| 1. |
- Brusini, Irene, et al.
(författare)
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Fully automatic estimation of the waist of the nerve fiber layer at the optic nerve head angularly resolved
- 2021
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Ingår i: Progress in Biomedical Optics and Imaging - Proceedings of SPIE. - : SPIE-Intl Soc Optical Eng. ; , s. 1D1-1D8
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Konferensbidrag (refereegranskat)abstract
- The present project aims at developing a fully automatic software for estimation of the waist of the nerve fiber layer in the Optic Nerve Head (ONH) angularly resolved in the frontal plane as a tool for morphometric monitoring of glaucoma. The waist of the nerve fiber layer is here defined as Pigment epithelium central limit –Inner limit of the retina – Minimal Distance, (PIMD). 3D representations of the ONH were collected with high resolution OCT in young not glaucomatous eyes and glaucomatous eyes. An improved tool for manual annotation was developed in Python. This tool was found user friendly and to provide sufficiently precise manual annotation. PIMD was automatically estimated with a software consisting of one AI model for detection of the inner limit of the retina and another AI model for localization of the Optic nerve head Pigment epithelium Central limit (OPCL). In the current project, the AI model for OPCL localization was retrained with new data manually annotated with the improved tool for manual annotation both in not glaucomatous eyes and in glaucomatous eyes. Finally, automatic annotations were compared to 3 annotations made by 3 independent annotators in an independent subset of both the not glaucomatous and the glaucomatous eyes. It was found that the fully automatic estimation of PIMD-angle overlapped the 3 manual annotators with small variation among the manual annotators. Considering interobserver variation, the improved tool for manual annotation provided less variation than our original annotation tool in not glaucomatous eyes suggesting that variation in glaucomatous eyes is due to variable pathological anatomy, difficult to annotate without error. The small relative variation in relation to the substantial overall loss of PIMD in the glaucomatous eyes compared to the not glaucomatous eyes suggests that our software for fully automatic estimation of PIMD-angle can now be implemented clinically for monitoring of glaucoma progression.
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| 2. |
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| 3. |
- Galichanin, Konstantin, 1982-, et al.
(författare)
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Expression of active caspase 3 in the rat lens after in vivo exposure to subthreshold dose of UVR-B
- 2024
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Ingår i: BMC Ophthalmology. - : BioMed Central (BMC). - 1471-2415. ; 24
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Tidskriftsartikel (refereegranskat)abstract
- Purposes: The aim of this study is to investigate the time evolution of active caspase 3 within first 120 h in the rat lens after in vivo exposure to subthreshold dose of UVR-B.Methods: Twenty three six-week-old female albino Sprague-Dawley rats were exposed to subthreshold dose (1 kJ/m2) of UVR-B unilaterally and sacrificed at 24, 41, 70 and 120 h after exposure. Lenses were enucleated and active caspase 3 was detected by Western Blot. The time evolution of active caspase 3 was then plotted as a function of relative mean difference in active caspase 3 between exposed and nonexposed lenses.Results: There is expression of active caspase 3 in both exposed and nonexposed lenses but there is no difference in relative mean difference in active caspase 3 between exposed and nonexposed lenses in all four postexposure groups.Conclusions: Exposure to subthreshold dose of UVR-B does not induce apoptosis in the rat lens in vivo within first 120 h though there is a non-significant increase of active caspase 3 at 120 h. Increase in sample size might reduce the variation level in expression of active caspase 3 in the rat lenses.
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| 4. |
- Galichanin, Konstantin, et al.
(författare)
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Upregulation of GADD45a, TP53 and CASP3 mRNA expression in the rat lens after in vivo exposure to sub-threshold exposure to UVR B
- 2014
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Ingår i: Journal of Ocular Biology. - 2334-2838. ; 2:1, s. 5-
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Tidskriftsartikel (refereegranskat)abstract
- Purpose:The objective of the present study was to investigate the evolution of mRNA expression of the stress sensor GADD45α, the apoptosis initiator TP53 and the apoptosis executor CASP3 in the rat lens after in vivo exposure to sub-threshold dose of UVR-B.Methods:Forty six-week-old female albino Sprague-Dawley rats were unilaterally exposed to a sub-threshold dose, 1 kJ/m2 (1.1 W/m2 for 15 min), of UVR (λmax = 300 nm). Anesthetized and dilated eyes were exposed to UVB radiation. The animals were sacrificed at 1, 5, 24 and 120 h post-exposure. mRNA expression of the GADD45α, TP53 and CASP3 genes in the lenses was measured by quantitative RT‑PCR, and fold change in mRNA expression between exposed and unexposed lenses was calculated.Results:mRNA expression for GADD45α increased to a 1.2 fold change at 1 h after exposure and then returned to no change at 120 h. mRNA expression for TP53 increased with a regression coefficient of 0.04 h-1 to a maximum of 1.67 fold change. mRNA expression for CASP3 increased with a regression coefficient of 4.5 x10-3 rel. units/h to a 1.46 fold change at 120 h after exposure.Conclusions:A sub-threshold in vivo exposure to UVR-B causes a transient upregulation of the stress sensor GADD45α at 1 h after exposure, a saturating upregulation of TP53 and a subsequent constant upregulation of CASP3 in the rat lens.
