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Biomedical Optics Express

Biomedical Optics Express

  • Editor: Joseph A. Izatt
  • Vol. 4, Iss. 2 — Feb. 1, 2013
  • pp: 351–363
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In vivo imaging of the rodent eye with swept source/Fourier domain OCT

Jonathan J. Liu, Ireneusz Grulkowski, Martin F. Kraus, Benjamin Potsaid, Chen D. Lu, Bernhard Baumann, Jay S. Duker, Joachim Hornegger, and James G. Fujimoto  »View Author Affiliations


Biomedical Optics Express, Vol. 4, Issue 2, pp. 351-363 (2013)
http://dx.doi.org/10.1364/BOE.4.000351


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Abstract

Swept source/Fourier domain OCT is demonstrated for in vivo imaging of the rodent eye. Using commercial swept laser technology, we developed a prototype OCT imaging system for small animal ocular imaging operating in the 1050 nm wavelength range at an axial scan rate of 100 kHz with ~6 µm axial resolution. The high imaging speed enables volumetric imaging with high axial scan densities, measuring high flow velocities in vessels, and repeated volumetric imaging over time. The 1050 nm wavelength light provides increased penetration into tissue compared to standard commercial OCT systems at 850 nm. The long imaging range enables multiple operating modes for imaging the retina, posterior eye, as well as anterior eye and full eye length. A registration algorithm using orthogonally scanned OCT volumetric data sets which can correct motion on a per A-scan basis is applied to compensate motion and merge motion corrected volumetric data for enhanced OCT image quality. Ultrahigh speed swept source OCT is a promising technique for imaging the rodent eye, proving comprehensive information on the cornea, anterior segment, lens, vitreous, posterior segment, retina and choroid.

© 2013 OSA

1. Introduction

Current imaging methods for rodent eyes include fundus photography, fluorescein angiography, slit-lamp imaging, scanning laser ophthalmoscope, magnetic resonance imaging and ultrasound biomicroscopy [2

2. N. L. Hawes, R. S. Smith, B. Chang, M. Davisson, J. R. Heckenlively, and S. W. John, “Mouse fundus photography and angiography: a catalogue of normal and mutant phenotypes,” Mol. Vis. 5, 22 (1999). [PubMed]

8

8. M. Paques, J. L. Guyomard, M. Simonutti, M. J. Roux, S. Picaud, J. F. Legargasson, and J. A. Sahel, “Panretinal, high-resolution color photography of the mouse fundus,” Invest. Ophthalmol. Vis. Sci. 48(6), 2769–2774 (2007). [CrossRef] [PubMed]

]. Most of these methods only reveal two-dimensional information. Magnetic resonance imaging and ultrasound can perform three-dimensional (3-D) imaging, but resolution is limited. Optical coherence tomography (OCT) is a noninvasive imaging modality that can perform high-resolution imaging of tissue morphology in situ and in real time [9

9. D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and et, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991). [CrossRef] [PubMed]

]. OCT is analogous to ultrasound except that it measures the echo time delay and magnitude of backreflected or backscattered light. By scanning an optical beam on tissue, two-dimensional cross sectional and three-dimensional volumetric images can be generated. Spectral/Fourier domain OCT (SD-OCT) imaging of the rodent retina was first reported by Srinivasan et al. in 2006 [10

10. V. J. Srinivasan, T. H. Ko, M. Wojtkowski, M. Carvalho, A. Clermont, S. E. Bursell, Q. H. Song, J. Lem, J. S. Duker, J. S. Schuman, and J. G. Fujimoto, “Noninvasive volumetric imaging and morphometry of the rodent retina with high-speed, ultrahigh-resolution optical coherence tomography,” Invest. Ophthalmol. Vis. Sci. 47(12), 5522–5528 (2006). [CrossRef] [PubMed]

]. SD-OCT offers excellent resolution, but has limited imaging speed and imaging range due to spectrometer and camera performance limitations. Current standard commercial OCT systems for small animal imaging are based on 850 nm SD-OCT technology [10

10. V. J. Srinivasan, T. H. Ko, M. Wojtkowski, M. Carvalho, A. Clermont, S. E. Bursell, Q. H. Song, J. Lem, J. S. Duker, J. S. Schuman, and J. G. Fujimoto, “Noninvasive volumetric imaging and morphometry of the rodent retina with high-speed, ultrahigh-resolution optical coherence tomography,” Invest. Ophthalmol. Vis. Sci. 47(12), 5522–5528 (2006). [CrossRef] [PubMed]

12

12. K. H. Kim, M. Puoris’haag, G. N. Maguluri, Y. Umino, K. Cusato, R. B. Barlow, and J. F. de Boer, “Monitoring mouse retinal degeneration with high-resolution spectral-domain optical coherence tomography,” J. Vis. 8(1), 17, 1–11 (2008). [CrossRef] [PubMed]

] and have been used in studies for imaging the retina and limited portions of the anterior segment such as the cornea [13

13. G. Huber, S. C. Beck, C. Grimm, A. Sahaboglu-Tekgoz, F. Paquet-Durand, A. Wenzel, P. Humphries, T. M. Redmond, M. W. Seeliger, and M. D. Fischer, “Spectral domain optical coherence tomography in mouse models of retinal degeneration,” Invest. Ophthalmol. Vis. Sci. 50(12), 5888–5895 (2009). [CrossRef] [PubMed]

15

15. S. D. Hanlon, N. B. Patel, and A. R. Burns, “Assessment of postnatal corneal development in the C57BL/6 mouse using spectral domain optical coherence tomography and microwave-assisted histology,” Exp. Eye Res. 93(4), 363–370 (2011). [CrossRef] [PubMed]

]. SD-OCT enables high resolution imaging of the rodent retina using both 850 nm and 1050 nm wavelengths [10

10. V. J. Srinivasan, T. H. Ko, M. Wojtkowski, M. Carvalho, A. Clermont, S. E. Bursell, Q. H. Song, J. Lem, J. S. Duker, J. S. Schuman, and J. G. Fujimoto, “Noninvasive volumetric imaging and morphometry of the rodent retina with high-speed, ultrahigh-resolution optical coherence tomography,” Invest. Ophthalmol. Vis. Sci. 47(12), 5522–5528 (2006). [CrossRef] [PubMed]

16

16. S. Hariri, A. A. Moayed, A. Dracopolos, C. Hyun, S. Boyd, and K. Bizheva, “Limiting factors to the OCT axial resolution for in-vivo imaging of human and rodent retina in the 1060 nm wavelength range,” Opt. Express 17(26), 24304–24316 (2009). [CrossRef] [PubMed]

], but the limited imaging range is insufficient for imaging the whole anterior segment of the rodent eye. Recent advances in swept source/Fourier domain OCT (SS-OCT) enable in vivo ultrahigh speed imaging, offering a promising new technology for rodent eye imaging [17

17. B. Potsaid, B. Baumann, D. Huang, S. Barry, A. E. Cable, J. S. Schuman, J. S. Duker, and J. G. Fujimoto, “Ultrahigh speed 1050nm swept source/Fourier domain OCT retinal and anterior segment imaging at 100,000 to 400,000 axial scans per second,” Opt. Express 18(19), 20029–20048 (2010). [CrossRef] [PubMed]

,18

18. L. Wang, B. Hofer, Y. P. Chen, J. A. Guggenheim, W. Drexler, and B. Povazay, “Highly reproducible swept-source, dispersion-encoded full-range biometry and imaging of the mouse eye,” J. Biomed. Opt. 15(4), 046004 (2010). [CrossRef] [PubMed]

]. SS-OCT offers several advantages over SD-OCT, including less sensitivity variation with imaging depth, longer imaging range, higher detection efficiencies and reduced fringe washout. Furthermore, increased penetration into the choroid and optic nerve head with reduced sensitivity to ocular opacities has been reported for OCT imaging in the water absorption window at 1050 nm compared to standard 850 nm wavelengths [19

19. B. Povazay, K. Bizheva, B. Hermann, A. Unterhuber, H. Sattmann, A. Fercher, W. Drexler, C. Schubert, P. Ahnelt, M. Mei, R. Holzwarth, W. Wadsworth, J. Knight, and P. S. Russell, “Enhanced visualization of choroidal vessels using ultrahigh resolution ophthalmic OCT at 1050 nm,” Opt. Express 11(17), 1980–1986 (2003). [CrossRef] [PubMed]

,20

20. A. Unterhuber, B. Povazay, B. Hermann, H. Sattmann, A. Chavez-Pirson, and W. Drexler, “In vivo retinal optical coherence tomography at 1040 nm - enhanced penetration into the choroid,” Opt. Express 13(9), 3252–3258 (2005). [CrossRef] [PubMed]

].

