Automatic estimation of the cross-sectional area of the waist of the nerve fibre layer at the optic nerve head.

PURPOSE: Glaucoma 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. METHODS: In 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. RESULTS: The 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). CONCLUSIONS: The 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.

Assessing the safety of new germicidal far-UVC technologies.

The COVID-19 pandemic underscored the crucial importance of enhanced indoor air quality control measures to mitigate the spread of respiratory pathogens. Far-UVC is a type of germicidal ultraviolet technology, with wavelengths between 200 and 235 nm, that has emerged as a highly promising approach for indoor air disinfection. Due to its enhanced safety compared to conventional 254 nm upper-room germicidal systems, far-UVC allows for whole-room direct exposure of occupied spaces, potentially offering greater efficacy, since the total room air is constantly treated. While current evidence supports using far-UVC systems within existing guidelines, understanding the upper safety limit is critical to maximizing its effectiveness, particularly for the acute phase of a pandemic or epidemic when greater protection may be needed. This review article summarizes the substantial present knowledge on far-UVC safety regarding skin and eye exposure and highlights research priorities to discern the maximum exposure levels that avoid adverse effects. We advocate for comprehensive safety studies that explore potential mechanisms of harm, generate action spectra for crucial biological effects and conduct high-dose, long-term exposure trials. Such rigorous scientific investigation will be key to determining safe and effective levels for far-UVC deployment in indoor environments, contributing significantly to future pandemic preparedness and response.

Validity of the self-rated 36-item World Health Organization Disability Assessment Schedule (WHODAS) 2.0 as a measure of functioning in Swedish psychiatric outpatients.

PURPOSE: The aim of this study was to investigate concurrent validity of the Swedish self-rated 36-item World Health Organization Disability Assessment Schedule (WHODAS) 2.0 by comparison with professional Global Assessment of Functioning (GAF) ratings in psychiatric outpatients. MATERIAL AND METHODS: A cross-sectional convenience sample of 444 patients was recruited from their regular psychiatric outpatient settings. The patients filled out the WHODAS 2.0; their clinicians provided clinical information and performed GAF ratings blinded to the patients' assessments. Analyses of correlations, variance components, and ROC curves were performed to investigate the validity of the WHODAS 2.0 through comparison with the GAF. The variance component analyses included working status, psychosocial problems, number of diagnostic groups, and remission status. GAF ratings were separated as total (GAF-T), symptoms (GAF-S), and functioning (GAF-F). RESULTS: There was significant correlation (p < 0.001) between WHODAS 2.0 total and domain scores and GAF-S, GAF-F, and GAF-T ratings. The correlations varied from r = 0.29 to r = 0.48, with the highest being between GAF-F rating and WHODAS 2.0 total score. Repeating the analyses for separate diagnostic groups replicated the findings, though not for psychotic, substance-related, and eating disorders. The WHODAS 2.0 showed good ability to distinguish impaired functioning below a fixed GAF-T cut-off of 70 (area under the curve: 0.74-0.78). The explained variance was lower for the WHODAS 2.0 than for the GAF (38.9% vs. 59.2%). CONCLUSIONS: Concurrent validity was found when comparing the Swedish self-administered 36-item version of WHODAS 2.0 with the expert-rated GAF in psychiatric outpatients.

Evidence for validity of the Swedish self-rated 36-item version of the World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) in patients with mental disorders: a multi-centre cross-sectional study using Rasch analysis.

BACKGROUND: The World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) is a generic instrument for the assessment of functioning in six domains, resulting in a total health-related disability score. The aim of this study was to investigate the psychometric properties of the Swedish-language version of the self-rated 36-item version in psychiatric outpatients with various common psychiatric diagnoses using Rasch analysis. A secondary aim was to explore the correlation between two methods of calculating overall scores to guide clinical practice: the WHODAS simple (summative) model and the WHODAS complex (weighted) model. METHODS: Cross-sectional data from 780 Swedish patients with various mental disorders were evaluated by Rasch analysis according to the partial credit model. Bivariate Pearson correlations between the two methods of calculating overall scores were explored. RESULTS: Of the 36 items, 97% (35 items) were within the recommended range of infit mean square; only item D4.5 (Sexual activities) indicated misfit (infit mean square 1.54 logits). Rating scale analysis showed a short distance between severity levels and disordered thresholds. The two methods of calculating overall scores were highly correlated (0.89-0.99). CONCLUSIONS: The self-administered WHODAS 2.0 fulfilled several aspects of validity according to Rasch analysis and has the potential to be a useful tool for the assessment of functioning in psychiatric outpatients. The internal structure of the instrument was satisfactorily valid and reliable at the level of the total score but demonstrated problems at the domain level. We suggest rephrasing the item Sexual activities and revising the rating scale categories. The WHODAS simple model is easier to use in clinical practice and our results indicate that it can differentiate function among patients with moderate psychiatric disability, whereas Rasch scaled scores are psychometrically more precise even at low disability levels. Further investigations of different scoring models are warranted.

