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

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

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

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

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

RNFLT and mean ONH parameters averaged across all study time-points for each control eye.

<p>‘—’—ONH parameters were not quantified in the control eye of OHT-65.</p><p>RNFLT and mean ONH parameters averaged across all study time-points for each control eye.</p

Early changes in ONH parameters, RNFLT, and ALCS pore geometry in the EG eye of monkey OHT-66.

<p>Values for (A) mean ALCSD, (B) mean RoC, (C) mean MRW, and (D) RNFLT are shown as a function of study time for all measured time-points (black circles) before and after the initial laser treatment (day 0). The black horizontal line in each plot indicates the baseline value for each parameter while the gray shaded region represents the 95% confidence interval for each parameter calculated from data measured in the fellow control eye. Yellow circles represent the time-point of first significant change in each plotted parameter, while vertical red lines represent the time-point of first significant change in ALCS pore geometry. The first parameter to significantly change from baseline values was (A) mean ALCSD (49 days after the initial laser treatment). The next parameter to significantly change from baseline was (B) mean RoC (130 days after the initial laser treatment), followed by simultaneous significant changes in ALCS pore geometry and mean MRW (168 days after the initial laser treatment). RNFLT was the last measured parameter to significantly change (182 days after the initial laser treatment).</p

LC pore parameters were analyzed on global and local levels in all normal eyes.

<p>(Rows 1, 3, 5) AOSLO montages of the ALCS scaled, registered, and overlaid on the corresponding SLO images in right and left eyes of 6 normal monkeys. (Rows 2, 4, 6) After manually marking LC pores (filled in white), pores were examined globally, in central and peripheral regions (separated by green boundaries) and in 60° sectors (divided by fuchsia meridians). Scale bar: 100 μm.</p