Prevalence of retinal pathologies in people over 60 years: the Tehran Geriatrics Eye Study.

AIM: To determine the prevalence of some retinal pathologies in people over 60y and their association with demographic and ocular factors. METHODS: A cross-sectional study was conducted in Tehran using multistage cluster sampling. After selecting subjects aged 60 and over, optometric, and ophthalmic examinations were done. For retinal examination, a 90 D lens was used and indirect ophthalmoscopy was performed after instilling tropicamide drops. Biometry was done using the IOL Master for all participants. RESULTS: Of 3791 people that were invited through cluster sampling, 3310 participated in the study (response rate=82%). The prevalence of retinal pigmented epithelium (RPE) change, drusen, geographic atrophy (GA), hypertensive retinopathy (HTR), nonproliferative diabetic retinopathy (NPDR), proliferative diabetic retinopathy (PDR), choroidal neovascularization (CNV), central retinal artery occlusion (CRAO), myopic retinopathy (MR), branch retinal vein occlusion (BRVO), and central retinal vein occlusion (CRVO) was 27.42%, 11.08%, 4.52%, 3.03%, 4.05%, 0.54%, 0.82%, 0.39%, 0.20%, 0.49%, and 0.19%, respectively. After removing the effect of age, the odds of NPDR were 1.68 times higher in women compared to men (P=0.014). After removing the effect of sex, the odds of drusen, RPE change, GA, CNV, BRVO, and CRVO increased with age. CONCLUSION: There is a higher prevalence of RPE change, drusen, GA, CNV and a lower prevalence of MR and CRAO in the elderly population of Tehran aged over 60y compared to global average values. Considering the correlation of most of the diseases with age and their effects on vision, attention should be paid to these diseases and the related screening programs to prevent vision impairment.

Subfoveal choroidal thickness in a general elderly population; Tehran geriatric eye study.

PURPOSE: To determine the distribution of subfoveal choroidal thickness (SFCT) and its associated demographic, ocular, and systemic factors in an elderly population. METHODS: This report is part of the Tehran Geriatric Eye Study (TGES); a population-based cross-sectional study that was conducted on the urban elderly population of Tehran, aged 60 years and above using multi-stage stratified random cluster sampling. Choroidal imaging was performed using Spectralis SD-OCT with enhanced depth imaging mode. RESULTS: The average SFCT was 265.3 ± 25.9 µm (95% CI: 262.8-267.7) in the whole sample. According to the multiple generalized estimating equation (GEE) model, pseudophakia had a statistically significant direct relationship with SFCT (coefficient = 5.69), and history of cerebrovascular accident (CVA) was significantly inversely related to SFCT (coefficient=-4.77). Moreover, there was a significant interaction between age and sex in the average SFCT so that with increasing age, the SFCT increased in men and decreased in women. CONCLUSION: The normal values of SFCT in the present study can be used as a reference database for clinical and research purposes. Age-sex interaction, pseudophakia, and history of CVA were significantly associated with SFCT in the elderly population. It is recommended that these factors be taken into account when interpreting SFCT data.

The association between visual impairment and mental disorders.

To determine the association between visual impairment (VI) and some mental disorders using the general health questionnaire (GHQ) in individuals aged 60 years and above in Tehran, Iran. The present population-based cross-sectional study was conducted on people aged 60 and older in Tehran, Iran using multi-stage cluster sampling. After selecting the samples, examinations including visual acuity measurement, refraction, and slit-lamp biomicroscopy were performed for all participants. The GHQ was used to examine mental disorders. Simple and multiple linear regressions were used to investigate the association between VI and mental disorders. Of the 3740 invitees, 3310 participated in the study (response rate: 88.50%). After applying the exclusion criteria, 2789 individuals were analyzed for this report. Mean score of physical, anxiety, social and depression disorders in people with and without VI was 3.74 ± 2.03, 5.81 ± 2.79, 7.56 ± 1.91, 1.32 ± 1.90, and 3.14 ± 1.76, 4.93 ± 2.71, 8.09 ± 1.99, 0.91 ± 1.38, respectively. The total score of GHQ in participants with and without VI was 18.43 ± 4.75 and 17.07 ± 4.19, respectively. The association between GHQ subscales and total GHQ score with VI by multiple linear regression showed that VI had a statistically significant direct association with physical symptoms (ß = 0.37; 95% CI 0.12 to 0.62) and anxiety (ß = 0.48; 95% CI 0.16 to 0.81). Nevertheless, depression had a borderline association with VI (ß = 0.21; 95% CI - 0.03 to 0.45) and social dysfunction did not have a statistically significant association with VI in the final linear regression model and did not remain in the model. Total GHQ score had a statistically significant association with VI (ß = 1.02; 95% CI 0.39 to 1.64) in the presence of covariates. Regarding the association between VI and GHQ components, the physical symptoms had the highest R2 (R2 = 0.159). Patients with VI suffer more from anxiety, depression, and physical symptoms regardless of age, sex, education, and other effective variables. The coincidence of aging with VI and the association of VI with mental disorders emphasizes the importance of a broader view of the elderly and the aging process.

