眼底横向显微成像系统的研制及应用

介绍了一套基于MEMS薄膜变形镜的人眼眼底横向显微成像系统。采用37单元MEMS薄膜变形反射镜作为波前校正元件,127微透镜阵列哈特曼夏克（Hartmann—Shack）波前传感器测量波前误差,在用计算机控制薄膜变形镜实现波前误差校正后,开启成像照明光源．用CCD相机记录视网膜图像。模拟眼试验表明．系统能够有效进行像差测量、校正和眼底成像,像差校正后成像质量达到衍射极限。临床试用表明,除少部分眼内比较浑浊的病人外,整个检查过程大部分病人都能够安全、快捷、可靠地进行。     

International transmission of tele-ophthalmology images

Tele-ophthalmic consultations were conducted between a hospital in East Java, Indonesia, and an ophthalmology centre in Perth, Western Australia. Twenty-two eyes of 14 subjects were screened for glaucoma using a hand-held fundus camera. Optic disc images comprised 267 x 234 pixels at 24 bit/pixel (187 kByte). The images were compressed and stored together with patient information on a laptop computer. The images were then transmitted to Perth using either a mobile phone or a satellite phone, taking 170 s or 240 s, respectively. Images were also compressed to five different compression levels before transmission. At a compression ratio of 1:5, the images were 36 kByte in size and took 29 s to transmit by mobile phone and 60 s by satellite phone. To measure the loss of quality, the root mean square error was calculated for each colour component, comparing the transmitted and original images. The coefficients of variation were 10% (green), 15% (blue) and 22% (red). The images received in Perth were considered to be of excellent quality and readily interpreted by ophthalmologists in terms of the likely presence of glaucoma.     

Diagnostic Accuracy of Detecting Diabetic Retinopathy by Using Digital Fundus Photographs in the Peripheral Health Facilities of Bangladesh: Validation Study

BackgroundDiabetic retinopathy can cause blindness even in the absence of symptoms. Although routine eye screening remains the mainstay of diabetic retinopathy treatment and it can prevent 95% of blindness, this screening is not available in many low- and middle-income countries even though these countries contribute to 75% of the global diabetic retinopathy burden.ObjectiveThe aim of this study was to assess the diagnostic accuracy of diabetic retinopathy screening done by non-ophthalmologists using 2 different digital fundus cameras and to assess the risk factors for the occurrence of diabetic retinopathy.MethodsThis validation study was conducted in 6 peripheral health facilities in Bangladesh from July 2017 to June 2018. A double-blinded diagnostic approach was used to test the accuracy of the diabetic retinopathy screening done by non-ophthalmologists against the gold standard diagnosis by ophthalmology-trained eye consultants. Retinal images were taken by using either a desk-based camera or a hand-held camera following pupil dilatation. Test accuracy was assessed using measures of sensitivity, specificity, and positive and negative predictive values. Overall agreement with the gold standard test was reported using the Cohen kappa statistic (κ) and area under the receiver operating curve (AUROC). Risk factors for diabetic retinopathy occurrence were assessed using binary logistic regression.ResultsIn 1455 patients with diabetes, the overall sensitivity to detect any form of diabetic retinopathy by non-ophthalmologists was 86.6% (483/558, 95% CI 83.5%-89.3%) and the specificity was 78.6% (705/897, 95% CI 75.8%-81.2%). The accuracy of the correct classification was excellent with a desk-based camera (AUROC 0.901, 95% CI 0.88-0.92) and fair with a hand-held camera (AUROC 0.710, 95% CI 0.67-0.74). Out of the 3 non-ophthalmologist categories, registered nurses and paramedics had strong agreement with kappa values of 0.70 and 0.85 in the diabetic retinopathy assessment, respectively, whereas the nonclinical trained staff had weak agreement (κ=0.35). The odds of having retinopathy increased with the duration of diabetes measured in 5-year intervals (P<.001); the odds of having retinopathy in patients with diabetes for 5-10 years (odds ratio [OR] 1.81, 95% CI 1.37-2.41) and more than 10 years (OR 3.88, 95% CI 2.91-5.15) were greater than that in patients with diabetes for less than 5 years. Obesity was found to have a negative association (P=.04) with diabetic retinopathy.ConclusionsDigital fundus photography is an effective screening tool with acceptable diagnostic accuracy. Our findings suggest that diabetic retinopathy screening can be accurately performed by health care personnel other than eye consultants. People with more than 5 years of diabetes should receive priority in any community-level retinopathy screening program. In a country like Bangladesh where no diabetic retinopathy screening services exist, the use of hand-held cameras can be considered as a cost-effective option for potential system-wide implementation.     