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| 5. |
- Kisonaite, Konstancija, et al.
(författare)
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AI-based detection of the inner limit of the minimal waist of the nerve fiber bundles in the ONH in subjects with peripapillary atrophy
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Purpose: To verify that a deep learning model developed by our research group does not wrongly identify the outer edge of the atrophic zone in eyes with peripapillary atrophy (PPA) rather than a point adjacent to the external limit of the minimal waist of the nerve fiber bundles in the ONH.Methods: Subjects with at least one eye with PPA were included. The ONH of the eye with PPA was imaged with colour photography, and the three-dimensional structure of the ONH was captured three times at one occasion with SS-OCT (Topcon Triton, Japan). Each capture was exported to a custom-made software for analysis. The custom-made software, AutoPimd, allowed fully automatic localization of the external limit of the minimal waist of the nerve fiber layer in space using deep learning-model. An en face visualization of the frontal plane of the ONH and user measurement in the en face view is possible. The en face view in the OCT volume was verified to render PPA as imaged in the photograph. The distance between the ONH center and the extreme edge of the PPA was measured in the en face view of the OCT. Then, the frontal plane distance between the ONH center and the fully automatically detected external limit of the minimal waist of the nerve fiber layer in the ONH was measured along the same frontal plane angle.Results: A 95 % confidence interval for the mean difference between the distance from center of the ONH to the extreme edge of the PPA, and the distance from the center of the ONH to the corresponding fully automatically detected outer limit of the minimal waist of the nerve fiber layer was estimated to 692 ± 192 μm (d.f = 5).Conclusion: Our AI model does not wrongly localize the outer limit of PPA as the external limit of the minimal waist of the nerve fiber layer. The structural representation of the external limit of the minimal waist of the nerve fiber bundles localized by our fully automatic AI model in eyes with PPA remains to be identified.
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| 6. |
- Kisonaite, Konstancija, et al.
(författare)
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Automatic estimation of the cross-sectional area of the waist of the nerve fiber layer at the optic nerve head
- 2023
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Ingår i: Acta Ophthalmologica. - : John Wiley & Sons. - 1755-375X .- 1755-3768.
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Tidskriftsartikel (refereegranskat)abstract
- PurposeGlaucoma leads to pathological loss of axons in the retinal nerve fibre layer at the optic nerve head (ONH). This study aimed to develop a strategy for the estimation of the cross-sectional area of the axons in the ONH. Furthermore, improving the estimation of the thickness of the nerve fibre layer, as compared to a method previously published by us.MethodsIn the 3D-OCT image of the ONH, the central limit of the pigment epithelium and the inner limit of the retina, respectively, were identified with deep learning algorithms. The minimal distance was estimated at equidistant angles around the circumference of the ONH. The cross-sectional area was estimated by the computational algorithm. The computational algorithm was applied on 16 non-glaucomatous subjects.ResultsThe mean cross-sectional area of the waist of the nerve fibre layer in the ONH was 1.97 ± 0.19 mm2. The mean difference in minimal thickness of the waist of the nerve fibre layer between our previous and the current strategies was estimated as CIμ (0.95) 0 ± 1 μm (d.f. = 15).ConclusionsThe developed algorithm demonstrated an undulating cross-sectional area of the nerve fibre layer at the ONH. Compared to studies using radial scans, our algorithm resulted in slightly higher values for cross-sectional area, taking the undulations of the nerve fibre layer at the ONH into account. The new algorithm for estimation of the thickness of the waist of the nerve fibre layer in the ONH yielded estimates of the same order as our previous algorithm.
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| 7. |
- Kisonaite, Konstancija, et al.
(författare)
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Estimation of the cross-sectional surface area of the waist of the nerve fiber layer at the optic nerve head
- 2022
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Ingår i: Progress in Biomedical Optics and Imaging. - : SPIE-Intl Soc Optical Eng.