Psychometric evaluation of the Swedish self-rated 36-item version of WHODAS 2.0 for use in psychiatric populations - using classical test theory.

AIM: The aim of this study was to evaluate the reliability and validity of the Swedish version of the self-rated 36-item WHODAS 2.0 in patients from Swedish psychiatric outpatient settings, using classical test theory. METHODS: The 36-item WHODAS 2.0, together with the Sheehan Disability Scale (SDS), was filled in by a sample of 780 participating psychiatric patients: 512 (65.6%) women, 263 (33.7%) men, and 5 (0.6%) who did not report any sex. RESULTS: The internal consistency, measured by Cronbach's alpha, for the different domains of functioning were between 0.70 and 0.94, and interpreted as good. The confirmatory factor analysis (CFA) revealed two levels: the first level consisted of a general disability factor, while the second level consisted of the six domains of the scale, respectively. The model had borderline fit. There was a significant correlation between WHODAS 2.0 36-item and SDS (n = 395). The WHODAS 2.0 differed significantly between diagnostic groups. CONCLUSION: The present study demonstrates that the Swedish self-rated 36-item version of WHODAS 2.0, within a psychiatric outpatient population, showed good reliability and convergent validity. We conclude that the self-rated 36-item Swedish version of WHODAS 2.0 can be used for valid interpretations of disability in patients with psychiatric health conditions.

Variance components for PIMD-2π estimation of the optic nerve head and consequences in clinical measurements of glaucoma.

PURPOSE: To estimate the sources of variation for Pigment epithelium central limit-Inner limit of the retina Minimal Distance averaged over 2π (PIMD-2π), 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-2π. The magnitude of the sources of variation for PIMD-2π measurements was estimated with an analysis of variance. RESULTS: A 95% confidence interval for mean PIMD-2π was estimated to 215 ± 12 µm (df = 38). The estimated variance for subjects was 1280 µm2 . The within-subject estimated variance for occasions, volumes and segmentations was 10 µm2 , 30 µm2 and 40 µm2 , respectively. The within-subject variances were used to model follow-up of PIMD-2π over time. A linear loss rate of 0.05 of baseline PIMD-2π/year was assumed. A significant PIMD-2π 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-2π change from baseline can be detected in approximately 18 months. Detection of significant PIMD-2π loss in a subject requires knowledge of normal age loss and measurement variability.

A strategy for OCT estimation of the optic nerve head pigment epithelium central limit-inner limit of the retina minimal distance, PIMD-2π.

PURPOSE: To develop a semi-automatic algorithm for estimation of pigment epithelium central limit-inner limit of the retina minimal distance averaged over 2π radians (PIMD-2π) and to estimate the precision of the algorithm. Further, the variances in estimates of PIMD-2π were to be estimated in a pilot sample of glaucomatous eyes. METHODS: Three-dimensional cubes of the optic nerve head (ONH) were captured with a commercial SD-OCT device. Raw cube data were exported for semi-automatic segmentation. The inner limit of the retina was automatically detected. Custom software aided the delineation of the ONH pigment epithelium central limit resolved in 500 evenly distributed radii. Sources of variation in PIMD estimates were analysed with an analysis of variance. RESULTS: The estimated variance for segmentations and angles was 130 µm2 and 1280 µm2 , respectively. Considering averaging eight segmentations, a 95 % confidence interval for mean PIMD-2π was estimated to 212 ± 10 µm (df = 7). The coefficient of variation for segmentation was estimated at 0.05. In the glaucomatous eyes, the within-subject variance for captured volumes and for segmentations within volumes was 10 µm2 and 50 µm2 , respectively. CONCLUSION: The developed semi-automatic algorithm enables estimation of PIMD-2π in glaucomatous eyes with relevant precision using few segmentations of each captured volume.

