High Resolution Imaging in How can retinal imaging help me Patients with Retinal Dystrophies evaluate patients? Testing Retinal Function Subjectively Can’t see vision cells Visual Acuity
Ophthalmic Photographers Society Typically: Measure visual Visual Field Testing: Perimetry Annual Midyear Meeting acuity, visual field sensitivity April 20, 2013 New tools let us study retinal structure and function with high-resolution Jacque Duncan, M.D. UCSF Department of Ophthalmology Humphrey Visual Field
Goldmann Visual Field
Fundus-guided Microperimetry Fundus-guided Microperimetry Evaluation of Macular Structure
SLO used to Normal values Color fundus photos provide infrared are 20 within 4 Fundus Autofluorescence fundus image to degrees of the track fundus fovea Infrared fundus photos landmarks Able to Fluorescein angiography
Resolution on demonstrate Optical Coherence Tomography (OCT) the order of tiny central several degrees and Non-invasive method of creating cross-sectional paracentral images in vivo scotomas
Fundus photos: a view to the back of the eye
Color: represents what can be seen on exam Fundus Autofluorescence: Short wavelength light excites fluorescent compounds in the RPE (Lipofuscin) Most prevalent fluorophore is A2E Accumulates in RPE with photoreceptor outer segment degradation Infrared: uses long wavelength light to visualize melanin and melanolipofuscin
Left Eye Color fundus photo Left eye fundus autofluorescence Ultrasound OCT OCT: measures retina in cross-section Like ultrasound:
Instead of differences in acoustic backscattering, OCT uses differences in reflectivity of light to image different tissues
High resolution: 2-10m Necessary to image retinal structures
No contact with eye required
Ideally suited to imaging ocular structures Resolution: 150 m Resolution: 2-3 m
Left eye infrared fundus photo
OCT: Cross-sectional image Spectral Domain Optical Coherence Scanning Laser Ophthalmoscopy resembles histology Tomography (OCT) (SLO):
Cross-sectional images of retinal structure in vivo Confocal images of retinal planes Non-invasive; doesn’t require perfectly clear media Can image autofluorescence from lipofuscin in RPE Axial resolution 3-4 um with spectral-domain systems Poor axial resolution (300um) Lateral resolution limited by aberrations induced by optics of cornea/lens ONL ELM EZ: ISe or IS/OS JXN Useful way to measure retinal structure IZ: OS/RPE JXN quantitatively in vivo Horizontal OCT across normal fovea
Adaptive Optics Scanning Laser Adaptive Optics Correct Aberrations Ophthalmoscope
Yuhua Austin AO + SLO = AOSLO Increasing Pupil Size Zhang Roorda
No AO (defocus and astigmatism corrected)
Adding Adaptive Optics Adaptive Optics Scanning Laser AO + SLO = AOSLO AO + SLO = AOSLO Ophthalmoscopy (AOSLO)
No AO (defocus and astigmatism corrected) Single frame with AO No AO (defocus and astigmatism corrected) Single frame with AO Multiple frames with AO Overcomes blur from optical aberrations Shack-Hartmann wavefront sensor Deformable mirror Image individual cones with high resolution
The left image is taken after best correction of defocus and astigmatism, but not high order aberrations. The second frame is a single frame taken after AO correction. The third frame is a co- added set of 10 frames which have been corrected for distortions due to eye movements. Signal 450 microns magnitude, resolution and contrast are improved after AO correction and virtually every cone is resolved in the registered frame.
Cone Spacing Increases with Eccentricity in Normal Eyes Cone Spacing is Similar in Normal AOSLO in Retinal Degenerations 3 Eyes Aged 14-72 2.5 2.5 Progressive loss of photoreceptors causes
2 vision loss 2 Can we image macular cones in patients with 1.5 1.5 AOSLO data from diseased photoreceptors? 20 normal eyes 1 best fit (+/- 95% limits) 1 Are diseased cones different in patients with 0.5 histological data (+/- 2 sd) Open Squares: < 40 yo different types of degeneration? Cone spacing (microns) Cone Spacing (arcminutes) Spacing Cone 0.5 Black Squares: 40-55 yo 0 Do certain phenotypes correlate with specific 036912 12 Red Squares: > 55 yo genetic mutations? Distance from fovea (degrees) 0 0246810 Curcio CA et al. J Comparative Neurology 1990; 292:497-523 Eccentricity (degrees) Duncan et al, IOVS, 2007
Stargardt Disease
1/10,000 patients in the U.S. Central vision loss due to macular degeneration of photoreceptors and RPE cells Stargardt Disease ABCA4 mutations identified in up to 80% Abnormal accumulation of autofluorescent lipofuscin in RPE cells Flecks, dark choroid on fluorescein angiography Evaluate macular cone structure in 8 STGD patients using high-resolution retinal imaging (AOSLO) Correlate cone structure with visual function using fundus-guided microperimetry (MP-1) B A Stargardt Disease: SD-OCT Findings
0.61868 2.0039 14 1.5848
1.9893 14 2.3122 16 2.2297 16 1.1987-0.029249 0.091239 1.3809 12 16 16 18 14
-0.49271
12 18 18 14 18 Normal subject: Vertical OCT across anatomic fovea 14 18 16
10 8 8 14 12 18 14 16 16
Central scotomatous region Superiorly shifted fixation to 4 2 0 Transition Zone with IZ present 8 0 0 0 0
D 0 0 0 10
C 0 0