Standard commercial SD-OCT systems for small animal imaging operate at the 850 nm wavelength range with imaging speeds up to 40,000 axial scans per second, 3-7 µm resolution, and <2.5 mm imaging range in tissue. The systems have interchangeable sample arm optics that enables scanning the small animal retina and anterior eye in different imaging modes. Several studies have been performed using commercial SD-OCT systems [13

13. G. Huber, S. C. Beck, C. Grimm, A. Sahaboglu-Tekgoz, F. Paquet-Durand, A. Wenzel, P. Humphries, T. M. Redmond, M. W. Seeliger, and M. D. Fischer, “Spectral domain optical coherence tomography in mouse models of retinal degeneration,” Invest. Ophthalmol. Vis. Sci. 50(12), 5888–5895 (2009). [CrossRef] [PubMed]

15

15. S. D. Hanlon, N. B. Patel, and A. R. Burns, “Assessment of postnatal corneal development in the C57BL/6 mouse using spectral domain optical coherence tomography and microwave-assisted histology,” Exp. Eye Res. 93(4), 363–370 (2011). [CrossRef] [PubMed]

]. However, the limited imaging range of the systems constrain the imaging modes and require retinal, corneal, anterior lens and posterior lens imaging to be performed separately, thereby making it difficult to perform simultaneous imaging of these ocular structures.

This study demonstrates OCT imaging in the rodent eye using a 1050 nm wavelength SS-OCT prototype system at 100,000 axial scans per second with ~6 µm axial resolution and >5.3 mm imaging range. In comparison to the human eye, the rodent eye has a large lens filling up most of the vitreous cavity, making it challenging to image the anterior segment. The OCT system described here is especially suited for rodent eye imaging because of the long imaging range which can accommodate typical rodent eye lengths of ~6 mm in rats and ~3 mm in mice. OCT imaging protocols using high-definition, high transverse pixel density three-dimensional imaging with dense raster scanning are demonstrated. Long imaging ranges and improved sensitivity roll-off enable comprehensive imaging of the anterior eye along with sections of the posterior lens surface and retina simultaneously. Long wavelength OCT systems at 1050 nm improve visualization of deeper tissue structure compared to 850 nm where standard commercial OCT systems operate. The high speed and deep imaging penetration is ideal for Doppler OCT of posterior eye blood vessels. High speed also enables four-dimensional (4-D) time resolved volumetric imaging of dynamic responses of the eye.

2. Methods

2.1. Ultrahigh speed swept source/Fourier domain system

An ultrahigh speed swept source/Fourier domain OCT instrument was built for small animal imaging (Fig. 1A
Fig. 1 (A) Schematic of ultrahigh speed swept source/Fourier domain OCT instrument. GS – galvanometric scanners, RR – retroreflector, LS – LED light stimulus, DBP – dual balanced photodetector, A/D – analog-to-digital converter, TRG – trigger signal. (B) Spectrum of the light source. (C) Point spread function showing axial resolution. (D) Sensitivity roll-off.
). A short external cavity, tunable light source (Axsun Technologies, Inc.) centered at 1044 nm which had a 3-dB bandwidth of 103 nm and a 10-dB bandwidth of 111 nm was used (Fig. 1B). The axial scan rate of the OCT system was 100 kHz, set by the sweep rate of the laser. Light from the laser was split into a single pass reference arm and a pre-objective scanning sample arm where the galvanometric scanners are placed in the back focal plane of the objective lenses. Returning light from the reference and sample arms was combined in a second (50:50) fiber coupler and the interferometric signal was detected using a low distortion 330 MHz dual balanced photodetector receiver (prototype; Thorlabs, Inc.). The signal from the photodetector was digitized by a high-speed 8 bit analog-to-digital converter at 1 GSPS (ATS9870; Alazar Technologies, Inc.). Different scan lenses in the sample arm were used to provide different transverse spot sizes and depths of focus. A long working distance infrared microscope objective (M Plan NIR 5X; Mitutoyo Corp.) was used for retinal imaging. The transverse spot size was ~12 µm full width at half maximum (FWHM) measured in air with a beam profiling camera and the incident power was 1.6 mW. For anterior eye and full eye length imaging as well as for posterior eye imaging, a 75 mm focal length achromatic lens was used. The transverse spot size was ~21 µm FWHM in air and the incident power was 2.5 mW. Unlike human eye imaging, a telecentric scanning interface was used for both anterior segment and retinal imaging of the rodent eye. A #1.5 coverslip and index matching gel (Goniosol) was used over the corneal during the retinal and posterior eye imaging procedures. An LED light stimulus was placed adjacent to the sample arm interface without blocking the OCT beam. The measured axial resolution of the system was 6 µm in tissue. The measured sensitivity of the system was 102 dB with a Nyquist limited depth range of 9.1 mm in tissue where the −6-dB roll-off depth was at 2.5 mm in tissue and the −20-dB roll-off depth was at 5.3mm in tissue. The sensitivity roll-off was limited by the bandwidth of the balanced photodetector and finite light source coherence length (the roll-off from the coherence length itself introduces a 6 dB sensitivity drop at 6 mm in air).

2.2. Animal preparation

Sprague-Dawley rats and C57BL/6 mice were used to demonstrate the imaging capability of the OCT system. Animals were anesthetized intraperitoneally with ketamine (40-80 mg/kg body weight) and xylazine (5-10 mg/kg body weight) for all structural imaging studies. During anterior eye and full eye length imaging, artificial tear drops were applied to prevent cornea dehydration. To perform retinal and posterior eye imaging, eyes were dilated with topically applied tropicamide (1%) drops, and a thin microscope coverslip was placed on the cornea with Hydroxypropyl methylcellulose (Goniosol, 2.5%) to remove corneal refraction and preserve corneal hydration. To perform functional imaging studies, imaging the pupillary reflex, animals were anesthetized intraperitoneally by a cocktail containing ketamine (40 mg/kg body weight), xylazine (3 mg/kg body weight), and acepromazine (1.5 mg/kg body weight). These studies were in compliance with the guidelines of the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research, and performed under a protocol approved by the MIT Committee on Animal Care. After anesthetization, the animal was placed in a comfortable mounting tube fixed on a height and tilt adjustable stage pivoted about the animal's eye.

