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    Re: Star sparkle in sextant image
    From: Jared Sherman
    Date: 2004 Sep 27, 13:34 -0400
    Jim, what you call "sparkle" is similar to the lasik damage I have, which is a combination of increased glare (never had problems with that before), residual astigmatism, and double/triple vision from "ghosting" in each eye. This from what is called successful lasik surgery. As I told my optometrist afterwards, "And they let people drive who can see like this?!"
     
    The glare/ghosting apparently are not unique to lasik complications, but are "normal" eye defects in the population. A single LED light looks like a small dot to me in daylight, against a similarly bright background. But at night, set against a dark field, it has a "crown" around it similar to your images. That's a glare problem, in my case compounded by the multiple vision--which can come from physical aberrations in the normal eye.
     
    You might want to play with the interactive vision simulator at http://www.surgicaleyes.com to see the effects of glare, etc., and how they are defined, and change vision. Especially the vision involved with a bright point against a dark field.
     
    Astigmatism can be corrected by glasses, of course. A pinhole patch (an eyepatch or black paper with only a pinhole in the center) in front of your eye may also help, since it confines the image to the center of the eye, and there are fewer ways it can get distorted. (The lens, the cornea itself, is far from regular in most people. The latest technology literally draws topographic maps of both surfaces--and they don't form neat bull'seye images!)
       
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