F3P1: Vertical OCT across fixation and anatomic fovea Chen YM et al. Invest Ophthalmol Vis Sci 2011; 52:3281-92 Chen YM et al. Invest Ophthalmol Vis Sci 2011; 52:3281-92
Cone Spacing in Stargardt Disease: Age-Related Macular Lessons Learned from AOSLO Degeneration (AMD)
• Regions of increased cone spacing correlated Leading cause of vision loss among elderly in with reduced visual sensitivity Age-Related Macular the US • Cone structure was closest to normal at the Degeneration Deposits under the RPE (drusen) eventually kill location of eccentric fixation photoreceptors
• Cone structure was preserved in the Directly: geographic atrophy parapapillary region Indirectly: choroidal neovascularization • AOSLO may provide a sensitive measure of AOSLO provides opportunity to study cones at cone survival and disease progression the margin of geographic atrophy in AMD
Cones Preserved at the Border of GA Diagnostic Dilemmas: 48 year old man
Vision loss of unknown etiology Complains of blind spots in both eyes, Past medical history: unremarkable gradually progressing over the past 2-3 Atypical cases of common diseases Medications: none years No prior chloroquine, hydroxychloroquine, New tools to explore the macula allow First noticed trouble locating mouse pointer assessment of cone structure and function thioridazine OS 5 years ago, then OD Family history: Mother developed reduced Fundus-guided Microperimetry Reports difficulty with glare at night, vision central vision in her 30s, stopped driving at Spectral Domain OCT in shadows and recognizing pastel colors age 38 and is now legally blind; her AOSLO images of macular cones Denies photosensitivity or reduced side deceased sister and mother also had vision vision problems…
Some vision problems Eye Examination
Vision loss in her early 30s Still driving, age 70 BCVA: 20/25 OD, 20/40 OS IOP 19 OU Significant vision loss in her early 40s No APD Anterior Segment: Trace NS OU, no
c/o vision loss in his vitreous cell early 40s Dilated Fundus Examination: No known Consanguinity
3 11613
Humphrey Visual Fields Fluorescein Angiogram Goldmann Visual Fields Differential Diagnosis?
Early-onset AMD? No drusen, young Myopic Degeneration? Not myopic Multifocal choroiditis? No signs of inflammation Histoplasmosis? No peripapillary or peripheral changes Late-onset Stargardt No dark choroid, old, AD Disease? family history Pattern Dystrophy? AD history, no patterns Adult Vitelliform? No vitelliform lesions Central Areolar Choroidal +AD, +atrophy Dystrophy?
Fundus Autofluorescence OCT Genetic Testing Carver Nonprofit Genetic Testing Laboratory (www.carverlab.org) Fee for service testing for many mutations DNA sequencing of the entire coding sequence of the RDS gene revealed a heterozygous CGG>TGG nucleotide substitution Amino acid change of Arg172Trp in the peripherin/RDS gene
Peripherin/RDS gene Conclusions: AMD vs. Hereditary How can retinal imaging help me take Chromosome 6p (human), 17 (mouse) Maculopathy care of my patients? In mice: retinal degeneration, slow (RDS) Often the cause of vision problems is not Photoreceptor disc membrane-associated Earlier onset, bilateral, symmetric macular obvious from examination alone glycoprotein, essential for outer segment disc lesions stabilization; forms complex with ROM1 Advances in retinal imaging can shed light on Implications for other family members In humans: mutations can cause ADRP, pattern diagnosis and implicate photoreceptors as
dystrophy, adult vitelliform, central areolar Take a family history source of vision loss choroidal dystrophy, RP albescens, CRD, and AD Consider genetic testing: SDOCT provides high resolution cross-sectional macular dystrophy www.carverlab.org retinal images
Sometimes RP, pattern and fundus flavimaculatus eyeGENE all in same family AOSLO images individual photoreceptors
Weleber RG, Carr RE, Murphey WH et al., Arch Ophthalmol 1993; 111:1531-42 AOSLO in Retinal Disease: AOSLO in Retinal Disease: The Present The Future Acknowledgements High resolution images of cone photoreceptors Promising new technology for vision on a microscopic scale Reema Syed, UCSF Austin Roorda, UC science Berkeley Shiri Soudry, UCSF Cones are preserved in regions with preserved Brandon Lujan, UC May provide a sensitive measure of cone Moreno Menghini, UCSF visual function and around the optic disc in Berkeley survival during degeneration and in Kavitha Ratnam, UCSF STGD Pavan Tiruveedhula, UC response to therapy Katherine Talcott, UCSF Berkeley Cones are visible at the border of geographic May yield insight into mechanism of cell Yingming Chen, Yuhua Zhang, University atrophy and over drusen University of Toronto of Alabama, Birmingham death in several different types of retinal Radha Ayyagari, UCSD diseases
Acknowledgements
The Foundation Fighting Blindness Research to Prevent Blindness Jahnigen Career Development Scholars Award (American Geriatrics Society) American Health Assistance Foundation Macular Degeneration Fund Hope for Vision Karl Kirchgessner Foundation That Man May See, Inc. The Bernard A. Newcomb Macular Degeneration Fund NIH – BRP Adaptive Optics Instrumentation for Advanced Ophthalmic Imaging (PI: David Williams)