Glaucoma DiagnosisGlaucoma is a disease when intraocular pressure (IOP) is increased and vision loss and blindness results. A team at the University of California at Davis has designed a bionic contact lens capable of monitoring IOP and alerting its wearer when the pressure levels are too high.• Structural material: polydimethylsiloxane (PDMS)• 3-D replica mold of two-step SU-8 process on silicon substrate is used to

form the lens.• The main sensing channel is defined using traditional SU-8 processing,

with a drain and buffer channel and microfluidic interconnects. • A two step soft-bake is used for the thick SU-8 to minimize the internal

stress during the soft-bake and post-exposure bake process.

Glucose MonitorKnowing diabetic patients must constantly monitor their blood-glucose levels through finger pricks, a team at the University of Washington is developing a bionic contact lens capable of monitoring these levels for them. • A 10μm parylene substrate layer on a silicone wafer develops the dual sensor

in a ring configuration maximizing the fenestration of oxygen diffusion barrier• Titanium (10nm), Palladium (20nm) and Platinum

(100nm) are evaporated and patterned on the wafer• Positive photoresist (about 6μm), and a second parylene

layer are deposited on the whole wafer• Chromium (10nm) and Nickel (100nm) are evaporated

to form the etching mask. • This process is repeated to form a second etching mask,

but with openings to the sensor area

Visual DisplayMany bionic contact lenses require an informationrelay method, so a team from the University ofWashington is developing a contact lens with aretina display imbedded on the surface that willallow information to be displayed onto reality.• The lens is made of a polymer substrate called polyethylene terephthalate (PET). • An antenna about 5 mm radius, 0.5 mm width, and 5.0 μm thick around the

outside edge of the contact functions mainly to transmit radio frequency or take in information.

• The antenna receives power and with the current design, there is a limited amount of power available for the contact lens.

• Integrated electronic circuits built with layers of metal a few nanometers thick and LEDs one-third of a millimeter across are for LED control

• Circuits are connected to a chip at the top of the lens, which harvests power and turns it into voltage necessary to power the LEDs (peak emission about 475nm).

Infrared and UV VisionThe University of Michigan is developing a contact lens that grants the wearer the ability to perceive light waves in the infrared an UV spectrum. In dangerous situations firefighters can detect the heat coming from specific rooms to determine the safety of an environment before they enter it.• Graphene is an allotrope of carbon one atom thick

• Sensitive to range of wavelengths from ultraviolet (~10 to 400nm) to infrared (~700nm to 1mm)

• Strong effect when struck byphotons electrons absorb energy and become “hot carriers”

• Light strikes the top graphene layer “hot carrier” electrons travel throughdielectric to opposite graphene layer, creating a charge build up and strong change in conductance

• Phototransistor generates around 1 amp per watt of light energy– about 100 times more sensitive than raw graphene.

The Bionic Contact LensKatelyn Axman (kfa7@pitt.edu), Rachel Sides (res136@pitt.edu)

A bionic contact lens is a contact lens medium onto which numerous applications can be imposed. These applications are very diverse, which causes the bionic contact lens to be a very versatile technology. This poster explores four of the current applications as a means to display that the applications are endless.

Component Tear Concentration

Blood Concentration

Na+ 120-165mM 130-145mMK+ 20-42mM 3.5-5mMCa2+ 0.4-1.1mM 2.0-2.6mMMg2+ 0.5-0.9mM 0.7-1.1mMCl- 118-135mM 95-125mMHCO3- 20-26mM 24-30mMGlucose 0.1-0.6mM 3.3-6.5mMUrea 3.0-6.0mM 3.3-6.5mMLactate 2-5mM 0.5-0.8mMPyruvate 0.05-0.35mM 0.1-0.2mM

Ascorbate 0.008-0.04mM 0.04-0.06mM

Total protein ~7g/L ~70g/L

Main tear film chemical concentrations and the corresponding levels in the blood

Glaucoma Monitor Fabrication Process

Retina display imbedded on PET

Images of fabricated parylene sensor and contact pads on the sensors

Contact lens molded with an embedded glucose sensor