Exploring the relationship between activities and emotional experience using a diary in a mental health inpatient setting.

Mental health inpatient milieus have repeatedly been found to be associated with passivity, social disengagement, and low levels of interaction with staff. However, little is known about patients' experiences related to different ward activities. In the present study, we aimed to study the reports of activities and associated experiences of patients admitted to acute psychiatric inpatient wards. Disengaged, inactive, and solitary activities were hypothesized to be associated with less reward and more distress than their counterparts. We also aimed to investigate if such activities predicted distress, and if they were associated with clinical severity. Participants (n = 102) recorded their activities along with concurrent ratings of reward and distress in a structured 1-day diary, and nurses provided clinical severity ratings. On average, 3.74 of the 11 hours assessed (34%) were spent doing nothing, only 0.88 hours (8%) were spent with staff, and most of the time was spent in solitude. Doing nothing, being alone, and passivity were associated with the greatest levels of distress and lowest levels of reward, whereas informal socializing demonstrated the opposite pattern. Distress was not predicted by activity or reward when adjusting for baseline distress. Clinical severity was not associated with the amount of time spent alone or the experience of reward during activity. In conclusion, the risk for passivity and social disengagement during admission prevails. This activity pattern could have detrimental emotional consequences and warrants action, but more studies are needed to determine if activity actually precedes emotional experience.

Objective automated quantification of fluorescence signal in histological sections of rat lens.

Visual quantification and classification of fluorescent signals is the gold standard in microscopy. The purpose of this study was to develop an automated method to delineate cells and to quantify expression of fluorescent signal of biomarkers in each nucleus and cytoplasm of lens epithelial cells in a histological section. A region of interest representing the lens epithelium was manually demarcated in each input image. Thereafter, individual cell nuclei within the region of interest were automatically delineated based on watershed segmentation and thresholding with an algorithm developed in Matlab™. Fluorescence signal was quantified within nuclei, cytoplasms and juxtaposed backgrounds. The classification of cells as labelled or not labelled was based on comparison of the fluorescence signal within cells with local background. The classification rule was thereafter optimized as compared with visual classification of a limited dataset. The performance of the automated classification was evaluated by asking 11 independent blinded observers to classify all cells (n = 395) in one lens image. Time consumed by the automatic algorithm and visual classification of cells was recorded. On an average, 77% of the cells were correctly classified as compared with the majority vote of the visual observers. The average agreement among visual observers was 83%. However, variation among visual observers was high, and agreement between two visual observers was as low as 71% in the worst case. Automated classification was on average 10 times faster than visual scoring. The presented method enables objective and fast detection of lens epithelial cells and quantification of expression of fluorescent signal with an accuracy comparable with the variability among visual observers. © 2017 International Society for Advancement of Cytometry.

Measuring temperature in the lens during experimental heat load indirectly as light scattering increase rate.

The current study aims to experimentally estimate the temperature in the lens due to heat load indirectly from the measurement of increases in the rate of temperature-induced light scattering. The lens was extracted from Sprague­Dawley rats and put into a temperature-controlled cuvette filled with a balanced salt solution. Altogether, 80 lenses were equally divided into four temperature groups. Each lens was exposed for 5 min to temperature depending on the group to which it belonged while the intensity of forward light scattering was recorded. The inclination coefficients of light scattering increase at the temperature of 37°C, 40°C, 43°C, and 46°C were estimated as a CI(0.95), 3.1 ± 0.8 , 4.4 ± 0.8 , 5.5 ± 0.9 , and 7.0 ± 0.8 × 10 ? 4 ?? tEDC / s , respectively. The Arrhenius equation implies that the natural logarithm of the inclination coefficient is linearly dependent on the inverse of the temperature. The proportionality constant and the intercept were 9.6 ± 2.4 × 10 3 ?? K and 22.8 ± 7.7 , respectively. The activation energy was 8.0 ± 2.0 × 10 1 ?? kJ · mol ? 1 . The current experiment implies that if averaging 20 measurements of inclination coefficients in a new experiment at constant heat load, the confidence limits for predicted temperature correspond to ± 1.9°C. With the proportionality constant and the intercept estimated in the current experiment, the in vivo temperature in the lens can be determined retrospectively with sufficient resolution.

