telescopic vision contact lens -...
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1/23/2011 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
UCSD Photonics
Telescopic Vision Contact Lens
Eric Tremblay*, Ashkan Arianpour, and Joseph Ford University of California San Diego,
Jacobs School of Engineering
Dirk Beer Pacific Science & Engineering Group
UCSD Photonics Systems Integration Lab Presentation at SPIE BIOS Ophthalmic Technologies XXI (7885-35), San Francisco CA, 1/23/2011 9:30 AM
1/23/2011 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
UCSD Photonics Motivation for a Magnifying Contact Lens
Age-Related Macular Degeneration (AMD) • Disease attacks macula, destroying sharp central vision
• Major cause of visual impairment in older adults (>50yrs) • >1.75 million US residents with AMD; 3 million expected by 2020
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1Eye Diseases Prevalence Research Group, Arch. Ophthalmol. 122, 564-572 (2004)
Limitations: •Tunnel vision (limited Field of View): require head movement
Bioptic telescopes
• head tilts for magnification • difficulties w/ social interaction
In-the-Spectacle-Lens Telescopic device (in development)
Peli, E., et al. J. Biomed. Opt. 13, 034027 (2008)
Low-vision aids: Head-mounted telescope
Houston, K., Indiana J. Optom. 12, 2-6 (2009)
1/23/2011 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
UCSD Photonics Eye Mounted Low-Vision Aids
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2-4x magnification eye mounted telescope: Scanning with natural eye movement Compatibility with social interaction
Goal: Switchable 3x telescope thin enough to fit into a wearable contact lens
Implantable Miniature Telescope (IMT)
• Monocular surgical solution, 2.2x - 2.8x mag. • Avoids vestibular conflict
• FDA approved Lane, S. S. et al. Curr. Opin. Ophthalmol. 17, 94–98 (2006)
Implanted Intraocular telescope
Isen, A., Encyclopedia of contact lens practice. 13, Suppl 13. 53-55 (1963)
Feinbloom Mini-Scope • 4.4 mm thick even for only 2x mag
• Not easily wearable
Contact lens telescopes
Popular Science Sept 1960
1/23/2011 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
UCSD Photonics
E. J. Tremblay et al., “Ultra-Thin Cameras Using Annular Folded Optics”, Appl. Opt. 46, pp. 463-471 (2007).
8-Reflection Lens Design: 38mm Focal length
5mm thickness
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object
Conventional Refractive Lens Concentric reflectors
Conventional Refractive Lens
UCSD Concentric Multi-Reflection Lens Concept
• Tight fabrication and assembly tolerances eliminated by diamond turning as a single element. • Diffraction effects from large obscuration mitigated by increased lens diameter
Single element diamond turned
and coated 8-reflection lens
1/23/2011 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
UCSD Photonics
Input image file: 80˚ field of view Central pupil: 1x mag
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Normal Vision
80° FOV
20° FOV
Annular pupil: 2.8x mag
20° FOV
Telescopic Vision
• Thickness reduced by # of concentric reflections
Multi-Reflection Contact Lens
Telescopic Vision Contact Lens Concept
Switch State 2
Switch state 1
• Liquid Crystal switching glasses • Integrated polarizer on contact lens
Switching
1/23/2011 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
UCSD Photonics 6-Reflection Afocal Telescope
Compatible with both lab and vision use (held close to eye)
Air
13 mm Φ
Center: 1.36 mm thick planar surfaces
Aspheric reflectors
Aspheric reflectors
Planar aperture
Thickness: 1.5 mm max
12 mm Φ
10 mm Φ
3 mm Φ
3x magnification (lens + eye EFL = 51.5 mm)
+/- 2.5°
Calcium Fluoride 13 mm x 1.5 mm (radial)
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Telescopic: F / 7.76 12 mm (outer) 10 mm (inner) 6.63 mm effective diameter 51.5 mm EFL
Clear: F / 5.66 3 mm diameter 17 mm EFL
12 mm
Aperture
1/23/2011 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
UCSD Photonics 6-Reflection Telescope Calculated Performance
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6-Reflection Telescope Contact + Eye (1.7˚ field)
30 cyc/˚ 90 cyc/˚ (104 cyc/mm)
Spatial Frequency
Mod
ulus
of t
he O
TF
0
0.5
1 MTF
<neuronal threshold>
Eye’s Optics (5˚ field)
30 cyc/˚ (104 cyc/mm)
15 cyc/˚
Spatial Frequency M
odul
us o
f the
OTF
0
1
0.5
MTF
Comparing Normal & Magnified Vision
50μm
Spot Diagram
0˚ 1˚
2˚ 2.5˚
Visible light spectrum MTF
(over 5˚ FOV)
100 cyc/mm
FOV 9.5deg (RI >10%) 4mm iris
10 deg
Relative illumination
3x Magnification (same spatial freq. @ retina)
• 3x magnified contrast higher @ 30 cyc/˚ (20/20 Snellen acuity)
• 3x magnified contrast above neuronal contrast limit at 90 cyc/˚
1/23/2011 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
UCSD Photonics 1st Test: 6-Reflection Telescope
Central “normal” image 1/13 sec exposure
Magnified image 1/6 sec exposure
Object distance = 68cm
6-Reflection Lens fabricated by diamond turning Tested with conventional camera (not model eye), 50mm F/1.4 lens on Canon 5D MkII SLR camera
