Neuropathological comorbidity associated with argyrophilic grain disease.

Argyrophilic grain disease (AGD) is a common four-repeat tauopathy in elderly people. While dementia is a major clinical picture of AGD, recent studies support the possibility that AGD may be a pathological base in some patients with mild cognitive impairment, late-onset psychosis, bipolar disorder and depression. AGD often coexists with various other degenerative changes. The frequency of AGD in progressive supranuclear palsy (PSP) cases was reported to range from 18.8% to 80%. The frequency of AGD in corticobasal degeneration (CBD) cases tends to be higher than that in PSP cases, ranging from 41.2% to 100%. Conversely, in our previous study of the frequencies of mild PSP and CBD pathologies in AGD cases, five of 20 AGD cases (25%) had a few Gallyas-positive tufted astrocytes, six cases (30%) had a few granular/fuzzy astrocytes, and one case (5.0%) had a few Gallyas-positive astrocytic plaques in the putamen, caudate nucleus and/or superior frontal gyrus. Both Gallyas-positive tufted astrocytes and Gallyas-negative tau-positive granular/fuzzy astrocytes preferentially developed in the putamen, caudate nucleus and superior frontal cortex in AGD cases, being consistent with the predilection sites of Gallyas-positive tufted astrocytes in PSP cases. Further, in AGD cases, the quantities of Gallyas-positive tufted astrocytes, overall tau-positive astrocytes, and tau-positive neurons in the subcortical nuclei and superior frontal cortex were significantly correlated with Saito AGD stage, respectively. The frequency of AGD in AD cases was reported to reach up to 25% when using four-repeat tau immunohistochemistry. Pretangles are essential pathologies in AGD; however, the Braak stage of three-repeat tau-positive NFTs, which may indicate mild AD pathology or primary age-related tauopathy, was not correlated with Saito AGD stage. Clinicians should be aware of the possibility that coexisting AGD may impact clinical and radiological features in cases of other degenerative diseases.

Astrocytic Tau Pathologies in Argyrophilic Grain Disease and Related Four-repeat Tauopathies.

Neurodegenerative diseases in which tau accumulation plays a cardinal role in the pathogenic process are called tauopathies, and when tau isoforms having four repeats of the microtubule binding sites, four-repeat tau, are selectively accumulated as pathological hallmarks, the term four-repeat tauopathy is used. The major four-repeat tauopathies are progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), and argyrophilic grain disease (AGD). Historically, neuronal cytopathologies, e.g., neurofibrillary tangles and ballooned neurons, were emphasized as characteristic lesions in PSP and CBD. Now, however, astrocytic tau pathologies, i.e., tufted astrocytes (TAs) and astrocytic plaques (APs), are considered to be highly disease-specific lesions. Although granular/fuzzy astrocytes (GFAs) frequently develop in the limbic system in AGD cases, the specificity is not conclusive yet. Some AGD cases have a few TAs, and to a lesser frequency, a few APs in the frontal cortex and subcortical nuclei. The number of astrocytic tau pathologies including TAs and GFAs increases with the progression of AGD. In this paper, histopathological features of astrocytic tau pathologies in PSP, CBD, and AGD are first reviewed. Then, recent findings regarding the coexistence of these tauopathies are summarized from a viewpoint of astrocytic tau pathologies. Further biochemical and pathological studies focusing tau-positive astrocytic lesions may be useful to increase understanding of the pathological process in four-repeat tauopathies and to develop novel therapeutic strategies for patients with these diseases.

Pick's disease with neuronal four-repeat tau accumulation in the basal ganglia, brain stem nuclei and cerebellum.

