The shape of the blind spot in the visual fields is based on the shape of the optic disk. A blind spot shape can be easily generated by going to https://www.masterdocs.com/visualfields/start.php. You might care to collect blind spot shapes and optic disk shapes in the same people and check the correlation. We have an ImageJ-based program for generating geometric morphometric statistics from these shapes, and a separate program that generates composite images from multiple observations in the same individual or from single observations in groups of people. You can email me at [EMAIL PROTECTED] for further details if you are interested.
Colin Taylor >From: morphmet <[EMAIL PROTECTED]> >Reply-To: [email protected] >To: morphmet <[email protected]> >Subject: Morphometrics overkill for this problem? >Date: Wed, 10 Oct 2007 11:24:39 -0400 > >Hi, > >I'm completely new to this field. I'm wanting to look at variation in >optic disc shape (assess heritability) as a possible predictor for optic >nerve diseases (eg glaucoma). > >Essentially, the basic form of an optic disc is a vertically shaped oval >(although some peoples discs are more circular and even (rarely) >horizontally oval). The curves which make up the shape are not >completely smooth however, and usually there are subtle changes in >curvature around this 'oval' shape. Also, optic discs usually are not >perfectly symmetrical. > >I'm unsure how to tackle this shape problem. Initially, I thought of >treating each disc as a smooth and symmetrical oval and calculating 2 >curvatures (for the steep and flat curves of the oval (assuming >symmetry)) and describing this as some sort of shape or form factor. > >Then I stumbled onto morphometrics. Which leads me to ask 2 questions: > >1. Would using geometric morphometrics be considered overkill (by those >who know enough about it) for this type of problem? In my readings it >seems (Elliptic?) Fourier analysis could be used in this case. > >2. Is there any way of converting this information into a meaningful >biological variable? Can the numbers you get from whatever analysis you >do be used in a biological sense, or are they only meaningful when >describing the shape mathematically? (sorry if I haven't explained this >well). Ultimately, I'm wanting to do genetic analyses on a sample of >people and want to be able to make associations with shape. > >Thanks for your time, > >Regards, > >Paul > > > > >-- >Replies will be sent to the list. >For more information visit http://www.morphometrics.org > -- Replies will be sent to the list. For more information visit http://www.morphometrics.org