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Test Setup
Object distance = 68cm
1/23/2011 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
UCSD Photonics 6-Reflection Telescope, Viewed Through Camera
Central “normal” image 1/13 sec exposure
Magnified image 1/6 sec exposure
Tested with conventional imager, Canon 50mm F/1.4 lens on Canon 5DMkII SLR camera
Group 2,1 (4 lp/mm, 0.63’ resolution)
Vertical Group 2,1 (4 lp/mm, 0.63 arc min resolution)
Horizontal Group 2,4 (5.66 lp/mm,
0.45’ resolution)
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1/23/2011 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
UCSD Photonics
smooth skirt
4-Reflection Contact Lens Telescope
2.8x magnification (lens + eye EFL = 47.6 mm)
+/- 2.5°
PMMA Acrylic 8 mm x 1.17 mm (radial)
Center: 1 mm thick curved to match eye
Thickness: 1.17 mm max
8 mm Φ
6.2 mm Φ
2.2 mm Φ
Aspheric reflectors
Transmissive diffractive optic (achromatization)
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Telescopic: F / 9.4 8 mm (outer), 6.2 mm (inner) 5.05 mm effective diameter 47.7 mm EFL
Clear: F / 7.8 2.18 mm diameter 17 mm EFL
8 mm
Aperture
1/23/2011 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
UCSD Photonics 4-Reflection Contact Lens Calculated Performance
50μm
Relative illumination
FOV 17.5 deg (RI >10%) 4mm pupil
12 deg
Spot Diagram
0˚ 1˚
2˚ 2.5˚
100 cyc/mm
Visible light spectrum MTF
(over 5˚ FOV)
Comparing Normal & Magnified Vision
4-Reflection Telescope Contact + Eye (1.8˚ field)
30 cyc/˚ 81 cyc/˚ (104 cyc/mm)
Spatial Frequency
Mod
ulus
of t
he O
TF
0
0.5
1 MTF
<neuronal threshold>
(Near diffraction limit for annular aperture)
<neuronal threshold>
Eye’s Optics (5˚ field)
30 cyc/˚ (104 cyc/mm)
15 cyc/˚
Spatial Frequency M
odul
us o
f the
OTF
0
1
0.5
MTF
<neuronal threshold> 2.8x Magnification (same spatial freq. @ retina)
• 2.8x magnified contrast equal @ 30 cyc/˚ (20/20 Snellen acuity)
• 2.8x magnified should reach 81 cyc/˚ (neuronal contrast limit)
1/23/2011 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
UCSD Photonics
Zemax model made compatible w/ fabrication constraints:
1:1 Laboratory Eye Model
Optical performance over 9 deg (18deg FOV), 5mm iris
40 μm
Fused Silica Aspheric Optics
Curved Image Surface - Optimized over 30° field - 22 mm radius of curvature
Fovea (±2.5˚)
9° 15°
4.5° 0°
Iris / Aperture stop: Designed at 4-6 mm diameter
Cornea, 12 mm diameter, 1 mm thick IOL, 10 mm diameter, 3.7 mm thick
Immersion fluid: water
Iris Aperture
Fiber Plate
Intraocular Lens
Cornea Lens
Immersion seal (distilled water)
CMOS Sensor
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• Based on the “Eye_Retinal_Image” model by Rod Watkins (available in the Zemax Knowledge base)
• Two fused silica aspheres immersed in distilled water • Edges thickened for handling and mounting • 4 - 6 mm aperture (for design optimization) • 34.5˚ FOV (limited by 10mm fiber faceplate diameter)
1/23/2011 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
UCSD Photonics
Scale Laboratory Eye Model
Sigma 50mm
F/1.4 HSM
Canon 70-200mm F/2.8L
IS Canon 5D Mark II 21 Mpix full frame
SLR
Eye Model
Assembled Eye Model & Relay System
Model Eye & Relay system
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30 cycles/˚ (103 cyc/mm on fiber plate)
Max resolution: 1.06 arc minutes (Group [2,2] w/ 358mm objective)
Measured Spatial Frequency Response (SFR) (slanted edge)
• Assembled with 4mm iris • fiber plate focused using spring-loaded aluminum clamp
Images captured with eye + relay
Relay System
• Face-to-face macro relay • 1.4x – 4x magnification • Individual 4μm fibers resolved
1/23/2011 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
UCSD Photonics
Normal Vision (contact center + model eye; 0.5 sec exp)
USAF 1951 Resolution chart imaged through f=36cm F/5 objective (focused at infinite conjugate). Same object distance for both. Lens was designed to work at > 10m conjugates, so with this apparent object distance, both telephoto and normal vision modes are in focus.
4-Reflection Contact Lens on Eye Model
2.8x Magnified Vision (through contact + model eye; 2 sec exp)
Max resolution: 1.06 arc min
(group 2,2)
Max resolution: 1.34 arc min
(group 1,6)
1/23/2011 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
UCSD Photonics Conclusion
• Current work / next steps – Refinement of optical design (RGP materials, optimization of size
for comfort and optical performance) – Biocompatible fabrication for wear on the eye and clinical trial – Optical Switching technologies
Acknowledgements: This work is supported by DARPA via contract 25677A- DARPA/HR0011-10-1-0005 Fabrication Services:
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• First demonstration of a thin reflective magnifying contact lens
– Dual magnification optical paths (1x & 3x) make on-demand view switching a possibility
– Promising approach for low vision aid (AMD) and other applications (military, sports, etc.)
1/23/2011 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
UCSD Photonics
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Thank you