Should Have Gone to Specs Savers.....

[TJExcalibur]

After my post "Is It Me" I had a chat with my local optician, not Spec Savers.  She told me the fov decreases with age and told me I should not expect a higher fov than 65 degrees at my age which is 74. Eyepieces over 68 degrees are usually of no advantage to the elderly unless you are prepared to constantly move your eye to focus. Here is a link to a site she suggested but states it is not as good as an optician test with precise equipment.

http://www.testvision.org/disclaimer.html

[rockystar]

presumably this it to do with peripheral vision degrading with age?

worth Testing though, save money on those wide angle eyepieces. Having said that, I like my 24mm 82degree, even though I'm sure i can't see all of it, it does mean I don't have to move the scope as often.

[michael.h.f.wilkinson]

Actually, I am not quite sure about this. The eye only sees a sharp image in a little circle near the fovea, and this does not change with age, I gather. Large FOV EPs always will require eye motion, and indeed the eye is never really totally still, but goes through cycles of rapid movements and short periods of fixation on one point (so called saccade-fixate cycle). What will change with age is the degree of accommodation the eye will allow to overcome any field curvature. If the latter is well corrected large FOV EPs should work well enough

[Mak the Night]

Normal limits

The normal (monocular) human visual field extends to approximately 60 degrees nasally (toward the nose, or inward) from the vertical meridian in each eye, to 107 degrees temporally (away from the nose, or outwards) from the vertical meridian, and approximately 70 degrees above and 80 below the horizontal meridian [2] [3] .[4] The binocular visual field is the superimposition of the two monocular fields. In the binocular field, the area left of the vertical meridian is referred to as the left visual field (which is temporally for the left, and nasally for the right eye); a corresponding definition holds for the right visual field. The four areas delimited by the vertical and horizontal meridian are referred to as upper/lower left/right quadrants. In the United Kingdom, the minimum field requirement for driving is 60 degrees either side of the vertical meridian, and 20 degrees above and below horizontal. The macula corresponds to the central 17 degrees diameter of the visual field; the fovea to the central 5.2 degrees, and the foveola to 1–1.2 degrees diameter.[5][6] ~ Wikipedia

https://en.wikipedia.org/wiki/Visual_field

[TJExcalibur]

14 minutes ago, michael.h.f.wilkinson said:

Actually, I am not quite sure about this. The eye only sees a sharp image in a little circle near the fovea, and this does not change with age, I gather. Large FOV EPs always will require eye motion, and indeed the eye is never really totally still, but goes through cycles of rapid movements and short periods of fixation on one point (so called saccade-fixate cycle). What will change with age is the degree of accommodation the eye will allow to overcome any field curvature. If the latter is well corrected large FOV EPs should work well enough

Clear Outside tells me I will have 2 hours of clear sky tonight. If so I will do a comparison with the a Celestron X cell 18mm and a ES 82 18mm. Must admit I may be different as I was born blind in one eye and the other is getting weary as I get older. I will ask swimbo foe her opinion, hoping it does not take as long as choosing a pair of shoes. 

[Mak the Night]

3 hours ago, TJExcalibur said:

Clear Outside tells me I will have 2 hours of clear sky tonight. If so I will do a comparison with the a Celestron X cell 18mm and a ES 82 18mm. Must admit I may be different as I was born blind in one eye and the other is getting weary as I get older. I will ask swimbo foe her opinion, hoping it does not take as long as choosing a pair of shoes. 

I hope you get those two hours. I'd be interested to read the comparison between the X-Cel and the ES 18mm. I have an 18.2mm DeLite, but I've been using my 9mm X-Cel a lot recently on my Newtonian as I needed 250x for Mars. I should be receiving my 7mm X-Cel soon. I'm quite impressed with the X-Cel for what they cost.

[bingevader]

4 hours ago, TJExcalibur said:

Clear Outside tells me I will have 2 hours of clear sky tonight. If so I will do a comparison with the a Celestron X cell 18mm and a ES 82 18mm. Must admit I may be different as I was born blind in one eye and the other is getting weary as I get older. I will ask swimbo foe her opinion, hoping it does not take as long as choosing a pair of shoes. 

What 'scope are you using.

I'd be interested in the comparison too.

The ES 82° 18mm is one of my favourites and gives lovely views in my 8" 'scope.

I have the 7mm X-Cel LX, Mak the Night, and like it a lot.

On a clear night it works very pleasantly on the moon with a 2x Barlow with my 8" 'scope.

[Mak the Night]

18 minutes ago, bingevader said:

What 'scope are you using.

I'd be interested in the comparison too.