It is very rare that cases of Pick's disease, a representative three-repeat (3R) tauopathy, also have significant four-repeat (4R) tau accumulation. Here, we report a Pick's disease case that clinically showed behavioral variant frontotemporal dementia without motor disturbance during the course, and pathologically had 3R tau-positive Pick bodies as well as numerous 4R tau-positive neuronal cytoplasmic inclusions (NCIs). Abundant 3R tau-positive 4R tau-negative spherical or horseshoe-shaped Pick bodies were found in the frontotemporal cortex, limbic region, striatum and pontine nucleus. On the other hand, many 4R tau-positive, 3R tau-negative, Gallyas-negative dot-, rod- or intertwined skein-like NCIs were found mainly in the subthalamic nucleus, pontine nucleus, inferior olivary nucleus and cerebellar dentate nucleus. Tufted astrocytes, astrocytic plaques, argyrophilic grains or globular glial inclusions were absent. Double-labeling immunofluorescence demonstrated that 3R tau was hardly accumulated in 4R tau-positive inclusions. On tau immunoblotting, while 60 and 64 kDa bands were demonstrated in the frontal cortex, 60, 64 and 68 kDa bands, as well as the 33 kDa tau fragments that are reported to be characteristic of progressive supranuclear palsy brains, were found in the basal ganglia and cerebellum. No mutation was identified in the tau gene. The present case suggests that, although probably rare, some Pick's disease cases have non-negligible 4R tau pathology in the subcortical nuclei, and that such 4R tau pathology can affect the evaluation of the distribution of AT8-positive tau pathology in Pick's disease cases.

Genotype-phenotype relationships in familial amyotrophic lateral sclerosis with FUS/TLS mutations in Japan.

INTRODUCTION: We investigated possible genotype-phenotype correlations in Japanese patients with familial amyotrophic lateral sclerosis (FALS) carrying fused in sarcoma/translated in liposarcoma (FUS/TLS) gene mutations. METHODS: A consecutive series of 111 Japanese FALS pedigrees were screened for copper/zinc superoxide dismutase 1 (SOD1) and FUS/TLS gene mutations. Clinical data, including onset age, onset site, disease duration, and extramotor symptoms, were collected. RESULTS: Nine different FUS/TLS mutations were found in 12 pedigrees. Most of the patients with FUS/TLS-linked FALS demonstrated early onset in the brainstem/upper cervical region, and relatively short disease duration. A few mutations exhibited phenotypes that were distinct from typical cases. Frontotemporal dementia was present in 1 patient. CONCLUSIONS: This study revealed a characteristic phenotype in FUS/TLS-linked FALS patients in Japan. FUS/TLS screening is recommended in patients with FALS with this phenotype. Muscle Nerve 54: 398-404, 2016.

Regional Differences in Tear Film Stability and Meibomian Glands in Patients With Aqueous-Deficient Dry Eye.

OBJECTIVES: To noninvasively investigate regional differences in tear film stability and meibomian glands in patients with aqueous-deficient dry eye. METHODS: Forty-nine dry eyes and 31 normal eyes were analyzed. A corneal topographer with a tear film scanning function was used for noninvasive tear film break-up time (NI-TFBUT) measurements and meibomian gland observations. The NI-TFBUT values and location of the first tear film break-up point were recorded in four quadrants. Meibomian gland loss was graded for each eyelid using meiboscores. Lid margin abnormality was scored from zero to four according to the number of existing abnormalities. The NI-TFBUT values and meiboscores were compared between two groups, and regional differences in NI-TFBUT values and meiboscores were analyzed. Also, the correlation between the NI-TFBUT and ocular surface examination results were investigated. RESULTS: The NI-TFBUT values and meiboscores were significantly lower and higher, respectively, for the dry eye group than for the normal group. In the dry eye group, the occurrence rate for first tear film break-up was the highest in the inferior nasal quadrant, and the mean meiboscore was significantly higher for the upper eyelids than for the lower eyelids. The NI-TFBUT and lid margin abnormality scores showed a weak negative correlation, and the NI-TFBUT values and meiboscores showed no correlation. CONCLUSIONS: Compared to normal eyes, aqueous-deficient dry eyes show significant regional differences in tear film stability and meibomian glands. Considering these regional differences, the overall observation of the ocular surface, including both upper and lower eyelids, will aid clinicians in understanding this condition better.