Prevalence and Associated Factors of Pseudoexfoliation Syndrome in an Iranian Elderly Population: The Tehran Geriatric Eye Study.

PURPOSE: To investigate the prevalence and associated factors of pseudoexfoliation syndrome (PEX) in an Iranian elderly population. METHODS: This study, a population-based cross-sectional study conducted on individuals ≥60 years in Tehran, the capital of Iran in 2019 using a multi-stage stratified random cluster sampling. All study participants underwent complete ocular examination (including measurement of uncorrected and best-corrected visual acuity, refraction, slit-lamp biomicroscopy). The PEX was diagnosed based on the presence of white fluffy dandruff-like pseudoexfoliative material on the pupillary margin, on the anterior lens capsule, and/or the trabecular meshwork. RESULTS: Of the 3791 invitees, 3310 participated in the TGES (response rate: 87.3%). After applying exclusion criteria, the data of 3274 individuals were analyzed for this report. The overall prevalence of PEX was 3.63% (95% CI:2.67-4.58) in this study. 81.1% of PEX cases were bilateral. The prevalence of PEX increased significantly with advancing age in a linear trend from 2.38% (95%: 1.27-3.48) in the age group 60-64 years to 6.48% (95%: 2.02-10.95) in the age group ≥80 years (OR = 1.05, p = 0.008). According to the multiple logistic regression model, advancing age (OR: 1.06, p = 0.002) and the presence of cataract (OR: 5.02, p < 0.001) were significantly associated with increased odds of PEX. CONCLUSION: The results showed a lower prevalence of PEX in the Iranian elderly compared to previous studies on the elderly population. Advancing age and cataracts were the only associated factors of PEX in the present study.

Axial length and anterior chamber indices in elderly population: Tehran Geriatric Eye Study.

AIM: To determine the normative distribution of axial length (AL), anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), and some of their associated factors in subjects aged 60 and over. METHODS: In this cross-sectional study, 160 clusters were sampled using multi-stage cluster sampling in Tehran, Iran. After a preliminary interview, the participants underwent optometric examinations including visual acuity and refraction measurement followed by slit lamp biomicroscopy. Finally, ocular imaging was done using the Pentacam AXL to measure AL, ACD, ACV, and ACA. RESULTS: A total of 4519 eyes of 2436 participants were evaluated, of whom 58.0% (n=1412) were female. The mean age of the subjects was 67.32±6.05y (range: 60-95y). The mean AL, ACD, ACV, and ACA was 23.22 mm (23.18-23.27 mm), 2.61 mm (2.59-2.62 mm), 126.56 mm3 (125.08-128.04 mm3), and 30.61° (30.3°-30.92°), respectively. In the multivariable model, after adjusting for the effect of both eyes, the longest and shortest AL was seen in myopic and hyperopic subjects, respectively. AL, ACD, ACV and ACA were significantly larger in men compared to women (P<0.001). Except ACA, other evaluated parameters showed an inverse correlation with age (P<0.001), however, this correlation was insignificant for AL (P=0.623). CONCLUSION: Normative value of AL, and other biometric parameters are specific for each ethnicity, age and sex group. Any alteration in these parameters and their effect on refraction should be considered in this age group, especially in case of cataract surgery.

Corneal topographic indices of scheimpflug camera in type 2 diabetic and non-diabetic elderly populations.