2.3. OCT image acquisition

OCT cross-sectional previews along with a real-time OCT en face fundus image were used for alignment. For retinal imaging, six raster scans with orthogonal fast scan axis orientation (horizontal and vertical) each consisting of 700 × 700 axial scans requiring an acquisition time of ~5 seconds for each raster (~30 seconds total) were acquired. The six volumetric data sets were then registered using motion correction software and merged. For anterior eye and full eye length imaging, two raster scans with orthogonal fast scan axes (horizontal and vertical) consisting of 500 × 500 axial scans requiring an acquisition time of <3 seconds each were acquired, motion corrected and merged. For posterior eye and Doppler imaging, six orthogonal 500 × 500 axial scan raster scans were acquired, motion corrected, and merged, where each scan was acquired in <3 seconds. For high-speed dynamic volumetric OCT imaging, repeated raster scans with 100 × 100 axial scans were taken in sequence to achieve ~10 volumes per second. The high speed repeated volumes were not motion corrected.

2.4. Doppler OCT

Doppler OCT is a functional extension of OCT which provides velocity and flow information. In Fourier domain OCT, the complex OCT spectral data is processed and the phase information is used for velocity and flow calculations in Doppler OCT [21

21. R. Leitgeb, L. Schmetterer, W. Drexler, A. Fercher, R. Zawadzki, and T. Bajraszewski, “Real-time assessment of retinal blood flow with ultrafast acquisition by color Doppler Fourier domain optical coherence tomography,” Opt. Express 11(23), 3116–3121 (2003). [CrossRef] [PubMed]

25

25. B. Baumann, B. Potsaid, M. F. Kraus, J. J. Liu, D. Huang, J. Hornegger, A. E. Cable, J. S. Duker, and J. G. Fujimoto, “Total retinal blood flow measurement with ultrahigh speed swept source/Fourier domain OCT,” Biomed. Opt. Express 2(6), 1539–1552 (2011). [CrossRef] [PubMed]

]. A simple phase subtraction of neighboring oversampled OCT axial scans generates quantitative Doppler OCT measurements which was used to visualize the vasculature in eyes:

vz(z)=λ04πnf[φi+1(z)φi(z)],
(1)

where λ0 is the center wavelength of the light, n is the refractive index, f is the sweep rate, and φi(z) is the phase profile of the ith axial scan after Fourier transformation. The maximum detectable velocity before phase wrapping, determined by the imaging speed, is ±20 mm/s in tissue. In theory, the minimum detectable axial velocity is determined by the phase stability of the light source, and was measured to be 1.8 mrad. In practice, the minimum measurable axial velocity in tissue is limited by the phase decorrelation associated with trigger jitter and scanning the beam [25

25. B. Baumann, B. Potsaid, M. F. Kraus, J. J. Liu, D. Huang, J. Hornegger, A. E. Cable, J. S. Duker, and J. G. Fujimoto, “Total retinal blood flow measurement with ultrahigh speed swept source/Fourier domain OCT,” Biomed. Opt. Express 2(6), 1539–1552 (2011). [CrossRef] [PubMed]

]. After applying a phase compensation algorithm where bulk motion was calculated and removed using a histogram-based method [23

23. S. Makita, Y. Hong, M. Yamanari, T. Yatagai, and Y. Yasuno, “Optical coherence angiography,” Opt. Express 14(17), 7821–7840 (2006). [CrossRef] [PubMed]

], the standard deviation of phase differences between successive sweeps over a mirror was measured to be 0.11 rad, corresponding to a minimum measurable axial velocity of 0.7 mm/s in tissue.

2.5. OCT volumetric registration

Although the imaging was performed with the animals under anesthesia, motion artifacts persist from breathing and heartbeat. Motion during the acquisition of volumetric OCT data distorts the data and is a source of error in quantitative measurements. A motion correction algorithm was recently developed for orthogonally scanned volumetric OCT data [26

26. M. F. Kraus, B. Potsaid, M. A. Mayer, R. Bock, B. Baumann, J. J. Liu, J. Hornegger, and J. G. Fujimoto, “Motion correction in optical coherence tomography volumes on a per A-scan basis using orthogonal scan patterns,” Biomed. Opt. Express 3(6), 1182–1199 (2012). [CrossRef] [PubMed]

]. Motion correction is performed by estimating dense displacement fields, which describe the motion of each A-scan, for each input volume and using the time structure of the acquisition process as a constraint. After optimizing a global objective function, the displacement fields are estimated for each volume to correct for motion, then a single volume is constructed by merging each motion corrected volume. Motion corrected volumes do not show visible motion artifacts and a merged registered volume has improved signal quality. The motion corrected, merged volumetric data more accurately represents structure and morphology than individual volumes which can have motion artifacts.

2.6. Light stimulation

For the pupil response experiments, a white light LED stimulus with ~800 cd/cm2 luminance was used. The LED light source was placed adjacent to the OCT beam without blocking the OCT scan. Two stimulus protocols were used: a continuous >5 second stimulus and a short ~1 second flash stimulus. The stimulus was activated during OCT data acquisition of repeated raster scans.

3. Results

3.1. 3-D retinal imaging in unpigmented rat eye and pigmented mouse eye

Three-dimensional volumetric OCT imaging of the unpigmented Sprague-Dawley rat retina and pigmented C57BL/6 mouse retina is demonstrated in Fig. 2
Fig. 2 Imaging of the unpigmented Sprague-Dawley rat retina. Registered and merged OCT data set generated from 6 orthogonally scanned OCT data sets. (700 × 700 axial scans over a 2.4 mm × 2.4 mm region) (A) OCT fundus view. (B) Retinal layers visualized in the cropped, enlarged OCT image. (C) 3-D rendering. (D, E, F) OCT images in the X direction. (G, H, I) OCT images in the Y direction.
and Fig. 3
Fig. 3 Imaging of the pigmented C57BL/6 mouse retina. Registered and merged data set generated from 6 orthogonally scanned OCT data sets. (700 × 700 axial scans over a 1.2 mm × 1.2 mm region) (A) OCT fundus view. (B) Retinal layers shown in the cropped, enlarged OCT image (C) 3-D rendering. (D, E. F) OCT images in the X direction. (G, H, I) OCT images in the Y direction.
, respectively. The animals were anesthetized so that measurement time is not limited by blinking or motion, as is the case for human ophthalmic imaging. A coverslip was placed on the cornea to remove the refractive power of the air-corneal interface, focusing and scanning the OCT beam directly on the retina through the weaker refraction from the lens. Six orthogonally scanned 700 × 700 axial scan data sets were registered and merged.

Scans were performed over a 1.2 × 1.2 mm2 area of the mouse eye and a 2.4 × 2.4 mm2 area of the rat eye. Each data set is acquired in ~5 seconds. An OCT fundus view is generated by axially summing the merged OCT data set (Fig. 2A and Fig. 3A). Cross-sectional images from the merged data set enable visualization of major retinal layers including the inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), photoreceptor inner segment and outer segment (IS/OS) junction, retinal pigment epithelium (RPE), choroid (CH), and sclera (SC) in both the Sprague-Dawley rat and C57BL/6 mouse eyes (Fig. 2B and Fig. 3B).

In addition, the retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), and external limiting membrane (ELM) are visible in the Sprague-Dawley rat (Fig. 2B). The smaller size of the mouse retina limited the visibility of smaller features. Isotropic transverse sampling of the retina allows for volumetric rendering that shows the structural details of the retina in 3-D (Fig. 2C and Fig. 3C). Since the 3-D OCT volumetric data set is motion corrected, we can extract cross-sectional images in any position and direction without motion artifacts (Figs. 2D2I and Figs. 3D3I). Notice that neither cross sectional images visualized in the horizontal and vertical direction nor the 3-D volumetric rendering exhibit motion artifacts.