Development and evaluation of a short version of the quality of life questionnaire for dementia.

BACKGROUND: There are many quality of life (QOL) instruments for evaluating dementia patients. The QOL questionnaire for Dementia (QOL-D) is one of such instruments and a validated objective measure of QOL for patients with dementia. It comprises 31 items encompassing six domains. However, with 31 items, its length is a disadvantage. The purpose of this study was to develop a short version of QOL-D (short QOL-D). METHODS: We used data from two studies. The participants were 264 inpatients with dementia in the first sample and 395 outpatients at a memory clinic in the second sample. We used maximum likelihood factor analysis with promax rotation to reduce the number of items. RESULTS: We produced a nine-item version of QOL-D (short QOL-D) with positive (six items) and negative (three items) dimensions. The correlation coefficients of short and total versions of QOL-D were 0.892-0.918 for total scores, 0.903-0.936 for positive dimension scores, and 0.788-0.837 for negative dimension scores. Total short QOL-D scores showed a significant correlation to the Geriatric Depression Scale score and the apathy score of the Neuropsychiatric Inventory. CONCLUSIONS: The short QOL-D produced results comparable with that of the full version. Reducing the number of items may make administration of the instrument easier.

Argyrophilic grain disease as a neurodegenerative substrate in late-onset schizophrenia and delusional disorders.

To study the relationship between neurodegenerative diseases including argyrophilic grain disease (AGD) and late-onset schizophrenia and delusional disorders (LOSD; onset ≥40 years of age), we pathologically examined 23 patients with LOSD, 71 age-matched normal controls, and 22 psychiatric disease controls (11 depression, six personality disorder, two bipolar disorders, and three neurotic disorders cases). In all LOSD cases (compared to age-matched normal controls), the frequencies of Lewy body disease (LBD), AGD, and corticobasal degeneration (CBD) were 26.1 % (11.3 %), 21.7 % (8.5 %), and 4.3 % (0.0 %), respectively. There was no case of pure Alzheimer's disease (AD). The total frequency of LBD, AGD, and CBD was significantly higher in LOSD cases than in normal controls. Argyrophilic grains were significantly more severe in LOSD than in controls, but were almost completely restricted to the limbic system and adjacent temporal cortex. In LOSD patients whose onset occurred at ≥65 years of age (versus age-matched normal controls), the frequencies of LBD and AGD were 36.4 % (19.4 %) and 36.4 % (8.3 %), respectively, and AGD was significantly more frequent in LOSD patients than in normal controls. In LOSD patients whose onset occurred at <65 years of age, the frequencies of LBD, AGD, and CBD were 16.7, 8.3, and 8.3 %, comparable to those of age-matched normal controls (10.2, 5.1, and 0.0 %). In all psychiatric cases, delusion was significantly more frequent in AGD cases than in cases bearing minimal AD pathology alone. Given these findings, LOSD patients may have heterogeneous pathological backgrounds, and AGD may be associated with the occurrence of LOSD especially after 65 years of age.

Subjective depressive mood and regional cerebral blood flow in mild Alzheimer's disease.

BACKGROUND: Depressive symptoms are common in patients with Alzheimer's disease (AD) and increase the caregiver burden, although the etiology and pathologic mechanism of depressive symptoms in AD patients remain unclear. In this study, we tried to clarify the cerebral blood flow (CBF) correlates of subjective depressive symptoms in AD. METHODS: Seventy-six consecutive patients with AD were recruited from outpatient units of the Memory Clinic of Okayama University Hospital. Subjective depressive symptoms were evaluated using the short version of the Geriatric Depression Scale (GDS). All patients underwent brain SPECT with 99mTc-ethylcysteinate dimer, and the SPECT images were analyzed by the Statistical Parametric Mapping 8 program. RESULTS: No significant differences between groups with high and low GDS scores were found with respect to age, sex, years of education, and revised Addenbrooke's Cognitive Examination scores. Compared to patients with low scores on GDS, patients with high scores showed significant hypoperfusion in the left inferior frontal region. CONCLUSIONS: The left inferior frontal region may be significantly involved in the pathogenesis of subjective depressive symptoms in AD. Subjective and objective depressive symptoms may have somewhat different neural substrates in AD.