PURPOSE: The present study was conducted to determine the corneal topographic indices of Scheimpflug camera in type 2 diabetes patients without diabetic retinopathy (DR), DR and non-diabetic elderly populations. METHODS: A total of 1105 participants were selected using random cluster sampling from Tehran, Iran and categorized into three groups including type 2 diabetes patients without diabetic retinopathy (DR), DR and non-diabetic. The diabetic group had HbA1c levels ≥ 6.4% with no other systemic problems. The non-diabetic participants had normal eye findings and no systemic diseases. The pachymetric progression index (PPI) values were measured using the Pentacam AXL. RESULTS: A total of 1105 participants including 429 diabetes patients (38.46% male) and 676 non-diabetic (38.76% male) subjects entered the study. Only PPIavg and PPImax were higher in the diabetics versus non-diabetics (P = 0.019 and 0.010, respectively). There was a significant difference in PPImax between the three groups (P = 0.036). There were significant differences only in index of vertical asymmetry (IVA), central keratoconus index (CKI), PPI average, and PPI max between different stages of diabetic retinopathy (DR) (P = 0.045, 0.005, 0.002, and 0.004, respectively). There was a significant difference in index of Surface Variance (ISV), index of vertical asymmetry (IVA), PPIavg, and PPImax between diabetes patients with and without DR (P = 0.016, 0.022, < 0.001, and < 0.001, respectively). CONCLUSION: According to the results, diabetes and DR change several topographic indices. In addition, the HbA1c level may affect pachymetric progression index max. Therefore, special attention should be paid to these patients for different treatment strategies.

Distributed Coding of Evidence Accumulation across the Mouse Brain Using Microcircuits with a Diversity of Timescales.

The gradual accumulation of noisy evidence for or against options is the main step in the perceptual decision-making process. Using brain-wide electrophysiological recording in mice (Steinmetz et al., 2019), we examined neural correlates of evidence accumulation across brain areas. We demonstrated that the neurons with drift-diffusion model (DDM)-like firing rate activity (i.e., evidence-sensitive ramping firing rate) were distributed across the brain. Exploring the underlying neural mechanism of evidence accumulation for the DDM-like neurons revealed different accumulation mechanisms (i.e., single and race) both within and across the brain areas. Our findings support the hypothesis that evidence accumulation is happening through multiple integration mechanisms in the brain. We further explored the timescale of the integration process in the single and race accumulator models. The results demonstrated that the accumulator microcircuits within each brain area had distinct properties in terms of their integration timescale, which were organized hierarchically across the brain. These findings support the existence of evidence accumulation over multiple timescales. Besides the variability of integration timescale across the brain, a heterogeneity of timescales was observed within each brain area as well. We demonstrated that this variability reflected the diversity of microcircuit parameters, such that accumulators with longer integration timescales had higher recurrent excitation strength.

Corneal densitometry and associated factors in an elderly population.

CLINICAL RELEVANCE: Knowing normative corneal optical density (COD) values is important for identifying pathologic corneal changes. BACKGROUND: The aim of this work is to determine the distribution and associated factors of COD in the elderly population. METHODS: This report is a part of a cross-sectional population-based study conducted on the elderly population (≥60 years) of Tehran, Iran from Jan 2019 to Jan 2020. Using a multi-stage stratified random cluster sampling method, a total of 160 clusters were randomly selected from 22 districts of Tehran city. Study participants underwent a complete ocular examination including measurement of visual acuity, refraction, and slit-lamp biomicroscopy. Corneal densitometry was evaluated using the Pentacam HR. Generalized estimating equation (GEE) models were used to investigate associations of COD with study variables. RESULTS: A total of 3633 eyes from 2068 individuals were analysed. Of these, 1256 (60.7%) were female, and the mean age of the individuals was 66.42 ± 5.28 (60 to 95) years. The mean entire COD was 21.96 ± 4.45 greyscale unit (GSU) (95% CI: 21.57-22.34). There was a statistically significant difference in the mean COD between the anterior, central, and posterior layers (p < 0.001); the highest and lowest average COD was related to the anterior and posterior corneal layers, respectively. The lowest and highest mean COD were observed in the 0-2 mm [17.21GSU (95% CI:16.87-17.55)], and 10-12 mm annular zones [31.4 GSU (95% CI: 30.89-31.91)], respectively (p < 0.001). According to the multiple GEE model, the COD had a statistically significant direct relationship with age, central corneal thickness, and mean keratometry, while it was significantly inversely associated with female sex, anterior chamber depth, white-to-white distance, and corneal volume. CONCLUSION: These normal values of COD in the present study could be used as reference data in older adults. The associated factors of COD should be taken into account to avoid misinterpretation of physiologic changes as pathologic processes.

