Hi Francesco,
we have been using what we call 'scleral markers' for our video eye
trackers for about three years now. You do not say why you wnat
to use markers, but we originally started using them in order to
record ocular torsion more accurately than the usual iris landmark
approaches.
Basically we use a dye equivalent to that used in mascara, and this
is perfectly visible in IR. We are currently trying to improve the form
and reproducibility of the markers.
Regards
Andy Clarke
Date sent: Wed, 8 Nov 2000 16:02:34 +0100 (MET)
Subject: ways to mark the eye
From: Francesco Maringelli <[log in to unmask]>
To: [log in to unmask]
Send reply to: [log in to unmask]
> Sorry the lack of information in the first email.
> We cannot use contact lenses or anything that may affect even slightly the
> person' vision, so it must be applied to the cornea or the sclera. By
> visible under IR light, I mean the marker must reflect IR - the tracking
> device uses infra red illumination and infra red blocking filter.
> Unfortunately, the most common markers for the eye (gentian blue or
> gential violet or even bengal rosa) do not reflect enough IR light to be
> visible in this case! (There seems to be more quasi-black bodies around
> than we expected ;() So if any one has any suggestions for what we could
> try or experience in this area, it would be much appreciated.
>
> Thanks again for your attention.
>
> All the best,
>
> Francesco
>
>
> Francesco Maringelli
> International School for Advanced Studies
> Cognitive Neuroscience Sector
> Trieste - Italy
>
>
A H Clarke
Vestibular Research Lab
UKBF / ENT Department
Freie Universitaet Berlin
Tel: 030 8445 2434
Fax: 030 834 2116
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