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.

PURPOSE: To estimate the variation in measurements of neuro-retinal rim area (NRA) determined by confocal scanning laser tomography and consequences for clinical follow-up. METHODS: Altogether, 24 healthy subjects were randomized on -320 µm, 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 6.0 × 10-2  mm2 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. RESULTS: The 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 54 months of follow-up is required for detection of change from baseline. CONCLUSIONS: The 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.

Lamellar changes in the keratoconic cornea.

PURPOSE: The purpose of this study was to identify ultrastructural changes associated with ectasia and to determine the association between lamellar count and corneal thinning. METHODS: Five surgically removed keratoconic corneal buttons and four, non-keratoconic, normal eye bank control corneas were processed for transmission electron microscopy using an established protocol, ensuring minimal tissue distortion. A sequence of overlapping digital images, spanning the full apical cone corneal thickness, was assembled. A seamless digital montage was printed at 5000× magnification. Lamellae were counted in the anterior-posterior orientation, along a linear line, using established criteria for identification of individual lamellae. RESULTS: The stromal thickness estimated as a 95% confidence interval for the mean, CI (0.95), in the keratoconic corneas was 372 ± 62 µm, while in the normal cornea, it was 446 ± 89 µm. All keratoconic corneas showed ultrastructural evidence of lamellar splitting and a loss of interweaving anterior lamellae. In the keratoconic corneas, the median total linear stromal lamellar absolute count tangential to the corneal surface was 362, (25th percentile; 75th percentile) = (355; 365) lamellae and in the normal cornea, 246, (25th percentile; 75th percentile) = (239; 251). The linear lamellar density in the keratoconic corneas was estimated as CI (0.95) 117 ± 22 and 86 ±19 lamellae per 100 µm in the anterior and posterior portion of the stroma, respectively. In normal cornea, the linear lamellar density was estimated as CI (0.95) 51 ± 8 and 80 ± 20 lamellae per 100 µm. The mean difference of linear lamellar count between the anterior and the posterior portion of the cornea was estimated as CI (0.95) 31 ± 23 for keratoconic corneas and -29 ± 28 for the normal corneas. CONCLUSIONS: The current morphometric analysis of ultrastructural changes suggests that ectasia and thinning in keratoconus is associated with lamellar splitting into multiple bundles of collagen fibrils and loss of anterior lamellae. These structural changes, possibly in addition to lateral shifting of lamellae due to the pressure gradient over the cornea, are a potential explanation to the central loss of mass.

Temperature-controlled in vivo ocular exposure to 1090-nm radiation suggests that near-infrared radiation cataract is thermally induced.

The damage mechanism for near-infrared radiation (IRR) induced cataract is unclear. Both a photochemical and a thermal mechanism were suggested. The current paper aims to elucidate a photochemical effect based on investigation of irradiance-exposure time reciprocity. Groups of 20 rats were unilaterally exposed to 96-W/cm(2) IRR at 1090 nm within the dilated pupil accumulating 57, 103, 198, and 344 kJ/cm(2), respectively. Temperature was recorded at the limbus of the exposed eye. Seven days after exposure, the lenses were macroscopically imaged and light scattering was quantitatively measured. The average maximum temperature increases for exposure times of 10, 18, 33, and 60 min were expressed as 7.0 ± 1.1, 6.8 ± 1.1, 7.6 ± 1.3, and 7.4 ± 1.1 °C [CI (0.95)] at the limbus of the exposed eye. The difference of light scattering in the lenses between exposed and contralateral not-exposed eyes was 0.00 ± 0.02, 0.01 ± 0.03, -0.01 ± 0.02, and -0.01 ± 0.03 transformed equivalent diazepam concentration (tEDC), respectively, and no apparent morphological changes in the lens were observed. An exposure to 96-W/cm(2) 1090-nm IRR projected on the cornea within the dilated pupil accumulating radiant exposures up to 344 kJ/cm(2) does not induce cataract if the temperature rise at the limbus is <8 °C. This is consistent with a thermal damage mechanism for IRR-induced cataract.

Specific spatial distribution of caspase-3 in normal lenses.

