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- Kronschlager, Martin, et al.
(author)
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Apoptosis in Rat Cornea After In Vivo Exposure to Ultraviolet Radiation at 300 nm
- 2015
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In: Cornea. - 0277-3740 .- 1536-4798. ; 34:8, s. 945-949
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Journal article (peer-reviewed)abstract
- Purpose:Peak toxicity for in vivo ultraviolet radiation (UVR) exposure to the lens is in the 300-nm wavelength region. However, little is known about corneal cell damage at 300 nm. The purpose of the study was to determine the time evolution of apoptosis in the cornea after in vivo exposure to 300-nm UVR.Methods:Altogether, 16 Sprague Dawley rats were divided into 4 groups and unilaterally exposed to 5 kJ/m(2) UVR ((max): 300 nm; (0.5): 10 nm) for 15 minutes. After a predetermined latency period of 1, 5, 24, and 120 hours, depending on the group, the animals were killed and eyes were enucleated. Eye globes were further cryosectioned in 10-m thick midsagittal sections. For the detection of apoptosis, the TUNEL method was applied.Results:TUNEL-positive signals were observed in the superficial epithelial cells in the exposed and control eyes at all latency periods. At 5 hours, TUNEL staining was detected in the exposed corneas in epithelial cells, keratocytes, and endothelial cells with a maximum signal at 24 hours. At 120 hours, no TUNEL staining was found in endothelial cells and only occasionally in keratocytes in exposed corneas. Signs of ulceration and stromal thinning were observed at 120 hours.Conclusions:UVR in the 300-nm wavelength region induces TUNEL staining in all 3 corneal layers. TUNEL staining of all 3 corneal layers is an early postexposure event observed after a 5-hour latency period. Corneal sterile keratolysis occurs in the time window of 24 to 120 hours probably induced by neutrophils.
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| 2. |
- Sandberg Melin, Camilla, et al.
(author)
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Variance components in confocal scanning laser tomography measurements of neuro-retinal rim area and the effect of repeated measurements on the power to detect loss over time
- 2016
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In: Acta Ophthalmologica. - : Wiley. - 1755-375X .- 1755-3768. ; 94:7, s. 705-711
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Journal article (peer-reviewed)abstract
- PurposeTo estimate the variation in measurements of neuro-retinal rim area (NRA) determined by confocal scanning laser tomography and consequences for clinical follow-up. MethodsAltogether, 24 healthy subjects were randomized on -320m, Moorfields and Standard NRA plane strategies. Additionally, NRA was measured in 32 glaucoma subjects. Variance components for subjects, visits and measurements were estimated with analysis of variance. Sample sizes required to detect a 6.0x10(-2)mm(2) NRA change were estimated assuming a significance level of 0.05 and a power of 0.8. Consequences for independent group, and paired comparison design, respectively, were analysed. Further, precision in estimates within subjects over time was investigated. ResultsThe variation of NRA among subjects was considerably larger than the variation among visits and measurements. For glaucoma subjects, the variation among visits and measurements were of the same order but larger than in healthy subjects. It was found that independent group comparisons require inconveniently large sample sizes. Within-subject paired comparisons over time require sample sizes of below 15 subjects. The estimated variations for glaucoma subjects imply that 54months of follow-up is required for detection of change from baseline. ConclusionsThe variance for subjects is substantial in relation to those for visits and measurements. Cross-sectional independent group comparisons of levels of NRA are unsuitable, due to considerable subject variation. Levels of NRA differences within subjects between visits can be estimated with acceptable precision. Neuro-retinal rim area (NRA) measurement can be used for long-term follow-up of glaucoma progression.
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| 3. |
- Söderberg, Per, 1956-, et al.
(author)
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Does infrared or ultraviolet light damage the lens?
- 2016
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In: Eye (London. 1987). - : Springer Science and Business Media LLC. - 0950-222X .- 1476-5454. ; 30:2, s. 241-246
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Journal article (peer-reviewed)abstract
- In daylight, the human eye is exposed to long wavelength ultraviolet radiation (UVR), visible radiation and short wavelength infrared radiation (IRR). Almost all the UVR and a fraction of the IRR waveband, respectively, left over after attenuation in the cornea, is absorbed in the lens. The time delay between exposure and onset of biological response in the lens varies from immediate-to-short-to-late. After exposure to sunlight or artificial sources, generating irradiances of the same order of magnitude or slightly higher, biological damage may occur photochemically or thermally. Epidemiological studies suggest a dose-dependent association between short wavelength UVR and cortical cataract. Experimental data infer that repeated daily in vivo exposures to short wavelength UVR generate photochemically induced damage in the lens, and that short delay onset cataract after UVR exposure is photochemically induced. Epidemiology suggests that daily high-intensity short wavelength IRR exposure of workers, is associated with a higher prevalence of age-related cataract. It cannot be excluded that this effect is owing to a thermally induced higher denaturation rate. Recent experimental data rule out a photochemical effect of 1090 nm in the lens but other wavelengths in the near IRR should be investigated.
