Transcript No Slide Title

Dhaval
1
Desai , Nathan
1
Kleinhans ,
1
Liske ,
1
Piechura ,
Holly
Laura
Kellen
1,2
3
Advisor: Professor Wally Block, PhD ; Client: B’Ann Gabelt
1
Sheedy
1 Department of Biomedical Engineering, 2 Department of Radiology, 3 Ophthalmology and Visual Sciences
Abstract
Design Criteria
Prototype Testing
• Device must be automated or require minimal manual labor
• Device must support weights up to 50 pounds
• Device should be able to rotate 15° to 30° from horizontal in
pitch and roll directions
• Pitch and roll motion of the platform should allow a
resolution of approximately 2°
Glaucoma is the second leading cause of blindness in the
world. Currently, no cure exists for glaucoma and the inability
to diagnose this disease in its early stages exacerbates the
problem. The incorporation of eye-imaging tools such as OCT
(Optical Coherence Tomography), HRT (Heidelberg Retinal
Tomography), and GDxVCC (Confocal Laser Polarimetry) in
conjunction with chemotherapeutics and gene therapy offer
promising solutions to diagnose and cure glaucoma.
However, in order to make strides towards a cure, fine
adjustments in the positioning of the eye of animal subjects
are necessary to obtain quality images of the retina and
nerve. The goal of this project is to construct an automated
positioning device that provides accurate alignment of the
animal for successive scans in longitudinal research studies
that may one day unearth the cure for glaucoma.
• Moveable weight
-Able to easily move 51 pounds without statistically
significant decrease in speed
• Maximum pitch and roll of 19° from horizontal
• Reproducibility of board position
Final Design
The final design is named the Linear Actuator model. It
consists of two plates constructed from High Density
Polyethylene (HDPE) held together by two linear actuators and
a stainless steel rod. Each actuator is controlled by a
momentary switch, which allows for extension and contraction
of the actuators.
Problem Statement
Vertical Displacement (centimeters)
44
42
40
Pitch A; set point 43.5cm
Pitch B; set point 36.5cm
38
Pitch C; set point 30.8cm
36
Roll A; set point 41.6cm
Roll B; set point 37.9cm
34
Roll C; set point 33.3cm
32
30
Glaucoma:
• Eye disorder characterized by high intraocular pressure
• Increased pressure causes damage of the nerve fibers and
the optic disc
• Results in loss of peripheral vision
• No current cure exists
• Second leading cause of blindness in the world
Roll
0
Actuator 1 –
Provides rotation
about the pitch
direction
2
3
Trial Number
Figure 6: Testing data regarding reproducibility of specific angles in
pitch and roll directions. Vertical displacement from base of
prototype was recorded to gauge accuracy. Lines indicate initial
displacement, while data points indicate position after each trial.
Pitch
Actuator 2 –
Provides rotation
about the roll
direction.
1
Figure 3: The actuators and the
center support are connected
to a bearing that allows for the
necessary rotation.
Future Work
• Incorporate digital inclinometer for digital readout
• Validate reproducibility with animal testing
Figure 2: The Linear Actuator model
• Replace bearings if greater rotation needed
• Devise a way to shorten overall height of prototype
Figure 4: The inclinometer
magnetically attaches to the metal
piece on the top plate, providing
information on degree of rotation.
References
• Glaucoma Research Foundation. www.glaucoma.org
• National Glaucoma Research. American Health Assistance Foundation.
www.ahaf.org
Figure 1: Glaucoma is a high intraocular
pressure that may lead to blindness.
Client Motivation:
Aim 1: Early diagnosis of glaucoma
• Measure nerve fiber layer thickness in normal vs.
glaucoma eyes
Aim 2: Explore treatment options
• Test different chemotherapeutics and gene therapy
• Monitor nerve fiber layer parameters at several time
points
• Animal model: Monkey
• Track the movements of chemotherapeutics and
gene therapy vectors over time.
• Glaucoma Resource Guide. National Eye Institute.
www.nei.nih.gov/health
• Linear Motors and Electric Actuators. www.mcmastercarr.com
• Firgelli Automations. www.firgelliauto.com
Figure 5: The switches,
which are powered by
a power adapter,
control each actuator
independently.
Acknowledgments
Thanks to our client, B’Ann Gabelt and Carol Rasmussen for their
cooperation. We would also like to thank Mike Tomkowiak for his input.
Lastly, we would like to acknowledge our advisor, Wally Block, for his
continued support and encouragement.