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Results: 14

1.
Fig. 5

Fig. 5. From: Adaptive optics scanning laser ophthalmoscope with integrated wide-field retinal imaging and tracking.

LSO/tracker optomechanical integration module in SolidWorks for the new AOSLO interface as implemented at IU and PSI. Wide field of regard >30 deg enables the small AOSLO raster to be steered anywhere within it. The final pair of large spherical mirrors and a paraxial eye are indicated as optical surfaces only.

R. Daniel Ferguson, et al. J Opt Soc Am A Opt Image Sci Vis. ;27(11):A265-A277.
2.
Fig. 10

Fig. 10. From: Adaptive optics scanning laser ophthalmoscope with integrated wide-field retinal imaging and tracking.

Averaging stabilized AOSLO cone photoreceptor images. (a) Single image of cones, 4 to 5 μm in diameter. (b) 200-frame average during tracking. Note that some information at the cone spatial frequency is preserved, even though the net broadening appears to be several cone diameters.

R. Daniel Ferguson, et al. J Opt Soc Am A Opt Image Sci Vis. ;27(11):A265-A277.
3.
Fig. 8

Fig. 8. From: Adaptive optics scanning laser ophthalmoscope with integrated wide-field retinal imaging and tracking.

Montage of cone images obtained in a 56 year old male. Fixation was maintained just beyond the left end of the image (at fovea). AOSLO steering mirror (M2) was moved horizontally in a series of steps to ~11 deg eccentricity. At each location a series of frames of video were acquired, aligned, and averaged to create the montage.

R. Daniel Ferguson, et al. J Opt Soc Am A Opt Image Sci Vis. ;27(11):A265-A277.
4.
Fig. 11

Fig. 11. From: Adaptive optics scanning laser ophthalmoscope with integrated wide-field retinal imaging and tracking.

Eye motion from AOSLO image cross-correlation. (a) No-tracking 100-image average, rms motion is 75.7 μm shown in the x-y displacement graph below it. (b) Tracking, rms motion 5.5 μm, and (c) fully de-warped and overlaid images as a benchmark for perfect (<1 cone diameter) alignment. The final graph at bottom right shows the total radial displacement over time for tracking and non-tracking. Note tracking transients <30 μm.

R. Daniel Ferguson, et al. J Opt Soc Am A Opt Image Sci Vis. ;27(11):A265-A277.
5.
Fig. 6

Fig. 6. From: Adaptive optics scanning laser ophthalmoscope with integrated wide-field retinal imaging and tracking.

Examples of the LSO (915 nm), tracker (1050 nm), and AOSLO features provided in the GUI interface: AOSLO raster is visible in the LSO image to facilitate positioning, as are lower-resolution LSO features and landmarks seen in the AOSLO images; track beam overlay is shown relative to optic disc anatomy, as is a fixation coordinate (central dot at left), which was not calibrated to the LCD fixation display when these images were obtained: the shadows are due to a temporary fixation post with an LED attached.

R. Daniel Ferguson, et al. J Opt Soc Am A Opt Image Sci Vis. ;27(11):A265-A277.
6.
Fig. 13

Fig. 13. From: Adaptive optics scanning laser ophthalmoscope with integrated wide-field retinal imaging and tracking.

AOSLO cross-correlation software residual tracking errors (black), and hardware tracking signals (gray), in micrometers, compared in subject # 6. (a, b) X- and Y-positions versus time; a blink occurs at ~6.7 s. With superior tracking, the residual AOSLO corrections should become smaller as the tracking mirror positions reflect higher-fidelity tracking. Some pupil drift interacting with the pupil mismatch between the tracker and the AOSLO raster can cause the AOSLO image drift seen in (a) or saccadic “bleedthrough” seen in (b).

R. Daniel Ferguson, et al. J Opt Soc Am A Opt Image Sci Vis. ;27(11):A265-A277.
7.
Fig. 4

Fig. 4. From: Adaptive optics scanning laser ophthalmoscope with integrated wide-field retinal imaging and tracking.

Optical integration scheme. Pupils are combined before entering the final, wide-field ocular interface section. Dichroic beamsplitters (DCs) enable the various bands to be combined. With the appropriate dichroics, fluorescence imaging can be incorporated as well. The tracking mirror, TY, is conjugate to the center of rotation of the eye and steers all beams in common. TX (not shown) is just beyond the next pupil plane downstream.

R. Daniel Ferguson, et al. J Opt Soc Am A Opt Image Sci Vis. ;27(11):A265-A277.
8.
Fig. 2

Fig. 2. From: Adaptive optics scanning laser ophthalmoscope with integrated wide-field retinal imaging and tracking.

Zemax simulations: near-diffraction-limited performance across a small imaging field. The angles were adjusted for 8 deg eccentricity along a diagonal. The Mirao mirror simulates a correction for the best field. Wavefronts for the four corners and the center of a 2.25 deg (diagonal) imaging field are shown. All rms wavefront errors are less than 0.11 μm. For AOSLO imaging fields near 0 deg eccentricity, variation is markedly smaller, with rms errors typically below 0.08 μm.

