AbstractMany people, especially elderly individuals, have

afflictions such as tremors, loss of dexterity, arthritis, and Multiple Sclerosis, which inhibit their ability to administer eye drops. As a result, these people may exert too much force on the medication bottle and streaming can occur. Streaming wastes the medication and leads to an increase in healthcare cost. Consequently, it is desirable to develop a device to prevent streaming and allow the patient to accurately administer a single drop of medication into the eye with ease, safety, and comfort. Such a device was constructed by incorporating two curved paddles to squeeze the bottle, a conical eyepiece for position accuracy, and an adjustable screw to act as a stopper and prevent over squeezing.

Our Client – Lynn Buhmann

• Nurse practitioner at Wausau Clinics

• Deals with patients of glaucoma, Parkinson’s, Multiple Sclerosis, Rheumatoid arthritis, and tremors

• Patients are typically elderly and live independently

Common Eye Diseases

• Glaucoma: Increased pressure within the eyeball

• Macular degeneration: Gradual loss of vision

• Cataracts: Opacity of the lens

Motivation

• Difficulty delivering eye drops due to– Tremors– General loss of dexterity

• Because of these etiologies – Medication is wasted– Patient costs are increased

• Many patients suffer from multiple diseases and need several medications daily

Problem Statement

• To develop an eye drop device that can – Administer one drop of medication– Assist the user in placing the eye drop into the eye– Accommodate different types of medications (different

bottle sizes)– Conserve medication to reduce cost

Patented Eye Droppers

• Illuminated tips (US Patent, 5,584,823)• Attachments to prevent the bottle from touching

the eye (US Patent, 5,059,188)• Alignment glasses (US Patent, 5,255,024)

Alignment Glasses

Patented Devices

• Most patents guide the eye in the administration process

• Some patents ensure that the bottle does not touch the eye

• No mechanism to prevent streaming

• No assistance in squeezing the bottle

• No attempt at saving medication (cost)

Advantages Disadvantages

Marketed Devices: ™AutoDrop

• Bottle inserted into device

• Device rests over eye to assist patient in eye drop placement

• Does not control the quantity of drops administered

Marketed Devices: ™Autosqueeze

• Dropper bottle slides into device

• Does not control the amount of medication administered

• Does not prevent streaming

Design Specifications

• Controls the number of drops• Easy to squeeze• Accommodates several bottle sizes• Durable• Inexpensive• Simple design• Easy to clean• Maintain sterility of medication• Ergonomically correct device

Construction

• Purchased parts from US Plastics and Cole-Parmer

• Shaped and assembled all parts in the engineering machine shop

• Glued together

Prototype: Features

• Polypropylene; acrylic; nylon

• Cost: < $15.00

• Adjustable screw-turning mechanism

• Etched bottom of the cone fits most eyes– Cushioned for additional comfort

• Bored-out portion on the side allows bottles to slide into the device

Advantages

• When properly calibrated, consistently delivers one drop

• Requires minimal muscle control from the user• Improves accuracy of drop placement• Prevents streaming of medication

Disadvantages

• Some calibration is necessary as the bottle empties

• Fails to accommodate a large variety of bottles, such as small or narrow bottles

• Not aesthetically pleasing

Testing in Progress

Testing/Calibration

• Purchased four common shapes of eye drop bottles, each 15 mL

• Tested each bottle at a certain screw setting until no drops could come out

• Rotated the screw until a single drop could be emitted again

• This process was repeated until the bottle was empty• Data were normalized by dividing the number of drops at

a certain screw setting by the total number of drops of that bottle

dropstotal

settingscrewatdropsofnumber

Calibration Curve

Future Work

• Construction of a better prototype– Incorporate a larger variety of bottles– Require less calibration– More aesthetically pleasing

• Research plastic molding techniques

• Research different materials

Acknowledgements

• Thanks to:– Professor Tompkins– Lynn Buhmann

References

• Buhmann, L. Personal Interview. January 30, 2004

• Glaucoma Research Foundation. “What is glaucoma?” Accessed: January 20, 2004. URL: http://www.glaucoma.org

• Lal, A. 1993. Drop volume of commercial anti-glaucoma eye drops. Indian Journal of Pharmocology. 25: 163-4.

• US Patent, 5,059,188• US Patent, 5,255,024.• US Patent, 5,584,823.