Assessment of intraocular pressure measurement between Goldman applanation tonometer, rebound tonometer, non-contact tonometer, and its correlation with central corneal thickness

Purpose: To compare readings of intraocular pressure (IOP) taken with the Goldmann applanation tonometer (GAT), the non?contact tonometer (NCT), and the rebound tonometer (RBT), and to compare their correlation with central corneal thickness (CCT). Methods: This was a prospective, cross?sectional, observational study to which patients above 18 years of age were enrolled. A total of 400 eyes of 200 non?glaucomatous patients underwent IOP recordings using the GAT, NCT, and RBT, and CCT was also noted. Informed consent of the patients was taken. The IOP readings taken via the three methods were compared and correlated with CCT. Paired t test was used to compare the two devices. Simple and multivariate linear regression analyses were used to study the relationship between factors. A P value less than 0.05 was considered significant. Correlation was determined using the Pearson correlation coefficient, and a Bland–Altman graph was plotted. Results: Mean IOP measured by the NCT was 15.65 ± 2.80 mmHg, by the RBT was 14.23 ± 3.05 mmHg, and by the GAT was 14.69 ± 2.97 mmHg. The mean CCT was 510.61 ± 33.83 microns. The difference between mean IOP recorded by the NCT and that by the RBT was 1.41 ± 2.39 mmHg, between the NCT and GAT was 0.95 ± 2.03 mmHg, and between the GAT and RBT was 0.45 ± 2.22 mmHg. The difference between the IOP values was statistically significant (P < 0.005). All tonometers showed a statistically significant correlation with CCT, but it was observed that the NCT had a stronger correlation (0.4037). Conclusion: The IOP readings taken by all the three methods were comparable; however, RBT values were closer to GAT values. CCT did influence the IOP values, and this should be kept in mind while evaluating.

Risk factors for contralateral anterior cruciate ligament injury after primary anterior cruciate ligament reconstruction / 中国修复重建外科杂志

OBJECTIVE@#To investigate the risk factors of contralateral anterior cruciate ligament (ACL) injury after primary ACL reconstruction.@*METHODS@#A retrospective review was conducted on the 716 patients with ACL injury who received primary ACL reconstruction surgery and met the selection criteria between January 2012 and September 2018. After a mean follow-up period of 7.6 years (range, 4-10 years), 65 patients (9.1%) experienced contralateral ACL injury (injured group) and 651 patients (90.9%) did not (uninjured group). There was no significant difference in age, body mass index, and preoperative Lachman test degree between groups ( P>0.05). However, the proportion of female in the injured group was significantly higher than that of male ( P<0.05), and the preoperative posterior tibial slope (PTS) was significantly higher than that of the uninjured group ( P<0.05). Using the outcome of contralateral ACL injury as the dependent variable, the clinical data of the patient was first used as the independent variable, and univariate COX regression was used to analyze the prognostic influencing factors. Then, the indicators with differences in univariate COX regression were used as the independent variable, and multivariate COX regression was used to analyze the independent risk factors affecting prognosis. Log-Rank (Mantel-Cox) test was used to test and analyze the occurrence time of contralateral ACL injury in patients of different genders; X-tile software was used to analyze the occurrence time of contralateral ACL injury in patients with different PTS using Log-Rank (Mantel-Cox) test and PTS cut-off values.@*RESULTS@#Univariate COX regression analysis showed that gender and PTS were influence factors for contralateral ACL injury ( P<0.05); further multivariate COX regression analysis showed that female and increased PTS were independent risk factors for contralateral ACL injury ( P<0.05). The Log-Rank (Mantel-Cox) test results showed that the contralateral ACL injury occurred in female at 8.853 (8.600, 9.106) years, which was significantly shorter than that in male [9.661 (9.503, 9.819) years] ( χ 2=20.323, P<0.001). Using X-tile software to analyze the cut-off value of PTS, it was found that the cut-off value of PTS for contralateral ACL injury was 10.92°. According to the Log-Rank (Mantel-Cox) test, it was found that the contralateral ACL injury occurred in 5.762 (4.981, 6.543) years in patients with PTS≥10.92°, which was significantly shorter than patients with PTS<10.92° [9.751 (9.650, 9.853) years]( χ 2 =302.479, P<0.001).@*CONCLUSION@#Female and PTS≥10.92° after primary ACL reconstruction are independent risk factors for contralateral ACL injury.