免散瞳眼底照相仪在糖尿病视网膜病变社区防治中临床疗效评价

目的:探索免散瞳眼底照相仪在糖尿病视网膜病变社区防治中临床疗效。方法:本次研究对象为100例疑似糖尿病视网膜病变患者,均进行免散瞳眼底照相仪检查,随访分析此项检查在视网膜病变分期中正确率以及图像质量。结果:免散瞳眼底照相仪图像质量可以评估的有78.05%,对视网膜病变Ⅰ期诊断正确率为96.00%,对Ⅱ期诊断正确率为95.83%,对Ⅲ期诊断正确率为94.74%,对Ⅳ期诊断正确率为94.44%。同时对糖尿病视网膜病变敏感度为95.35%,特异度为92.86%,漏诊率为4.65%,误诊率为7.14%。结论:在评估糖尿病视网膜病变患者时,运用免散瞳眼底照相仪检查,可及时发现眼底病变,为后期随访提供详细参考信息。     

Picture archiving and fundus imaging in a glaucoma clinic

Ophthalmological image archiving and distribution can be automated using a picture archiving and communication system (PACS). A fundus PACS has been in clinical use since February 2000 at the ophthalmology clinic of Tampere University Hospital. It consists of a digital fundus camera, an imaging workstation, from which new patients can be added to the archive, 10 viewing stations and an image archive server. In glaucoma imaging, the fundus images taken from a patient are transferred from the imaging workstation to the image archive server and are then immediately available from the physician's viewing workstation; the transfer time of an average image, of 350 kbit, is 0.0035 s, even though the archive is located 5 km away. After 18 months of operation there were over 16,000 images archived; these took 5.3 GByte of a total storage capacity of 41.9 GByte. The network and archive server achieved 99% reliability in use. Digital imaging makes it possible to shift ophthalmology clinics towards more patient-oriented treatment procedures.     

A simple telemedicine system using a digital camera

Radiographs on a viewing box were photographed at a remote hospital in South Africa using a digital camera with a resolution of 1024 x 768 pixels at 24-bit colour depth. The resultant images were stored in JPEG format and transmitted as email attachments to be read on a PC monitor by radiologists in Durban and Cape Town. Twenty-seven images were received, of which 23 were of diagnostic quality (85%). The mean file size was 120 kByte. For quality control purposes, 100 chest radiographs were photographed at a base hospital and read by a radiologist blinded to the diagnosis. In this study 96 images were of diagnostic quality (96%) and the correct diagnosis was made in 90 cases (94%). Incorrect readings were made in six cases (6%): small pulmonary nodules (less than 1 cm in diameter) were missed in five cases and in one case early apical tuberculosis was missed. Digital camera technology permits simple, inexpensive telemedicine. Limited spatial resolution is a concern when reading chest images with small pulmonary nodules and infiltrates.     

荧光定量RT-PCR快速检测A型流感病毒

目的利用荧光定量RT-PCR技术建立一种快速检测A型流感病毒的方法。方法根据A型流感M2基因的相对保守序列分别设计一对引物及其相应的Taqman探针,建立、优化反应体系后,利用十倍稀释法检验方法的灵敏度并建立相对定量标准曲线并与普通RT-PCR法进行比较;特异性检验后进行临床标本的检验。结果A型流感病毒检测反应的灵敏度为2·56×10-6TCID50,标准曲线相关系数为0·999,扩增效率为108·5%,5种非A型流感病毒病原体检测均为阴性,说明此方法具有很好的稳定性、重现性和特异性。结论本研究建立荧光定量RT-PCR技术可以准确检测A型流感病毒,不仅灵敏度高、稳定性好,而且可以对病毒滴度进行定量检测。     

Screening for Diabetic Retinopathy in Rural Areas: The Potential of Telemedicine

Diabetic retinopathy is a common cause of blindness, and screening can identify the disease at an earlier, more treatable stage. However, rural individuals with diabetes may have limited access to needed eye care. The objective of this project was to demonstrate the feasibility of a diabetic retinopathy screening program using a state-of-the-art nonmydriatic digital fundus imaging system. The study involved a series of patients screened in primary care and public health locations throughout seven predominantly rural counties in eastern North Carolina. Images of each fundus were obtained and sent to a retinal specialist. The retinal specialist reviewed each image, recorded image quality, diagnosed eye disease and made recommendations for subsequent care. Of 193 volunteers with a history of diabetes mellitus, 96.3 percent reported that they were very comfortable or comfortable with the camera. Eighty-five percent of images were rated as good or fair by the retinal specialist. The retinal specialist also reported being very certain or certain of the diagnosis in 84 percent of cases. Image quality correlated highly with the certainty of diagnosis (Spearman's rank order correlation coefficient = 0.79; P < 0.001). The average time since the previous examination by an eye care specialist for diabetic subjects was two years. Approximately 62 percent of diabetic patients had diagnosable eye conditions, the most common of which was diabetic retinopathy (40.9 percent). In this convenience sample, African Americans, despite similar age and disease duration, were more likely to have retinopathy. Digital imaging is a feasible screening modality in rural areas, may improve access to eye care, and may improve compliance with care guidelines for individuals with diabetes mellitus.     