Corticobasal degeneration initially developing motor versus non-motor symptoms: a comparative clinicopathological study.

BACKGROUND: Clinical presentations of pathologically confirmed corticobasal degeneration (CBD) vary, and the heterogeneity makes its clinical diagnosis difficult, especially when a patient lacks any motor disturbance in the early stage. METHODS: We compared clinical and pathological features of four pathologically confirmed CBD cases that initially developed non-motor symptoms, including behavioural and psychiatric symptoms but without motor disturbance (CBD-NM), and five CBD cases that initially developed parkinsonism and/or falls (CBD-M). The age range at death for the CBD-NM and CBD-M subjects (58-85 years vs 45-67 years) and the range of disease duration (2-18 years vs 2-6 years) did not significantly differ between the groups. RESULTS: Prominent symptoms in the early stage of CBD-NM cases included self-centred behaviours such as frontotemporal dementia (n = 1), apathy with and without auditory hallucination (n = 2), and aggressive behaviours with delusion and visual hallucination (n = 1). Among the four CBD-NM cases, only one developed asymmetric motor disturbance, and two could walk without support throughout the course. Final clinical diagnoses of the CBD-NM cases were frontotemporal dementia (n = 2), senile psychosis with delirium (n = 1), and schizophrenia (n = 1). Neuronal loss was significantly less severe in the subthalamic nucleus and substantia nigra in the CBD-NM cases than in the CBD-M cases. The severity of tau pathology in all regions examined was comparable in the two groups. CONCLUSION: CBD cases that initially develop psychiatric and behavioural changes without motor symptoms may have less severe degenerative changes in the subthalamic nucleus and substantia nigra, and some CBD cases can lack motor disturbance not only in the early stage but also in the last stage of the course.

Multidimensional analysis of schoolteachers' occupational stress by the New Brief Job Stress Questionnaire: focusing on gender differences.

This study investigated teachers' occupational stress using a comprehensive job stress questionnaire, or the New Brief Job Stress Questionnaire, while considering gender differences. A total of 1,825 elementary and junior high school teachers participated in the study. The results revealed that female teachers significantly exhibited more psychological and physical stress reactions and perceived less job resource availability than did male teachers. Moreover, multiple regression analyses demonstrated that support from family and friends was a larger factor associated with mental health outcomes among female teachers than among male teachers. The impacts of marital status also differed between male and female teachers. Job demands were strongly associated with psychological and physical stress reactions among teachers. Meanwhile, job resources were more strongly associated with positive workplace outcomes, such as workplace engagement and social capital, than were job demands. Administrators should consider the distinctive nature of teachers' occupational stress in addition to its gender specific influence. Organizational support, such as securing teachers' autonomy, encouraging their career development, and acknowledging diversity, should be considered to foster teachers' work engagement and create a cohesive environment in the school workplace.

Pure argyrophilic grain disease revisited: independent effects on limbic, neocortical, and striato-pallido-nigral degeneration and the development of dementia in a series with a low to moderate Braak stage.