Correction methods for noncontact intraocular pressure measurement in patients with keratoconus and healthy individuals / Métodos de correção para medição sem contato da pressão intraocular em indivíduos normais e com ceratocone

ABSTRACT Purpose: The objective of this study was to investigate the usefulness of four different algorithms to correct noncontact intraocular pressure measurement errors in keratoconus patients and normal individuals. Methods: Noncorrected intraocular pressure and corrected intraocular pressures were measured in one eye of 34 patients with keratoconus and 34 age- and gender-matched healthy controls using Corvis Scheimpflug Technology. The correlation of noncorrected intraocular pressure and corrected intraocular pressures with age, axial length, corneal shape, thickness, and biomechanics was calculated. Corrected intraocular pressures were compared with noncorrected intraocular pressure using paired t test and Bland-Altman plots (95% limits of agreement). Results: The noncorrected intraocular pressure correlated with corneal thickness and biomechanical parameters in both groups (all p≤0.047), and front and back mean keratometry in the keratoconus group (r=-0.39, p=0.02, and r=0.39, p=0.02, respectively). After adjustment with different intraocular pressure correction algorithms, biomechanically corrected intraocular pressure showed a minimal correlation with corneal features and a nonsignificant difference with noncorrected intraocular pressure in the healthy group (-0.1 ± 1.1 mmHg, p=0.58; 95% limits of agreement: -2.3 to 2.1 mmHg). Conclusions: Measuring intraocular pressure using noncontact tonometry and its corrected forms with a corneal thickness-based simple linear formula in patients with keratoconus is associated with many errors. Using more complex formulas that take into consideration more corneal stiffness parameters in addition to corneal thickness, such as biomechanically corrected intraocular pressure formula, may be more reliable and beneficial in this group of patients.

RESUMO Objetivo: Investigar a utilidade de quatro algoritmos diferentes para corrigir erros de medição sem contato da pressão intraocular em pacientes saudáveis e com ceratocone. Métodos: A pressão intraocular não corrigida e as pressões intraoculares corrigidas foram medidas em um olho de 34 pacientes com ceratocone e 34 pacientes do grupo controle saudável pareados por idade e gênero usando a tecnologia Corvis Scheimpflug. Foi calculada a correlação da pressão intraocular não corrigida e das pressões intraoculares corrigidas com idade, comprimento axial e formato, espessura e biomecânica da córnea. As pressões intraoculares corrigidas foram comparadas com a pressão intraocular não corrigida usando o teste t pareado, e gráficos de Bland-Altman (limites de concordância de 95%). Resultados: A pressão intraocular não corrigida correlacionou-se com a espessura da córnea e com os parâmetros biomecânicos em ambos os grupos (todos p≤0,047) e a ceratometria média frontal e posterior no grupo com ceratocone (r=-0,39, p=0,02, r=0,39, p=0,02, respectivamente). Após o ajuste com diferentes algoritmos de correção da pressão intraocular, a pressão intraocular corrigida biomecanicamente revelou uma correlação mínima com as características da córnea e uma diferença não significativa com a pressão intraocular não corrigida no grupo saudável (-0,1 ± 1,1 mmHg, p=0,58; limites de concordância de 95%: -2,3 a 2,1 mmHg). Conclusões: A medição da pressão intraocular usando tonometria sem contato e suas formas corrigidas usando fórmulas lineares, simples, baseadas na espessura da córnea em pacientes com ceratocone estão associadas a muitos erros. O uso de fórmulas mais complexas que consideram mais parâmetros de rigidez da córnea além da espessura da córnea, como fórmula de pressão intraocular corrigida biomecanicamente, pode ser mais confiável e benéfico neste grupo de pacientes.