Epidemiology of Ocular Trauma in the Elderly: A Population-Based Study.

Purpose: To determine the prevalence of different types of ocular trauma and their relationship with some factors in the elderly population. Methods: The present population-based cross-sectional study was conducted on the elderly population aged 60 years and above in Tehran, Iran, using multi-stage stratified random cluster sampling in 2019. After selecting the samples and their participation in the study, demographic information and history of ocular trauma were obtained through an interview. Psychological evaluation was performed using the Goldberg's 28-question General Health Questionnaire. All study participants underwent optometric and ophthalmological examinations. Results: Three thousand three hundred and ten people participated in the study (response rate: 87.3%). Of these, 1912 individuals (57.8%) were female and the mean age of individuals was 68.25 ± 6.55 (from 60 to 97) years. 7.46% (95% confidence interval [CI]: 6.51-8.41) of the study participants reported a history of ocular trauma. Blunt and chemical traumas were the most and the least common types of ocular trauma, respectively (5.72% and 0.16%). 3.93% of cases visited an ophthalmologist for ocular trauma, 1.67% reported a history of hospitalization, and 1.47% underwent surgery. The prevalence of visual impairment in individuals with a history of ocular trauma was 12.53%. Visual impairment was more prevalent in people with a history of ocular trauma than those without a history of ocular trauma (P < 0.05). History of ocular trauma was only significantly related to low education level (odds ratio = 0.63, 95% CI = 0.40-0.99). Participants with a history of ocular trauma had more anxiety and higher mean psychological distress score than those without a history of ocular trauma (P = 0.035). Conclusions: The development of preventive programs against the occurrence of ocular trauma can play an important role in reducing the psychological damage of affected patients while reducing visual disorders. These interventions should be especially considered in groups with a lower education level.

The prevalence of red-green color vision deficiency and its related factors in an elderly population above 60 years of age.

AIM: To determine the prevalence of red-green (RG) color vision deficiency (CVD) in an elderly population and its related factors. METHODS: This report is a part of the Tehran Geriatric Eye Study: a cross-sectional population-based study that was conducted on the elderly population (≥60y) of Tehran, Iran using multi-stage stratified random cluster sampling. All study participants underwent complete ocular examination, including the measurement of uncorrected and best-corrected visual acuity, objective and subjective refraction, and slit-lamp biomicroscopy. The color vision was tested using Ishihara plates with the near optical correction in place. RESULTS: Of the 3791 invitees, 3310 participated in the study. The data of 2164 individuals were analyzed after applying the exclusion criteria. The prevalence of R-G CVD was 3.73% (95%CI: 2.37%-5.09%) in the whole sample; the prevalence of protanomaly, protanopia, and deuteranopia was 1.51%, 1.76%, and 0.45%, respectively. The prevalence of R-G CVD was significantly higher in males than in females. The prevalence of RG CVD increased with advancing age from 2.91% in the age group 60-64y to 5.8% in the age group ≥80y (P=0.070). According to the multiple logistic regression model, male sex, and glaucoma were significantly related to RG CVD. Older age and hypertension also had a marginally significant relationship with RG CVD. CONCLUSION: Changes in color vision occur in the elderly due to the aging process and some physiological and pathological factors. Since the change in visual perception may affect the person's performance, this aspect of the visual system's function should also be taken into consideration in the examinations of the elderly.

Auto-refraction versus subjective refraction in different phakic and pseudophakic conditions: the Tehran Geriatric Eye Study (TGES).