Reflex-free Digital Fundus Photography Using a Simple and Portable Camera Adaptor System. A Viable Alternative

Purpose: To describe a digital single lens reflex (dSLR) camera adaptor for posterior segment photography. Method: A total of 30 normal canine and feline animals were imaged using a dSLR adaptor which mounts between a dSLR camera body and lens. Posterior segment viewing and imaging was performed with the aid of an indirect lens ranging from 28-90D. Coaxial illumination for viewing was provided by a single white light emitting diode (LED) within the adaptor, while illumination during exposure was provided by the pop-up flash or an accessory flash. Corneal and/or lens reflections were reduced using a pair of linear polarizers, having their azimuths perpendicular to one another. Results: Qualityhigh-resolution, reflection-free, digital images of the retina were obtained. Subjective image evaluation demonstrated the same amount of detail, as compared to a conventional fundus camera. A wide range of magnification(s) [1.2-4X] and/or field(s) of view [31-95 degrees, horizontal] were obtained by altering the indirect lens utilized. Conclusion: The described adaptor may provide an alternative to existing fundus camera systems. Quality images were obtained and the adapter proved to be versatile, portable and of low cost.     

双眼视野抑制暗点检测仪的研制

本文介绍了应用于眼科临床的双眼视野抑制暗点检测仪,该仪器应用计算机控制步进电机给出注视标和斜视标,用CCD摄像头实时监测眼球位置,判断眼球在测试期间是否移动。计算机以患者手动开关的状态判断暗点的存在。     

多功能计算机阅片系统及其应用研究

本文介绍了一种多功能计算机阅片系统及其在临床和医学教育中的应用,该系统能对标准教学片进行数字化存贮和管理,教学时,教师可任意调出存贮在计算机中的图像,由若干个图像监视器同时显示,供学生观看,该系统具有丰富的图像处理软件,在临床上可作为图像分析和处理的工具,由于系统成本低,功能多,适合我国国情,值得在医学领域推广应用。     

Hand-held digital video-camera for eye examination and follow-up

We developed a hand-held digital colour video-camera for eye examination in primary care. The device weighed 550 g. It featured a charge-coupled device (CCD) and corrective optics. Both colour video and digital still images could be taken. The video-camera was connected to a PC with software for database storage, image processing and telecommunication. We studied 88 normal subjects (38 male, 50 female), aged 7-62 years. It was not necessary to use mydriatic eye drops for pupillary dilation. Satisfactory digital images of the whole face and the anterior eye were obtained. The optic disc and the central part of the ocular fundus could also be recorded. Image quality of the face and the anterior eye were excellent; image quality of the optic disc and macula were good enough for tele-ophthalmology. Further studies are needed to evaluate the usefulness of the equipment in different clinical conditions.     

The validity of self-reported diabetes quality of care measures.

OBJECTIVE: First, to test the validity of self-reported quality of care and treatment measures compared with medical records and administrative data for: eye examinations, hemoglobin A1C tests, and use of insulin and oral agents for adult patients with diabetes; and secondly to assess the consistency between medical record information and administrative data for the same measures plus microalbumin testing. DESIGN: Cross-sectional study using data from telephone survey, primary care medical and eye records, and administrative claims. SETTING: Statewide health maintenance organization in Minnesota, USA, 1995. STUDY PARTICIPANTS: Four hundred and forty adults with diabetes, aged 31-64 years. MAIN OUTCOME MEASURES: Validity++ of self-reported diabetes quality of care measures compared with a criterion standard combining information from primary care and eye records with information from administrative data; and reliability of medical record information compared with administrative data. RESULTS: Although the sensitivity of self-reported eye examination was high (89%), the specificity was low (65%). Self-report of hemoglobin A1C also had high sensitivity (99%) and a lower specificity than that of eye examination (28%). The two information sources (medical records and claims) used in the criterion standard each contained complementary and non-overlapping information. Reliability was highest for microalbumin testing (kappa, 0.75) and lowest for eye examination (kappa, 0.37). CONCLUSIONS: Quality of care measures for diabetes are often drawn from a variety of sources. To the extent that data sources are biased, the measures can be misleading. Self-report is likely to lead to an overestimate of eye screening and the measurement of hemoglobin A1C. Reported rates of quality of care should be inspected carefully. The 'same' rate taken from different sources may vary.     

