Adaptive Optics Ophthalmoscopy: Results and Applications

Home , Dichromacy

Aristophanis Pallikaris VEIC, University of Crete

Wavefront Congress Images of a Point Source vs Pupil Diameter

1 mm 2 mm 3 mm 4 mm

pupil images

followed by

psfs for changing pupil size 5 mm 6 mm 7 mm Adaptive Optics Principle

Deformable Mirror

Imaging Wavefront Camera Sensor High Resolution Retinal Images

Heidi Hofer and Matt McMahon Power Spectrum

Yellot’s ring

1/r r Triangular mosaic that is fairly regular r = √3/2 * center-to-center spacing Photoreceptor Dystrophies

Non-Pathological Retina Photoreceptor Dystrophy Roorda et al 2000 Trichromatic Cone Mosaic

Average L:M = 2:1

Roorda & Wiliams, 1999 Alternate Cause of Color Blindness

Normal Protanope Deuteranope

Red-Green Dichromacy Carroll et al 2004 Alternate Cause of Color Blindness

Complete loss of M cones

Replacement of L cones Cone Directionality

Refracted

n2 θ2

n1>n2 θc θ1 Reﬂected

n n3 2

n1>n2, n3

n2 -2 mm Cone Directionality

Registered sum of 8 images along -1 mm 9 different positions

1°eccentricity

-2 mm -1 mm 0 mm 1 mm 2 mm

1 mm

2 mm

5 arcmin Cone Directionality y t i 140 s n e 120 t n I

100 d e 80 z i l a 60 m r 40 o

N 20 0 -6 -4 -2 0 2 4 6 Pupil Position (mm) Roorda and Williams 2002 Imaging of AMD with Adaptive Optics

Drusen displaces the RPE and results in loss of pigments.

Without AO With AO Stacey Choi Changes in cone reflectance over time

Pallikaris A et al 2003 5 arcmin Disc Shedding of Extrafoveal Human Cones

A, B. Electron micrograph of two cones and their associated RPE apical processes C. Phagosome surrounded by RPE apical processes D, E. Cone outer segment tip

R. H. Steinberg et al. Confocal Scanning Laser Tomography Live AO Correction

1.5 deg

Slide Courtesy A. Roorda KV left eye, fovea SB KV#2 AR

KV OC

registered photoreceptor images from AOSLO Direct Visualization of Leukocytes

• No fluorescent dyes required • Identify ghost vessels (non-perfused capillaries) • 95% confident of velocity changes as small as 0.076 mm/sec Slide Courtesy A. Roorda Martin J., Roorda, A. IOVS under revision Diabetic Retinopathy

Earliest structural changes are found in the retinal capillaries Glaucoma

Optic Disk for an Eye Optic Disk for with Glaucoma. Normal Eye.

Early detection and treatment can control glaucoma and prevent further damage. Imaging glaucoma in a monkey model

Slide Courtesy A. Roorda Lamina Cribrosa

1 degree

Abhiram Vilupuru, Nalini Rangaswamy, Laura Frishman, Ron Harwerth Imaging glaucoma in a monkey model

1 degree

Slide Courtesy A. Roorda Abhiram Vilupuru, Laura Frishman, Ron Harwerth OCT with Adaptive Optics

Without AO

With AO

•Increase of the transverse resolution to 5-10 μm •Signal to noise ratio increase by up to 9 dB B. Hermann et al 2004 Discussion

• Adaptive optics ophthalmoscopy allow the microscopical view of the retina

• Adaptive optics ophthalmoscopy may be used both for basic science and clinical applications

• Further improvement of adaptive optics system along with the combination of other retinal imaging enhancing methods could enable three-dimensional visualization of photoreceptors, ganglion cells or RPE cells. Acknowledge

Austin Roorda and Colleagues David R. Williams and Colleagues

Thank you H E

Summer School R A

20– 26 June (Part I) K L I 27 June –1 July (Part II) O N

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C R E

Aegean Retina T E

1 – 3 July 2005 2 0 0 5 www.EyeInstituteCrete.com