Biomedical Engineering and the Eye

Eye Anatomy

3 major categories of eyesight problems

1. _____________2. Nearsightedness

(___________)3. Farsightedness

(___________)

Astigmatism

Myopia

Hyperopia

Astigmatism

• ___________is not evenly round

• Light focuses at _________________

_________________ inside the eye• Some parts of what you

look at are in focus, other parts are blurry

• Fix by _____________cornea

Nearsightedness

• Unable to see __________ things clearly

• Eyeball is ___________• Light focuses in front of

the retina• Glasses or flattening the

cornea fixes it

Farsightedness

• Unable to see ___________things clearly

• Eyeball is too _________• Cornea is too _________• Light focuses behind retina• Glasses or making the

cornea rounder fixes this

LASIK surgery

• Vision correction procedure• Uses two different biomedical devices– _________________– ____________ laser

• Reshapes the ______• Changes the way light is refracted (bent) into

the eyeball• Light will then focus on retina…CLEAR VISION!

Microkeratome

• Very precise, mechanical shaver– Like a razor for your eye

• __________________is guided over the eye on a ___________________

• Cuts a thin, outer layer of the ____________away from the eye

• Tracks have a ring– Ring uses suction to hold eye

still

Video on microkeratome

Excimer Laser

• “_________” laser– Does not heat up

• Removes ____________tissue by exposing it to UV light

• Very precise tool

Continuous Medical Implants

Treat:• ___________– Inflammation of the

inside of the eye

• ______________________________________ (DME)

• Age-related macular degeneration (AMD)

Retisert• ________________________

________________________– About the size of one grain of

rice!

• Surgically implanted in the eye– 1 hour outpatient procedure

• Releases medicine ________________________________________________– Controls inflammation

• Intraocular pressure and cataracts can develop

I-vation

• __________________________________• Helical metal screw• Medication slowly released into eye

Artificial Retinas

Treat:• ___________________– Genetic– Breakdown of

____________________– Loss of night vision, then

peripheral vision, then all vision

Artificial Retinas• Implanted in the

____________________• Stimulates __________ for

blind patients– Can see blurry shapes

• 2-mm wide chip• Light powers 5,000

____________________• Causes ______________

signal to _____________ cells in the back of the eye

• __________pass signal on to the ____________

Design!