Transcript Optical Coherence Tomography Research Plan

Financial Disclosure
Calhoun Vision
consultant, equity
Clarity Massey Labs
consultant, equity
Cornea and Anterior Segment Imaging
OCT: Diagnosis and Surgical Planning
Ronald E. Smith, M.D.
Doheny Eye Institute
USC Keck School of
Medicine
OCT now approaches histology in resolution
Normal retina imaged by RTVue OCT (5 micron resolution)
Histology
of human
retina
Axial Resolution (FWHM)
Optical coherence tomography (OCT) has
higher resolution than other imaging modalities.
1 mm
OCT
10 mm
100 mm
1 mm
Ultrasound
CT
MRI
There is a revolution in OCT technology –
speed is taking off!
A generational leap
26,000
OptoVue
RTVue 2006
Fourier domain
Speed
(A-scans
/sec)
Time domain
400
100
Zeiss
OCT1/2
1996
16
Zeiss Stratus
2002
Resolution
10
(mm)
5
• RTVue has 65x speed & 2x resolution of Stratus
FD OCT
TD OCT
Simultaneous
2048 pixels at a time
Sequential
1 pixel at a time
Small blood vessels
Motion artifact
IS/OS
Choroidal vessels
512 A-scans in 1.28 sec
1024 A-scans in 0.04 sec
Higher speed, higher definition and higher signal.
Optical Coherence Tomography (OCT)
• Retinal OCT
– In common clinical usage
– Macular diseases
– Glaucoma
• Corneal and Anterior Segment OCT (CAS-OCT)
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Early clinical development
Keratorefractive surgery
AC-IOL planning
Narrow Angle
Other surgical anatomy and pathologies
OCT is used to for anterior eye diseases and
surgery as well
LASIK
Lens implantation
Seeing through opaque cornea
Narrow angle glaucoma
Higher resolution allows better
visualization of LASIK flap
Average of 16 frames
4 months after LASIK with Moria CB
CAS-OCT in LASIK Planning
• Corneal thickness map
– Determine available ablation depth
– Distinguish FF keratoconus from warpage
• Flap & stromal bed thickness maps*
– Distinguish ectasia from normal regression
– Calculate available enhancement ablation
depth
*Not available on slit-scanning tomography
Scan Pattern for Corneal Mapping
8 x 10-mm radial line scans
3-D reconstruction
Conclusion: OCT Pachymetry Map
• Excellent repeatability (SD < 2 mm)
• Agrees well with ultrasound OCT (1%)
• Agrees well with programmed ablation
depth (5%, better than ultrasound)
• Useful in confirming keratoconus
056-CP
Post-LASIK interface fluid & epithelial
ingrowth
Epithelial ingrowth
Fibrosis
Fluid
Case 2 Unrecognized Keratectasia
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Consulted for poor vision OS
LASIK OU 9 years ago
2 enhancements OS
MR
- 1.00 +0.75 x 60º
20/40 OS
461
Cornea
244
Stroma
OS
LASIK Flap
217
Case 2 Conclusions
• Keratectasia
– LASIK enhancement not advised
– RGP v. Intacs
• OCT shows
– Thick flap
– Thin residual posterior stromal bed: may be
cause or result of keratectasia
Intacs
CASE # 2 Opaque corneal graft
and glaucoma
OCT: IOL synechiae & pupil block
0 degree
-90 degree
-45 degree
-135 degree
DLEK (Jonathon Song, MD)
Linking OCT to lasers to performed the most
precise corneal surgeries
Corneal
thickness
map
OCT scanning
Femtosecond
laser cutting
Partial thickness
corneal transplant
This will greatly benefits patients whose vision is
limited by corneal irregularity and opacity (i.e. corneal
scars and keratoconus)
Advanced keratoconus
Deep corneal scar
Anterior Segment OCT
for Narrow Angle Glaucoma
Vikás Chopra MD
Assistant Professor
Doheny Eye Institute
Dept of Ophthalmology
USC Keck School of Medicine
Results:
Angle Configuration Pre- & Post-PI vs.
post- CE/IOL
Example:
Angle Configuration D in Dark and Light
Conditions
Room Lights
OFF
Room Lights
ON
Conclusions:
Narrow Angle Detection using AS-OCT
• AS-OCT has the potential for large-scale
screening for narrow, occludable angles
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Rapid
Non-contact
Ease of image acquisition
Ease of image analysis with custom software
Corneal & Anterior Segment OCT
• LASIK
– Pachymetry map
– Flap & stromal bed
thickness
• Intacs implant depth
• Corneal opacity,
edema
• Uveitis
– AC cell counting
• Iris mass
• IOL
– AC width
– Corneal Clearance
• Accommodation
• Narrow angle
glaucoma
– Angle opening
distance, TISA
Center for Ophthalmic Optics & Laser
(COOL)
David Huang, MD, PhD
Ou Tan, PhD
Maolong Tang, PhD
Ake Lu, PhD
Yimin Wang, PhD
Yan Li, MS
Sylvia Ramos, COA Julie Schallhorn