I am trying to image an ex vivo eye ball under the acoustic excitation. The frequency response data strongly depend on how I place the eyeball. Additionally the holder that I use to place eyeball vibrates as well and its frequency response messes up the eyeball frequency response. It is not very easy to subtract the bulky motion of the holder from eyeball data, so I need a way to exclude holder vibration completely. I would be very happy to hear different suggestions. Thanks in advance.
I have seen the eyeball holder for ex-vivo ultrasonic imaging. That holder was of Plexiglas, with cavity similar to eye-orbit. This cavity with eyeball placed in it, was covered with ring fixation. This fixation did some pressure on eyeball so the cornea surface was nearly the same shape as in-vivo. Of course the ultrasonic imaging is with frequencies around 10MHz. You mentioned the acoustic excitation, this means low frequencies? What if you use silicon rubber holder with elasticity like living tissues? I try to imagine, that your excitation is related with research of new method to estimate intra-ocular pressure?
Dear Rytis,
Thank you so much for your reply, yes the frequency range is much lower, between 50-500 Hz and yes we are trying to measure IOP level of the eyeball. Silicon rubber sounds interesting, I will check that for sure. Can you mention the name of the research group that you see this eyeball configuration, I may get in touch with them to get more information about the company and etc.
Thank you one more time,
All the best,
Dear Imran,
the plastic holder was in our lab somewhere. But this was for 10MHz imaging, not for 50-500Hz excitation-vibration. So plastic no use for you. But the silicon rubber maybe, that one I did not see anywhere, I imagine it as possible solution. Best regards, Rytis
P.S. the vibration at sound frequencies we tried with master program student. But we did experiments with rubber-balloon, not with real ex-vivo eye. We did not use any holder, just balloon in water on plastic plate covering soundspeaker.
In my opinion if you are trying to model eyeball you must fixate it by elastic springs which are similar to muscular system which fixates it in-vivo with similar properties. These springs shall connect it to a rigid structure.
Dear all,
Thank you so much for your replies, now I know what I need in my experiments.
Greatly appreciated your responses!
All the best,
Imran
If you want to study the only eyeball properties, the elastic springs should be as compliant as possible in order to minimally bias measurements.
If the springs are too complicated, consider vacuum suction. We used a device with a semispherical cavity in which the eyeball rested snugly. the cavity had a hole on the back, offset so as not to interfere with the optical nerve stub, and a syringe was connected via rigid rubber tubing. By pulling on the syringe, a "vacuum" was created, which fixed the eyeball very nicely.
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