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Applied Optics Feb 2024Head movement must be stabilized to enable high-quality data collection from optical instrumentation such as eye trackers and ophthalmic imaging devices. Though...
Head movement must be stabilized to enable high-quality data collection from optical instrumentation such as eye trackers and ophthalmic imaging devices. Though critically important for imaging, head stabilization is often an afterthought in the design of advanced ophthalmic imaging systems, and experimental devices often adapt used and/or discarded equipment from clinical devices for this purpose. Alternatively, those seeking the most stable solution possible, including many users of adaptive optics ophthalmoscopy systems, utilize bite bars. Bite bars can provide excellent stability but are time consuming to fabricate, decreasing imaging efficiency, and uncomfortable for many patients, especially the elderly and/or those with prosthodontics such as dentures who may refuse participation in a study that requires one. No commercial vendors specifically offer head mount solutions for experimental ophthalmic imaging devices, resulting in nearly every custom device having a different solution for this commonly encountered problem. Parallelizing the head stabilization apparatus across different custom devices may improve standardization of experimental imaging systems for clinical trials and other multicenter investigations. Here we introduce a head mount design for ophthalmic imaging that is modular, adjustable, and customizable to the constraints of different experimental imaging configurations. The three points of head contact in our solution provide excellent stabilization across a range of head sizes and shapes from small children to adults, and the ease of adjustment afforded by our design minimizes the time to get participants stabilized and comfortable.
Topics: Adult; Aged; Child; Humans; Data Collection; Diagnostic Imaging; Eye; Face; Ophthalmoscopy
PubMed: 38437390
DOI: 10.1364/AO.513801 -
Ophthalmic & Physiological Optics : the... Sep 2022Retinoscopy is a skill that requires the integration of procedural skill and declarative knowledge. Whilst the actual technique is simple, retinoscopy is a complex skill...
PURPOSE
Retinoscopy is a skill that requires the integration of procedural skill and declarative knowledge. Whilst the actual technique is simple, retinoscopy is a complex skill to acquire and is one that students often find challenging. This study compared the strategies that novices, third-year students and experts use when performing retinoscopy, with the aim of identifying the key stages of learning that may enlighten teaching practice.
METHOD
This study employed a protocol-based approach in which the verbal protocols and cognitive strategies of novices, students and experts were recorded and then subjected to 'problem space' analysis.
RESULTS
Clear differences existed when the retinoscopy of novices, students and experts was directly compared using a standardised simulated task. Experts were more accurate in performance and used defined strategies to reach the goal. The presence of these strategies significantly predicted the accuracy of the retinoscopy result.
CONCLUSION
This study highlights the importance of meta-cognitive strategies and the need for an adequate theoretical foundation in skill acquisition. The underpinning knowledge provides a pedagogic tool that specifies activities which are beneficial to learning a clinical skill.
Topics: Clinical Competence; Humans; Learning; Retinoscopy; Students
PubMed: 35598151
DOI: 10.1111/opo.13007 -
Clinical Nutrition ESPEN Aug 2023Oral lutein (L) and zeaxanthin (Z) supplementation enhances macular pigment optical density (MPOD) and plays a protective role in the development of age-related macular...
BACKGROUND & AIMS
Oral lutein (L) and zeaxanthin (Z) supplementation enhances macular pigment optical density (MPOD) and plays a protective role in the development of age-related macular degeneration (AMD). Fluorescence lifetime imaging ophthalmoscopy (FLIO) is a novel in vivo retinal imaging method that has been shown to correlate to classical MPOD measurements and might contribute to a metabolic mapping of the retina in the future. Our aim was to show that oral supplementation of L and Z affects the FLIO signal in a positive way in patients with AMD.
METHODS
This was a prospective, single center, open label cohort study. Patients with early and intermediate AMD received oral L and Z supplementation during three months, and were observed for another three months after therapy termination. All visits included measurements of clinical parameters, serum L and Z concentration, MPOD measurements using heterochromatic flicker photometry, dual wavelength autofluorescence imaging, and FLIO. Correlation analysis between FLIO and MPOD were performed.