PURPOSE: To determine the distribution of active caspase-3 in rat eye lens epithelium. METHODS: In total, 120 sagittal sections from forty rats were assessed for active caspase-3 labelling using immunohistochemistry. Lens epithelial cells were counted, and the fraction of active caspase-3 labelled cells and their relative positions were identified in each section. RESULTS: Active caspase-3 is present in normal lens epithelium. The active caspase-3 expression was higher in the anterior pole of the lens. Probability of radial spatial distribution of labelling was fitted with a logistic model. The increase rate and the inflection point were estimated as CI (0.95) to 23 ± 3 cells and 114 ± 3 cells, respectively. CONCLUSION: The gradually decreasing active caspase-3 labelling from the anterior pole to the periphery suggests that active caspase-3 may be involved in normal protein turnover caused by, for example, incident light.

1090 nm infrared radiation at close to threshold dose induces cataract with a time delay.

PURPOSE: To investigate whether infrared radiation (IRR)-induced cataract is instant or is associated with a time delay between the exposure and the onset of lens light scattering after an exposure to just above threshold dose. METHODS: Six-weeks-old albino Sprague-Dawley female rats were unilaterally exposed to 197 W/cm2 IRR at 1090 nm within the dilated pupil. In the first experiment, the animals were exposed with four exposure times of 5, 8, 13 and 20 second, respectively. At 24 hr after exposure, the light scattering in both exposed and contralateral not exposed lenses was measured. Based on the first experiment, four postexposure time groups were exposed unilaterally to 1090 nm IRR of 197 W/cm2 for 8 second. At 6, 18, 55 and 168 hr after exposure, the light scattering in both lenses was measured. RESULTS: A 197 W/cm2 IRR-induced light scattering in the lens with exposures of at least 8 second. Further, after exposure to IRR of 197 W/cm2 for 8 second, the light-scattering increase in the lens was delayed approximately 16 hr after the exposure. CONCLUSION: There is a time delay between the exposure and the onset of cataract after exposure to close to threshold dose implicating that either near IRR cataract is photochemical or there is a time delay in the biological expression of thermally induced damage.

Behavioral activation in acute inpatient psychiatry: a multiple baseline evaluation.

BACKGROUND AND OBJECTIVES: The present study employed a multiple baseline study design with repeated measures to explore clinical outcomes, therapy mechanisms, and feasibility of Behavioral Activation for persons admitted to inpatient psychiatry. METHODS: Six adult inpatients with depressive symptoms and different psychiatric disorders were randomized to different lengths of baseline standard inpatient treatment. Subsequently a 5-day, 10-session Behavioral Activation protocol was added. Daily self-report outcome and process measures were administered and supplemented with hourly self-reports and clinician assessments before and after each study phase. RESULTS: After a relatively stable baseline, at least four participants showed marked gradual improvements both in terms of outcome as well as activation and avoidance as Behavioral Activation was initiated. The temporal relation between process and outcome differed somewhat across metrics. In most instances however, change in activation and avoidance either coincided or preceded decreased depression. LIMITATIONS: We did not include some relatively common disorders, did not control for the effects of increased attention, did not investigate treatment integrity, and did not conduct follow-up after discharge. Raters were not blind and measures were mainly focused on depressive symptoms. All received concurrent medical treatment. CONCLUSIONS: This preliminary study further supports the promise of Behavioral Activation as an inpatient treatment for persons with a variety of psychiatric disorders. Results also lends preliminary support for the purported mechanisms of Behavioral Activation.

Cataract after repeated daily in vivo exposure to ultraviolet radiation.

Epidemiological data indicate a correlation between lifelong exposure to ultraviolet radiation and cortical cataract. However, there is no quantitative experimental data on the effect of daily repeated in vivo exposures of the eye to UVR. Therefore, this experiment was designed to verify whether the dose additivity for UVR exposures holds through periods of time up to 30 d. Eighty rats were conditioned to a rat restrainer 5 d prior to exposure. All animals were divided into four exposure period groups of 1, 3, 10, and 30 d of exposure to UVR. Each exposure period group of 20 animals was randomly divided into five cumulated UVR dose subgroups. Eighteen-wk-old non-anesthetized albino Sprague-Dawley rats were exposed daily to UVR-300 nm for 15 min. One week after the last exposure, animals were sacrificed. The lenses were extracted for macroscopic imaging of dark-field anatomy, and degree of cataract was quantified by measurement of the intensity of forward lens light scattering. Maximum tolerable dose (MTD(2.3:16)), a statistically defined standard for sensitivity for the threshold for UVR cataract, was estimated for each exposure period. Exposed lenses developed cataract with varying appearance on the anterior surface. Single low doses of UVR accumulated to cause cataract during periods up to 30 d. MTD(2.3:16) for 1, 3, 10, and 30 d of repeated exposures was estimated to 4.70, 4.74, 4.80, and 6.00 kJ m(-2), respectively. In conclusion, the lens sensitivity to UVR-B for 18-wk-old Sprague-Dawley rats decreases with the increasing number of days being exposed.