Agyrophilic grains (AGs) are age-related limbic-predominant lesions in which four-repeat tau is selectively accumulated. Because previous methodologically heterogeneous studies have demonstrated inconsistent findings on the relationship between AGs and dementia, whether AGs affect cognitive function remains unclear. To address this question, we first comprehensively evaluated the distribution and quantity of Gallyas-positive AGs and the severity of neuronal loss in the limbic, neocortical, and subcortical regions in 30 cases of pure argyrophilic grain disease (pAGD) in Braak stages I-IV and without other degenerative diseases, and 34 control cases that had only neurofibrillary tangles with Braak stages I-IV and no or minimal Aß deposits. Then, we examined whether AGs have independent effects on neuronal loss and dementia by employing multivariate ordered logistic regression and binomial logistic regression. Of 30 pAGD cases, three were classified in diffuse form pAGD, which had evident neuronal loss not only in the limbic region but also in the neocortex and subcortical nuclei. In all 30 pAGD cases, neuronal loss developed first in the amygdala, followed by temporo-frontal cortex, hippocampal CA1, substantia nigra, and finally, the striatum and globus pallidus with the progression of Saito AG stage. In multivariate analyses of 30 pAGD and 34 control cases, the Saito AG stage affected neuronal loss in the amygdala, hippocampal CA1, temporo-frontal cortex, striatum, globus pallidus, and substantia nigra independent of the age, Braak stage, and limbic-predominant age-related TDP-43 encephalopathy (LATE-NC) stage. In multivariate analyses of 23 pAGD and 28 control cases that lacked two or more lacunae and/or one or more large infarctions, 100 or more AGs per × 400 visual field in the amygdala (OR 10.02, 95% CI 1.12-89.43) and hippocampal CA1 (OR 12.22, 95% CI 1.70-87.81), and the presence of AGs in the inferior temporal cortex (OR 8.18, 95% CI 1.03-65.13) affected dementia independent of age, moderate Braak stages (III-IV), and LATE-NC. Given these findings, the high density of limbic AGs and the increase of AGs in the inferior temporal gyrus may contribute to the occurrence of dementia through neuronal loss, at least in cases in a low to moderate Braak stage.

Burden of caregivers for patients with mild cognitive impairment in Japan.

BACKGROUND: Caregivers of patients with mild cognitive impairment (MCI) already experience a need for increased services comparable to that of individuals caring for Alzheimer's disease patients. However, there have been only a few studies on the MCI caregiver burden. In this study, we examined MCI caregiver burden in a larger number of consecutive outpatients in Japan. METHODS: One hundred and four consecutive caregivers of people with MCI participated in this study. The caregiver burden was evaluated by the short version of the Japanese version of the Zarit Burden Interview (sZBI). RESULTS: About 20% of the caregivers reported a clinically significant burden. The multiple linear regression analysis showed that the caregiver burden was significantly associated with neurobehavioral symptoms (p < 0.001) and memory problems (p = 0.022) of the patient. CONCLUSIONS: The caregiver burden of MCI patients should be given more attention. The management of neurobehavioral symptoms may be important to reduce the burden on caregivers of MCI patients.

Molecular assembly and dynamics of fluorescent protein-tagged single KCa1.1 channel in expression system and vascular smooth muscle cells.