3.2. Anterior eye and full eye length imaging in rat and mouse eyes

The long imaging range of SS-OCT also enabled 3-D anterior eye and full eye length OCT imaging in the rat eye and mouse eye using sample arm optics with a larger transverse spot size and longer depth of field. Anterior eye and full eye length imaging provides 3-D information on the anterior chamber and crystalline lens structure as well as biometric information on the full eye length. The animal eye is placed directly in front of the scan lens under anesthesia and after dilation. Two orthogonally scanned 500 × 500 axial scan data sets were registered and merged.

The scans were performed over a 2.6 × 2.6 mm2 area of the mouse eye and a 7 × 7 mm2 area of the rat eye. Figure 4A
Fig. 4 Anterior eye and full eye length OCT imaging in the Sprague-Dawley rat and C57BL/6 mouse eye. (A, E) En face view of the volumetric data set registered and merged from two orthogonally scanned 500 × 500 axial scan volumes. The rat eye was scanned over a 7 mm × 7 mm area. The mouse eye was scanned over a 2.6 mm × 2.6 mm area. (B, C, F, G) Cross-sectional images in the horizontal and vertical direction generated from averaging neighboring 5 frames. The red arrows point to the rat lens nucleus. The green box is a region in the image where the contrast was adjusted to better visualize signal from the rat retina. (D) Extracted en face cross section at the red line position showing the Y-shaped suture pattern in the rat lens anterior. (H) Summed en face view over the rat lens posterior as indicated in the red dotted box, which shows the pattern of opacities in the mouse lens.
is an OCT en face view of a Sprague-Dawley rat eye. The Y-shaped shadow in the center of the eye is the lens suture pattern on the anterior crystalline lens which can be visualized when an en face cross section at appropriate depth is extracted from the volume (Fig. 4D). Cross sectional images in Fig. 4B and Fig. 4C reveal detailed structures of the cornea, iris, and lens, as well as visible signal from the vitreous and retina. A thin liquid film from the eye drops is visible on the cornea of the rat eye. In addition to lens sutures, the nucleus is visible in the cross sectional images.

Figure 4E is an OCT en face view of a C57BL/6 mouse eye. This particular mouse eye exhibits lens opacities which can be visualized by summing en face pixels near the posterior lens surface, as shown in Fig. 4H. Cross sectional images in Fig. 4F and Fig. 4G reveal detailed structures of the cornea, iris, lens, vitreous and retina. The 3-D data set illustrates the larger lens volume compared to vitreous volume in the rat and mouse eyes. The irises and pupils are dilated. Ocular biometry measurements of the eyes can be performed after refraction correcting the OCT images in the axial direction.

3.3. 3-D posterior eye imaging in unpigmented rat eye

In order to better image the posterior eye of the unpigmented Sprague-Dawley rat, the focus was advanced towards the posterior eye and a coverslip was placed on the eye to minimize corneal refraction. Although the larger transverse spot size decreases the transverse resolution compared to the retinal imaging mode described in section 3.1, the longer focal depth and long imaging range enables visualization of the posterior lens, vitreous and retina. Figure 5
Fig. 5 Posterior eye imaging of the unpigmented Sprague-Dawley rat including retina, vitreous, and posterior lens. (A) OCT en face view of the registered and merged data set from six orthogonally scanned 500 × 500 axial scan volumes. Imaging of the rat posterior eye was performed over a 2.6 mm × 2.6 mm area. (B) En face cross section showing inverted Y-shaped posterior lens sutures. (C, D) Cross-sections from the registered data set showing the retina, hyaloid vessel and posterior part of the crystalline lens. The red line indicates the depth position of the en face cross section. (E) 3-D rendering of the data set (Media 1).
is a posterior eye data set generated from registering and merging six orthogonally scanned volumes of 500 × 500 A-scans each. The scans were performed over a 2.6 × 2.6 mm2 area of the rat eye. The data set shows the posterior lens surface, where the Y-shaped lens sutures can be visualized in an inverted orientation as seen on the en face image in Fig. 5B. The hyaloid vessel as well as floaters can be seen in the vitreous. Retinal layers can be clearly visualized in cross-sectional images (Figs. 5C5D). The deep penetration of 1050 nm wavelength light allows visualization of tissue structure in the choroid and sclera. The fundus image shows that major retinal blood vessels radiate from the center of the optic disk.

3.4. 3-D Doppler imaging in unpigmented rat eye

Doppler OCT imaging of the Sprague-Dawley rat was performed using the phase difference of neighboring axial scans in the six orthogonally scanned 500 x 500 axial scan data sets acquired in the posterior eye imaging mode described in section 3.3. The larger spot size decreases the number of samples required to obtain Doppler OCT information over the same scan area compared to the retinal imaging mode in section 3.1. The Doppler OCT data sets were merged using motion correction information (displacement fields) from the registered intensity images (Fig. 6
Fig. 6 Doppler OCT imaging in a unpigmented Sprague-Dawley rat retina. Doppler OCT analysis was performed using posterior eye OCT data (6 orthogonally scanned 500 × 500 axial scan OCT data sets over a 2.6 mm × 2.6 mm region). The 6 Doppler OCT volumes were merged using the displacement fields from registered structural OCT data. (A) OCT fundus image. (B, C, D) OCT color Doppler images with blood flow information overlaid on structural images. (E) 3-D Doppler OCT angiography (Media 2).
). Intensity and Doppler OCT cross-sections present complementary information on the structure and function of the retina. When the Doppler image is overlaid on its structural counterpart (Figs. 6B6D), the combined images may provide insight into the relationship between structural and functional changes of the retina in pathology and disease progression. A 3-D rendering of the vasculature in the retina and choroid is shown in Fig. 6E. Two types of vessels can be distinguished in the retina by looking at the direction of blood flow. When blood moves towards the OCT beam, the Doppler shift is positive, as indicated with the red (warm) color. The retinal arteries are oriented in this direction and are hence visualized in red. On the other hand, blood returning from retinal tissue produces negative Doppler shifts. Consequently, retinal veins are visualized in a blue (cold) color. In the rat retina, arterial and venous vascular systems can overlap one another. Since Doppler OCT can only measure flow velocities in the axial direction, the vessels appear to be discontinuous or disconnected when they are perpendicular to the OCT beam. In addition to retinal vessels and the central retinal artery, some choroidal vessels, as well as long posterior ciliary arteries are also visible owing to the deep penetration of 1050 nm wavelength light.

3.5. 4-D imaging of pupillary response in rat and mouse eyes

High speed OCT imaging enables time resolved volumetric 4-D imaging of the dynamic responses of the eye to stimulus. A Sprague-Dawley rat and a C57BL/6 mouse were sedated lightly to preserve pupillary responses. Figures 7
Fig. 7 Dynamic response of the Sprague-Dawley rat eye to long (Media 3) and short duration (Media 4) light stimulus. Volumetric imaging was performed at ~10 volumes per second. Each volume consists of 100 × 100 axial scans over a 7 mm × 7 mm area. Changes of the pupil area before, during, and after light stimulus are shown in plot. (A, B, C) (D, E, F) Selected time points illustrate the structural changes in the eye over time. An OCT en face view, central orthogonal cross-sections, as well as a 3-D rendering are shown for each time point.
and 8
Fig. 8 Dynamic response of the C57BL/6 mouse eye to long (Media 5) and short duration (Media 6) light stimulus. Volumetric imaging was performed at ~10 volumes per second. Each volume consists of 100 × 100 axial scans over a 3.5 mm × 3.5 mm area. Changes of the pupil area before, during, and after light stimulus are shown in plot. (A, B, C) (D, E, F) Selected time points illustrate the structural changes in the eye over time. An OCT en face view, central orthogonal cross-sections, as well as a 3-D rendering are shown for each time point.
are demonstrations of 4-D imaging of the pupillary response in the rat and mouse eye. OCT volumes of 100 × 100 axial scans were acquired at ~10 volumes per second for 5 seconds. Scans were performed over a 7 × 7 mm2 area of the rat eye and a 3.5 × 3.5 mm2 area of the mouse eye. All volumes were scanned with a horizontal fast scan axis and motion correction was not performed. A continuous stimulus and a short ~1 second flash stimulus were applied to both the rat and mouse eyes. 3-D dynamics can be visualized and quantitative measurements of the pupil area can be obtained. Despite the high volume rate of the acquisition, motion is visible in the data sets predominantly due to breathing and heartbeat. As more light enters the eye, the iris responds by rapid contraction, which leads to the decrease in pupil diameter. When the stimulus is turned off, the iris muscles slowly relax. The pupil area from each acquired volume was measured.

