Poster 2
| High Definition Video Exploration of Epi-LASIK Surgery and Bowman’s Membrane Using the Moria System James S. Lewis, MD Elkins Park, PA 19027 USA |
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Purpose:
To investigate the Moria Epi-LASIK microkeratome and the nature of the surface it leaves behind.
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Method:
High Definition surgical video was gathered during a number of Epi-LASIK procedures. The Ikegami 20-DI 2-chip HD camera mounted on a standard Zeiss Operating Microscope collected uncompressed video directly to a 6 terrabyte RAID. Video was captured in 12-bit color using a PCIe card from BlackMagicDesign. Final Cut Pro Studio 2 was used to edit the video. Enhanced video imaging (EVI) was achieved through the construction of a custom filter (video transform) written by the author.
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Results:
The Moria system elegantly cleaves a continuous flap of epithelium from Bowman’s membrane. The surface left behind by the Moria Epi-LASIK microkeratome is pristine. EVI effectively grades the corneal stromal texture in Epi-LASIK, SBK, and LASIK.
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Conclusion:
The surface quality of Bowman’s membrane is much smoother than the stromal surface produced by mechanical or femtosecond laser microkeratomes.
This may explain why the image quality following Epi-LASIK is superior.
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Moria Epi-LASIK Microkeratome (row 1) |
Moria Epi-LASIK Microkeratome (row 2) |
Bowman’s membrane after Epi-LASIK pass (row 3) |
Bowman’s membrane after Epi-LASIK pass (row 4) |
Bowman’s membrane after Epi-LASIK pass (row 5) |
Bowman’s membrane after Epi-LASIK pass (row 6) |
Bowman’s membrane after Epi-LASIK pass (row 7) |
| The Ikegami 20-DI HD camera captures uncompressed video images (1920 x 1080) in full 10-bit color at 1.465 gigabits per second. This is more than 10 times the data and consequently video information possible with a professional 3-chip DV camera. Given the outstanding quality of the camera and the Zeiss surgical microscope we can study Moria’s Epi-LASIK procedure in exquisite detail. In the first two rows of images notice the integrity of the epithelial flap as it is gently cleaved from the underlying corneal surface. Near the end of the surgical pass the epithelial demonstrates its fragile nature as it folds on itself like gelatin. We know the epithelial flap is approximately 50 µicrons in thickness.
The next row of images shows the almost mirror-like appearance of Bowman’s membrane. A fiber optic halogen light source from Mastel emphasizes the incredibly smooth and reflective nature of the surface. The pristine quality of the Bowman’s membrane may explain the outstanding visual results found in Epi-LASIK. A mathematical transform was applied to the uncompressed digital video images of the corneal surface prior to the application of excimer laser. This process provides an in-vivo method for assessing stromal bed quality. This SEM-like process, called EVI, demonstrates how Epi-LASIK (row 5) is smoother than SBK (row 6) which is in turn is smoother than LASIK (row 7). EVI also seems to imply that the corneal surface created by the Moria Epi-LASIK microkeratome is smoother than the one generated by the Amoil’s brush (row 5). Surprisingly, the corneal surface produced by the Moria OUP SBK microkeratome is nearly identical to the surface produced by the Femtosecond laser. Finally, the stromal bed smoothness from older LASIK procedures shows us how much progress we have made. |
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| Poster Code: RS-D2-278, Panel No.:278, Presentation Day: June 29,2008 Poster One Poster Two |
