Orbscan results - how to interpret

[Dixie Gabel]

My husband, Jeff, was diagnosed with KC about 5 yrs ago. He has always had one "lazy" eye so he grew up being very, VERY protective of his good eye. We went in for a contact lens fitting about 1.5 yrs ago and it was so difficult and traumatic for everyone invovled that they basically gave up and said that he is just not a good candidate for contacts. We have recently seen another specialist to discuss the possibility of Intacs. We left with an appointment for lens fitting and a copy of the ORBSCANs that were taken.

I would like to know more about all the information on the orbscan results. What do all the numbers mean and how do they compare to normal results and to other KC results?

Can someone help me understand these charts or direct me to a website?

Thank you.

P.s. I'm glad you are all here so we don't have to go through this alone.

[GarethB]

Hi Dixie,

Welcome to the forum.

The scan basiclly shows in two dimensions the contours of the eye, a bit like a contour map you would use in the mountains to get an idea of how steep they are.

If you think of the colours of a rainbow red is where the stepest areas would be and blue would be less steep. My scans have 4 pictures, the one with all the rainbow colours gives an idea of the astigmatism. Because KC is irregular astigmatism you get many different numbers.

The second picture on mine gives the overall angle of the astigmatism, like where is it worst, for me it is the 10 O'Clock postion.

The third one on mine shows the corneal thickness which is important as KC is a condition where the cornea thins.

The fourth picture on my printout is like the first, but is for the back of the cornea.

From this the specialist can get a more detailed idea of how severe the KC is and with the many types of lenses, (many of which have a back surface that approximate the shape of the KC cone) would be a good starting poiint to get a comfortable fit and the best possible corrected vision.

The data also gives something measurable which was not around 20 years ago so should the KC progress, there is solid data to compare it against.

Hope this helps some.

[jayuk]

Dixie

Are you able to scan it in and put it on here?....

J

[Dixie Gabel]

Sorry it took so long to post the scans, but here they are:

http://i35.photobucket.com/albums/d163/ ... yescan.jpg

http://i35.photobucket.com/albums/d163/ ... yescan.jpg

[GarethB]

Hi Dixie,

Basically your right eye has worse KC than the left because the colour at the 6 O'Clock position where your KC has gone beyond red to purple.

It is quite localised too (well compared to mine).

The top left scan is a map of the front of the cornea and the top right is a scan of the back of the cornea.

Bottom right is the corneal thickness which is normally 550 to 600 microns. You can see your right eye is thinnest at 401 compared to the left at 429.

The set of numbers in the middle give the level of astigmatism, the higher the wrose it is I am afraid. Anything above 6 diopters starts in the UK to be considerd specialist prescription. This also gives the angle of where the owrst astigmatism is too.

One of the proffesionals will be able to go into more detail but I do not know what benefir that would bring.

To say KC is mild or severe is a relative term. Mine is considerd severe, but I do not find it debilitating, corrected or whereas someone who's KC is mild can find things very debilitating.

Hope this helps.

Gareth

[BlackA]

Dixie, I am very sorry for your husband.

I am not specialist but I will try to add something.

Looking in the web I got this classification:
mild keratoconus (K2<45 D)
moderate keratoconus (K2 between 45 D and 52 D)
severe keratoconus (K2>52 D)

For what I understand Jeff has 45.1 in the left eye and 51 in the right one.

The left eye is similar to mine. Just for comparision I have 20/200 without lens and 20/30 with the RPG. The fitting is not trivial but should be ok in the end.
The right could be more complicated.

Another important thing you can get out of the orbscan is the thinnest point in the cornea which is 429 and 401 in your case. This is important since the doctors recommend a minimum of 450 for the INTACS procedure (although I think it can be done with less)

Best regards

[Dixie Gabel]

Thank you, Gareth. Your explanation helped to fill in some of the gaps in my understanding of the orbscans.

My husband is going in for a lens fitting next week, hopefully a mild sedative will help him get through that difficult process.

[GarethB]

Dixie,

No sedative should be needed, I managed to get through it Ok and I have a phobia of things getting in or being put in my eye. This explains why I still have trouble putting lenses in, but after a few minutes all is well again.

Yes the lenses will be uncomfortable at first, especially if hubby has never worn any type of contact lens before and their will be floods of tears. Not often due to pain, more usually as the eyes reflex of tear production to wash out the lens kicks in, but this does soon disipate in most cases. The optom will put the lenses in and ot and you will be surprised at how swiftly they can do this, you barely notice it happening.

Let us know how you both get on.

Regards

Gareth

[BlackA]

About how a normal eye is...

Elevation patterns of the posterior corneal surface:
http://bjo.bmj.com/cgi/content/full/83/7/774/F1

Patterns of normal corneal thickness:
http://bjo.bmj.com/cgi/content/full/83/7/774/F2

The full article is :
http://bjo.bmj.com/cgi/content/full/83/7/774

Hope it helps

[GarethB]

Just come across my old scans and my left eye the best which is mild KC at 42D has the thinest cornea at 575 microns and there is a nice yellow ring round the graft on both which is by no means circular, after 18 years they have a distinctive square shape with rounded corners!

The right graft which is a year older and has KC in the ungrafted part is moderate at 49D is the thicker graft at 604 micron at its thinnest.

If these were ungrafted corneas, they would be considerd ideal for C3R as there is plenty of thickness left!