A Didactic
Surgical Simulator for the Continuous Curvilinear Capsulorhexis Procedure
During Cataract Surgery
Roger Webster, Ph.D.1,
Joseph Sassani, M.D.2, Matt Harris 1, Markus Schill,
Ph.D. 3, Clemens Wagner, Ph.D. 3,
1Department of Computer, Science
School of Science and Mathematics, Caputo Hall, D&E Communications Wing,
Millersville University, Millersville, PA.
Roger.Webster@millersville.edu
2 Department
of Ophthalmology, Penn State University College of Medicine, Milton S. Hershey
Medical Center, Hershey, PA USA 17033
3 VRmagic
GmbH, B6, 23–29 C, Postfach 10 32 18, 68032,
Abstract. Software
for successfully simulating the capsulorhexis procedure during cataract surgery
is described. The continuous curvilinear capsulorhexis technique, developed by
Gimbel and Neuhann, has become the standard method of anterior capsulorectomy
for phacoemulsification. Our didactic simulator software begins by having the
user make a small incision in the center of the lens. The user then uses a virtual
angled forceps tool to pull the virtual tissue towards the 12 o’clock
position and curving the tear to the left. A virtual flap of tissue is thus
created. The surgeon then grasps the folded over flap of tissue and begins to
tear in a circular motion such that the tear force vector is tangential to the
circumference of the tear circle. All too often beginning surgeons attempt to
complete the capsulorhexis procedure without the proper re-grasping of the flap
of torn tissue close to the tear point. This can cause the tear to run
“downhill”. In this case the tear will resist any attempt to
redirect the tear uphill possibly causing severe damage to the tissue. As the
novice surgeon continues to pull, the tear gets worse, no matter what the
direction of the pull vector. In addition, anterior bowing of the lens
diaphragm as well as shallow anterior chambers can accentuate this
“downhill” tear phenomenon. In younger patients the tear may also
follow the radial course of the zonule rather than the desired circular
pattern. Our didactic capsulorhexis simulator models these various tear
problems and provides a learning environment with software helpers to guide the
user to a successful procedure without the dangers of using live patients.
Our
simulator software runs on the EYESI™ eye simulator hardware (VRMagic,
GmBH
Figure 1 User at the EYESI™
Capsulorhexis Simulator. Figure 2 Tearing the capsule. Figure 3 In Level1 the
user is guided through the procedure.
Acknowledgments.
This project is funded, in part, by the Lions Club
International, National Science Foundation under grant number EIA-0116616, the
Neimeyer-Hodgson Grants Program, the Havemeier-Gibson Endowment for Computer
Science and by the Penn State University College of Medicine Department of
Ophthalmology.
References/Literature.
[1] Michael Sinclair, J. Peifer, R. Haleblain, M. Luxenberg,
K. Green, D. Hull, “Computer-simulated Eye Surgery - A Novel Teaching
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[2] Clemens Wagner, M. Schill, R. Manner, “Collision
Detection and Tissue Modeling in a VR-Simulator for Eye Surgery”,
Eighth Eurographics Workshop on Virtual Environments (2002),
[3] Norman Jaffe, M. Jaffe, G. Jaffe, Cataract Surgery and
its Complications, Sixth Edition, Mosby Press,
[4] Ehud Assia, D. Apple, J. Tsai, E. Lim, “The
Elastic Properties of the Lens Capsule in Capsulorhexis”, American
Journal of Ophthalmology, Vol. 111, No. 5, May, 1991, pps. 628-632.
[5] James Morgan, R. Ellingham, R. Young, G. Trmal, “The
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[6] H.J. Burd, S.J. Judge, J.A. Cross, Numerical Modeling of
the Accommodating Lens, Vision Research, Vol. 42, 2002, pps. 2235-2251.
[7] Sarah
Frisken and B. Mirtich, A Survey of Deformable Modeling in Computer Graphics, MERL
Technical Report TR-97-19, November 1997, http://www.merl.com/reports/TR-97-19/.
[8] Roger Webster, R. Haluck, B. Mohler, R. Ravenscroft, E. Crouthamel,
T. Frack, S. Terlecki, J. Sheaffer, Elastically Deformable 3D Organs for Haptic
Surgical Simulators, Proceedings of the Medicine Meets Virtual Reality
Conference, MMVR 2002, Newport Beach, California, January 23-26, 2002, IOS
Press, pps. 570-572.
[9] Mathieu Desbrun, G. Debunne, A. Barr,
M, Cani, Interative Multi-Resolution Animation of Deformable Models, Proceedings
of the Annual ACM SIGGRAPH Conference, ACM Press, Los Angeles, California,
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[10] Roger Webster, J. Sassani, R. Shenk, G. Zoppetti,
"Simulating the Continuous Curvilinear Capsulorhexis Procedure During
Cataract Surgery", Proceedings of the Annual
IASTED International Conference on Modeling and Simulation (MS 2004),
[11] Roger Webster, J. Sassani, R. Shenk, N. Good, "A
Haptic Surgical Simulator for the Continuous Curvilinear Capsulorhexis
Procedure During Cataract Surgery", Proceedings of the Annual Medicine
Meets Virtual Reality Conference, (MMVR '2004), Newport Beach, California,
Sponsored by Aligned Management Association and the University of California at
Irvine, January 15-17, 2004, pps. 404-406.
[12] Roger Webster, J. Sassani, R. Haluck, R. Shenk, M.
Harris, J. Blumenstock, J. Gerber, C. Billman, A. Benson,
"Simulating the Curvilinear Capsulorhexis Cataract Procedure on the
EYESI™ System", Poster Presentation and Proceedings of the Annual
Medicine Meets Virtual Reality Conference, (MMVR '2005), Long Beach,
California, Sponsored by Aligned Management Association and the University of
California at Irvine, January 24-29, 2005, pps. 592-595.
Paper published in Proceedings of MMVR: Capsulorhexis.pdf file
Videos: Videos of Capsulorhexis simulation
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Last Updated 06-19-2007