RESULTS
Twenty-one patients completed the follow up period. Serum L and Z concentrations significantly increased during supplementation (mean difference 244.8 ng/ml; 95% CI: 81.26-419.9, and 77.1 ng/ml; 95% CI: 5.3-52.0, respectively). Mean MPOD units significantly increased (mean difference 0.06; 95% CI: 0.02-0.09; at 0.5°, 202; 95% CI: 58-345; at 2°, 1033; 95% CI: 288-1668; at 9° of eccentricity, respectively) after three months of supplementation with macular xanthophylls, which included L and Z. Median FLIO lifetimes in the foveal center significantly decreased from 277.3 ps (interquartile range 230.2-339.1) to 261.0 ps (interquartile range 231.4-334.4, p = 0.027). All parameters returned to near-normal values after termination of the nutritional supplementation. A significant negative correlation was found between FLIO and MPOD (r = 0.57, p < 0.0001).
CONCLUSIONS
FLIO is able to detect subtle changes in MPOD after L and Z supplementation in patients with early and intermediate AMD. Our findings confirm the previous described negative correlation between FLIO and MPOD. Macular xanthophylls seem to contribute to short foveal lifetimes. This study is registered at ClinicalTrials.gov (identifier number NCT04761341).
Topics: Humans; Lutein; Macular Pigment; Zeaxanthins; Pilot Projects; Prospective Studies; Cohort Studies; Macular Degeneration; Dietary Supplements; Ophthalmoscopy
PubMed: 37344061
DOI: 10.1016/j.clnesp.2023.05.009 -
Journal of Biophotonics Sep 2022Multispectral imaging is used in various applications including astronomy, industry and agriculture. In retinal imaging, the single-shot multispectral image stack is...
Multispectral imaging is used in various applications including astronomy, industry and agriculture. In retinal imaging, the single-shot multispectral image stack is typically acquired and analyzed. This multispectral analysis can provide information on various structural or metabolic properties. This paper describes the multispectral improvement of a video-ophthalmoscope, which can acquire retinal video sequences of the optic nerve head and peripapillary area using various spectral light illumination. The description of the multispectral video imaging is provided and several applications are described. These applications include multispectral retinal photoplethysmography, visualization of spontaneous vein pulsation and multispectral RGB image generation.
Topics: Fiber Optic Technology; Lighting; Ophthalmoscopes; Ophthalmoscopy; Optic Disk; Retina
PubMed: 35604408
DOI: 10.1002/jbio.202200094 -
Methods in Molecular Biology (Clifton,... 2022Retinal examination and imaging are relatively simple methods for studying the dynamic impact of cerebral malaria on the microcirculation of the central nervous system....
Retinal examination and imaging are relatively simple methods for studying the dynamic impact of cerebral malaria on the microcirculation of the central nervous system. Retina and brain are affected similarly by Plasmodium falciparum. Unlike the brain, the human retina can be directly observed using commercially available clinical instruments in the setting of a critical care unit, and this can be done repeatedly and non-invasively. Additional information about blood-tissue barriers can be gained from fluorescein angiography. Non-ophthalmologist clinician scientists are usually unfamiliar with ophthalmoscopy and retinal imaging, and some readers may feel that these techniques are beyond them. This chapter aims to quell these fears by providing a step-by-step description of how to examine and photograph the human retina in children with cerebral malaria.
Topics: Child; Humans; Malaria, Cerebral; Ophthalmoscopy; Plasmodium falciparum; Retina; Retinal Diseases
PubMed: 35881386
DOI: 10.1007/978-1-0716-2189-9_54 -
Journal of AAPOS : the Official... Jun 2022We introduce a portable retinoscopy device designed to allow simultaneous views of the retinoscope's reflex. With built-in Wi-Fi, it allows for viewing from any phone,...
We introduce a portable retinoscopy device designed to allow simultaneous views of the retinoscope's reflex. With built-in Wi-Fi, it allows for viewing from any phone, tablet, or computer. The device easily attaches to a Welch Allyn retinoscope and could facilitate the teaching of retinoscopy for students, ophthalmic technicians, residents, and physicians.
Topics: Humans; Retinoscopy
PubMed: 35469977
DOI: 10.1016/j.jaapos.2022.02.003 -
Vestnik Oftalmologii 2022Papilledema (choked disk) is a sign of intracranial hypertension (ICH) - condition that presents danger not only for patient's vision, but also for their life. Despite... (Review)
Review
Papilledema (choked disk) is a sign of intracranial hypertension (ICH) - condition that presents danger not only for patient's vision, but also for their life. Despite the fact that ICH is usually a neurosurgical pathology, sometimes an ophthalmologist is the first doctor such patients visit, most often in a primary healthcare clinic. At the same time, as practice shows, not all ophthalmologists are well aware about in this pathology; difficulties occur in differential diagnosis of papilledema against similar changes of the optic nerve head seen during ophthalmoscopic examination. This article reviews scientific literature on ICH, including benign ICH, diagnosis and differential diagnosis of papilledema. The authors also share their decades-long experience of working in a neurosurgical facility.