AIM: To compare the subjective refraction data with non-cycloplegic auto-refraction findings in the geriatric population above 60 years of age according to the different crystalline lens conditions. METHODS: This report is a part of the Tehran Geriatric Eye Study (TGES) that was conducted from January 2019 to January 2020 on elderly population 60 years of age and above in Tehran. The samples were selected by multi-stage stratified random cluster sampling. Of 3791 individual invitees, 3310 (response rate: 87.3%) participated in this study. All study participants underwent non-cycloplegic auto-refraction (auto-refractometer/keratometer Nidek ARK-510) and subjective refraction. RESULTS: Regarding the sphere, eyes with mixed cataract had the worst limits of agreement (LoA: -1.24 to 0.87) and the best agreement was related to the pseudophakic eyes (LoA: -0.83 to 0.54). The highest (0.27±0.31 D) and lowest (0.21±0.27 D) differences between the two methods regarding the cylinder power were observed in eyes with cortical cataract and normal eyes, respectively. The worst LoA between the two methods in measuring the cylinder power was related to the eyes with mixed cataract (LoA: -0.44 to 0.96). Regarding the J0 (horizontal/vertical components of astigmatism), the mean values of J0 obtained by auto-refraction were tended more toward against the rule direction in all crystalline lens conditions, and the two methods had the greatest difference in cortical cataract cases (0.05±0.17 D). Regarding the J45 (oblique components of astigmatism), the lowest (0±0.11 D) and highest (-0.01±0.12 D) differences were observed in normal eyes and eyes with cortical cataract, respectively. CONCLUSION: The auto-refractometer/keratometer Nidek ARK-510 results in the elderly with different phakic and pseudophakic conditions do not correspond well with subjective refraction findings. This discrepancy in spherical findings is more pronounced in individuals with mixed cataract than in other cases.

Residual refractive errors in pseudophakic eyes and related factors: a population-based study.

AIM: To determine residual refractive error after cataract surgery in pseudophakic eyes and its relationship with age, sex, and axial length (AL). METHODS: In this population-based cross-sectional study, the sampling was performed on individuals aged 60y and above in Tehran, Iran using a multi-stage stratified random cluster sampling method. Pseudophakic eyes with a best-corrected visual acuity of 20/32 or better were analyzed and their refractive results were reported. RESULTS: The mean spherical equivalent (SE) refraction was -0.34±0.97 diopters (D) and the mean absolute SE was 0.72±0.74 D with a median of 0.5 D. Moreover, 32.68% (n=546, 95%CI: 30.27%-35.08%), 53.67% (n=900, 95%CI: 51.23%-56.1%), 68.99% (n=1157, 95%CI: 66.96%-71.02%), and 79.73% (n=1337, 95%CI: 77.69%-81.76%) of the eyes had a residual SE within ±0.25, ±0.50, ±0.75, and ±1.00 D of emmetropia, respectively. According to the multiple logistic regression model, increasing age was associated with a statistically significant decrease in predictability for all cut points. Moreover, the predictability based on all cut points was significantly lower in individuals with an AL longer than 24.5 mm than in those with an AL between 22 to 24.5 mm. CONCLUSION: Based on the results, the accuracy of intraocular lens (IOL) power calculation is lower for those who underwent cataract surgery during the last 5y in Tehran, Iran. Among the most important influential factors, the choice of IOL or it's power disproportionate to eye conditions and age can be mentioned.

Distribution and associated factors of intraocular pressure in the older population: Tehran Geriatric Eye Study.

