[vsnet-chat 170] First results of eyesight survey.

[Fraser Farrell <fraserf@dove.net.au>]

G'day all,

The responses to this survey so far are summarized below:

(1) How many need to wear spectacles/contact lenses?
      Always                 -  25
      Sometimes              -   7  (5 were for reading only)
      Never                  -  11
      total responses        -  43

(2) Number of observers in each category:
      Longsighted            -   9
      Shortsighted           -  20
      Astigmatic             -  11  (9 were also shortsighted)
      Other problems         -   3
      total responses        -  32


The dioptre(s) of corrective lenses ranged from -1.5 to -9.5 with most
in the -2 to -4 interval.  Only one observer reported significantly
different dioptres for each eye.

Several observers possess contact lenses but nobody wears them for
"serious" observing.  Reasons given include: light scattering/loss from
lens scratches, a tendency for the lens to dry out - changing its
optical properties - while doing an estimate, and lenses falling out or
sticking to the eyepiece!

All but two full-time spectacle wearers remove their specs to look
through the eyepiece.  This highlights a common problem with
commercially available eyepieces - the user's cornea has to be quite
close for the eyepiece to perform as intended.  Many observers then have
to wear their specs to aim the telescope and/or look at charts; leading
to a cycle of specs on - specs off dozens of times per hour.

Three of the part-time spectacle wearers do the same as above.  The
others seem to be able to get through an observing session without using
their spectacles at all.

Nobody claimed to split Beta Ori naked-eye, and nobody admitted to
needing a Guide Dog to find their telescope <g>.


Thanks to all those who responded.  I have appended a copy of the
survey questions to this message, for those of you who missed seeing
them.  Hopefully the vsnet team will place the questions and results on
their web site for general viewing.


cheers,
Fraser Farrell
Variable Stars Group
Astronomical Society of South Australia

WWW: http://vsnet.gist.net.au/assa/   email: fraserf@dove.net.au
traditional:  GPO Box 199, Adelaide, SA 5001, Australia


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Eyesight Survey questions:

(1) Do you wear spectacles/contact lenses?
        (a)  Never          <- go to question 5
        (b)  For reading
        (c)  Always, except when asleep or in the shower!
        (d)  Only at Fancy Dress Parties

(2) If you wear spectacles/contact lenses, do you remove them when
    looking through the eyepiece?

(3) Are you long-sighted or short-sighted?  What dioptre(s)?

(4) Are you astigmatic in either or both eyes?

(5) How would you describe your naked-eye vision _without_
    spectacles/contacts?
        (a) I can see Proxima Cen <g>
        (b) I can split Beta Ori
        (c) I can see more than 6 stars in the Pleiades
        (d) I can split Theta & Iota Ori
        (e) I can see the 7 brightest stars in Orion
        (f) I can see Alpha Ori at maximum
        (g) I can't see Orion (even during power failures)
        (h) My Guide Dog helps me to find my telescope

(6) Do you have any non-refractive eye problems?  Eg: glaucoma,
    cataracts, colour blindness, retinal damage.


To assure confidentiality, please send your answers to
fraserf@dove.net.au  - NOT vsnet mail servers!
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