Ocular temperature elevation induced by threshold in vivo exposure to 1090-nm infrared radiation and associated heat diffusion.

An in vivo exposure to 197 W/cm 2 1090-nm infrared radiation (IRR) requires a minimum 8 s for cataract induction. The present study aims to determine the ocular temperature evolution and the associated heat flow at the same exposure conditions. Two groups of 12 rats were unilaterally exposed within the dilated pupil with a close to collimated beam between lens and retina. Temperature was recorded with thermocouples. Within 5 min after exposure, the lens light scattering was measured. In one group, the temperature rise in the exposed eye, expressed as a confidence interval (0.95), was 11±3°C at the limbus, 16±6°C in the vitreous behind lens, and 16±7°C on the sclera next to the optic nerve, respectively. In the other group, the temperature rise in the exposed eye was 9±1°C at the limbus and 26±11°C on the sclera next to the optic nerve, respectively. The difference of forward light scattering between exposed and contralateral not exposed eye was 0.01±0.09 tEDC. An exposure to 197 W/cm 2 1090-nm IRR for 8 s induces a temperature increase of 10°C at the limbus and 26°C close to the retina. IRR cataract is probably of thermal origin.

Modelling the time evolution of active caspase-3 protein in the rat lens after in vivo exposure to ultraviolet radiation-B.

PURPOSE: To introduce a model for the time evolution of active caspase-3 protein expression in albino rat lens up to 24 hours after in vivo exposure to low dose UVR in the 300 nm wavelength region (UVR-300 nm). METHODS: Forty Sprague-Dawley rats were unilaterally exposed in vivo to 1 kJ/m2 UVR-300 nm for 15 minutes. At 0.5, 8, 16, and 24 hours after the UVR exposure, the exposed and contralateral not-exposed lenses were removed and processed for immunohistochemistry. The differences in the probability of active caspase-3 expression at four different time points after exposure were used to determine the time evolution of active caspase-3 expression. A logistic model was introduced for the expression of active caspase-3. The parameters for the exposed and the not exposed lenses were estimated for the observation time points. RESULTS: The exposure to UVR-300 nm impacted on the parameters of the logistic model. Further, the parameters of the model varied with time after exposure to UVR-300 nm. CONCLUSION: The logistic model predicts the impact of exposure to UVR-300 nm on the spatial distribution of probability of active caspase-3 protein expression, depending on time.

Topically applied caffeine induces miosis in the ketamine/xylazine anesthetized rat.

The aim of the present study was to examine if topically applied caffeine influences pupil size in ketamine/xylazine anesthetized animals. Two experiments were carried out. In the first experiment, caffeine was topically applied to one of the eyes of 10 ketamine/xylazine anesthetized animals, while vehicle only was topically applied to the contralateral eye. In the second experiment, caffeine was topically applied to both eyes in one group of 10 ketamine/xylazine anesthetized rats, while in another group both eyes vehicle only was topically applied to both eyes. In both experiments pupil diameter was measured at 0, 10, 20, 40 and 60 min after topical application. In three of the animals, the pupil was dilated with tropicamide 5 mg/ml at 60 min after the topical application of caffeine and the pupil diameter was measured. The first experiment showed a relative miosis in caffeine treated eyes as compared to the vehicle treated eye, that changed over time. The second experiment in line with the first experiment, also showed that topically applied caffeine causes a relative miosis as compared to vehicle only that changes over time. Eyes treated with caffeine reacted with quick dilatation after tropicamide application. Topical caffeine antagonizes ketamine/xylazine anesthesia induced mydriasis in a time dependent manner.