Assessment of changes in eye redness by a photographic method and the relation to sensory eye irritation

Is indoor environment a risk factor of building-related symptoms?

The indoor environment, particularly indoor air quality (IAQ), is significantly associated with building-related symptoms (BRSs) in humans. In our previous studies, we demonstrated a significant relationship between BRSs and indoor chemical concentrations. In Japan, the Ministry of Health, Labor, and Welfare (MHLW) guideline recommends an air quality target of 13 volatile organic compounds (VOCs) and a provisional target of 400 μg/m3 for total VOCs (TVOC). The objective of this study was to determine the relationship between TVOC levels and the risk of BRSs using the Japanese provisional target TVOC level of 400 μg/m3. The relationship between odor intensity and BRSs while the TVOC levels were under 400 μg/m3 was also examined. The study was conducted in a laboratory house (LH) on the campus of Chiba University from 2017-2019. The study included 149 participants who spent 60 minutes in the LH. The participants were asked to evaluate the IAQ of the LH. A significant relationship between the risk of BRSs and the provisional target TVOC level was observed (odds ratio: 2.94, 95% confidence interval: 1.18-7.35). Furthermore, a significant relationship between odor intensity and risk of BRSs in spaces with TVOC levels less than 400 μg/m3 was detected (odds ratio: 6.06, 95% confidence interval: 1.21-30.44). In conclusion, the risk of BRSs is significantly lower in spaces with low TVOC levels and low odor intensity. Reducing the concentration of airborne chemicals and odor intensity may improve IAQ and prevent BRSs.

Neurobiological and Pharmacological Perspectives of D3 Receptors in Parkinson’s Disease

The discovery of the D3 receptor (D3R) subtypes of dopamine (DA) has generated an understandable increase in interest in the field of neurological diseases, especially Parkinson’s disease (PD). Indeed, although DA replacement therapy with l-DOPA has provided an effective treatment for patients with PD, it is responsible for invalidating abnormal involuntary movements, known as L-DOPA-induced dyskinesia, which constitutes a serious limitation of the use of this therapy. Of particular interest is the finding that chronic l-DOPA treatment can trigger the expression of D1R–D3R heteromeric interactions in the dorsal striatum. The D3R is expressed in various tissues of the central nervous system, including the striatum. Compelling research has focused on striatal D3Rs in the context of PD and motor side effects, including dyskinesia, occurring with DA replacement therapy. Therefore, this review will briefly describe the basal ganglia (BG) and the DA transmission within these brain regions, before going into more detail with regard to the role of D3Rs in PD and their participation in the current treatments. Numerous studies have also highlighted specific interactions between D1Rs and D3Rs that could promote dyskinesia. Finally, this review will also address the possibility that D3Rs located outside of the BG may mediate some of the effects of DA replacement therapy.

Validation of Computerized Quantification of Ocular Redness

Purpose

To show feasibility of computerized techniques for ocular redness quantification in clinical studies, and to propose an automatic, objective method.

Methods

Software for quantification of redness of the bulbar conjunctiva was developed. It provides an interface for manual and automatic sclera segmentation along with automated alignment of region of interest to enable estimation of changes in redness. The software also includes the redness scoring methods: (1) contrast-limited adaptive histogram equalization (CLAHE) in red-green-blue (RGB) color model, (2) product of saturation and hue in hue-saturation-value (HSV), and (3) average of angular sections in HSV. Our validation pipeline compares the scoring outcomes from the perspectives of segmentation reliability, segmentation precision, segmentation automation, and the choice of redness scoring methods.

Results

Ninety-two photographs of eyes before and after provoked redness were evaluated. Redness in manually segmented images was significantly different within human observers (interobserver, P = 0.04) and two scoring sessions (intraobserver, P < 0.001). Automated segmentation showed the smallest variability, and can therefore be seen as a robust segmentation method. The RGB-based scoring method was less sensitive in redness assessment.

Conclusions

Computation of ocular redness depends heavily on sclera segmentation. Manual segmentation appears to be subjective, resulting in systematic errors in intraobserver and interobserver settings. At the same time, automatic segmentation seems to be consistent. The scoring methods relying on HSV color space appeared to be more consistent.

Translational Relevance

Computerized quantification of ocular redness holds great promise to objectify ocular redness in the standard clinical care and, in particular, in clinical trials.