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Konferensbidrag (refereegranskat)abstract
- Glaucoma is a global disease that leads to blindness due to pathological loss of retinal ganglion cell axons in the optic nerve head (ONH). The presented project aims at improving a computational algorithm for estimating the thickness and surface area of the waist of the nerve fiber layer in the ONH. Our currently developed deep learning AI algorithm meets the need for a morphometric parameter that detects glaucomatous change earlier than current clinical follow-up methods. In 3D OCT image volumes, two different AI algorithms identify the Optic nerve head Pigment epithelium Central Limit (OPCL) and the Inner limit of the Retina Closest Point (IRCP) in a 3D grid. Our computational algorithm includes the undulating surface area of the waist of the ONH, as well as waist thickness. In 16 eyes of 16 non-glaucomatous subjects aged [20;30] years, the mean difference in minimal thickness of the waist of the nerve fiber layer between our previous and the current post-processing strategies was estimated as CIμ(0.95) 0 ±1 μm (D.f. 15). The mean surface area of the waist of the nerve fiber layer in the optic nerve head was 1.97 ± 0.19 mm2. Our computational algorithm results in slightly higher values for surface areas compared to published work, but as expected, this may be due to surface undulations of the waist being considered. Estimates of the thickness of the waist of the ONH yields estimates of the same order as our previous computational algorithm.
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| 8. |
- Sandberg Melin, Camilla, et al.
(författare)
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Variance components for PIMD‐2π estimation of the optic nerve head and consequences in clinical measurements of glaucoma
- 2020
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Ingår i: Acta Ophthalmologica. - : John Wiley & Sons. - 1755-375X .- 1755-3768. ; 98:2, s. 190-194
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Tidskriftsartikel (refereegranskat)abstract
- Purpose To estimate the sources of variation for Pigment epithelium central limit-Inner limit of the retina Minimal Distance averaged over 2 pi (PIMD-2 pi), and further to analyse their consequences for clinical measurements of glaucoma. Methods Forty subjects with early to moderate stage glaucoma were included. Three SD-OCT volumes of the optic nerve head (ONH) were captured at two occasions. Each volume was segmented three times for PIMD-2 pi. The magnitude of the sources of variation for PIMD-2 pi measurements was estimated with an analysis of variance. Results A 95% confidence interval for mean PIMD-2 pi was estimated to 215 +/- 12 mu m (df = 38). The estimated variance for subjects was 1280 mu m(2). The within-subject estimated variance for occasions, volumes and segmentations was 10 mu m(2), 30 mu m(2) and 40 mu m(2), respectively. The within-subject variances were used to model follow-up of PIMD-2 pi over time. A linear loss rate of 0.05 of baseline PIMD-2 pi/year was assumed. A significant PIMD-2 pi change could be detected in approximately 16-18 months with evenly spaced visits every 4 or 6 months. Conclusions Due to the small within-subject estimated variances, a clinically undesirable PIMD-2 pi change from baseline can be detected in approximately 18 months. Detection of significant PIMD-2 pi loss in a subject requires knowledge of normal age loss and measurement variability.
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| 9. |
- Steinvall, Ove, et al.
(författare)
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Laser dazzling impacts on car driver performance
- 2013
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Konferensbidrag (refereegranskat)abstract
- A growing problem for the Police and Security Forces has been to prevent potentially hostile individuals to pass a checkpoint, without using lethatl violence. Therefore the question has been if there is a laser or any other strong light source that could be used as a warning and dazzling device, without lethal or long term effects. To investigate the possibilities a field trial has been performed at a motor-racing track. A green CW laser with an irradiance on the eye of maximum 0.5 MPE, as defined by ICNIRP [1] and the ANZI standard [2], was used as a dazzle source. Ten drivers have been driving with dipped headlights through a course of three lines with orange cones. In every line there has been only one gate wide enough to pass without hitting the cones. The time through the course, the choice of gates and the number of cones hit have been measured. For every second trial drive through the track, the driver was exposed to the laser dazzler. The background illuminances ranged from a thousand lux in daylight to about ten millilux in darkness. The protective effect of the sun-visor of the car was investigated. The drives visual system was carefully examined before and after experimental driving and a few weeks after the experimental driving to verify that no pathological effects, that could potentially be induced by the laser exposure, pre-existed or occurred after the laser exposure. An analysis of variance for a within subjects design has been used for evaluation. It was found that green laser light can have an obvious warning effect in daylight. Dazzling does reduce the drivers ability to make judgments and manouver the car in twilight and darkness. A sun-visor can reduce the glare and give the driver an improved control, but that perception can be unjustified. No damage to the visual system was observed.
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