The large-conductance Ca(2+)-activated K(+) (K(Ca)1.1, BK) channel has pivotal roles in the regulation of vascular tone. To clarify the molecular dynamics of BK channels and their functionally coupled protein on the membrane surface, we examined single-molecule imaging of fluorescent-labeled BK subunits in the plasma membrane using total internal reflection fluorescence (TIRF) microscopy. The dynamic mobility of yellow fluorescent protein (YFP)-tagged BKα subunit (BKα-YFP) expressed in human embryo kidney 293 (HEK) cells was detected in TIRF regions at the level of individual channels and their clusters on the plasma membrane with a diffusion coefficient of 6.7 × 10(3) nm(2)/s. When BKα-YFP was coexpressed with cyan fluorescent protein (CFP)-tagged BKß1 subunit (BKß1-CFP) in HEK cells, the mobility was reduced by ∼50%. Fluorescent image analyses suggest that green fluorescent protein (GFP)-tagged BKα subunit (BKα-GFP) expressed in vascular smooth muscle cells (VSMCs), at low density, preferentially formed a heterotetrameric molecular assembly with native BKα subunits, rather than homotetrameric BKα-GFP. Movement of BKα-YFP in VSMCs (0.29 × 10(3) nm(2)/s) was far more restricted than BKα-YFP/BKß1-CFP in HEK cells (2.5 × 10(3) nm(2)/s). Actin disruption by pretreatment with cytochalasin D in VSMCs appeared to increase the mobile behavior of BKα-YFP, which was then significantly reduced by addition of jasplakinolide. Most BKα-YFP colocalized with caveolin 1 (Cav1)-CFP in VSMCs, but unexpectedly not frequently in HEK cells. Fluorescence resonance energy transfer analyses showed the direct interaction between BKα-YFP and Cav1-CFP, particularly in VSMCs. These results, obtained by single molecule imaging in living cells, indicate that the dynamics of BKα molecules on the membrane surface are strongly restricted or regulated by its auxiliary ß-subunit, cytoskeleton, and direct interaction with Cav1 in VSMCs.

Frontal assessment battery and brain perfusion imaging in Alzheimer's disease.

BACKGROUND: The frontal assessment battery (FAB) is reported to be a useful tool for assessing frontal dysfunction. However, the neural substrates involved in patients with Alzheimer's disease (AD) remain to be elucidated. The aim of the present study was to identify the regional perfusion patterns of the brain associated with performance scores on the FAB of patients with AD using brain perfusion assessed by single photon emission computed tomography (SPECT). METHODS: Twenty-four AD patients with high scores and 24 age- and sex-matched AD patients with low scores on the FAB were selected from 470 consecutive Japanese patients of the Memory Clinic of Okayama University Hospital. All 48 participants underwent brain SPECT with 99mTc-ethylcysteinate dimer, and the SPECT images were analyzed by statistical parametric mapping. RESULTS: No significant differences were found between high and low FAB scoring groups with respect to Addenbrooke's Cognitive Examination scores, Mini-Mental State Examination scores, or the depression score of the Neuropsychiatric Inventory subscale. Compared with patients with high scores on the FAB, AD patients with low scores showed significant hypoperfusion in the left middle frontal gyrus (MFG) and the right superior frontal gyrus (SFG) extending to the left SFG. CONCLUSION: Our results suggest that functional activity of the SFG and MFG is closely related to the FAB score. The FAB might be a promising strategy to detect early stages of AD with low SFG and MFG function.

Depressive symptoms and stress among nurses in the COVID unit: A 7-month cohort study.

AIM: Previous studies have reported high prevalence of depression and anxiety symptoms among frontline nurses caring for COVID-19 patients. Yet, only a limited number of prospective studies examining nurses' mental health problems have been performed. The present study aimed to examine depressive symptoms and COVID-19-related stresses among nurses working specifically in a hospital COVID unit over a 7-month period. METHODS: In this study, depressive symptoms and COVID-19-related stresses of a total of 28 nurses who worked in the COVID unit were assessed using the Quick Inventory of Depressive Symptom (QIDS) and the Tokyo Metropolitan Distress Scale for Pandemic (TMDP) over the 7-month period from December 2020 to June 2021. RESULTS: The mean QIDS scores in all participants fluctuated during the study period, showing a high correlation with the reported number of new COVID-19 cases in the region. The mean TMDP scores showed a gradual decline over the period. Scores on the social stress factor of the TMDP demonstrated a statistically significant correlation with the QIDS scores. CONCLUSIONS: The results indicate that the number of new COVID-19 patients in the region is associated with depressive symptoms among nurses in the hospital COVID unit. Scores on the social stress factor in the TMDP are also correlated with depressive symptoms among nurses.

Association between working overtime and psychological stress reactions in elementary and junior high school teachers in Japan: a large-scale cross-sectional study.