Reliability of a New Symptom Score in a Titrated Quantitative Conjunctival Provocation Test Supported by an Objective Photodocumentation

BACKGROUND

Allergen provocation tests are useful methods for proving the clinical relevance of an allergen-specific sensitization. Among these methods, the conjunctival provocation test (CPT) represents an easy-to-use tool. However, its readout parameters have not yet been internationally standardized or validated. Photodocumentation has been shown as a good option for objectifying a CPT reaction, supporting the local investigator assessment. Based on test-retest reliability of the score and an objective digital photoanalysis of the conjunctival redness, this study aimed to prove the reproducibility of a new CPT scoring system for use in clinical trials (ClinicalTrials.gov identifier: NCT02690740).

METHODS

A titrated quantitative CPT was conducted outside of the pollen season in a final cohort of 23 adult patients with birch or grass pollen-induced allergic rhinoconjunctivitis. Conjunctival symptoms were analyzed using a standardized symptom score. Conjunctival redness was also evaluated by an external observer and correlated with a digital photoanalysis using MATLAB software.

RESULTS

A test-retest correlation of 0.6 (p < 0.01) was found for the symptom score results. Likewise, a correlation of 0.65 (p < 0.01) was observed in the digital photoanalysis. The total symptom score showed a decrease in the mean value of 0.48 score points in the retest.

CONCLUSIONS

This study reveals both a valuable test-retest correlation of the proposed score as well as a good correlation of eye redness with the (objective) photodocumentation. Based on our results, we can recommend the use of this scoring system as a valuable clinical protocol for future clinical trials.

Objectifying the conjunctival provocation test: photography-based rating and digital analysis

BACKGROUND

Patients with allergic rhinoconjunctivitis are susceptible to both nasal and ocular symptoms. The conjunctival provocation test (CPT) is an established diagnostic procedure used in allergic rhinoconjunctivitis, particularly to document a patient's current reactivity to allergens. To date, there are no international guidelines defining the CPT. No approved evaluation method exists for interpreting CPT results. This paper aims to establish the digital analysis of macroimages as an objective, validated and standardized method for interpreting CPT results.

METHODS

In a clinical immunotherapy trial with 155 patients, treatment progress was documented based on the CPT. Local investigators used a symptom score to grade tearing, reddening and the patients' subjective perception of symptoms (mucosal irritation). A central observer rated conjunctival hyperemia via digital photography. Digital image analysis software was utilized to determine conjunctival hyperemia.

RESULTS

Spearman's correlation between the local investigators' and the central observer's ratings was r = 0.729 (p < 0.001); the percentage of total agreement was 48% (based on 739 photos). Digital image analysis (based on 48 photos) had a high percentage of total agreement with the central observer's ratings (69%) but a low percentage of total agreement with the investigators' ratings (38%). The corresponding correlations were r = 0.264 and 0.064, respectively.

CONCLUSION

Photography-based rating by a central observer may represent a valuable supplement to the local investigator's assessment for making an objective evaluation of CPT results. Digital image analysis possesses the potential of being an objective evaluation method compared to the wide-spread subjective evaluation by the investigators.

Assessment of Upper Respiratory Tract and Ocular Irritative Effects of Volatile Chemicals in Humans

Accurate assessment of upper respiratory tract and ocular irritation is critical for identifying and remedying problems related to overexposure to volatile chemicals, as well as for establishing parameters of irritation useful for regulatory purposes. This article (a) describes the basic anatomy and physiology of the human upper respiratory tract and ocular mucosae, (b) discusses how airborne chemicals induce irritative sensations, and (c) reviews practical means employed for assessing such phenomena, including psychophysical (e.g., threshold and suprathreshold perceptual measures), physiological (e.g., cardiovascular responses), electrophysiological (e.g., event-related potentials), and imaging (e.g., magnetic resonance imaging) techniques. Although traditionally animal models have been used as the first step in assessing such irritation, they are not addressed here since (a) there are numerous reviews available on this topic and (b) many rodents and rabbits are obligate nose breathers whose nasal passages differ considerably from those of humans, potentially limiting generalization of animal-based data to humans. A major goal of this compendium is to inform the reader of procedures for assessing irritation in humans and to provide information of value in the continued interpretation and development of empirical databases upon which future reasoned regulatory health decisions can be made.

Evaluating the human response to chemicals: odor, irritation and non-sensory factors

Although airborne chemicals can directly elicit adverse reactions via stimulation of the olfactory and trigeminal nerves, such as sensory irritation of the mucous membranes of the eyes, nose and throat, an individual's subjective experience is often the result of a complex sequence of events involving those sensory, physiological signals and psychological processes involved in perception, memory and judgment. To evaluate the contribution of these processes, an information-processing model of chemosensory perception is introduced. The model incorporates (1) the perception of odor and trigeminal irritation, and accompanying physiological and somatic changes that follow directly from the encounter with volatile organic compounds (VOCs) in the environment (bottom-up processing), and (2) any physiological/ somatic changes and subjective experiences of irritancy that are influenced by cognitive processes that have been primed by the perception of odor (top-down processing). The model is illustrated with data from our laboratory, and its utility in the context of setting occupational exposure limits is discussed.

