Fundus topographical distribution patterns of ocular toxoplasmosis

BACKGROUND: To establish topographic maps and determine fundus distribution patterns of ocular toxoplasmosis (OT) lesions. METHODS: In this retrospective study, patients who presented with OT to ophthalmology clinics from four countries (Argentina, Turkey, UK, USA) were included. Size, shape and location of primary (1°)/recurrent (2°) and active/inactive lesions were converted into a two-dimensional retinal chart by a retinal drawing software. A final contour map of the merged image charts was then created using a custom Matlab programme. Descriptive analyses were performed. RESULTS: 984 lesions in 514 eyes of 464 subjects (53% women) were included. Mean area of all 1° and 2° lesions was 5.96±12.26 and 5.21±12.77 mm2, respectively. For the subset group lesions (eyes with both 1° and 2° lesions), 1° lesions were significantly larger than 2° lesions (5.52±6.04 mm2 vs 4.09±8.90 mm2, p=0.038). Mean distances from foveola to 1° and 2° lesion centres were 6336±4267 and 5763±3491 µm, respectively. The majority of lesions were found in temporal quadrant (p<0.001). Maximum overlap of all lesions was at 278 µm inferotemporal to foveola. CONCLUSION: The 1° lesions were larger than 2° lesions. The 2° lesions were not significantly closer to fovea than 1° lesions. Temporal quadrant and macular region were found to be densely affected underlining the vision threatening nature of the disease

Opto-mechanical artificial eye with accommodative ability.

The purpose of this study was to describe the design and characterization of a new opto-mechanical artificial eye (OMAE) with accommodative ability. The OMAE design is based on a second-pass configuration where a small source of light is used at the artificial retina plane. A lens whose focal length can be changed electronically was used to add the accommodation capability. The changes in the OMAE's aberrations with the lens focal length, which effectively changes the accommodative state of the OMAE, were measured with a commercial aberrometer. Changes in power and aberrations with room temperature were also measured. The OMAE's higher-order aberrations (HOAs) were similar to the ones of the human eye, including the rate at which fourth-order spherical aberration decreased with accommodation. The OMAE design proposed here is simple, and it can be implemented in an optical system to mimic the optics of the human eye

Examining In Vivo Changes in Lamina Cribrosa in Non-human Primates with Experimental Glaucoma

Glaucoma is a disease that results in the degeneration of retinal ganglion cell axons and the death of retinal ganglion cells (RGCs). It is one of the leading causes of permanent blindness worldwide. Clinical examinations currently in practice are limited in their ability to detect glaucoma prior to loss of RGC axons. The main goal of this work is to characterize early changes in the optic nerve head of monkeys with experimental glaucoma (EG) using in vivo and non-invasive methods to better understand the mechanisms behind glaucoma. In vivo images of the lamina cribrosa were acquired using a spectral domain optical coherence tomography and an adaptive optics scanning laser ophthalmoscope (AOSLO). We transformed 2D AOSLO images onto a 3D anterior lamina cribrosa surface (ALCS) and computed the 3D morphometry of the ALCS. Using principal component analysis (PCA), we estimated the predominant local ALCS beam orientation directly from raw grayscale in vivo images without the need for binary segmentation. Subsequently, we developed an automated method to segment the lamina cribrosa pores using level sets. Our 3D transformation method provides a better representation of the ALCS from in vivo images. Following 3D transformation, mean pore area increased by 5.1 ± 2.0% in 11 normal eyes and 16.2 ± 5.9% in 4 glaucomatous eyes due to the increased curvatures. Our PCA technique yielded small errors in local orientation (0.2 ± 0.2◦) when tested on synthetic data, accurately determined local beam orientation and was repeatable in control eyes over time. In addition, automated segmentation of pore boundaries using level sets method was comparable to manual segmentation (sensitivity = 83%, specificity = 95%) and yielded repeatable values over time. In conclusion, the PCA beam orientation and level sets segmentation methods can be used to accurately and objectively detect and track in vivo changes in lamina cribrosa microarchitecture during the progression of EG.Computer Science, Department o

Decreased Vision in Multiple Sclerosis is Associated With Novel Foveal Features Visualized Using Adaptive Optics