This study aimed to investigate the relationship between working overtime and psychological stress reactions among school teachers. It also evaluated the interaction of overtime work types (on weekdays, on holidays, and bringing work home) and task content (educational, peripheral and both). This cross-sectional study was conducted on Japanese elementary and junior high school teachers. Primary outcome was psychological stress reactions measured with the Brief Job Stress Questionnaire. Participants were asked how long they work overtime on weekdays, holidays, and at home. Participants were also asked whether they engaged in educational tasks and/or peripheral tasks during that overtime work. Multiple linear regression analyses were applied and 6,135 participants were included in the analyses after imputing missing data. Working hours of all three types were significantly correlated with higher psychological stress reactions. Moreover, engaging in both educational and peripheral tasks showed higher psychological stress reactions than in only educational tasks when working overtime on weekdays and holidays. In conclusion, reducing overtime work regardless of work types is crucial for mitigating psychological stress reactions for teachers. It might also be possible to manage the psychological stress reactions by splitting the role of task contents, when working overtime on weekdays and holidays at school.

Modification of the surgical procedure to enable the complete resection of lung cancer with carcinomatous pleuritis.

Carcinomatous pleuritis, accompanied by pleural dissemination or malignant pleural effusion, is listed as one of the factors limiting adequate surgical treatment. It is relatively easy to peel the parietal pleura of the chest wall and mediastinum during a pleuropneumonectomy, but it is quite difficult to peel the parietal pleura of the diaphragm. A pleuropneumonectomy was conducted with the combined resection of the pericardium and all layers of the diaphragm without opening of the peritoneum through a posterolateral subcostal approach. This approach thus made it possible to perform a complete resection of the diaphragm relatively easily in a reliable manner, and also contributed to a more thorough resection of pleural dissemination without a second thoracotomy.

Homogeneous catalytic system for reversible dehydrogenation-hydrogenation reactions of nitrogen heterocycles with reversible interconversion of catalytic species.

The first homogeneous catalytic system for the efficient reversible dehydrogenation-hydrogenation reactions of nitrogen heterocycles in one flask has been developed using the pyridonate Cp*Ir complex as the single catalyst at relatively low temperature. The reversible catalytic reactions proceed with the reversible interconversion of catalytic species and can be nearly quantitatively repeated five times with almost no loss of efficiency. The remarkable feature of the present homogeneous catalytic system is that the reversible dehydrogenation-hydrogenation reactions proceed with the reversible interconversion of the catalytic species, depending on the absence or presence of hydrogen.

The Effect of Ocular Surface Regularity on Contrast Sensitivity and Straylight in Dry Eye.

Purpose: To investigate the association between visual function and ocular surface regularity in dry eye. Methods: We enrolled 52 eyes of 52 dry eye patients (34 dry eyes with superficial punctate keratopathy [SPK] in the central corneal region [central SPK] and 18 dry eyes without central SPK) and 20 eyes of 20 normal control subjects. All eyes had a best-corrected distance visual acuity better than 20/20. We measured two indices of contrast sensitivity function under photopic conditions: contrast sensitivity and letter contrast sensitivity. The area under the log contrast sensitivity function (AULCSF) was calculated from the obtained contrast sensitivity data. Straylight was quantified using a straylight meter. Results: Dry eyes with central SPK had significantly decreased contrast sensitivity function, including AULCSF and letter contrast sensitivity than those without central SPK and normal eyes (P < 0.05 for each). While the straylight values in both dry eye groups did not differ, straylight values were greater than those in normal eyes (P < 0.05 for both). In dry eye, the AULCSF and letter contrast sensitivity negatively correlated with the central SPK score (R = -0.485, P < 0.001, and R = -0.541, P < 0.001, respectively). Conclusions: In dry eye, reduced contrast sensitivity in part results from central SPK overlying the optical zone and the increased straylight results from tear film instability rather than central SPK.