Assessment of ocular and nasal irritation in asthmatics resulting from fragrance exposure

BACKGROUND

Many asthmatics report worsening of symptoms following exposure to odours and sensory irritants commonly found in household and cosmetic products. Despite this, little evidence exists to confirm the degree to which such subjective reports are correlated with localized, objective changes in the upper or lower airways following a fragranced product exposure.

OBJECTIVE

Subjective symptom reports were compared to objective measures in mild asthmatics, moderate asthmatics and non-asthmatics following exposure to one of two fragranced household aerosol mixtures and a clean air control condition to determine if asthmatics reported greater subjective symptoms of nasal congestion or exhibited objective measures of elevated ocular irritation and nasal congestion following exposure than did healthy controls.

METHODS

Measures of nasal mucosal swelling, using acoustic rhinometry, and photographic assessments of ocular hyperemia, using macro-photography, were taken before exposure, immediately after an initial 5-min exposure and again following a 30-min exposure to either of two, fragranced aerosol products and a clean air control. Self-reports of nasal patency at each time-point were also obtained.

RESULTS

Although moderate asthmatics tended to report more nasal congestion following fragranced product exposure than did non-asthmatics, no exposure-related changes in ocular redness or nasal mucosal swelling were observed among the three groups. Spirometry readings also failed to show evidence of any exposure-related changes in pulmonary function.

CONCLUSION

Despite claims that exposure to fragranced products may trigger ocular and respiratory symptoms among asthmatics, we found no evidence that 30 min of exposure to one of two fragranced aerosols elicited objective adverse effects in the ocular or nasal mucosa of mild and moderate asthmatics. While physiological mechanisms of fragrance impact may yet be responsible for some of the adverse reports among asthmatics following fragrance exposure, such reports may also reflect a non-physiological locus of symptom perception triggered by other sensory cues.

Effects in the eyes caused by exposure to office dust

This Danish Office Dust Experiment compares the responses of 24 normal non-sensitive adult subjects to exposure to normal office dust in the air at 136 and 390 micrograms/m3 (median) and to their responses in clean air. The exposure duration was 5 1/4 h in a climate chamber under controlled conditions. The dust had no major identifiable specific reactive compounds. The overall conclusion is that healthy subjects without any hypersensitive reactions seem to respond to exposure to the house dust. The effects observed were all found in interaction with response modifying factors. The effects were a decrease in inflammatory cells in tear fluids, increased epithelium defects, and a decrease in break-up time. No effect was seen on eye reddening, or eye sensitivity to CO2. As no specific hypotheses could be specified before the study for the observed interactions, no definitive conclusions can be made. Furthermore, it seemed that there was no consistency in the interacting factors after the exposure and the next morning. A tentative analysis of the effects of the importance of personal characteristics showed that only a minority within the subject group may respond to the exposure. However, no common set of sensitivity measures could be defined for these responders.

Experimental exposure to methyl tertiary-butyl ether. II. Acute effects in humans

Methyl tertiary-butyl ether (MTBE) is widely used in gasoline as an oxygenate and octane enhancer. Acute effects, such as headache, nausea, and nasal and ocular irritation, have been associated with the exposure to gasoline containing MTBE. The aim of this study was to assess acute health effects up to the Swedish occupational exposure limit value, both with objective methods and a questionnaire. Ten healthy male volunteers were exposed to MTBE vapor for 2 h at three levels (5, 25, and 50 ppm), during light physical work (50 W). All subjects rated the degree of irritative symptoms, discomfort, and CNS effects before, during, and after all three exposure occasions using a questionnaire. Answers were given on a 100-mm visual analog scale, graded from "not at all" to "almost unbearable." Ocular (redness, tear film break-up time, self-reported tear film break-up time, conjunctival epithelial damage, and blinking frequency) and nasal (mouth and nasal peak expiratory flow, acoustic rhinometry, biochemical inflammatory markers, and cells in nasal lavage) measurements were performed mainly at the highest exposure level. The ratings of solvent smell increased dramatically (ratings up to 50% of the scale) as the volunteers entered the chamber and declined slowly with time (p < 0.05, repeated-measures ANOVA). All other questions were rated from "not at all" to "hardly at all" (0-10% of the scale) with no significant relation to exposure. The eye measurements showed no effects of MTBE exposure. Blockage index, a measure of nasal airway resistance calculated from the peak expiratory flows, increased significantly after exposure; however, the effect was not related to exposure level. In addition, a nonsignificant tendency of decreased nasal volume was seen in the acoustic rhinometry measurements, but with no clear dose-effect relationship. In conclusion, our study suggests no or minimal acute effects of MTBE vapor upon short-term exposure at relatively high levels.