Evaluation of meibomian gland morphology and anterior segment parameters by Sirius topography systems in polycystic ovary syndrome

Purpose: To compare findings in specular microscopy, corneal topography, and noncontact meibography in polycystic ovary syndrome (PCOS) patients with healthy controls. Methods: A total of 40 women with PCOS and 32 healthy controls were enrolled in the study. Schirmer’s test, Ocular Surface Disease Index (OSDI), noninvasive tear break-up time (NITBUT), the mean keratometry (Km), maximum keratometry (Kmax), central (CCT), thinnest (TCT) and apical (ACT) corneal thicknesses, meibomian gland (MG) loss, meiboscores, morphology of MGs, endothelial cell density (ECD), coefficient of variation (CV), and percentage of hexagonal cells (PHEX) were analyzed. Correlations between anti-Mullerian hormone (AMH) and sex hormones and the findings of PCOS patients were evaluated. Results: Mean OSDI score, intraocular pressure, Km and Kmax values, the mean MG loss of upper and lower eyelids, lower eyelid meiboscore, and degree of morphological abnormalities of MGs were higher in cases with PCOS than healthy controls. There were no significant differences between groups in Schirmer results, first and average NITBUT, mean values of TCT, ACT, CCT, ECD, CV, and PHEX (P > 0.05, for all). There were correlations between plasma AMH level and Kmax, back Km and PHEX, and between estradiol (E2) and PHEX; there were negative correlations between E2 and total MG loss and CV and between total testosterone and ACT. Conclusion: Loss and morphological deterioration of the MGs are observed in PCOS patients, even if the tear parameters are not impaired yet. In eyes with PCOS, keratometry values become steeper in proportion to AMH levels. The PCOS patients should be followed carefully for the development of corneal ectasia.

The Outcome of Fixing Distal Femur Periprosthetic Fracture around Total Knee Replacement using a Locking Plate Non-Contact Bridging (NCB)

@#Introduction: Surgical fixation of peri-prosthetic distal femur fractures around knee replacements poses a challenge, especially in frail patients, with variable outcomes reported in the literature. This study looks at the outcomes of a consecutive series of patients presenting with such fractures and treated by using a locking plate fixation. Materials and methods: A total of 21 consecutive patients who were admitted to our trauma unit over 31 months and underwent fixation with the Non-Contact Polyaxial Locking plate system were retrospectively identified and their acute treatment with follow-up outcomes were analysed. Results: The mean age was 81 years and 71% were in ASA grades 3 and 4. Fracture morphologies were classified as per the Su classification, yielding 8 (38%) classified as Su one, 4 (19%) as Su two, and 9 (43%) as Su type three. Postoperatively, 2 patients (9.5%) died due to hospital-acquired pneumonia, and another 2 patients (9.5%) developed wound infections necessitating further return to theatre. Additionally, 2 (9.5%) patients had distal femoral replacements due to non-union. Mean discharge time was 28 days with 12 patients (55% of patients) starting protected weight-bearing six weeks after surgery. Conclusion: The incidence of morbidity, mortality was significant and re-operation was required in patients treated as described, and these were partly attributed to the patient’s average age and the pre-existing comorbidities. Significant variations were noted in the time to discharge, rehabilitation, and time to achieve fracture union. However, the majority of fractures did eventually unite. Patients with comminuted fractures and insufficient bone stock are more likely to progress to non-union and end up requiring revision knee arthroplasty.