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| 4. |
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| 5. |
- Söderberg, Per G., et al.
(author)
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Near infrared radiation damage mechanism in the lens
- 2015
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In: OPHTHALMIC TECHNOLOGIES XXV. - : SPIE. - 9781628413977
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Conference paper (peer-reviewed)abstract
- The current data strongly indicates that there is no photochemical effect of in vivo exposure to 1090 nm near IRR radiation within the pupil. Four groups of 20 Sprague-Dawley rats were unilaterally exposed in vivo to 96 W.cm(-2) centered inside the pupil for 10, 18, 33 and 60 min, respectively depending on group belonging. This resulted in radiant exposure doses of 57, 103, 198 and 344 kJ.cm(-2). Temperature evolution at the limbus during the exposure and difference of intensity of forward light scattering between the exposed and the contralateral not exposed eye was measured at 1 week after exposure. The temperature at the limbus was found to increase exponentially towards an asymptote with an asymptote temperature of around 7 degrees C and a time constant (1/k) of around 15 s. No increase of light scattering was found despite that the cumulated radiant exposure dose was [80; 250] times the threshold for photochemically induced cataract suggested by previous empirical data. It is concluded that at 1090 nm near IRR there is no photochemical effect.
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| 6. |
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| 7. |
- Söderberg, Per, 1956-, et al.
(author)
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Katarakt - : ett optiskt problem i ögats lins
- 2016
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In: Läkartidningen. - 0023-7205 .- 1652-7518. ; 113, s. 1532-1536
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Journal article (peer-reviewed)abstract
- Katarakt definieras som nedsatt syn på grund av en optisk störning i ögats lins.Cirka 50 procent av kataraktsjukdomen antas associerad med genetiska faktorer.Ultraviolett strålning är epidemiologiskt starkt associerad med barkkatarakt, och rökning med kärnkatarakt.Störning av proteinkoncentrationsgradienten i linsen orsakar ljusspridning.Kemiska förändringar i linsens vattenlösliga proteiner kan orsaka aggregation av dessa.Betydande teknisk utveckling inom kataraktkirurgi reflekteras i en linjär ökning av antalet kataraktoperationer i Sverige under de senaste 35 åren.I snö och vid vatten bör solglasögon av filterkategori 3 användas för att skydda ögonen.
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| 8. |
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| 9. |
- Söderberg, Per, 1956-, et al.
(author)
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Optic nerve head morphometry for glaucoma diagnosis, optimization of clinical measurement strategy
- 2019
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In: Proceedings of SPIE. - : SPIE. - 0277-786X. ; 10858, s. 45:1-45:8
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Journal article (peer-reviewed)abstract
- The present study aimed to develop a strategy for evaluation of instant PIMD-2 pi measurements as a basis for clinical monitoring of glaucoma. PIMD-2 pi is a morphometric measure of the waist of the nerve fiber layer at the optic nerve head (ONH). Clinical measurements of PIMD-2 pi in patients with early to moderate stage glaucoma demonstrated a high variability among subjects. The high variability among subjects renders comparison of instant PIMD-2 pi measurements to tolerance limits for normality derived from a normative database inefficient. It is suggested to instead compare sequential measurements of PIMD-2 pi within a patient. Initially, the difference between an instant measurement and the average of previous measurements can be compared to tolerance limits for difference between measurements within subject. Once, a potential loss of PIMD-2 pi is detected, a sufficient number of measurements within a sufficiently wide time interval can be used to estimate the PIMD-2 pi loss rate with regression and the deviation of the estimated loss rate can be evaluated as a 95 % confidence interval for the loss rate. If the upper confidence limit excludes 0, a significant loss rate has been detected. The currently proposed strategy has the potential to detect glaucoma earlier than the current gold standard, computer perimetry, with less inconvenience for the patient.
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