AIM: To determine the distribution and associated factors of intraocular pressure (IOP) in an Iranian elderly population 60 years of age and above. METHODS: The present report is part of the Tehran Geriatric Eye study (TGES), a population-based cross-sectional study that was conducted on the residents of Tehran 60 years of age and above. The sampling was performed using multistage stratified random cluster sampling methods from 22 districts of Tehran, Iran. Demographic and history information, blood samples, and blood pressure were collected from all participants. Ocular examinations included measurement of uncorrected and best-corrected visual acuity, objective and subjective refraction, and slit-lamp biomicroscopy. The IOP was measured using Goldmann applanation tonometry (GAT). Corneal imaging and ocular biometry were performed using Pentacam AXL. RESULTS: The data of 3892 eyes of 2124 individuals were analyzed for this report. The mean age of the study participants was 66.49±5.31y (range: 60 to 95y). The mean IOP was 15.2 mm Hg (95%CI: 15.1 to 15.4), 15.3 mm Hg (95%CI: 15.1 to 15.5) and 15.1 mm Hg (95%CI: 15.0 to 15.3) in all participants, males, and females, respectively. Of the study participants, 1.3% had an IOP of ≥20 mm Hg. The mean IOP increased from 15.1 mm Hg in the age group 60-64y to 16.3 mm Hg in the age group ≥80y. According to the final multiple GEE model, the IOP was statistically significantly higher in men than in women. All the studied age groups, except for the 75-79-year-old age group, had significantly higher IOP compared to the 60-64-year-old age group. The IOP was significantly higher in underweight compared to other body mass index groups. Moreover, the IOP had a statistically significant direct relationship with the mean corneal power (mean CP), central corneal thickness (CCT), and systolic blood pressure. CONCLUSION: The present study presents the distribution of IOP in an Iranian elderly population. A higher IOP (within the range 14 to 17 mm Hg) is significantly associated with older age, male sex, high systolic blood pressure, increased mean CP, and CCT. These factors should be considered in the clinical interpretation of IOP.

High prevalence of refractive errors in an elderly population; a public health issue.

PURPOSE: To determine the prevalence of myopia and hyperopia and their associated demographic and ocular factors in people 60 years of age and above. METHODS: The sampling was performed using a multi-stage stratified random cluster sampling method. The complete demographic and case history information were collected through an interview. Then, all participants underwent optometric examinations including measurement of uncorrected and best-corrected visual acuity, objective, and subjective refraction. Myopia and hyperopia were defined as a spherical equivalent (SE) refraction worse than -0.50 diopters (D) and + 0.50 D, respectively. RESULTS: Three thousand three hundred ten of 3791 invitees participated, and the data of 3263 individuals were analyzed for this report. The mean age of participants was 68.25 ± 6.53 (60 to 97) years, and 1895 (58.1%) of them were female (number of male/female participants = 1368/1895). The prevalence of myopia and hyperopia was 31.65% (95% CI: 29.68 -33.61) and 45.36% (95% CI: 43.36 -47.37), respectively. The prevalence of severe myopia and hyperopia was 1.14% (95% CI: 0.73 -1.55) and 2.27% (95% CI: 1.57 -2.97), respectively. Based on the results of multiple logistic regression, the prevalence of myopia had a statistically significant direct relationship with age (OR: 1.04; p < 0.001), history of glaucoma surgery (OR:2.75; p < 0.001), pseudophakia (OR: 2.27; p < 0.001), axial length (OR:3.05; p < 0.001), and mean keratometry (OR:1.61; p < 0.001). The education level was significantly inversely related to the myopia prevalence. Moreover, a history of glaucoma surgery (OR:0.44; p < 0.001), pseudophakia (OR = 0.15; p < 0.001), axial length (OR:35; p < 0.001) and mean keratometry (OR:0.62; p < 0.001) were significantly inversely related to the prevalence of hyperopia. 19% and 40.02% of myopic and hyperopic patients had complete visual acuity after correction of refractive error, respectively. CONCLUSION: The prevalence of refractive errors was high in the Iranian elderly population. A large percentage of the elderly still did not have complete visual acuity after the correction of refractive errors indicating the necessity for attention to other ocular diseases in this age group. The history of cataract and glaucoma surgery could be associated with a myopic shift of refractive error.

Are binocular alignment and convergence amplitude different between phakic and pseudophakic older patients?