R. Daniel Ferguson, et al. J Opt Soc Am A Opt Image Sci Vis. ;27(11):A265-A277.
9.
Fig. 12

Fig. 12. From: Adaptive optics scanning laser ophthalmoscope with integrated wide-field retinal imaging and tracking.

Eye tracking hierarchy. Eye motion can be partitioned between closed-loop optical tracking (hardware): AOSLO cross-correlation (software) and (a) non-tracking case, X-Y (software aligned); (b) tracking, hardware analog X-Y position signals, (c) tracking, residual X-Y frame errors (software); (d) fine-aligned 100-frame average, net result of software and hardware combined; resulting images aligned to within a single cone diameter. Real-time, on-line software mapping for fine alignment will be difficult from fixation alone. The path from (a) to (d) is greatly assisted in the stabilization hierarchy by hardware tracking through (b) and (c).

R. Daniel Ferguson, et al. J Opt Soc Am A Opt Image Sci Vis. ;27(11):A265-A277.
10.
Fig. 7

Fig. 7. From: Adaptive optics scanning laser ophthalmoscope with integrated wide-field retinal imaging and tracking.

Average foveal cone image montage obtained from a 27 year old male. Cones are imaged to within approximately 50 μm of the foveal center (the subject fixated the bottom left corner of the raster). Region shown is approximately 1.6×2.0 deg. Some residual distortion shows minor edge artifacts in the montage between different field sizes. Imaging wavelength was 840 nm with a 12 nm bandwidth. Imaging power was 180 μW, beacon power was 40 μW.

R. Daniel Ferguson, et al. J Opt Soc Am A Opt Image Sci Vis. ;27(11):A265-A277.
11.
Fig. 9

Fig. 9. From: Adaptive optics scanning laser ophthalmoscope with integrated wide-field retinal imaging and tracking.

The function of active eye tracking. Tracking: (a) Single frame with vessel and nerve fiber, (b) 10-frame average, (c) 100-frame average. Non-tracking: (d) 100-frame average. Short-term (<1 s) and long-term (several seconds) rms tracking/registration errors are subject-dependent and span the range of ~5 to 15 μm and without tracking from ~50 to >300 μm. Eye tracking can significantly improve stable overlap and efficiency of sequential AOSLO image capture by limiting the magnitude of eye movement excursions

R. Daniel Ferguson, et al. J Opt Soc Am A Opt Image Sci Vis. ;27(11):A265-A277.
12.
Fig. 14

Fig. 14. From: Adaptive optics scanning laser ophthalmoscope with integrated wide-field retinal imaging and tracking.

Measured loss of averaged AOSLO image contrast (rms image sharpness) as a function of averaging interval over a 100-frame AOSLO video sequence (normalized to single-frame contrast). The diamonds are for an AOSLO video focused on blood vessels (BV/RNFL). The tracking (solid) and non-tracking (open) cases approach different contrast levels. The case of random data (zero frame overlap at all spatial frequencies) is included for comparison. The triangles are for cones; note the small difference because cones mosaics are dominated by features smaller than the rms displacement for either the tracking or the non-tracking cones.

R. Daniel Ferguson, et al. J Opt Soc Am A Opt Image Sci Vis. ;27(11):A265-A277.
13.
Fig. 1

Fig. 1. From: Adaptive optics scanning laser ophthalmoscope with integrated wide-field retinal imaging and tracking.

Unfolded diagram of the Integrated Indiana AOSLO Implementation. Though the layout is similar to many other AO implementations, there are three regions where the optics are folded vertically for astigmatism compensation. The first two are shown shaded, and the third is at the final large spherical mirror (sph 12). The wide-field imaging/eye-tracking module integrates those features efficiently in a compact package. Other unique features a supercontinuum light source, which is filtered, separated into selected bands, and delivered via single-mode fiber to the main imaging system.

R. Daniel Ferguson, et al. J Opt Soc Am A Opt Image Sci Vis. ;27(11):A265-A277.
14.
Fig. 3

Fig. 3. From: Adaptive optics scanning laser ophthalmoscope with integrated wide-field retinal imaging and tracking.

Zemax simulations of wavefront corrections for 2 deg AOSLO scans in 3 locations, corresponding to (a) the top (+15 deg) of the field, (b) center (0deg), and (c) bottom (−15 deg) of the field in a paraxial eye. Left panel, uncorrected system wavefront errors; center panel, compensating Mirao surface sags to third order with scales in μm; right panel, resulting corrected wavefronts. The average rms error after AO correction is <0.15 waves (0.11 μm at 750 nm). The maximum stroke (Mirao sag) needed to compensate system aberrations over the 30 deg field is <10 μm.

R. Daniel Ferguson, et al. J Opt Soc Am A Opt Image Sci Vis. ;27(11):A265-A277.

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