Kulcsar C.,University Paris - Sud |
Besnerais G.L.,ONERA |
Odlund E.,Imagine Eyes |
Levecq X.,Imagine Eyes
Optics InfoBase Conference Papers | Year: 2013
Retinal images sequences provided by adaptive optics instruments have to be processed before clinical exploitation. We present a robust procedure that accounts for non-translational motions and variable image quality to deliver improved reconstructed images. © OSA 2013.
Sahin B.,National University of Ireland |
Lamory B.,Imagine Eyes |
Levecq X.,Imagine Eyes |
Harms F.,Imagine Eyes |
Dainty C.,National University of Ireland
Biomedical Optics Express | Year: 2012
Adaptive optics, when integrated into retinal imaging systems, compensates for rapidly changing ocular aberrations in real time and results in improved high resolution images that reveal the photoreceptor mosaic. Imaging the retina at high resolution has numerous potential medical applications, and yet for the development of commercial products that can be used in the clinic, the complexity and high cost of the present research systems have to be addressed. We present a new method to control the deformable mirror in real time based on pupil tracking measurements which uses the default camera for the alignment of the eye in the retinal imaging system and requires no extra cost or hardware. We also present the first experiments done with a compact adaptive optics flood illumination fundus camera where it was possible to compensate for the higher order aberrations of a moving model eye and in vivo in real time based on pupil tracking measurements, without the real time contribution of a wavefront sensor. As an outcome of this research, we showed that pupil tracking can be effectively used as a low cost and practical adaptive optics tool for high resolution retinal imaging because eye movements constitute an important part of the ocular wavefront dynamics. © 2012 Optical Society of America.
Rocha K.M.,Cleveland Clinic |
Rocha K.M.,Federal University of São Paulo |
Vabre L.,Imagine Eyes |
Chateau N.,Imagine Eyes |
Krueger R.R.,Cleveland Clinic
Journal of Refractive Surgery | Year: 2010
PURPOSE: To evaluate the changes in visual acuity and visual perception generated by correcting higher order aberrations in highly aberrated eyes using a large-stroke adaptive optics visual simulator. METHODS: A crx1 Adaptive Optics Visual Simulator (Imagine Eyes) was used to correct and modify the wavefront aberrations in 12 keratoconic eyes and 8 symptomatic postoperative refractive surgery (LASIK) eyes. After measuring ocular aberrations, the device was programmed to compensate for the eye's wavefront error from the second order to the fifth order (6-mm pupil). Visual acuity was assessed through the adaptive optics system using computer-generated ETDRS optotypes and the Freiburg Visual Acuity and Contrast Test. RESULTS: Mean higher order aberration root-meansquare (RMS) errors in the keratoconus and symptomatic LASIK eyes were 1.88±0.99 μm and 1.62±0.79 μm (6-mm pupil), respectively. The visual simulator correction of the higher order aberrations present in the keratoconus eyes improved their visual acuity by a mean of 2 lines when compared to their best spherocylinder correction (mean decimal visual acuity with spherocylindrical correction was 0.31±0.18 and improved to 0.44±0.23 with higher order aberration correction). In the symptomatic LASIK eyes, the mean decimal visual acuity with spherocylindrical correction improved from 0.54±0.16 to 0.71±0.13 with higher order aberration correction. The visual perception of ETDRS letters was improved when correcting higher order aberrations. CONCLUSIONS: The adaptive optics visual simulator can effectively measure and compensate for higher order aberrations (second to fifth order), which are associated with diminished visual acuity and perception in highly aberrated eyes. The adaptive optics technology may be of clinical benefit when counseling patients with highly aberrated eyes regarding their maximum subjective potential for vision correction. Copyright ©SLACK Incorporated.
Odlund E.,University of Kent |
Raynaud H.-F.,University of Paris 13 |
Kulcsar C.,University of Paris 13 |
Harms F.,Imagine Eyes |
And 4 more authors.
Applied Optics | Year: 2010
The transient response of a deformable mirror to be used in a closed-loop adaptive-optics imaging system is modeled and evaluated. A theoretical model is developed that describes the motion of the mirror membrane. This allows an adaptive control to achieve reduced overshoot and short settling time. Applicability of the model is tested on a mirao 52-e electromagnetic deformable mirror using a specially designed highspeed adaptive-optics test bench. This test bench permits precise mirror motion measurements up to 10 kHz. © 2010 Optical Society of America.
Viard C.,Imagine Eyes |
Nakashima K.,CIC |
Lamory B.,Imagine Eyes |
Paques M.,CIC |
And 2 more authors.
Progress in Biomedical Optics and Imaging - Proceedings of SPIE | Year: 2011
This research is aimed at characterizing in vivo differences between healthy and pathological retinal tissues at the microscopic scale using a compact adaptive optics (AO) retinal camera. Tests were performed in 120 healthy eyes and 180 eyes suffering from 19 different pathological conditions, including age-related maculopathy (ARM), glaucoma and rare diseases such as inherited retinal dystrophies. Each patient was first examined using SD-OCT and infrared SLO. Retinal areas of 4°x4° were imaged using an AO flood-illumination retinal camera based on a large-stroke deformable mirror. Contrast was finally enhanced by registering and averaging rough images using classical algorithms. Cellular-resolution images could be obtained in most cases. In ARM, AO images revealed granular contents in drusen, which were invisible in SLO or OCT images, and allowed the observation of the cone mosaic between drusen. In glaucoma cases, visual field was correlated to changes in cone visibility. In inherited retinal dystrophies, AO helped to evaluate cone loss across the retina. Other microstructures, slightly larger in size than cones, were also visible in several retinas. AO provided potentially useful diagnostic and prognostic information in various diseases. In addition to cones, other microscopic structures revealed by AO images may also be of interest in monitoring retinal diseases. © 2011 Copyright SPIE - The International Society for Optical Engineering.
