Optical Coherence Tomography (OCT) might be a workable technology, it would at least be my first approach. If you have an OCT device (or can borrow it), you should quickly find out whether it fulfills your needs. NOTE: If you would use an OCT that is designed for skin measurements check the laser safety aspects for the eye before you apply it.

Thanks for idea Fokko Pieter Wieringa. OCT uses IR rays which usually donot cross the iris making it a challenge to image the ciliary body. I am looking for something that would show the ciliary muscles inside the ciliary body. Appreciate your response.

We easily see CB all time at 20 um2 resolution with MRI and with manganese-enhanced MRI, the melanin really lights up. On the other hand, if you don't care about imaging the posterior segment, then you might get to 10-15 um with MRI. That still might be enough given the small size of the CB muscles. They are really small.

Thanks for opening up a new idea Bruce. Do you have experience with imaging the eye using Mn enhanced MRI. Also, is there literature showing ciliary body images by this technique, I will get a better idea of what to expect during the study - most of the existing literature is on imaging of neuronal structures. FYI, we are expecting to measure the ciliary muscle volume and track it at various time points, does this sound feasible by the Mn-enhanced MRI?

Lots of experience! Here are a few recent links that show CB (although that was NOT what the papers are about)

Figure 2 in http://www.sciencedirect.com/science/article/pii/S0197458014002267

Figure 2 in http://www.ncbi.nlm.nih.gov/pubmed/23457553

Figure 1 in http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3283205/figure/f1/

Figure 3 in http://www.ncbi.nlm.nih.gov/pubmed/20596255

P.S. there is this as well

http://www.abstractsonline.com/plan/ViewAbstract.aspx?mID=2511&sKey=7518d181-5c13-4319-8f9f-8f6717e3878d&cKey=2cda4550-74f4-476d-876a-1d7b1beed8a9&mKey=1ea90e66-c548-49e0-9f05-30da7938d511

Those are impressive pictures, however these are the limitations I see with the method when it comes to measuring the ciliary muscle volume

1. Mn lights up the melanin in the ciliary epithelium, so we assume that the ciliary muscle is within the highlighted area.

2. the pictures show a continuity of the iris, ciliary body and choroid, obviously because all are lined by the pigmented layer. In order to measure the ciliary muscle volume, there needs to be a clear demarcation between the above structures, else there will be inconsistencies in temporal measurements.

In fact, UBM shows a similar structure too, the ciliary body is visualized well. However it is difficult to delineate the ciliary muscle, especially the posterior limit. We take the anterior limit as the scleral spur. Any more ideas addressing the above limitations are welcome.