Machine learning empowered COVID-19 patient monitoring using non-contact sensing:An extensive review / 药物分析学报

The severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),which caused the coronavirus disease 2019(COVID-19)pandemic,has affected more than 400 million people worldwide.With the recent rise of new Delta and Omicron variants,the efficacy of the vaccines has become an important question.The goal of various studies has been to limit the spread of the virus by utilizing wireless sensing technologies to prevent human-to-human interactions,particularly for healthcare workers.In this paper,we discuss the current literature on invasive/contact and non-invasive/non-contact technologies(including Wi-Fi,radar,and software-defined radio)that have been effectively used to detect,diagnose,and monitor human activities and COVID-19 related symptoms,such as irregular respiration.In addition,we focused on cutting-edge machine learning algorithms(such as generative adversarial networks,random forest,multilayer perceptron,support vector machine,extremely randomized trees,and k-nearest neighbors)and their essential role in intelligent healthcare systems.Furthermore,this study highlights the limitations related to non-invasive techniques and prospective research directions.

Review on Development of Heart Rate and Respiratory Core Vital Characteristics Monitoring Technology / 中国医疗器械杂志

Life monitoring technology as the basis of health evaluation, in recent years, its related technology research also has new development, in which cardiopulmonary parameters are the core physiological indicators to measure the basic state of vital signs, the analysis of its monitoring technology is particularly important. In this study, the main means of life monitoring are analyzed, and the monitoring technology of cardiopulmonary parameters is the main focus. What is more, the research status and development of contact and non-contact cardiopulmonary monitoring technology at home and abroad were also considered. Lastly, this study will be combined with the radar wave vital signs monitoring technology, which has been achieved good results in the field of cardiopulmonary monitoring, in order to provide a reference for the long-term development of life monitoring field and the technology integration of intelligent pension, intelligent automobile and other related industries.

Research on non-contact respiratory rate measurement method based on video information / 生物医学工程学杂志

Traditional methods of non-contact human respiratory rate measurement usually require complex devices or algorithms. Aiming at this problem, a non-contact respiratory rate measurement method based on only the RGB video information was proposed in this paper. The method consisted of four steps. Firstly, spatial filtering was applied to each frame of the input video. Secondly, a gray compensation algorithm was used to compensate for the gray level change caused by the environmental light. Thirdly, the gray levels of each pixel over time were filtered separately by a low-pass filter. Finally, the region of interest was determined based on the filtering results, and the respiration rate of the human is measured. The physical measurement experiments were designed, and the measurement accuracy was compared with that of the biological radar. The error of the proposed method was between - 5.5% and 3% in different detection directions. The results show that the non-contact respiration rate measurement method can effectively measure the human respiration rate.

A Light Adaptive Heart Rate Detection Method Based on Webcam / 中国医疗器械杂志

In order to extract the pulse wave signal of blood volume effectively in the case of uneven light, a light-adaptive heart rate detection method based on webcam was proposed. In this method, adaptive gamma transform is applied to face image sequence to eliminate the influence of illumination. The pulse wave source signal was extracted from the forehead area and the blood volume pulse wave was obtained by wavelet filtering. The heart rate is estimated by Fourier transform analysis. The Bland-Altman analysis indicates that the method used in this paper is in good agreement with the measurement results of the electronic sphygmomanometer, and the adaptive gamma transformation used in this paper eliminates the influence of light interference, and the measurement error of heart rate is significantly reduced, which is completely able to meet the requirements of daily heart rate monitoring.