Salas M.,Medical University of Vienna |
Drexler W.,Medical University of Vienna |
Levecq X.,Imagine Eyes |
Lamory B.,Imagine Eyes |
And 5 more authors.
Biomedical Optics Express | Year: 2016
We present a new compact multi-modal imaging prototype that combines an adaptive optics (AO) fundus camera with AO-optical coherence tomography (OCT) in a single instrument. The prototype allows acquiring AO fundus images with a field of view of 4°x4° and with a frame rate of 10fps. The exposure time of a single image is 10 ms. The short exposure time results in nearly motion artifact-free high resolution images of the retina. The AO-OCT mode allows acquiring volumetric data of the retina at 200kHz A-scan rate with a transverse resolution of ~4 μm and an axial resolution of ~5 μm. OCT imaging is acquired within a field of view of 2°x2° located at the central part of the AO fundus image. Recording of OCT volume data takes 0.8 seconds. The performance of the new system is tested in healthy volunteers and patients with retinal diseases. © 2016 Optical Society of America.
Kulcsar C.,French National Center for Scientific Research |
Fezzani R.,French National Center for Scientific Research |
Fezzani R.,ONERA |
Le Besnerais G.,ONERA |
And 2 more authors.
2014 International Workshop on Computational Intelligence for Multimedia Understanding, IWCIM 2014 | Year: 2014
Recent retinal imaging systems, including those featuring adaptative optics (AO) correction, produce sequences of images having a very high spatial resolution, but possibly affected by a low Signal-to-Noise Ratio (SNR). A simple, fast and efficient way to improve SNR in many cases is to average images. However, image quality appears to be highly variable from one frame to another, and sequences feature large inter-frame global motions due to eye movements. We consider in this paper both global and local motion estimation to deliver enhanced images or to detect vessel activity. We tackle the problem of retinal vessels local motions due to bloodstream. If not accounted for, these motions lead to some blurring of the enhanced image, which in turn degrades image analysis, for instance the estimation of the thickness of the vessels wall or the wall-to-lumen ratio. Interframe local motions need thus to be estimated. We propose to compensate for local motions using a fast optical flow estimation called FOLKI developed at ONERA/DTIM, which combines very fast computational times with a good accuracy. The method is then applied to detect vessel activity. Improvements are demonstrated both in terms of final image quality and of local activity detection, on sequences recorded on Imagine Eyes' rtx1 system. © 2014 IEEE.
PubMed | Imagine Eyes and Medical University of Vienna
Type: Journal Article | Journal: Biomedical optics express | Year: 2016
We present a new compact multi-modal imaging prototype that combines an adaptive optics (AO) fundus camera with AO-optical coherence tomography (OCT) in a single instrument. The prototype allows acquiring AO fundus images with a field of view of 4x4 and with a frame rate of 10fps. The exposure time of a single image is 10 ms. The short exposure time results in nearly motion artifact-free high resolution images of the retina. The AO-OCT mode allows acquiring volumetric data of the retina at 200kHz A-scan rate with a transverse resolution of ~4 m and an axial resolution of ~5 m. OCT imaging is acquired within a field of view of 2x2 located at the central part of the AO fundus image. Recording of OCT volume data takes 0.8 seconds. The performance of the new system is tested in healthy volunteers and patients with retinal diseases.
Imagine Eyes | Date: 2012-01-27
The invention relates to a high-resolution retinal imaging method and device notably comprising an emission source (LSr) for emitting a light beam for the illumination of the retina of an eye (10) of a subject, a detection device (12) capable of detecting spatial-frequency structures of 250 cycles/mm measured in the plane of the retina, an optical imaging system (16) allowing for the formation of an image of at least a part of the retina on the detection device (12), a device (15) for measuring optical defects with an analysis plane of the optical defects, a correction device (14) comprising a correction plane and intended to correct, in said correction plane, the light rays from said emission source (LSr) and backscattered by the retina as a function of the optical defects measured by the measurement device (15). The correction and analysis planes are optically conjugated with a predetermined plane (17) of the eye, and the input pupil of said optical imaging system has a diameter of between a first value min and a second value max, the first value being defined to allow for the detection by said detection device (12), at an imaging wavelength, of structures of the retina exhibiting a spatial frequency of 250 cycles per millimeter, and the second value being less than 5.75 mm.
Imagine Eyes | Date: 2012-02-21
The invention relates, according to one aspect, to a retinal imaging device including at least one source (LS_(a), LS_(r)) for emitting a light beam in order to illuminate the retina of an eye (10) of a subject, a retinal imaging path including a detection device (12) having a detection plane (121) and an optical imaging system (L1, L5, L6), an analysis path including a device (15) for measuring optical defects having an analysis plane (151) for receiving a set of light rays backscattered by the retina and optical means for adjoining said analysis plane and a predetermined plane in the input space of said imaging system of the imaging path, a correction device (14) shared by said analysis and imaging paths, which includes a correction plane (141) and which is intended to correct, in said correction plane, the light rays from said emission source and backscattered by the retina according to the optical defects measured by the device for measuring optical defects. The retinal imaging device further includes a light blackout system (20), which is positioned in an adjacent plane or which coincides with said correction plane, or which is positioned in an image plane of said correction plane located on an optical path shared by the analysis and imaging paths, and which is sized so as to at least partially black out the reflections of the light rays from said emission source by the corneal surface.