Advanced Optics for
Ophthalmology
Jim Schwiegerling, PhD
Optical Sciences
Ophthalmology & Vision Sciences
University of Arizona
Accommodation
Relaxed ciliary
muscle pulls zonules
taut an flattens
crystalline lens.
Constrict ciliary
muscle releases
tension on zonules and
crystalline lens bulges.
Presbyopia
solidsmack.com/cad/the-mystery-of-the-disappearing-solidworks-drawing-view/
visionhelp.wordpress.com/2012/07/21/presbyopia-old-man-look-at-my-life/presbyopia2/
Presbyopia
Your ability to accommodate
reduces steadily with age.
Typically, you don’t notice
the effects until it affects your
ability to read comfortably.
This is presbyopia.
Scatter
Scatter creates a large halo
around light sources and
reduces contrast of a scene.
Tom van den Berg Netherlands Institute for Neuroscience
Cataract
Cataracts are an opacification of the crystalline lens in the eye. Early stages
cause reduce light levels and scatter. Advanced stages cause (preventable)
blindness.
Cataract extraction with intraocular lens implantation is the most widely
performed surgery in the US. Roughly 20 million blind people worldwide
due to cataracts.
http://webeye.ophth.uiowa.edu/eyeforum/cases/128-Posterior-Polar-Cataract.htm
Couching
telemedicine.orbis.org &
Wellcome Library London
Cataract Extraction
1735 – The French oculist
Jacques Daviel (1693–1762)
developed a method for the
removal of cataracts from
the eye
www.daviddarling.info/encyclopedia/S/science_in_the_eighteenth_century.html
Aphakia
http://www.righttosightandhealth.org/senegal-pictures-2011/
Harold Ridley
Ridley noticed that shards from the canopy (PMMA)
of RAF pilots lodge in their eyes did not get rejected
by the body’s immune system. Proposed making an
implantable lens out of the material.
Intraocular Lenses (IOLs)
Reading Glasses
• Conventional IOLs fix cataracts,
but not presbyopia.
• Still need reading glasses to see
up close.
Multifocal IOLs
Far
Near
Multifocal come in a variety of forms,
but the basic concept is to have two
different powers simultaneously on a
single lens. One power allows for
distance vision, while the other allows
for near vision.
Variations in zone size, number of
zones, power distribution, progressives,
aspherics and diffractives all exist.
Simulated Images
Multifocal Lens
Single Vision Lens
Distance Vision
Near Vision
Refractive Multifocal
Diffraction Grating
Diffractive Lens
•Addition of refractive lens
causes light to converge to
two points
+1
0
Diffractive Multifocal
http://www.midlandseyespecialist.com
Diffractive IOLs
• Refractive IOLs tend to have
more visual artifacts
compared to diffractive
lenses.
• Most multifocal IOLs today
are diffractive lenses.
• These lenses are also limited
because they give two
distinct planes of focus.
Trifocal Diffractive Lens
•Alternating step heights
causes light to converge to
three points
+2
+1
0
Diffractive IOLs
Bifocal Diffractive
Trifocal Diffractive
Tech Launch Arizona
Accommodating IOL
Accommodating IOL
Cataract Treatment Evolution
• Lens displacement or removal – Blindness to light
perception.
• Aphakic Spectacles – Vision, limited field of view.
• IOL – Normal distance vision.
• Multifocal IOL – Distance and reading vision.
• Trifocal IOL – Distance, intermediate and reading vision.
• Accommodating IOL – Can focus at all ranges, like young
healthy eye (in progress).
What’s Needed in General
• 76 million baby boomers.
• An understanding that people want “normal” or even
enhanced abilities in their medical devices and treatments.
• Communication between physicians, scientists and
engineers.
• Time & Support.
What’s Needed
• Materials which are biocompatible and mechanical
properties can be defined. (e.g. curvature changing IOL
and phaco ersatz).
• Chemistry & Biochemistry, BME, AME.
What’s Needed
• New imaging modalities to visualize crystalline lens in
vivo. e.g. OCT, High-frequency Ultrasound, MRI.
• Medical Imaging, Optical Sciences, ECE
What’s Needed
• Miniature electronics, batteries, wireless recharging, solar
power.
• ECE, Material Science, Optical Sciences
What’s Needed
• Drugs which slow the formation of cataracts, or reduce the
scatter from cataracts after they have formed.
• Biochemistry, Pharmacology
What’s Needed
• Portable diagnostics & treatments.
• Telemedicine, ECE, Optical Sciences
Summary
• Thin slice of cataracts and their treatment, but many other
medical conditions can be analyzed in the same way.
• Many of the solutions are multidisciplinary. How to
communicate needs and capabilities?
• Strong and flexible Tech Transfer to work with medical
device companies.