Aerosol formation during non-contact "air-puff" tonometry and its significance for prevention of COVID-19 / 中华实验眼科杂志

Objective@#To evaluate the aerosol concentration(PM2.5,PM10.0 and aerosol particle number) formation in non-contact "air-puff" tonometry and provide suggestions for medical workers to take appropriate daily protection during the prevalence of 2019-nCoV.@*Methods@#A cross-sectional study was carried out in this study. Thirty healthy subjects were enrolled on February 22, 2020 at Eye Hospital of Wenzhou Medical University. The intraocular pressure (IOP) was measured by non-contact "air-puff" tonometer in the ophthalmic consulting room and the hall with or without masks. PM2.5, PM10.0 and aerosol particles were recorded by air quality detector. The cumulative effects of IOP measurement, PM2.5, PM10.0 and aerosol particle number were analyzed, and the aerosol density of subjects with and without masks was compared.@*Results@#The PM2.5, PM10.0 and aerosol particles produced by the non-contact "air-puff" tonometry and increased with the increase of spray times. The IOP curves of 60 eyes of 30 subjects were measured respectively in two environments of medical consulting room and medical institution hall. It was found that PM2.5, pm10.0 and particle number fluctuated and increased with the increase of IOP measurement person times, showing cumulative effect, and the accumulation speed of aerosol density in hall was faster than that in consulting room. The density of PM2.5 and PM10.0 produced without gauze mask were (53.417±2.306) and (85.350± 3.488) μg/m3, which were higher than those of (50.567±0.862) and (80.617±1.463) μg/m3 with gauze mask. The differences were statistically significant (P=0.028, 0.019).@*Conclusions@#Aerosol can be produced by non-contact "air-puff" tonometer spraying, and it fluctuates with the increase of spraying times, showing a cumulative effect. The aerosol accumulation is higher in the hall with insufficient air circulation. And more aerosol can be produced without gauze mask.

Comparative measurement of intraocular pressure by Rebound and non-contact tonometry in patients wearing bandage contact lenses after pterygium excision / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To compare the measurement of intraocular pressure(IOP)through a bandage contact lens with the “native” measurement by rebound tonometry and non-contact tonometry in patients after pterygium excision. <p>METHODS: Fifty consecutive patients(50 eyes)undergone pterygium excision(unilateral nasal, primary pterygium, horizontal length <4mm), and conjunctival autografting were included in this prospective study. IOP measurements were obtained by Rebound tonometry and non-contact tonometry in random order with(lens measurement)and without(native measurement)a bandage contact lens half a month after operation. We compared the mean values(validity parameter)and standard deviation(precision parameter)of the two individual measurements in each case using the paired t-test 14d after surgery. <p>RESULTS: With the rebound tonometry we detected statistically significant higher values in the contact lens measurements(18.20±3.19 <i>vs</i> 15.17±3.80mmHg in the native measurements; <i>P</i><0.001), a good correlation with <i>r</i>=0.884 and mean difference was 3.04±1.79mmHg; With the non-contact tonometry we detected statistically significant higher values in the contact lens measurements(15.74±3.23 <i>vs</i> 13.19±3.89mmHg in the native measurements; <i>P</i><0.001), a good correlation with <i>r</i>=0.876 and mean difference was 2.55±1.88mmHg. In the contact lens measurements and native measurements, we detected statistically significant higher values by Rebound tonometry than that by non-contact tonometry(<i>P</i><0.001), and mean difference was 2.46±1.45mmHg, 1.98±1.67mmHg. <p>CONCLUSION: The use of rebound tonometry and non-contact tonometry shows good consistency between lens measurement and native measurement. However, it should be noted that the average of the measurements over contact lens by rebound tonometry and non-contact tonometry were found to be higher than that in native measurement, and the average of the measurements with and without lens by rebound tonometer was found to be higher than what was measured by non-contact tonometry.