4. Discussion and conclusion

Structural and Doppler angiographic imaging of the rodent eye was demonstrated using a novel ultrahigh speed swept source/Fourier domain OCT instrument. The swept source OCT was based on a recently developed instrument for high speed ophthalmic OCT imaging at long wavelengths [17

17. B. Potsaid, B. Baumann, D. Huang, S. Barry, A. E. Cable, J. S. Schuman, J. S. Duker, and J. G. Fujimoto, “Ultrahigh speed 1050nm swept source/Fourier domain OCT retinal and anterior segment imaging at 100,000 to 400,000 axial scans per second,” Opt. Express 18(19), 20029–20048 (2010). [CrossRef] [PubMed]

]. The long imaging range and high imaging speed of SS-OCT, along with the deep penetration into tissue of 1050 nm wavelength light enables 3-D volumetric imaging of the retina and posterior eye, as well as the anterior eye and full eye length. A registration algorithm was applied to remove motion artifacts and merge multiple data sets for enhanced visualization.

OCT has been widely used for in vivo retinal imaging of rodent models. This manuscript presents the first motion corrected 3-D OCT images in rat and mouse eyes using SS-OCT. Although current 1050 nm wavelength SS-OCT technology has limited resolution compared to 850 nm SD-OCT, the improved tissue penetration provides additional information in the choroid and sclera. Motion correction enables large volumes to be acquired without motion artifacts and merging improves image quality. Although visibility of features is poorer in the mouse compared with the rat, for retinal imaging, major retinal layers including the retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), external limiting membrane (ELM), photoreceptor inner segment and outer segment (IS/OS) junction, retinal pigment epithelium (RPE), choroid (CH), and sclera (SC) can be resolved. Doppler OCT provides motion contrast highlighting the retinal vasculature and enables differentiating arteries and veins. Quantitative information of blood flow velocity can also be obtained. No obvious artifacts due to pulsatility remain in the motion corrected and merged Doppler OCT data which was obtained from multiple orthogonally scanned volumes. The deep penetration into tissue allowed Doppler OCT imaging of the long posterior ciliary arteries.

The main advantages of SS-OCT compared to SD-OCT are increased sensitivities, imaging speed, and imaging range. For rodent eye imaging, the high speeds and extended range enable 3-D imaging of the retina, posterior eye, anterior eye and full eye length. Combined with image registration motion correction, we demonstrated 3-D in vivo SS-OCT full eye length volumetric imaging while preserving corneal, iris, lens, and retinal topography in both rats and mice. This promises to allow quantitative measurements tracking the changes in morphogenesis and pathological processes in the same animal eye over time.

SS-OCT at 1050 nm may provide new means for in vivo rodent hyaloid vessel and lens development studies. In our results, we were able to visualize the hyaloid vessel, lens nucleus, lens opacities, and lens suture patterns. Comparing Fig. 4D with Fig. 5B, it can be seen that suture patterns in the anterior and posterior pole of the crystalline lens have opposite orientations. Lens fibers make up the bulk of the lens and form lens suture patterns which produce an upright 'Y' pattern anteriorly and an inverted 'Y' pattern posteriorly. This is the first time that the lens suture pattern in the rat eye has been visualized using OCT. In the mouse eye, we could observe lens opacities possibly induced by ketamine-xylazine anesthesia (Fig. 4E) suggesting that cataract characterization may be possible [27

27. L. Calderone, P. Grimes, and M. Shalev, “Acute reversible cataract induced by xylazine and by ketamine-xylazine anesthesia in rats and mice,” Exp. Eye Res. 42(4), 331–337 (1986). [CrossRef] [PubMed]

]. Meanwhile in the mouse full eye length image, the retina remains highly visible despite the lens opacities. This also suggests that the reduced scattering of 1050 nm wavelength light will be useful for OCT retinal imaging even in rodent eyes with cataracts.

We also performed the first demonstration of 4-D time resolved volumetric OCT imaging of the mouse and rat full eye length. 4-D OCT dynamic imaging could provide spatial-temporal information of 3-D volumetric datasets for functional imaging studies. A simple demonstration of pupillometry is shown in this paper. In addition to pupil area, 4-D OCT provides information of the iris structure. The contraction of the iris was visualized in 3-D. Other 4-D OCT applications include imaging of structural and blood flow responses to intraocular pressure [29

29. Z. Zhi, W. O. Cepurna, E. C. Johnson, J. C. Morrison, and R. K. Wang, “Impact of intraocular pressure on changes of blood flow in the retina, choroid, and optic nerve head in rats investigated by optical microangiography,” Biomed. Opt. Express 3(9), 2220–2233 (2012). [CrossRef] [PubMed]

,30

30. Z. Zhi, X. Yin, S. Dziennis, T. Wietecha, K. L. Hudkins, C. E. Alpers, and R. K. Wang, “Optical microangiography of retina and choroid and measurement of total retinal blood flow in mice,” Biomed. Opt. Express 3(11), 2976–2986 (2012). [CrossRef] [PubMed]

] and the dynamics of neurovascular function in the eye [31

31. V. J. Srinivasan, M. Wojtkowski, J. G. Fujimoto, and J. S. Duker, “In vivo measurement of retinal physiology with high-speed ultrahigh-resolution optical coherence tomography,” Opt. Lett. 31(15), 2308–2310 (2006). [CrossRef] [PubMed]

,32

32. W. Choi, B. Baumann, J. J. Liu, A. C. Clermont, E. P. Feener, J. S. Duker, and J. G. Fujimoto, “Measurement of pulsatile total blood flow in the human and rat retina with ultrahigh speed spectral/Fourier domain OCT,” Biomed. Opt. Express 3(5), 1047–1061 (2012). [CrossRef] [PubMed]

].

To conclude, SS-OCT is a powerful imaging technique providing comprehensive 3-D information on the rodent eye including motion corrected posterior eye, anterior eye and full eye length imaging, retinal imaging with Doppler OCT angiography, as well as 4-D dynamic imaging of functional responses of the eye. While standard excisional biopsy and histology require enucleating the eye, OCT can perform repeated, noninvasive in situ imaging and quantitative measurements of the rodent retina. Therefore, SS-OCT technology for rodent eye imaging is a potentially useful tool for in vivo imaging of disease phenotypes such as corneal opacity, uveitis, keratitis, glaucoma, cataract, retinoblastoma, retinal degeneration, retinal vascular disease and myopia.