PURPOSE: To compare the binocular alignment status and convergence amplitude between phakic and pseudophakic older adults. METHODS: The present report is a part of the Tehran Geriatric Eye Study (TGES), a population-based study performed on the elderly population above 60 years of age in Tehran, Iran. All study participants were transferred to the examination site and underwent complete ocular examinations including the measurement of uncorrected and best-corrected visual acuity, objective and subjective refraction, unilateral and alternating cover tests, and slit-lamp biomicroscopy. RESULTS: Of 3791 invitees, 3310 participated in the TGES (response rate: 87.3%). After applying the exclusion criteria, the data of 1969 individuals were analyzed for this report. The mean of far exophoria, far esophoria, near exophoria, and near esophoria was 5.09 ± 3.66, 8.20 ± 9.60, 6.94 ± 3.69, 7.00 ± 5.83 prism diopter in phakic and 5.15 ± 2.43, 6.50 ± 5.80, 7.77 ± 4.00, 4.75 ± 1.50 prism diopter in pseudophakic individuals, respectively. The mean of far exotropia, far esotropia, near exotropia, and near esotropia was 14.92 ± 9.49, 22.00 ± 13.86, 15.09 ± 7.20, 21.33 ± 14.47 prism diopter in phakic and 19.67 ± 22.5, 8.00 ± 0, 17.36 ± 7.55, 17.36 ± 7.55, 0 prism diopter in pseudophakic individuals, respectively. Near exophoria (P = .003) was significantly higher in pseudophakic than in phakic participants after controlling the effects of age, sex, body mass index, diabetes, and hypertension. The mean near point of convergence was 7.94 ± 3.27 cm in phakic and 7.99 ± 3.3 cm in pseudophakic participants. CONCLUSION: Near exophoria was significantly higher in pseudophakic compared to phakic individuals while other deviations and near point of convergence were not significantly different between phakic and pseudophakic groups.

Online spike sorting via deep contractive autoencoder.

Spike sorting - the process of separating spikes from different neurons - is often the first and most critical step in the neural data analysis pipeline. Spike-sorting techniques isolate a single neuron's activity from background electrical noise based on the shapes of the waveforms obtained from extracellular recordings. Despite several advancements in this area, an important remaining challenge in neuroscience is online spike sorting, which has the potential to significantly advance basic neuroscience research and the clinical setting by providing the means to produce real-time perturbations of neurons via closed-loop control. Current approaches to online spike sorting are not fully automated, are computationally expensive and are often outperformed by offline approaches. In this paper, we present a novel algorithm for fast and robust online classification of single neuron activity. This algorithm is based on a deep contractive autoencoder (CAE) architecture. CAEs are neural networks that can learn a latent state representation of their inputs. The main advantage of CAE-based approaches is that they are less sensitive to noise (i.e., small perturbations in their inputs). We therefore reasoned that they can form the basis for robust online spike sorting algorithms. Overall, our deep CAE-based online spike sorting algorithm achieves over 90% accuracy in sorting unseen spike waveforms, outperforming existing models and maintaining a performance close to the offline case. In the offline scenario, our method substantially outperforms the existing models, providing an average improvement of 40% in accuracy over different datasets.

Application of bioactive glasses in various dental fields.

Bioactive glasses are a group of bioceramic materials that have extensive clinical applications. Their properties such as high biocompatibility, antimicrobial features, and bioactivity in the internal environment of the body have made them useful biomaterials in various fields of medicine and dentistry. There is a great variation in the main composition of these glasses and some of them whose medical usage has been approved by the US Food and Drug Administration (FDA) are called Bioglass. Bioactive glasses have appropriate biocompatibility with the body and they are similar to bone hydroxyapatite in terms of calcium and phosphate contents. Bioactive glasses are applied in different branches of dentistry like periodontics, orthodontics, endodontics, oral and maxillofacial surgery, esthetic and restorative dentistry. Also, some dental and oral care products have bioactive glasses in their compositions. Bioactive glasses have been used as dental implants in the human body in order to repair and replace damaged bones. Other applications of bioactive glasses in dentistry include their usage in periodontal disease, root canal treatments, maxillofacial surgeries, dental restorations, air abrasions, dental adhesives, enamel remineralization, and dentin hypersensitivity. Since the use of bioactive glasses in dentistry is widespread, there is a need to find methods and extensive resources to supply the required bioactive glasses. Various techniques have been identified for the production of bioactive glasses, and marine sponges have recently been considered as a rich source of it. Marine sponges are widely available and many species have been identified around the world, including the Persian Gulf. Marine sponges, as the simplest group of animals, produce different bioactive compounds that are used in a wide range of medical sciences. Numerous studies have shown the anti-tumor, anti-viral, anti-inflammatory, and antibiotic effects of these compounds. Furthermore, some species of marine sponges due to the mineral contents of their structural skeletons, which are made of biosilica, have been used for extracting bioactive glasses.

Social distancing in pedestrian dynamics and its effect on disease spreading.