Topics: Diagnosis, Differential; Humans; Intracranial Hypertension; Ophthalmoscopy; Optic Disk; Papilledema
PubMed: 36004596
DOI: 10.17116/oftalma202213804187 -
Annual Review of Vision Science Sep 2019Retinal function has long been studied with psychophysical methods in humans, whereas detailed functional studies of vision have been conducted mostly in animals owing... (Review)
Review
Retinal function has long been studied with psychophysical methods in humans, whereas detailed functional studies of vision have been conducted mostly in animals owing to the invasive nature of physiological approaches. There are exceptions to this generalization, for example, the electroretinogram. This review examines exciting recent advances using in vivo retinal imaging to understand the function of retinal neurons. In some cases, the methods have existed for years and are still being optimized. In others, new methods such as optophysiology are revealing novel patterns of retinal function in animal models that have the potential to change our understanding of the functional capacity of the retina. Together, the advances in retinal imaging mark an important milestone that shifts attention away from anatomy alone and begins to probe the function of healthy and diseased eyes.
Topics: Animals; Humans; Ophthalmoscopy; Optics and Photonics; Retina; Retinal Neurons; Tomography, Optical Coherence; Vision, Ocular
PubMed: 31525142
DOI: 10.1146/annurev-vision-091517-034239 -
Ophthalmic & Physiological Optics : the... Mar 2020Cones are at great risk in a wide variety of retinal diseases, especially when there is a harsh microenvironment and retinal pigment epithelium is damaged. We provide... (Review)
Review
PURPOSE
Cones are at great risk in a wide variety of retinal diseases, especially when there is a harsh microenvironment and retinal pigment epithelium is damaged. We provide established and new methods for assessing cones and retinal pigment epithelium, together with new results. We investigated conditions under which cones can be imaged and could guide light, despite the proximity of less than ideal retinal pigment epithelium.
RECENT FINDINGS
We used a variety of imaging methods to detect and localise damage to the retinal pigment epithelium. As age-related macular degeneration is a particularly widespread disease, we imaged clinical hallmarks: drusen and hyperpigmentation. Using near infrared light provided improved imaging of the deeper fundus layers. We compared confocal and multiply scattered light images, using both the variation of detection apertures and polarisation analysis. We used optical coherence tomography to examine distances between structures and thickness of retinal layers, as well as identifying damage to the retinal pigment epithelium. We counted cones using adaptive optics scanning laser ophthalmoscopy. We compared the results of five subjects with geographic atrophy to data from a previous normative ageing study. Using near infrared imaging and layer analysis of optical coherence tomography, the widespread aspect of drusen became evident. Both multiply scattered light imaging and analysis of the volume in the retinal pigment epithelial layer from the optical coherence tomography were effective in localising drusen and hyperpigmentation beneath the photoreceptors. Cone photoreceptors in normal older eyes were shorter than in younger eyes. Cone photoreceptors survived in regions of atrophy, but with greatly reduced and highly variable density. Regular arrays of cones were found in some locations, despite abnormal retinal pigment epithelium. For some subjects, the cone density was significantly greater than normative values in some retinal locations outside the atrophy.
SUMMARY
The survival of cones within atrophy is remarkable. The unusually dense packing of cones at some retinal locations outside the atrophy indicates more fluidity in cone distribution than typically thought. Together these findings suggest strategies for therapy that includes preserving cones.
Topics: Aging; Humans; Macular Degeneration; Ophthalmoscopy; Optics and Photonics; Retinal Cone Photoreceptor Cells; Retinal Pigment Epithelium; Tomography, Optical Coherence; Visual Acuity
PubMed: 32017191
DOI: 10.1111/opo.12670 -
Journal Francais D'ophtalmologie Oct 2023
Topics: Humans; Gallbladder Neoplasms; Retinal Hemorrhage; Ophthalmoscopy; Carcinoma in Situ
PubMed: 37100712
DOI: 10.1016/j.jfo.2023.01.025