Acknowledgments

The authors want to thank Allen C. Clermont and Dr. Edward P. Feener at the Joslin Diabetes Center for advice on small animal imaging, WooJhon Choi and Tsung-Han Tsai at MIT for technical discussions, as well as Dr. Caio V. Regatieri and Dr. Jason Y. Zhang at New England Eye Center, Tufts Medical Center for consultations in the anatomy, physiology and pathology of the eye. Financial support from the National Institutes of Health (NIH R01-EY011289-27, R01-EY013178-12, R01-EY013516-09, R01-EY018184-05, R01-EY019029-04, R01-CA075289-14, R01-HL095717-04, R01-NS057476-05), Air Force Office of Scientific Research (AFOSR FA9550-10-1-0063), Medical Free Electron Laser Program (FA9550-10-1-0551) and Deutsche Forschungsgesellschaft (DFG-GSC80-SAOT, DFG-HO-1791/11-1) is gratefully acknowledged. Dr. Ireneusz Grulkowski acknowledges partial support from KOLUMB Fellowship, Foundation for Polish Science (KOL/3/2010-I). Dr. Jay S. Duker is supported by an unrestricted grant from Research to Prevent Blindness as well as the Massachusetts Lions Clubs. Dr. Ireneusz Grulkowski is a visiting scientist from the Institute of Physics, Nicolaus Copernicus University, Torun, Poland.

References and links

1.

P. A. Tsonis, Animal Models in Eye Research (Academic, 2008).

2.

N. L. Hawes, R. S. Smith, B. Chang, M. Davisson, J. R. Heckenlively, and S. W. John, “Mouse fundus photography and angiography: a catalogue of normal and mutant phenotypes,” Mol. Vis. 5, 22 (1999). [PubMed]

3.

R. S. Smith, Systematic Evaluation of the Mouse Eye: Anatomy, Pathology, and Biomethods (CRC Press, Boca Raton, Fla., 2002).

4.

N. Nissirios, J. Ramos-Esteban, and J. Danias, “Ultrasound biomicroscopy of the rat eye: effects of cholinergic and anticholinergic agents,” Graefes Arch. Clin. Exp. Ophthalmol. 243(5), 469–473 (2005). [CrossRef] [PubMed]

5.

M. W. Seeliger, S. C. Beck, N. Pereyra-Muñoz, S. Dangel, J. Y. Tsai, U. F. Luhmann, S. A. van de Pavert, J. Wijnholds, M. Samardzija, A. Wenzel, E. Zrenner, K. Narfström, E. Fahl, N. Tanimoto, N. Acar, and F. Tonagel, “In vivo confocal imaging of the retina in animal models using scanning laser ophthalmoscopy,” Vision Res. 45(28), 3512–3519 (2005). [CrossRef] [PubMed]

6.

H. Cheng, G. Nair, T. A. Walker, M. K. Kim, M. T. Pardue, P. M. Thulé, D. E. Olson, and T. Q. Duong, “Structural and functional MRI reveals multiple retinal layers,” Proc. Natl. Acad. Sci. U.S.A. 103(46), 17525–17530 (2006). [CrossRef] [PubMed]

7.

M. Paques, M. Simonutti, M. J. Roux, S. Picaud, E. Levavasseur, C. Bellman, and J. A. Sahel, “High resolution fundus imaging by confocal scanning laser ophthalmoscopy in the mouse,” Vision Res. 46(8-9), 1336–1345 (2006). [CrossRef] [PubMed]

8.

M. Paques, J. L. Guyomard, M. Simonutti, M. J. Roux, S. Picaud, J. F. Legargasson, and J. A. Sahel, “Panretinal, high-resolution color photography of the mouse fundus,” Invest. Ophthalmol. Vis. Sci. 48(6), 2769–2774 (2007). [CrossRef] [PubMed]

9.

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and et, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991). [CrossRef] [PubMed]

10.

V. J. Srinivasan, T. H. Ko, M. Wojtkowski, M. Carvalho, A. Clermont, S. E. Bursell, Q. H. Song, J. Lem, J. S. Duker, J. S. Schuman, and J. G. Fujimoto, “Noninvasive volumetric imaging and morphometry of the rodent retina with high-speed, ultrahigh-resolution optical coherence tomography,” Invest. Ophthalmol. Vis. Sci. 47(12), 5522–5528 (2006). [CrossRef] [PubMed]

11.

M. Ruggeri, H. Wehbe, S. Jiao, G. Gregori, M. E. Jockovich, A. Hackam, Y. Duan, and C. A. Puliafito, “In vivo three-dimensional high-resolution imaging of rodent retina with spectral-domain optical coherence tomography,” Invest. Ophthalmol. Vis. Sci. 48(4), 1808–1814 (2007). [CrossRef] [PubMed]

12.

K. H. Kim, M. Puoris’haag, G. N. Maguluri, Y. Umino, K. Cusato, R. B. Barlow, and J. F. de Boer, “Monitoring mouse retinal degeneration with high-resolution spectral-domain optical coherence tomography,” J. Vis. 8(1), 17, 1–11 (2008). [CrossRef] [PubMed]

13.

G. Huber, S. C. Beck, C. Grimm, A. Sahaboglu-Tekgoz, F. Paquet-Durand, A. Wenzel, P. Humphries, T. M. Redmond, M. W. Seeliger, and M. D. Fischer, “Spectral domain optical coherence tomography in mouse models of retinal degeneration,” Invest. Ophthalmol. Vis. Sci. 50(12), 5888–5895 (2009). [CrossRef] [PubMed]

14.

A. Giani, A. Thanos, M. I. Roh, E. Connolly, G. Trichonas, I. Kim, E. Gragoudas, D. Vavvas, and J. W. Miller, “In vivo evaluation of laser-induced choroidal neovascularization using spectral-domain optical coherence tomography,” Invest. Ophthalmol. Vis. Sci. 52(6), 3880–3887 (2011). [CrossRef] [PubMed]

15.

S. D. Hanlon, N. B. Patel, and A. R. Burns, “Assessment of postnatal corneal development in the C57BL/6 mouse using spectral domain optical coherence tomography and microwave-assisted histology,” Exp. Eye Res. 93(4), 363–370 (2011). [CrossRef] [PubMed]

16.

S. Hariri, A. A. Moayed, A. Dracopolos, C. Hyun, S. Boyd, and K. Bizheva, “Limiting factors to the OCT axial resolution for in-vivo imaging of human and rodent retina in the 1060 nm wavelength range,” Opt. Express 17(26), 24304–24316 (2009). [CrossRef] [PubMed]

17.

B. Potsaid, B. Baumann, D. Huang, S. Barry, A. E. Cable, J. S. Schuman, J. S. Duker, and J. G. Fujimoto, “Ultrahigh speed 1050nm swept source/Fourier domain OCT retinal and anterior segment imaging at 100,000 to 400,000 axial scans per second,” Opt. Express 18(19), 20029–20048 (2010). [CrossRef] [PubMed]

18.

L. Wang, B. Hofer, Y. P. Chen, J. A. Guggenheim, W. Drexler, and B. Povazay, “Highly reproducible swept-source, dispersion-encoded full-range biometry and imaging of the mouse eye,” J. Biomed. Opt. 15(4), 046004 (2010). [CrossRef] [PubMed]

19.

B. Povazay, K. Bizheva, B. Hermann, A. Unterhuber, H. Sattmann, A. Fercher, W. Drexler, C. Schubert, P. Ahnelt, M. Mei, R. Holzwarth, W. Wadsworth, J. Knight, and P. S. Russell, “Enhanced visualization of choroidal vessels using ultrahigh resolution ophthalmic OCT at 1050 nm,” Opt. Express 11(17), 1980–1986 (2003). [CrossRef] [PubMed]

20.

A. Unterhuber, B. Povazay, B. Hermann, H. Sattmann, A. Chavez-Pirson, and W. Drexler, “In vivo retinal optical coherence tomography at 1040 nm - enhanced penetration into the choroid,” Opt. Express 13(9), 3252–3258 (2005). [CrossRef] [PubMed]

21.

