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Published byBrooklyn Cockman Modified over 9 years ago
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Financial Disclosure Calhoun Vision consultant, equity Clarity Massey Labs consultant, equity
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Cornea and Anterior Segment Imaging OCT: Diagnosis and Surgical Planning Ronald E. Smith, M.D. Doheny Eye Institute USC Keck School of Medicine
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OCT now approaches histology in resolution Normal retina imaged by RTVue OCT (5 micron resolution) Histology of human retina
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Optical coherence tomography (OCT) has higher resolution than other imaging modalities. 1 mm 100 m 10 m 1 m OCT Ultrasound Axial Resolution (FWHM) CT MRI
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There is a revolution in OCT technology – speed is taking off!
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A generational leap RTVue has 65x speed & 2x resolution of Stratus Zeiss OCT1/2 1996 Zeiss Stratus 2002 OptoVue RTVue 2006 26,000 400 100 16 10 5 Speed (A-scans /sec) Resolution ( m) Fourier domain Time domain
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FD OCT Simultaneous 2048 pixels at a time TD OCT Sequential 1 pixel at a time Higher speed, higher definition and higher signal. 1024 A-scans in 0.04 sec 512 A-scans in 1.28 sec Motion artifact Small blood vessels IS/OS Choroidal vessels
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Optical Coherence Tomography (OCT) Retinal OCT –In common clinical usage –Macular diseases –Glaucoma Corneal and Anterior Segment OCT (CAS-OCT) –Early clinical development –Keratorefractive surgery –AC-IOL planning –Narrow Angle –Other surgical anatomy and pathologies
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OCT is used to for anterior eye diseases and surgery as well LASIK Lens implantation Seeing through opaque cornea Narrow angle glaucoma
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Higher resolution allows better visualization of LASIK flap 4 months after LASIK with Moria CB Average of 16 frames
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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
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Scan Pattern for Corneal Mapping 8 x 10-mm radial line scans 3-D reconstruction
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Conclusion: OCT Pachymetry Map Excellent repeatability (SD < 2 m) Agrees well with ultrasound OCT (1%) Agrees well with programmed ablation depth (5%, better than ultrasound) Useful in confirming keratoconus
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Post-LASIK interface fluid & epithelial ingrowth 056-CP Fibrosis Epithelial ingrowth Fluid
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Case 2 Unrecognized Keratectasia Consulted for poor vision OS LASIK OU 9 years ago 2 enhancements OS MR - 1.00 +0.75 x 60º 20/40 OS
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Cornea Stroma LASIK Flap OS 217 244 461
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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
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Intacs
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CASE # 2 Opaque corneal graft and glaucoma
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OCT: IOL synechiae & pupil block 0 degree-45 degree -90 degree-135 degree
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DLEK (Jonathon Song, MD)
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Linking OCT to lasers to performed the most precise corneal surgeries OCT scanning Corneal thickness map Femtosecond laser cutting Partial thickness corneal transplant
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This will greatly benefits patients whose vision is limited by corneal irregularity and opacity (i.e. corneal scars and keratoconus) Deep corneal scar Advanced keratoconus
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Anterior Segment OCT for Narrow Angle Glaucoma Vikás Chopra MD Assistant Professor Doheny Eye Institute Dept of Ophthalmology USC Keck School of Medicine
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Results: Angle Configuration Pre- & Post-PI vs. post- CE/IOL
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Example: Angle Configuration in Dark and Light Conditions Room Lights ON Room Lights OFF
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Conclusions: Narrow Angle Detection using AS-OCT AS-OCT has the potential for large-scale screening for narrow, occludable angles Rapid Non-contact Ease of image acquisition Ease of image analysis with custom software
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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
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Center for Ophthalmic Optics & Laser (COOL) David Huang, MD, PhD Maolong Tang, PhDYan Li, MS Ou Tan, PhD Sylvia Ramos, COA Yimin Wang, PhD Ake Lu, PhDJulie Schallhorn
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