Comparative measurement of intraocular pressure by Rebound and non-contact tonometry in patients wearing bandage contact lenses after pterygium excision / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To compare the measurement of intraocular pressure(IOP)through a bandage contact lens with the “native” measurement by rebound tonometry and non-contact tonometry in patients after pterygium excision. <p>METHODS: Fifty consecutive patients(50 eyes)undergone pterygium excision(unilateral nasal, primary pterygium, horizontal length <4mm), and conjunctival autografting were included in this prospective study. IOP measurements were obtained by Rebound tonometry and non-contact tonometry in random order with(lens measurement)and without(native measurement)a bandage contact lens half a month after operation. We compared the mean values(validity parameter)and standard deviation(precision parameter)of the two individual measurements in each case using the paired t-test 14d after surgery. <p>RESULTS: With the rebound tonometry we detected statistically significant higher values in the contact lens measurements(18.20±3.19 <i>vs</i> 15.17±3.80mmHg in the native measurements; <i>P</i><0.001), a good correlation with <i>r</i>=0.884 and mean difference was 3.04±1.79mmHg; With the non-contact tonometry we detected statistically significant higher values in the contact lens measurements(15.74±3.23 <i>vs</i> 13.19±3.89mmHg in the native measurements; <i>P</i><0.001), a good correlation with <i>r</i>=0.876 and mean difference was 2.55±1.88mmHg. In the contact lens measurements and native measurements, we detected statistically significant higher values by Rebound tonometry than that by non-contact tonometry(<i>P</i><0.001), and mean difference was 2.46±1.45mmHg, 1.98±1.67mmHg. <p>CONCLUSION: The use of rebound tonometry and non-contact tonometry shows good consistency between lens measurement and native measurement. However, it should be noted that the average of the measurements over contact lens by rebound tonometry and non-contact tonometry were found to be higher than that in native measurement, and the average of the measurements with and without lens by rebound tonometer was found to be higher than what was measured by non-contact tonometry.

Accuracy of intraocular pressure measurements between non-contact tonometer and ICare rebound tonometer / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To analyze the accuracy of non-contact tonometer(NCT)and ICare rebound tonometer(RBT)in measuring intraocular pressure in glaucoma patients. <p>METHODS:A retrospective proportional control study. Totally 113 patients(185 eyes)with glaucoma were studied. Intraocular pressure was measured by RBT, NCT and Goldmann Applanation tonometer(GAT)at 9:00 and 16:00 and recorded as two sets of data, respectively. Their accuracy is evaluated by the rank sum test, and the international standard 8621 guide, Bland-Altman consistency analysis analyzed the consistency of the two groups of measurements, and the data were divided into two groups: abnormal intraocular pressure group(<10mmHg or >21mmHg)and normal intraocular pressure group(10-21mmHg). The consistency was analyzed between different groups. The spearman correlation analysis is adopted to analyze the correlation between ophthalmotonometers.<p>RESULTS: There were differences among the GAT, NCT and RBT measurements(<i>P</i><0.01). There was a strong correlation between the intraocular pressure measured value obtained by GAT and measured values obtained by RBT and NCT(<i>rs</i>=0.71, 0.77, <i>P</i><0.001). The measured values of NCT and GAT are close to each other without statistically significant differences(<i>P</i>=0.92). Compared with GAT, RBT has a higher intraocular pressure measured value, and there are significant differences(<i>P</i><0.05). However, compared with GAT, both NCT and RBT have a wide range of limits of agreement, and they are(-6.2-6.0mmHg)and(-5.2-7.6mmHg)respectively. In normal intraocular pressure groups, the ranges of limits of agreement are(-5.9-5.9mmHg)and(-4.3-7.5mmHg)respectively. In abnormal intraocular pressure groups, the ranges of limits of agreement are(-7.3-6.4mmHg)and(-7.5-5.6mmHg)respectively. The evaluation carried out in accordance with ISO 8612 guides indicates that the abnormal values more than the 95% of consistency restriction of NCT and RBT in the three groups are(3.9%, 11.3%, 12.2%)and(26.3%, 11.3%, 12.2%)respectively.<p>CONCLUSION: Both NCT and RBT cannot simply replace the GAT to measure the intraocular pressure of glaucoma patients. In glaucoma patients, with the deviation of the measured value from the normal intraocular pressure range, the measurement error of NCT and RBT also increase.