Multifocal electroretinography has demonstrated dysfunction of non-ganglion cell retinal components in people with MS not associated with structural abnormalities on OCT, which raises the possibility of previously unidentified retinal pathology in MS. The objective of this study was to identify structural pathologies in the foveal avascular zone of people with MS that may account for these functional changes

<i>In Vivo</i> Changes in Lamina Cribrosa Microarchitecture and Optic Nerve Head Structure in Early Experimental Glaucoma

<div><p>The lamina cribrosa likely plays an important role in retinal ganglion cell axon injury in glaucoma. We sought to (1) better understand optic nerve head (ONH) structure and anterior lamina cribrosa surface (ALCS) microarchitecture between fellow eyes of living, normal non-human primates and (2) characterize the time-course of <i>in vivo</i> structural changes in the ONH, ALCS microarchitecture, and retinal nerve fiber layer thickness (RNFLT) in non-human primate eyes with early experimental glaucoma (EG). Spectral domain optical coherence tomography (SDOCT) images of the ONH were acquired cross-sectionally in six bilaterally normal rhesus monkeys, and before and approximately every two weeks after inducing unilateral EG in seven rhesus monkeys. ONH parameters and RNFLT were quantified from segmented SDOCT images. Mean ALCS pore area, elongation and nearest neighbor distance (NND) were quantified globally, in sectors and regionally from adaptive optics scanning laser ophthalmoscope images. In bilaterally normal monkeys, ONH parameters were similar between fellow eyes with few inter-eye differences in ALCS pore parameters. In EG monkeys, an increase in mean ALCS Depth (ALCSD) was the first structural change measured in 6 of 7 EG eyes. A decrease in mean minimum rim width (MRW) simultaneously accompanied this early change in 4 of 6 EG eyes and was the first structural change in the 7^th EG eye. Mean ALCS pore parameters were among the first or second changes measured in 4 EG eyes. Mean ALCS pore area and NND increased in superotemporal and temporal sectors and in central and peripheral regions at the first time-point of change in ALCS pore geometry. RNFLT and/or mean ALCS radius of curvature were typically the last parameters to initially change. Survival analyses found mean ALCSD was the only parameter to significantly show an initial change prior to the first measured loss in RNFLT across EG eyes.</p></div

Mean (± st. dev.) pore parameters across all eyes of 6 bilaterally normal monkeys on global, regional, and sector scales.

<p>Mean (± st. dev.) pore parameters across all eyes of 6 bilaterally normal monkeys on global, regional, and sector scales.</p

IOP data for control and EG eyes throughout the duration of the study.

<p>IOP data for control and EG eyes throughout the duration of the study.</p

Longitudinal in vivo Ca2+ imaging reveals dynamic activity changes of diseased retinal ganglion cells at the single-cell level.

Retinal ganglion cells (RGCs) are heterogeneous projection neurons that convey distinct visual features from the retina to brain. Here, we present a high-throughput in vivo RGC activity assay in response to light stimulation using noninvasive Ca2+ imaging of thousands of RGCs simultaneously in living mice. Population and single-cell analyses of longitudinal RGC Ca2+ imaging reveal distinct functional responses of RGCs and unprecedented individual RGC activity conversions during traumatic and glaucomatous degeneration. This study establishes a foundation for future in vivo RGC function classifications and longitudinal activity evaluations using more advanced imaging techniques and visual stimuli under normal, disease, and neural repair conditions. These analyses can be performed at both the population and single-cell levels using temporal and spatial information, which will be invaluable for understanding RGC pathophysiology and identifying functional biomarkers for diverse optic neuropathies

Distinct changes in LC beam and pore structure were observed in early EG.

<p>(A-F) AOSLO montages of the ALCS were constructed, registered, and averaged across multiple time-points in the same EG eye for each monkey and overlaid on the corresponding SLO images to show the LC before (left) and after (right) the first statistically significant changes were seen in ALCS pore geometry in early experimental glaucoma. Large differences in beam and pore structure can be seen in 6 of 7 EG eyes over time. (A: OHT-63; B: OHT-64; C: OHT-65; D: OHT-66; E: OHT-68; F: OHT-69.) (G) ALCS pore structure did not change significantly over time in the EG eye of monkey OHT-67. Scale bar: 300 μm.</p