R. Leitgeb, L. Schmetterer, W. Drexler, A. Fercher, R. Zawadzki, and T. Bajraszewski, “Real-time assessment of retinal blood flow with ultrafast acquisition by color Doppler Fourier domain optical coherence tomography,” Opt. Express 11(23), 3116–3121 (2003). [CrossRef] [PubMed]

22.

B. White, M. Pierce, N. Nassif, B. Cense, B. Park, G. Tearney, B. Bouma, T. Chen, and J. de Boer, “In vivo dynamic human retinal blood flow imaging using ultra-high-speed spectral domain optical coherence tomography,” Opt. Express 11(25), 3490–3497 (2003). [CrossRef] [PubMed]

23.

S. Makita, Y. Hong, M. Yamanari, T. Yatagai, and Y. Yasuno, “Optical coherence angiography,” Opt. Express 14(17), 7821–7840 (2006). [CrossRef] [PubMed]

24.

Z. Zhi, W. Cepurna, E. Johnson, T. Shen, J. Morrison, and R. K. Wang, “Volumetric and quantitative imaging of retinal blood flow in rats with optical microangiography,” Biomed. Opt. Express 2(3), 579–591 (2011). [CrossRef] [PubMed]

25.

B. Baumann, B. Potsaid, M. F. Kraus, J. J. Liu, D. Huang, J. Hornegger, A. E. Cable, J. S. Duker, and J. G. Fujimoto, “Total retinal blood flow measurement with ultrahigh speed swept source/Fourier domain OCT,” Biomed. Opt. Express 2(6), 1539–1552 (2011). [CrossRef] [PubMed]

26.

M. F. Kraus, B. Potsaid, M. A. Mayer, R. Bock, B. Baumann, J. J. Liu, J. Hornegger, and J. G. Fujimoto, “Motion correction in optical coherence tomography volumes on a per A-scan basis using orthogonal scan patterns,” Biomed. Opt. Express 3(6), 1182–1199 (2012). [CrossRef] [PubMed]

27.

L. Calderone, P. Grimes, and M. Shalev, “Acute reversible cataract induced by xylazine and by ketamine-xylazine anesthesia in rats and mice,” Exp. Eye Res. 42(4), 331–337 (1986). [CrossRef] [PubMed]

28.

I. Grulkowski, J. J. Liu, B. Potsaid, V. Jayaraman, C. D. Lu, J. Jiang, A. E. Cable, J. S. Duker, and J. G. Fujimoto, “Retinal, anterior segment and full eye imaging using ultrahigh speed swept source OCT with vertical-cavity surface emitting lasers,” Biomed. Opt. Express 3(11), 2733–2751 (2012). [CrossRef] [PubMed]

29.

Z. Zhi, W. O. Cepurna, E. C. Johnson, J. C. Morrison, and R. K. Wang, “Impact of intraocular pressure on changes of blood flow in the retina, choroid, and optic nerve head in rats investigated by optical microangiography,” Biomed. Opt. Express 3(9), 2220–2233 (2012). [CrossRef] [PubMed]

30.

Z. Zhi, X. Yin, S. Dziennis, T. Wietecha, K. L. Hudkins, C. E. Alpers, and R. K. Wang, “Optical microangiography of retina and choroid and measurement of total retinal blood flow in mice,” Biomed. Opt. Express 3(11), 2976–2986 (2012). [CrossRef] [PubMed]

31.

V. J. Srinivasan, M. Wojtkowski, J. G. Fujimoto, and J. S. Duker, “In vivo measurement of retinal physiology with high-speed ultrahigh-resolution optical coherence tomography,” Opt. Lett. 31(15), 2308–2310 (2006). [CrossRef] [PubMed]

32.

W. Choi, B. Baumann, J. J. Liu, A. C. Clermont, E. P. Feener, J. S. Duker, and J. G. Fujimoto, “Measurement of pulsatile total blood flow in the human and rat retina with ultrahigh speed spectral/Fourier domain OCT,” Biomed. Opt. Express 3(5), 1047–1061 (2012). [CrossRef] [PubMed]

OCIS Codes
(170.3880) Medical optics and biotechnology : Medical and biological imaging
(170.4470) Medical optics and biotechnology : Ophthalmology
(170.4500) Medical optics and biotechnology : Optical coherence tomography

ToC Category:
Ophthalmology Applications

History
Original Manuscript: December 11, 2012
Revised Manuscript: January 14, 2013
Manuscript Accepted: January 18, 2013
Published: January 29, 2013

Citation
Jonathan J. Liu, Ireneusz Grulkowski, Martin F. Kraus, Benjamin Potsaid, Chen D. Lu, Bernhard Baumann, Jay S. Duker, Joachim Hornegger, and James G. Fujimoto, "In vivo imaging of the rodent eye with swept source/Fourier domain OCT," Biomed. Opt. Express 4, 351-363 (2013)
http://www.opticsinfobase.org/boe/abstract.cfm?URI=boe-4-2-351


