree if it is impaired in some way.

Ron

[LukeSkywatcher]

5 yrs between eye tests?. I have left it that long myself but the experts say to have one every 2 yrs.

[bomberbaz]

I have just had mine done today and advised 6mm although it wasnt a fully dark room and i only had max 2 mins to adapt to dark. This thread I did the other day has some more info regarding this. 

Hope you don't mind rich, not trying to hijack this you understand 

http://stargazerslounge.com/topic/223019-eye-pupil-dilation/

[RichM63]

Hijack away Baz, I would have posted into your thread if I had seen it beforehand.

Paul the full 5 year check is with the surgeon, the optometrist is around 2 years or more frequently depending on how often I break my specs but then it is really only to check for glaucoma and that my script is still valid.

I only had the dilation checked out of curiosity.