Joel S. Schuman

abstract purpose to determine the reproducibility of automated segmentation of the three-dimensional (3d) lamina cribrosa (lc) microarchitecture scanned in-vivo using optical coherence tomography (oct). methods thirty-nine eyes (8 healthy, 19 glaucoma suspects and 12 glaucoma) from 49 subjects were scanned twice using swept-source (ss−) oct in a 3.5×3.5×3.64 mm (400×400×896 pixels) volume centered on the optic nerve head, with the focus readjusted after each scan. the lc was automatically… Show more

abstract purpose to determine the reproducibility of automated segmentation of the three-dimensional (3d) lamina cribrosa (lc) microarchitecture scanned in-vivo using optical coherence tomography (oct). methods thirty-nine eyes (8 healthy, 19 glaucoma suspects and 12 glaucoma) from 49 subjects were scanned twice using swept-source (ss−) oct in a 3.5×3.5×3.64 mm (400×400×896 pixels) volume centered on the optic nerve head, with the focus readjusted after each scan. the lc was automatically segmented and analyzed for microarchitectural parameters, including pore diameter, pore diameter standard deviation (sd), pore aspect ratio, pore area, beam thickness, beam thickness sd, and beam thickness to pore diameter ratio. reproducibility of the parameters was assessed by computing the imprecision of the parameters between the scans. results the automated segmentation demonstrated excellent reproducibility. all lc microarchitecture parameters had an imprecision of less or equal to 4.2%. there was little variability in imprecision with respect to diagnostic category, although the method tends to show higher imprecision amongst healthy subjects. conclusion the proposed automated segmentation of the lc demonstrated high reproducibility for 3d lc parameters. this segmentation analysis tool will be useful for in-vivo studies of the lc. Show less

Aim: To evaluate the utility of gold nanorods (AuNRs) as a contrast agent for ocular optical coherence tomography (OCT).
Methods: Mice were intravitreally injected with sterile AuNRs coated with either poly(strenesulfate) (PSS-AuNRs) or anti-CD90.2 antibodies (Ab-AuNRs), and imaged using OCT. After 24 h, eyes were processed for transmission electron microscopy or rendered into single cell suspensions for flow cytometric analysis to determine absolute numbers of CD45+ leukocytes and subsets… Show more

Aim: To evaluate the utility of gold nanorods (AuNRs) as a contrast agent for ocular optical coherence tomography (OCT).
Methods: Mice were intravitreally injected with sterile AuNRs coated with either poly(strenesulfate) (PSS-AuNRs) or anti-CD90.2 antibodies (Ab-AuNRs), and imaged using OCT. After 24 h, eyes were processed for transmission electron microscopy or rendered into single cell suspensions for flow cytometric analysis to determine absolute numbers of CD45+ leukocytes and subsets (T cells, myeloid cells, macrophages, neutrophils). Generalised estimation equations were used to compare cell counts between groups.
Results: PSS-AuNRs and Ab-AuNRs were visualised in the vitreous 30 min and 24 h post-injection with OCT. At 24 h, a statistically significant increase in leukocytes, comprised primarily of neutrophils, was observed in eyes that received either AuNR in comparison to eyes that received saline. The accumulation of leukocytes was equal in eyes given PSS-AuNR or Ab-AuNR. Endotoxin-resistant C3H/HeJ mice also showed ocular inflammation after injection with AuNRs, indicating that the inflammatory response was not due to lipopolysaccharide contamination of AuNRs.
Conclusions: Although AuNRs can be visualised in the eye using OCT, they can induce ocular inflammation, which limits their use as a contrast agent. Show less

Aim: To evaluate the utility of gold nanorods (AuNRs) as a contrast agent for ocular optical coherence tomography (OCT).
Methods: Mice were intravitreally injected with sterile AuNRs coated with either poly(strenesulfate) (PSS-AuNRs) or anti-CD90.2 antibodies (Ab-AuNRs), and imaged using OCT. After 24 h, eyes were processed for transmission electron microscopy or rendered into single cell suspensions for flow cytometric analysis to determine absolute numbers of CD45+ leukocytes and subsets… Show more

Aim: To evaluate the utility of gold nanorods (AuNRs) as a contrast agent for ocular optical coherence tomography (OCT).
Methods: Mice were intravitreally injected with sterile AuNRs coated with either poly(strenesulfate) (PSS-AuNRs) or anti-CD90.2 antibodies (Ab-AuNRs), and imaged using OCT. After 24 h, eyes were processed for transmission electron microscopy or rendered into single cell suspensions for flow cytometric analysis to determine absolute numbers of CD45+ leukocytes and subsets (T cells, myeloid cells, macrophages, neutrophils). Generalised estimation equations were used to compare cell counts between groups.
Results: PSS-AuNRs and Ab-AuNRs were visualised in the vitreous 30 min and 24 h post-injection with OCT. At 24 h, a statistically significant increase in leukocytes, comprised primarily of neutrophils, was observed in eyes that received either AuNR in comparison to eyes that received saline. The accumulation of leukocytes was equal in eyes given PSS-AuNR or Ab-AuNR. Endotoxin-resistant C3H/HeJ mice also showed ocular inflammation after injection with AuNRs, indicating that the inflammatory response was not due to lipopolysaccharide contamination of AuNRs.
Conclusions: Although AuNRs can be visualised in the eye using OCT, they can induce ocular inflammation, which limits their use as a contrast agent. Show less

Optical coherence tomography captures a major role in clinical assessment in eye care. Innovative hardware and software improvements in the technology would further enhance its usefulness. In this review, we present several promising initiatives currently in development or early phase of assessment that we expect to have a future impact on optical coherence tomography.

Commercial optical coherence tomography (OCT) systems use global signal quality indices to quantify scan quality. Signal quality can vary throughout a scan, contributing to local retinal nerve fibre layer segmentation errors (SegE). The purpose of this study was to develop an automated method, using local scan quality, to predict SegE.

MRI has long been applied to clinical medical and neurological cases for the structural assessment of tissues as well as their physiological and functional needs and processes. These uses are at a variety of developmental stages in ophthalmology, from common use of clinical structural assessment for neuro-ophthalmology and evaluation of space-occupying lesions to the beginning stages of experimentally measuring functional activation of specific layers within the retina and measurement of… Show more

MRI has long been applied to clinical medical and neurological cases for the structural assessment of tissues as well as their physiological and functional needs and processes. These uses are at a variety of developmental stages in ophthalmology, from common use of clinical structural assessment for neuro-ophthalmology and evaluation of space-occupying lesions to the beginning stages of experimentally measuring functional activation of specific layers within the retina and measurement of physiological oxygen responses. New MRI methodologies, such as the use of orbital coils and Gd-DTPA image enhancement, have been researched, developed, and validated in the eye, opening new possibilities for this technology to enter the clinic. This review aims to summarize the clinical ophthalmological uses of MRI, focusing on the current use of the technology and future applications. Show less