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AGIS Visual Field

In gauging the severity of a patient’s glaucoma (an eye disorder resulting from increased pressure in the eye killing one’s optic nerve), the ophthalmology profession uses an incredibly labor intensive and arcane process first outlined in 1994 in the journal Ophthalmology in an article simply titled: “Advanced Glaucoma Intervention Study. 2. Visual Field Test Scoring and Reliability” (the link is to PubMed, I couldn’t find a digital copy anywhere… that’s how old it is!). The basic idea is to take measurements on the sensitivity to light of different parts of the eye and combine that data into a single score signifying the severity of a patient’s glaucoma. While I am puzzled as to why the scoring system is so onerous (it took me about half an hour trying to do one by hand), at my girlfriend’s request, I wrote some software to help speed up the process (and also act as a refresher for me on the world of programming!).

My first attempt was some software written in the C programming language which took raw visual field data in the form of comma-separated value files (CSVs) and would give the resulting scores both on the screen and in CSV. Having succeeded at that, I thought it might be interesting and potentially valuable to other ophthalmology researchers to create a web version with a more graphical interface (which didn’t require people to input data into an opaque comma separated value format).

In the hopes that it will help others (and that others might take this and build on it or let me know if I’ve made any errors), I’ve posted the tool to my webpage here. Instructions are pretty basic:

  • Sorry, but in the interest of me not going crazy trying to figure out all of IE6/7’s idiosyncracies, this is designed only to work for modern browsers like Chrome, Firefox, Safari, and IE9/10/beyond
  • Enter the visual field depression data (in decibels) from the visual field test into the appropriate boxes (the shaded entries correspond to the eye’s blind spot). You can click on “Flip Orientation” link to switch from left-eye to right-eye view if that is helpful in data entry. You can also click on “Clear” to wipe out all the data entered and start from scratch. An error will be triggered if non-numeric data is entered or if not all of the values have been filled out. Note: the software can accept depression values as negative or positive, the important thing is to stay consistent throughout each entry as the software is making a guess on depression values based on all the numbers being entered.
  • Click “calculate”