Identification of the stroke type of hemorrhage and ischemic based on microwave measurement technique / 国际生物医学工程杂志

Objective@#To establish a microwave scattering parameter acquisition system to detect cerebral hemorrhage and cerebral ischemia animal models, and to study the non-contact rapid identification methods for the two stroke types.@*Methods@#Rabbits were selected for modeling. Eight rabbits in the cerebral hemorrhage group were injected with autologous blood. Six rabbits in the cerebral ischemia group were treated with bilateral common carotid artery clamping and femoral artery bleeding. The measurement excitation source has a scanning frequency range of 300 kHz to 3 GHz and an intermediate frequency bandwidth of 30 kHz. The signal of the S21 phase was acquired. The collected microwave scattering signals were subjected to mean filtering, principal component analysis dimension reduction, and mean clustering and nearest neighbor analysis to realize the identification of stroke types.@*Results@#The microwave scattering measurement method can reflect the changes of cerebral hemorrhage and cerebral ischemia. The phase of S21 decreases with the increase of blood loss and increases with the increase of ischemic duration. The results of the differential experiment showed that all 14 models were correctly identified.@*Conclusions@#The stroke identification system based on microwave scattering measurement can effectively distinguish rabbit cerebral hemorrhage model and ischemic model. This technology is low cost, portable non-invasive, simple operation and fast, which make it be a promising method for identifying pre-hospital stroke types.

Relative Telomere Length in Blood Leukocytes of Patients with Anterior Cruciate Ligament Injury: A Pilot Study

@#Introduction: Anterior cruciate ligament (ACL) tear is the most common knee ligament injury, especially in athletes. The objective of this study was to investigate relative telomere length (RTL) in blood leukocytes of patients with ACL injury compared with that of controls. Materials and Methods: A total of 187 subjects were invited to participate in this study. Ninety-two patients with clinically diagnosed ACL rupture were enrolled. Ninety-five age and gender-matched healthy controls were also recruited. Blood leukocyte RTL were analysed using quantitative real-time polymerase chain reaction. Results:Patients with ACL rupture had significantly longer relative telomere length than healthy controls (P=0.002). The patients with ACL rupture were classified into two groups according to the sport history of patients which are contact sports and non-contact sports. RTL in patients with non-contact sports was significantly greater than those with contact sports (P=0.006). Moreover, RTL was inversely correlated with body mass index of patients with ACL injury (r=-0.34, P=0.001). Logistic regression analysis indicated that long RTL was associated with a higher risk of ACL rupture. Conclusion: The present study showed that subjects with ACL rupture had significantly greater telomere length compared with their age and gender-matched controls. This finding may result from the increases in physical activity and overexpression of telomerase which acts as a protective mechanism against ACL injury. RTL in blood leukocytes is associated with a risk of ACL rupture.

Comparison of Central Corneal Thickness Measurements between Noncontact Specular Microscopy and Ultrasound Pachymetry

PURPOSE: We compared and analyzed central corneal thickness (CCT) measurements according to the corneal thickness obtained with noncontact specular microscopy (NCSM) and ultrasound pachymetry (USP). METHODS: CCT was measured in the order of NCSM and USP by a single optometrist in 120 eyes of 120 healthy subjects. The measurements were compared between the devices and the measurement agreements and correlations between the devices were analyzed. To determine if the measurements differed depending on the thickness of the cornea, the patients were divided into three tertile groups from the thinnest patient by CCT measurement using USP, and then the differences in CCT measured by the two devices were analyzed. RESULTS: The CCT measurements using NCSM and USP were 548.25 ± 4.64 µm and 533.09 ± 35.96 µm, respectively. NCSM measurements were found to be thicker, showing statistically significant differences between the measurements (p < 0.001). The two examinations showed a high degree of correlation (r = 0.878; p < 0.01). In the three groups, the differences in CCT measurements between NCSM and USP were 12.93 ± 21.88 µm, 16.85 ± 15.89 µm, and 15.70 ± 20.46 µm, respectively, but the differences between the three groups were not statistically significant (p = 0.655). CONCLUSIONS: Our results show that although the differences in CCT measurements using NCSM and USP were consistent regardless of the corneal thickness, the CCT measurements by NCSM and USP were highly correlated.

