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- Owner-Petersen, Mette, et al.
(författare)
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Multi-object wavefront sensor with spatial filtering
- 2007
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Patent (övrigt vetenskapligt/konstnärligt)abstract
- The present invention relates to an adaptive optics sensor intended for simultaneous detection of several wavefronts on a common camera target. The sensor is intended for use in connection with multi-conjugate adaptive optics (MCAO), where several wavefront measurements are needed at the same time. The sensor includes a spatial filter taking out signals resulting from parasitic reflections of the reference sources and from unwanted parts of the object.
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| 3. |
- Schultz, Kristofer, et al.
(författare)
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Reduced CSF CART in dementia with Lewy bodies.
- 2009
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Ingår i: Neuroscience letters. - : Elsevier BV. - 0304-3940. ; 453:2, s. 104-6
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Tidskriftsartikel (refereegranskat)abstract
- Dementia with Lewy bodies (DLB) is the second most common form of neurodegenerative dementia after Alzheimer's disease (AD). The underlying neurobiological mechanism of DLB is not fully understood and no generally accepted biomarkers are yet available for the diagnosis of DLB. In a recent MRI study, DLB patients displayed hypothalamic atrophy whereas this region was not affected in AD patients. Cocaine and amphetamine regulated transcript (CART) is a neuropeptide expressed selectively in neurons in the hypothalamus. Here, we found that CSF CART levels were significantly reduced by 30% in DLB patients (n = 12) compared to controls (n = 12) as well as to AD patients (n = 14) using radioimmunoassay. Our preliminary results suggest that reduced CSF CART is a sign of hypothalamic dysfunction in DLB and that it may serve as a biomarker for this patient group.
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| 4. |
- Thaung, Jörgen, 1965, et al.
(författare)
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Dual-conjugate adaptive optics for wide-field high-resolution retinal imaging.
- 2009
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Ingår i: Optics express. - 1094-4087. ; 17:6, s. 4454-67
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Tidskriftsartikel (refereegranskat)abstract
- We present analysis and preliminary laboratory testing of a real-time dual-conjugate adaptive optics (DCAO) instrument for ophthalmology that will enable wide-field high resolution imaging of the retina in vivo. The setup comprises five retinal guide stars (GS) and two deformable mirrors (DM), one conjugate to the pupil and one conjugate to a plane close to the retina. The DCAO instrument has a closed-loop wavefront sensing wavelength of 834 nm and an imaging wavelength of 575 nm. It incorporates an array of collimator lenses to spatially filter the light from all guide stars using one adjustable iris, and images the Hartmann patterns of multiple reference sources on a single detector. Zemax simulations were performed at 834 nm and 575 nm with the Navarro 99 and the Liou- Brennan eye models. Two correction alternatives were evaluated; conventional single conjugate AO (SCAO, using one GS and a pupil DM) and DCAO (using multiple GS and two DM). Zemax simulations at 575 nm based on the Navarro 99 eye model show that the diameter of the corrected field of view for diffraction-limited imaging (Strehl >or= 0.8) increases from 1.5 deg with SCAO to 6.5 deg using DCAO. The increase for the less stringent condition of a wavefront error of 1 rad or less (Strehl >or= 0.37) is from 3 deg with SCAO to approximately 7.4 deg using DCAO. Corresponding results for the Liou-Brennan eye model are 3.1 deg (SCAO) and 8.2 deg (DCAO) for Strehl >or= 0.8, and 4.8 deg (SCAO) and 9.6 deg (DCAO) for Strehl >or= 0.37. Potential gain in corrected field of view with DCAO is confirmed both by laboratory experiments on a model eye and by preliminary in vivo imaging of a human eye.
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| 5. |
- Thaung, Jörgen, 1965, et al.
(författare)
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Dual-conjugate adaptive optics instrument for wide-field retinal imaging
- 2008
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Ingår i: Adaptive optics for industry and medicine, Proceedings of the sixth international workshop, National University of Ireland, Ireland 12-15 June 2007. - 1848161107 ; , s. 263-268
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Konferensbidrag (refereegranskat)abstract
- To date only conventional single-conjugate adaptive optics (SCAO) systems are used to correct ocular aberrations. A major shortcoming of SCAO is the severely restricted corrected field of view. This can be solved with multi-conjugate adaptive optics (MCAO), a solution that is costly and gives bulky instruments. Another problem, especially in the study of the human eye, is unwanted light from parasitic source reflections and light from unwanted object regions. We present a dual-conjugate adaptive optics (DCAO) demonstrator that will enable wide field high resolution imaging of the human retina in vivo, implementing five retinal guide stars, two OKO micromachined membrane deformable mirrors; a 15 mm 37 channel pupil conjugate mirror, and a 40 mm 79 channel mirror conjugated to a plane in the vitreous body approximately 3 mm in front of the retina. The AO system runs with a closed-loop measurement wavelength of 835 nm. It incorporates an array of collimator lenses to spatially filter the light from all guide stars using only one adjustable iris, and a single camera to image the Hartmann patterns of multiple reference sources. Optical simulations in Zemax indicate an increase of the retinal isoplanatic patch from a radius of 0.5 degrees using SCAO to approximately 3.5 degrees or more using DCAO. The advantage of this is a clinically useful imaging area that is approximately 50 times the size of an SCAO system. This is corroborated by measurements on a model eye while performing SCAO, ground layer adaptive optics (GLAO), and DCAO correction.
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