Toxicokinetics and acute effects of MTBE and ETBE in male volunteers

Methyl tertiary butyl ether (MTBE) is widely used in gasoline as an oxygenator and octane enhancer. There is also an interest in using the ethyl tertiary butyl (ETBE) and methyl tertiary amyl (TAME) ethers. We measured the blood, water, and olive oil/air partition coefficients in vitro of MTBE, ETBE, TAME and tertiary butyl alcohol (TBA), a metabolite of MTBE and ETBE. The results indicate similar uptake and distribution behavior for the three ethers and a slight affinity for fatty tissues. The partition coefficients of TBA indicate that this metabolite is not excreted via the lungs to any great extent and that it is preferentially distributed in body water. Further, we exposed 10 healthy male volunteers to MTBE vapor at 5, 25 and 50 ppm for 2 h during light physical exercise. Uptake and disposition were studied by measuring MTBE and TBA in inhaled and exhaled air, blood and urine. Low uptake, high post-exposure exhalation, and low blood clearance indicate slow metabolism of MTBE relative to many other solvents. A low recovery of TBA in urine (below 1% of uptake) indicates further metabolism of TBA. The concentration of MTBE and TBA in blood was proportional to exposure level suggesting linear kinetics up to 50 ppm. The half life of 7-10 h in blood and urine indicates that TBA would be more suitable than the parent compound as a biomarker for MTBE exposure. Subjective ratings (discomfort, irritative symptoms, CNS effects) and eye (redness, tear film break-up time, conjunctival damage, blinking frequency) and nose (peak expiratory flow, acoustic rhinometry, inflammatory markers in nasal lavage) measurements indicated no or minimal effects of MTBE.

Automatic quantitative measurement of ocular hyperemia

Evaluation of ocular hyperemia has been an important assessment in research studies of effects of contact lenses, medications, and pollutants on the eye. Hyperemia has been difficult to quantitate objectively. The purpose of this study was to validate a computer based image analysis system to quantitate hyperemia automatically and objectively in pixelated images of the external eye using two measures, the percent of the red color, RR, and the fraction of pixels which are blood vessels, VA. Validation was against an established photographic reference scale of ocular hyperemia and against the clinical pharmacologic effects of 0.5% dapiprazole hydrochloride, known to increase hyperemia, and 2.5% phenylephrine hydrochloride, known to decrease hyperemia. Color transparencies from the reference scale were converted to digital images. Temporal and nasal regions of the external eye were imaged directly to magnetic disk before and after pharmacologic intervention. Custom software automatically excluded unwanted regions, and quantitative image analysis produced RR and VA. RR and VA were each correlated with the reference scale. For each region and for each pharmacologic intervention, the mean RR and the mean VA, respectively, were compared at time zero and at a mean elapsed time of 713 +/- 47 s. RR and VA consistently increased as the hyperemia in the reference scale increased. Pearson correlation coefficients were 0.98 and 0.99, respectively, (p < 0.01). At 713 +/- 47 s after each pharmacologic intervention, RR and VA increased and decreased as expected (p < 0.001). Thus, this study successfully validated the methodology against expert clinical judgment and was able to measure automatically and objectively clinical changes in ocular hyperemia.

Critical review: the health significance of environmental odor pollution

Environmental odor pollution problems generate a significant fraction of the publicly initiated complaints received by air pollution control districts. Such complaints can trigger a variety of enforcement activities under existing state and local statutes. However, because of the frequently transient timing of exposures, odor sources often elude successful abatement. Furthermore, because of the predominantly subjective nature of associated health complaints, air pollution control authorities may predicate their enforcement activities upon a judgment of the public health impact of the odor source. Noxious environmental odors may trigger symptoms by a variety of physiologic mechanisms, including exacerbation of underlying medical conditions, innate odor aversions, aversive conditioning phenomena, stress-induced illness, and possible pheromonal reactions. Whereas relatively consistent patterns of subjective symptoms have been reported among individuals who live near environmental odor sources, documentation of objective correlates to such symptoms would require as-yet unproven research tools. Therefore, given our current state of knowledge, any differential regulatory response to environmental odor pollution, which is based upon the distinction between community "annoyance reactions" and "health effects," is a matter of legal--not scientific--interpretation.