The First Acanthamoeba keratitis Case of Non-Contact Lens Wearer with HIV Infection in Thailand

Acanthamoeba keratitis (AK) is a rare sight-threatening corneal infection, often reporting from contact lens wearers. An asymptomatic human immunodeficiency virus (HIV)-infected Thai male without history of contact lens use complained foreign body sensation at his left eye during motorbike riding. He had neither specific keratitis symptoms nor common drugs responding, which contributed to delayed diagnosis. By corneal re-scraping, Acanthamoeba-like cysts were detected by calcofluor white staining and agar culture. The etiological agent obtained from the culture was molecularly confirmed by Acanthamoeba spp.-specific PCR, followed by DNA sequencing. The results from BLAST and phylogenetic analysis based on the DNA sequences, revealed that the pathogen was Acanthamoeba T4, the major genotype most frequently reported from clinical isolates. The infection was successfully treated with polyhexamethylene biguanide resulting in corneal scar. This appears the first reported AK case from a non-contact lens wearer with HIV infection in Thailand. Although AK is sporadic in developing countries, a role of free-living Acanthamoeba as an opportunistic pathogen should not be neglected. The report would increase awareness of AK, especially in the case presenting unspecific keratitis symptoms without clinical response to empirical antimicrobial therapy.

Identification of the stroke type of hemorrhage and ischemic based on microwave measurement technique / 国际生物医学工程杂志

Objective To establish a microwave scattering parameter acquisition system to detect cerebral hemorrhage and cerebral ischemia animal models, and to study the non-contact rapid identification methods for the two stroke types. Methods Rabbits were selected for modeling. Eight rabbits in the cerebral hemorrhage group were injected with autologous blood. Six rabbits in the cerebral ischemia group were treated with bilateral common carotid artery clamping and femoral artery bleeding. The measurement excitation source has a scanning frequency range of 300 kHz to 3 GHz and an intermediate frequency bandwidth of 30 kHz. The signal of the S21 phase was acquired. The collected microwave scattering signals were subjected to mean filtering, principal component analysis dimension reduction, and mean clustering and nearest neighbor analysis to realize the identification of stroke types. Results The microwave scattering measurement method can reflect the changes of cerebral hemorrhage and cerebral ischemia. The phase of S21 decreases with the increase of blood loss and increases with the increase of ischemic duration. The results of the differential experiment showed that all 14 models were correctly identified. Conclusions The stroke identification system based on microwave scattering measurement can effectively distinguish rabbit cerebral hemorrhage model and ischemic model. This technology is low cost, portable non-invasive, simple operation and fast, which make it be a promising method for identifying pre-hospital stroke types.

Monitoring osseointegrated prosthesis loosening and fracture using electrical capacitance tomography

A noncontact, noninvasive, electrical permittivity imaging technique is proposed for monitoring loosening of osseointegrated prostheses and bone fracture. The proposed method utilizes electrical capacitance tomography (ECT), which employs a set of noncontact electrodes, arranged in a circular fashion around the imaging area, for electrical excitations and measurements. An inverse reconstruction algorithm was developed and implemented to reconstruct the electrical permittivity distribution of the interrogated region from boundary capacitance measurements. In this study, osseointegrated prosthesis phantoms were prepared using plastic rods and Sawbone femur specimens, which were subjected to prosthesis loosening and fracture monitoring tests. The results demonstrated that the spatial location and extent of prosthesis loosening and bone fracture could be estimated from the ECT reconstructed permittivity maps. The resolution of the reconstructed images was further enhanced by a limited region tomography algorithm, and its accuracy in terms of identifying the severity, location, and shape of bone fracture was also investigated and compared with conventional full region tomography.