automated animal board for positioning in ocular photography and imaging

Automated Animal Board for Positioning in Ocular

Photography and Imaging

Dhaval DesaiNathan Kleinhans

Holly LiskeLaura PiechuraKellen Sheedy

Client: B’Ann GabeltDepartment of Ophthalmology

Advisor: Wally Block, PhDDepartment of Biomedical Engineering

Glaucoma• High intraocular

pressure

• Damage of the nerve fibers and the optic disc

• Result: Vision loss

• Current cure: None

• Second leading cause of blindness in the world

Normal Vision

National Eye Institute

Vision with Glaucoma

National Eye Institute

Motivation

• Aim 1: Early diagnosis of glaucoma– Nerve fiber layer thickness– Normal vs. glaucoma

• Aim 2: Explore treatment options– Chemotherapeutics and gene therapy– Animal model: Monkey– Monitor nerve fiber layer parameters at

several time points

Problem Statement

Fine adjustments in the positioning of the eye are necessary to obtain quality images of the retina and nerve for glaucoma research. The goal of this project is to construct an automated positioning device that provides accurate alignment of the animal for successive scans.

Design Specification

• Automated or require minimal manual labor

• Support weights up to 50 lbs

• Rotate 30 degrees from horizontal in pitch and roll directions

Rotary Actuator Model

•Independent rotary actuators–Control pitch and roll

•Automated rotation

•Inclinometer to measure angular displacement

Rotary Actuator Model

Pros:• No center support of

plate required• Low center of gravity• Direct correlation to

handheld control

Cons:• Precision• Torque on actuators• Actuator cost

• Mechanical approach

• Tape runs through platform in both directions

• Relies on system of internal pulleys

• Small motor retrieves tape (normalizes)

Ticker-Tape Model

Ticker-Tape Model

Cons:• Manual• Normalizing may

decrease life in service

Pros:• Simple design• Easy to record

displacement• Inexpensive design

Linear Actuator Model• Employs two

electric linear actuators

• Ball and socket heads are mounted to actuators

• Central ball and socket column

• Inclinometer to measure angular displacement

Linear Actuator ModelPros: • Automated design• Continuous motion

and fine adjustment capabilities

Cons:• Complicated design• Actuators and

inclinometers are expensive

Design Matrix

Criteria Rotator Ticker Tape

Linear Actuator

Accuracy 4 7 7

Maximum loads 6 4 9

Cost 2 8 5

Ease of Manufacturing

6 4 6

Prototype Life 7 4 8

Total 25 27 35

Future Work

• Final Design modifications

• Choose and order materials

• Build prototype

• Test

References

• Glaucoma Research Foundation. www.glaucoma.org

• National Glaucoma Research. American Health Assistance Foundation. www.ahaf.org

• Glaucoma Resource Guide. National Eye Institute. www.nei.nih.gov/health

Questions?