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References

  1. P. A. Tsonis, Animal Models in Eye Research (Academic, 2008).
  2. N. L. Hawes, R. S. Smith, B. Chang, M. Davisson, J. R. Heckenlively, and S. W. John, “Mouse fundus photography and angiography: a catalogue of normal and mutant phenotypes,” Mol. Vis.5, 22 (1999). [PubMed]
  3. R. S. Smith, Systematic Evaluation of the Mouse Eye: Anatomy, Pathology, and Biomethods (CRC Press, Boca Raton, Fla., 2002).
  4. N. Nissirios, J. Ramos-Esteban, and J. Danias, “Ultrasound biomicroscopy of the rat eye: effects of cholinergic and anticholinergic agents,” Graefes Arch. Clin. Exp. Ophthalmol.243(5), 469–473 (2005). [CrossRef] [PubMed]
  5. M. W. Seeliger, S. C. Beck, N. Pereyra-Muñoz, S. Dangel, J. Y. Tsai, U. F. Luhmann, S. A. van de Pavert, J. Wijnholds, M. Samardzija, A. Wenzel, E. Zrenner, K. Narfström, E. Fahl, N. Tanimoto, N. Acar, and F. Tonagel, “In vivo confocal imaging of the retina in animal models using scanning laser ophthalmoscopy,” Vision Res.45(28), 3512–3519 (2005). [CrossRef] [PubMed]
  6. H. Cheng, G. Nair, T. A. Walker, M. K. Kim, M. T. Pardue, P. M. Thulé, D. E. Olson, and T. Q. Duong, “Structural and functional MRI reveals multiple retinal layers,” Proc. Natl. Acad. Sci. U.S.A.103(46), 17525–17530 (2006). [CrossRef] [PubMed]
  7. M. Paques, M. Simonutti, M. J. Roux, S. Picaud, E. Levavasseur, C. Bellman, and J. A. Sahel, “High resolution fundus imaging by confocal scanning laser ophthalmoscopy in the mouse,” Vision Res.46(8-9), 1336–1345 (2006). [CrossRef] [PubMed]
  8. M. Paques, J. L. Guyomard, M. Simonutti, M. J. Roux, S. Picaud, J. F. Legargasson, and J. A. Sahel, “Panretinal, high-resolution color photography of the mouse fundus,” Invest. Ophthalmol. Vis. Sci.48(6), 2769–2774 (2007). [CrossRef] [PubMed]
  9. D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and et, “Optical coherence tomography,” Science254(5035), 1178–1181 (1991). [CrossRef] [PubMed]
  10. V. J. Srinivasan, T. H. Ko, M. Wojtkowski, M. Carvalho, A. Clermont, S. E. Bursell, Q. H. Song, J. Lem, J. S. Duker, J. S. Schuman, and J. G. Fujimoto, “Noninvasive volumetric imaging and morphometry of the rodent retina with high-speed, ultrahigh-resolution optical coherence tomography,” Invest. Ophthalmol. Vis. Sci.47(12), 5522–5528 (2006). [CrossRef] [PubMed]
  11. M. Ruggeri, H. Wehbe, S. Jiao, G. Gregori, M. E. Jockovich, A. Hackam, Y. Duan, and C. A. Puliafito, “In vivo three-dimensional high-resolution imaging of rodent retina with spectral-domain optical coherence tomography,” Invest. Ophthalmol. Vis. Sci.48(4), 1808–1814 (2007). [CrossRef] [PubMed]
  12. K. H. Kim, M. Puoris’haag, G. N. Maguluri, Y. Umino, K. Cusato, R. B. Barlow, and J. F. de Boer, “Monitoring mouse retinal degeneration with high-resolution spectral-domain optical coherence tomography,” J. Vis.8(1), 17, 1–11 (2008). [CrossRef] [PubMed]
  13. G. Huber, S. C. Beck, C. Grimm, A. Sahaboglu-Tekgoz, F. Paquet-Durand, A. Wenzel, P. Humphries, T. M. Redmond, M. W. Seeliger, and M. D. Fischer, “Spectral domain optical coherence tomography in mouse models of retinal degeneration,” Invest. Ophthalmol. Vis. Sci.50(12), 5888–5895 (2009). [CrossRef] [PubMed]
  14. A. Giani, A. Thanos, M. I. Roh, E. Connolly, G. Trichonas, I. Kim, E. Gragoudas, D. Vavvas, and J. W. Miller, “In vivo evaluation of laser-induced choroidal neovascularization using spectral-domain optical coherence tomography,” Invest. Ophthalmol. Vis. Sci.52(6), 3880–3887 (2011). [CrossRef] [PubMed]
  15. S. D. Hanlon, N. B. Patel, and A. R. Burns, “Assessment of postnatal corneal development in the C57BL/6 mouse using spectral domain optical coherence tomography and microwave-assisted histology,” Exp. Eye Res.93(4), 363–370 (2011). [CrossRef] [PubMed]
  16. S. Hariri, A. A. Moayed, A. Dracopolos, C. Hyun, S. Boyd, and K. Bizheva, “Limiting factors to the OCT axial resolution for in-vivo imaging of human and rodent retina in the 1060 nm wavelength range,” Opt. Express17(26), 24304–24316 (2009). [CrossRef] [PubMed]
  17. B. Potsaid, B. Baumann, D. Huang, S. Barry, A. E. Cable, J. S. Schuman, J. S. Duker, and J. G. Fujimoto, “Ultrahigh speed 1050nm swept source/Fourier domain OCT retinal and anterior segment imaging at 100,000 to 400,000 axial scans per second,” Opt. Express18(19), 20029–20048 (2010). [CrossRef] [PubMed]
  18. L. Wang, B. Hofer, Y. P. Chen, J. A. Guggenheim, W. Drexler, and B. Povazay, “Highly reproducible swept-source, dispersion-encoded full-range biometry and imaging of the mouse eye,” J. Biomed. Opt.15(4), 046004 (2010). [CrossRef] [PubMed]
  19. B. Povazay, K. Bizheva, B. Hermann, A. Unterhuber, H. Sattmann, A. Fercher, W. Drexler, C. Schubert, P. Ahnelt, M. Mei, R. Holzwarth, W. Wadsworth, J. Knight, and P. S. Russell, “Enhanced visualization of choroidal vessels using ultrahigh resolution ophthalmic OCT at 1050 nm,” Opt. Express11(17), 1980–1986 (2003). [CrossRef] [PubMed]
  20. A. Unterhuber, B. Povazay, B. Hermann, H. Sattmann, A. Chavez-Pirson, and W. Drexler, “In vivo retinal optical coherence tomography at 1040 nm - enhanced penetration into the choroid,” Opt. Express13(9), 3252–3258 (2005). [CrossRef] [PubMed]
  21. R. Leitgeb, L. Schmetterer, W. Drexler, A. Fercher, R. Zawadzki, and T. Bajraszewski, “Real-time assessment of retinal blood flow with ultrafast acquisition by color Doppler Fourier domain optical coherence tomography,” Opt. Express11(23), 3116–3121 (2003). [CrossRef] [PubMed]
  22. B. White, M. Pierce, N. Nassif, B. Cense, B. Park, G. Tearney, B. Bouma, T. Chen, and J. de Boer, “In vivo dynamic human retinal blood flow imaging using ultra-high-speed spectral domain optical coherence tomography,” Opt. Express11(25), 3490–3497 (2003). [CrossRef] [PubMed]
  23. S. Makita, Y. Hong, M. Yamanari, T. Yatagai, and Y. Yasuno, “Optical coherence angiography,” Opt. Express14(17), 7821–7840 (2006). [CrossRef] [PubMed]
  24. Z. Zhi, W. Cepurna, E. Johnson, T. Shen, J. Morrison, and R. K. Wang, “Volumetric and quantitative imaging of retinal blood flow in rats with optical microangiography,” Biomed. Opt. Express2(3), 579–591 (2011). [CrossRef] [PubMed]
  25. B. Baumann, B. Potsaid, M. F. Kraus, J. J. Liu, D. Huang, J. Hornegger, A. E. Cable, J. S. Duker, and J. G. Fujimoto, “Total retinal blood flow measurement with ultrahigh speed swept source/Fourier domain OCT,” Biomed. Opt. Express2(6), 1539–1552 (2011). [CrossRef] [PubMed]
  26. M. F. Kraus, B. Potsaid, M. A. Mayer, R. Bock, B. Baumann, J. J. Liu, J. Hornegger, and J. G. Fujimoto, “Motion correction in optical coherence tomography volumes on a per A-scan basis using orthogonal scan patterns,” Biomed. Opt. Express3(6), 1182–1199 (2012). [CrossRef] [PubMed]
  27. L. Calderone, P. Grimes, and M. Shalev, “Acute reversible cataract induced by xylazine and by ketamine-xylazine anesthesia in rats and mice,” Exp. Eye Res.42(4), 331–337 (1986). [CrossRef] [PubMed]
  28. I. Grulkowski, J. J. Liu, B. Potsaid, V. Jayaraman, C. D. Lu, J. Jiang, A. E. Cable, J. S. Duker, and J. G. Fujimoto, “Retinal, anterior segment and full eye imaging using ultrahigh speed swept source OCT with vertical-cavity surface emitting lasers,” Biomed. Opt. Express3(11), 2733–2751 (2012). [CrossRef] [PubMed]
  29. Z. Zhi, W. O. Cepurna, E. C. Johnson, J. C. Morrison, and R. K. Wang, “Impact of intraocular pressure on changes of blood flow in the retina, choroid, and optic nerve head in rats investigated by optical microangiography,” Biomed. Opt. Express3(9), 2220–2233 (2012). [CrossRef] [PubMed]
  30. Z. Zhi, X. Yin, S. Dziennis, T. Wietecha, K. L. Hudkins, C. E. Alpers, and R. K. Wang, “Optical microangiography of retina and choroid and measurement of total retinal blood flow in mice,” Biomed. Opt. Express3(11), 2976–2986 (2012). [CrossRef] [PubMed]
  31. V. J. Srinivasan, M. Wojtkowski, J. G. Fujimoto, and J. S. Duker, “In vivo measurement of retinal physiology with high-speed ultrahigh-resolution optical coherence tomography,” Opt. Lett.31(15), 2308–2310 (2006). [CrossRef] [PubMed]
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