The ES 82° 18mm is one of my favourites and gives lovely views in my 8" 'scope.

I have the 7mm X-Cel LX, Mak the Night, and like it a lot.

On a clear night it works very pleasantly on the moon with a 2x Barlow with my 8" 'scope.

The 7mm certainly looks good, if it's as good as the 9mm it will be. I went mad and acquired an X-Cel Barlow as well lol.

[L8-Nite]

I went to spec savers to for an exam to find out what my actual dark adapted pupil size was. I was told that they couldn't (wouldn't) give me that information, which really peeved me off; I will never do business with them again.

[Paul73]

How could they give you a "dark adapted" pupil size without tieing up one of their rooms for 30 mins plus measuring time?

They deal in volume and selling glasses. To boycott them on this basis seems A little unfair. Speak to an independent and get a quote. You don't go to McDonnalds and order things that aren't on the menu. Same applies here.

It would be a really handy thing to know though .... 

Looking forward to hearing how you get on.

Paul

[Riemann]

On 02/07/2016 at 00:23, L8-Nite said:

I went to spec savers to for an exam to find out what my actual dark adapted pupil size was. I was told that they couldn't (wouldn't) give me that information, which really peeved me off; I will never do business with them again.

That sort of mindless behaviour drives me nuts.   Anyone would think they were their eyes not yours! 

 

[Stu]

On 2 July 2016 at 01:44, Paul73 said:

How could they give you a "dark adapted" pupil size without tieing up one of their rooms for 30 mins plus measuring time?

They deal in volume and selling glasses. To boycott them on this basis seems A little unfair. Speak to an independent and get a quote. You don't go to McDonnalds and order things that aren't on the menu. Same applies here.

It would be a really handy thing to know though .... 

Looking forward to hearing how you get on.

Paul

To be fair Paul, don't your pupils dilate within a very short time of being in the dark? It's the chemical changes in your eyes which take the time to happen.

Equally fair point that if they are not equipped to measure this quickly and easily then they are under no obligation. It was the 'won't' rather than 'can't' that would have frustrated me.

[saac]

Two questions - 

1.  Why would this information be useful  - I'm guessing to optimise eyepiece selection re eye relief etc.

2.  Could this not be done DIY at home - macro photograph using red light?

 

Jim

[cotterless45]

Specslavers are a franchise. Each store is run independantly. I've had some of the silliest advice, one told me to keep glasses on to avoid astigmatism. The next one told me I didn't have astigmatism. I found the photo of the retina most interesting, especially as one told me I had a bleed nearby and the next one said it was ok. At least it's not like the dentist , where they yank the things out as a last resort.

i can't see the point of 120 degree fov, the kidney beaning and moving around the fov in a 26mm Celestron Plossl is bad enough. Next one will tell you it isn't. After many years of doubting and naysaying , I picked up a 24mm tv Panoptic. Just amazing and so comfortable. I think comfort at the ep is mainly ignored.Until you talk to the next one !

old Nick.

[L8-Nite]

On ‎02‎/‎07‎/‎2016 at 01:44, Paul73 said:

How could they give you a "dark adapted" pupil size without tieing up one of their rooms for 30 mins plus measuring time?  ...........................

 

When I made the appointment I gave my reasons, and I was told I would have a full eye exam. Regardless of how long it took, I paid for my time there, and expected to get what I paid for; wouldn't you ?

[L8-Nite]

4 hours ago, saac said:

Two questions - 

1.  Why would this information be useful  - I'm guessing to optimise eyepiece selection re eye relief etc.

2.  Could this not be done DIY at home - macro photograph using red light?

 

Jim

1. Yes, to optimise eyepiece selection, especially when considering a high end purchase.

2. Don't know about DIY, but I wanted a professional diagnosis, as opticians have the equipment and ability to provide.

[L8-Nite]

8 hours ago, Stu said:

....................................... It was the 'won't' rather than 'can't' that would have frustrated me.

 

It was the " won't ".

[garryblueboy]

They have to add drops in the eye to fully dilate your pupils which means you can't drive or see clearly for several hours I had this done before I had laser surgery proberly why they don't offer the service as just siting in a dark room for a while is not enough for accurate results .

[Paul73]

On 3 July 2016 at 16:31, L8-Nite said:

When I made the appointment I gave my reasons, and I was told I would have a full eye exam. Regardless of how long it took, I paid for my time there, and expected to get what I paid for; wouldn't you ?

Put like that. Yes!! I'd ask for my money back or decline to pay.

Good point from Stu - I'd forgotten about the chemical changes.

Paul