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My Heidelberg Retina Tomograph (HRT-II) Results for 2007

Submitted by dave on Fri, 01/19/2007 - 1:30pm

These are my HRT results from today, 19-January-2007. This test was performed with an HRT-II, which is the same model used for my HRT test in 2006. However, today's tests were done by a different doctor (and different HRT operator) -- in fact, they were done in a different country.

Upon a quick examination, the doctor didn't seem to think there was much progression over the last year. However, I expect further input in the coming weeks.

My Left Eye Heidelberg Retina Tomograph (HRT-II)   HRT Left

My Right Eye Heidelberg Retina Tomograph (HRT-II) HRT Right

Click the thumbnail image or the link above to view the full size images

Here is a side-by-side comparison of the numbers. From the numbers, there does not seem to be much change in my left eye over the last 12 months. However, the numbers for my right eye are generally worse today than 12 months ago. Maybe the doctor didn't look at these numbers closely today or maybe the changes are not large enough to concern him. I'm not sure, but I'll post an update when I get more feedback.

  Left Right
  2006 2007 2006 2007
Disk Area 2.011 2.032 1.763 1.755
Cup Area 0.876 0.905 1.131 1.243
Rim Area 1.135 1.127 0.632 0.512
Cup Volume 0.208 0.217 0.371 0.444
Rim Volume 0.212 0.233 0.123 0.088
Cup/Disk Area Ratio 0.435 0.445 0.641 0.708
Linear Cup/Disk Ratio 0.66 0.667 0.801 0.842
Mean Cup Depth 0.261 0.287 0.426 0.441
Maximum Cup Depth 0.707 0.71 0.801 0.813
Cup Shape Measure -0.213 -0.162 0.025 0.043
Height Variation Contour 0.287 0.324 0.332 0.3
Mean RNFL Thickness 0.19 0.187 0.221 0.169
RNFL Cross Sectional Area 0.959 0.947 1.041 0.792
Reference Height 0.333 0.412 0.48 0.47
Topography Std. Dev. 13 10 11 19

It is probably worth noting that my IOP was higher for most of 2006 than it is right now. Hopefully, the next HRT and/or GDx will not show further loss of RNFL thickness. 

HRT contour lineUPDATE 26-January-2007. When I had this HRT test done, the technician showed me how the contour line is drawn. This contour line is shown in green on the image. This line has to be manually drawn by the technician.

The process of drawing the line involves selecting four points at the edge of the disc -- and having the skill to differentiate this from areas of peri-papillary atrophy, for example. Once the four points are selected, the software draws the green contour line. The technician can then flip the 3D image over (so the cup looks like a mountain) and visually inspect the contour line. If it doesn't look satisfactory, the technician can make adjustments and then check it again. The technician showed me how different selection points altered my analysis. A different technician had performed my prior HRT, and this technician ultimately agreed that the prior contour line (as defined by the 4 selection points) was good and she replicated those selection points for this test.

This contour line is used by the HRT software to calculate whether the disc is suspicious or not. In following glaucoma progress over time, the most important element in regard to this contour line is just consistency. It doesn't have to be drawn perfectly - but it should be drawn the same way every time. It helps if the same technician performs all HRT tests for you.

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