Nonpharmaceutical measures such as social distancing can play an important role in controlling the spread of an epidemic. In this paper, we use a mathematical model combining human mobility and disease spreading. For the mobility dynamics, we design an agent-based model consisting of pedestrian dynamics with a novel type of force to resemble social distancing in crowded sites. For the spreading dynamics, we consider the compartmental susceptible-exposed-infective (SEI) dynamics plus an indirect transmission with the footprints of the infectious pedestrians being the contagion factor. We show that the increase in the intensity of social distancing has a significant effect on the exposure risk. By classifying the population into social distancing abiders and nonabiders, we conclude that the practice of social distancing, even by a minority of potentially infectious agents, results in a drastic change in the population exposure risk, but it reduces the effectiveness of the protocols when practiced by the rest of the population. Furthermore, we observe that for contagions for which the indirect transmission is more significant, the effectiveness of social distancing would be reduced. This study can help to provide a quantitative guideline for policy-making on exposure risk reduction.

The Distribution of Keratometry in a Population Based Study.

PURPOSE: To determine the distribution of keratometry values in a wide age range of 6-90 years. METHODS: In this cross-sectional study, samples were selected from two villages in Iran using multi-stage random cluster sampling. After completing optometry and ophthalmic examinations for all cases, corneal imaging was done using Pentacam, and keratometry values were determined. RESULTS: Of the 3851 selected people, 3314 people participated in the study, and after applying the exclusion criteria, analyses were done on data from 2672 people. Mean age of the participants was 36.30 ± 18.51 years (from 6 to 90 years). Mean keratometry (mean-K) in flat and steep meridians was 42.98 (42.9-43.06) diopters (D) and 43.98 (43.91-44.07) D, respectively. Average of mean-K was 43.48 (43.41-43.56) D. Mean-K increased linearly up to the age of 70 years, and the cornea became slightly flat afterwards (coefficient = 0.01; P < 0.001). Mean-K was significantly higher in females (P < 0.001). Myopic cases had the highest mean-K (P < 0.001). The correlation of mean-K with age, gender, central corneal thickness, anterior chamber depth, pupil diameter, and spherical equivalent was investigated in a multiple regression model. Only older age and female gender showed a statistically significant association with mean-K. Overall, 31.62% (29.14-34.09) of the sample in this study had at least 1.0 D of corneal astigmatism. CONCLUSIONS: This is one of the few studies worldwide that demonstrates changes in keratometry in a wide age range from childhood to old age. Results indicated that age and gender are variables associated with keratometry.

The Prevalence and Risk Factors for Keratoconus: A Systematic Review and Meta-Analysis.

PURPOSE: This study was conducted to determine the prevalence and risk factors for keratoconus worldwide. METHODS: In this meta-analysis, using a structured search strategy from 2 sources, 4 electronic databases (PubMed, Web of Science, Google Scholar, and Scopus) and the reference lists of the selected articles were searched from inception to June 2018 with no restrictions and filters. The outcome of the study was the prevalence of keratoconus and its risk factors, including eye rubbing, family history of keratoconus, atopy, allergy, asthma, eczema, diabetes type I and type II, and sex. RESULTS: In this study, 3996 articles were retrieved, of which 29 were analyzed. These 29 articles included 7,158,241 participants from 15 countries. The prevalence of keratoconus in the whole population was 1.38 per 1000 population [95% confidence interval (CI): 1.14-1.62 per 1000]. The prevalence of keratoconus was 20.6 per 1000 (95% CI: 11.68-28.44 per 1000) in men and 18.33 per 1000 (95% CI: 8.66-28.00 per 1000) in women in studies reporting sex. The odds ratio of eye rubbing, family history of keratoconus, allergy, asthma, and eczema was 3.09 (95% CI: 2.17-4.00), 6.42 (95% CI: 2.59-10.24), 1.42 (95% CI: 1.06-1.79), 1.94 (95% CI: 1.30-2.58), and 2.95 (95% CI: 1.30-4.59), respectively. CONCLUSIONS: The results of this study, as the most comprehensive meta-analysis of keratoconus prevalence and risk factors, showed that keratoconus had a low prevalence in the world and eye rubbing, family history of keratoconus, allergy, asthma, and eczema were the most important risk factors for keratoconus according to the available evidence.