The Glenn A. Fry Lecture Treating with Spectacle Lenses: A Novel Idea!? "What has been is what will be, and what has been done is what will be done; there is nothing new under the sun.” Ecclesiastes 1:9 Eli Peli, MSc, OD, FAAO The Schepens Eye Research Institute Harvard Medical School

My First Refraction At the Haifa Zoo (1975) –Helping Jake Sivak The Mongoose refused to be fitted with any type of spectacles for day or night use

My Second Refraction Customer Helping Mogi Gur and Jake Sivak Determine refraction by listening to sounds of neural activity in the cortex, monitored with intracellular electrodes, while changing lenses

There must be easier ways to refract! Are there more ways to use the spectacle lenses? Yes. Multiplexing.

Multiplexing for Low Vision Provide peripheral (wide field-of-view) together with central (high resolution) vision in ways that make them perceptually separable and useful –Many different forms of multiplexing - Spatial (superposition), Temporal (alternating), Biocular, or Spectral (colors) –Maintaining free head & eye movements

Peripheral Prisms for Hemianopia Expands upper and lower fields by about 20 deg High power prisms (40  ) All positions of gaze affected Biocular multiplexing Prismatic color fringes mark eye of origin Spectral Multiplexing Left Hemianopia

Instantaneous View with Hemianopia Field expansion for homonymous hemianopia by optically induced peripheral exotropia. Opt. & Vis.Sci 77;

View with the Peripheral Prisms

Effect Demonstrated with Perimetry Without Prisms

Perimetry with Peripheral Prisms Without Prisms With Prisms

Cosmetically Acceptable Dangerous? MultiOptical, Sweden Peripheral Prisms Spectacles

Peripheral Prisms Spectacles New more attractive, safer designs Chadwick Optical

Solar Glare Need to block peripheral field Sunglasses and tinted visors-not dark enough Opaque visor-fixed Hand position is adjustable

Headlight Glare at Night Coming from a limited section of peripheral field

Multiplexing Glare Control Lenses Block peripheral view Top strip for solar glare Left strip for headlight glare Fine adjustments with head position are simple, accurate, and intuitive Lens Tint Clip-On

Patent Search US 5,428,409 US 4,338,003 US 5,252,997 US 4,828,380 US 3,199,296 All for Night GlareAll static - no movement

Traffic Lights at Night Difficult for drivers with color deficiency with low vision or both

Unilight ® LED traffic lights As seen in Fort Hood, TX & Cheyenne, WY As seen in Scottsdale AZ No position clue No shape clue

Multiplexing Spectacles for Red-Green Color Deficiency When traffic-light is noted, slight head tilt brings it into the red-tined zone Red light shines through Green light is blocked

Successful application of Temporal Multiplexing Bioptic Telescope Wide field through the carrier lens Occasional head tilt to gain high resolution Limitations –Ring scotoma, Cosmesis, Social eye contact

45 degree field

In-the-Lens Telescope

View from above t Lens thickness, t, limits width of field Galilean Telescope

Completely embedded in the lens t Mirrors Only Design

Looking Through the Carrier

Looking Through the Telescope

Wider Field-of-View In-the Lens Keplerian Telescope

t t Front View Side View Lens thickness, t, limits height of field

SimulVision-Spatial Multiplexing

Conclusion Multiplexing offers a new way of thinking about low vision devices –Electronics or optics Multiplexing is useful in other applications Cosmetic considerations are critical to the success of any spectacle born device –We are all vain “…vanity of vanities; all is vanity” Ecclesiastes 1:2

Thank You! Supported generously by NIH grants