Photostress recovery times in cases of central serous retinopathy

Photostress recovery times were measured in 50 normal individuals in the age group 20–50 years and in 27 patients who had developed central serous retinopathy. A flash generator of a commercially available fundus camera was used to provide the appropriate stimulus. The results showed that photostress recovery times were grossly abnormal in patients with central serous retinopathy for the first few weeks after the onset of symptoms, but gradually returned to normal values by 5 months and remained so thereafter. In a few patients during the recovery phase a transient paradoxical response was noted, whereby the photostress recovery times became less than in the unaffected control eye.

It appears that the use of a fundus camera to provide photostress stimulus has merit because the light source is subject only to slight variation in intensity, standardization of responses is possible and the technique can be employed on patients about to have fluorescein angiographic studies for diagnostic or documentation purposes.

     

The potential of digital monochrome images versus colour slides in telescreening for diabetic retinopathy

We explored the potential of digital monochrome images as an alternative to colour slides in screening for diabetic retinopathy. Twenty-eight patients with diabetes were recruited for the study and 20 actually participated. Using a fundus camera (Nikon 505AF) one set of three digital images and one set of three colour slides were taken per eye. Two independent ophthalmologists graded the colour slides and the digital images for diabetic retinopathy. The ophthalmologists spent about two minutes grading each set of images, suggesting that specialists could potentially screen a large number of patients. The agreement between the two screening methods was 0.95 and 0.89, with respect to disease or no disease. The agreement (kappa) between the two ophthalmologists for grade of retinopathy was 0.47 when colour slides were employed and 0.61 when digital monochrome images were employed. The results indicate that digital red-free monochrome images represent a superior screening tool for diabetic retinopathy. Tele-screening may be beneficial when patients have to travel substantial distances to visit an ophthalmologist.     

Evaluation of a digital store-and-forward colposcopic system--a pilot study to assess usability for telemedicine

We evaluated the diagnostic reliability of cervical examination using digital colposcopy compared with conventional binocular colposcopy. A total of 315 patients were examined and diagnosed by a colposcopist on-site. During the colposcopic examination, digital camera images were stored on a PC (median five pictures per patient). A second physician, experienced in colposcopy, re-evaluated the initial diagnostic findings using the stored digital images. The primary and secondary findings in each patient were categorized according to the Rome classification system. There was agreement between the primary and secondary examiners in 69% of cases (kappa=0.60). There was no systematic bias in terms of under- or over-rating. The proportion of non-assessable colposcopic examinations was 9%. Digital colposcopy was reliable and provided advantages in terms of a better follow-up examination and internal quality control of the diagnosis. The pilot study suggests that telecolposcopy may provide better training and further education for physicians and students, and may also improve the diagnostic possibilities in gynaecology.     

Development of a screening instrument to detect physical abuse and its use in a cohort of pregnant women in Sri Lanka

The objective of this study was to develop and validate a screening instrument (Abuse Assessment Questionnaire) to estimate the prevalence of physical abuse in a cohort of pregnant women in a district of Sri Lanka. The samples of 1200 pregnant women were identified by using a cluster sampling technique. Public health midwives (primary healthcare workers) were selected as interviewers and the antenatal clinic was identified as the setting to identify physical abuse. The reliability and validity (sensitivity 85.7%; specificity 89.7%) of the screening instrument proved to be high. The prevalence of physical abuse in categories 'ever-abuse', 'current abuse' and 'current pregnancy'were 18.3%, 10.6% and 4.7% respectively. In addition, 'current sexual abuse' was reported by 2.7% of women. The prevalence rates indicate that the physical abuse of women is a significant public health problem. The Abuse Assessment Questionnaire, administered by public health midwives, proved valuable in detecting physical abuse in pregnant women. If this instrument is used universally to screen Lankan women for physical abuse in antenatal clinics, it has good potential for early detection and intervention.     

Epidemic keratoconjunctivitis in a university medical center ophthalmology clinic; need for re-evaluation of the design and disinfection of instruments

During the period from early December 1987 to late January 1988, an outbreak of epidemic keratoconjunctivitis (EKC) caused by adenovirus type 8 occurred at a university medical center eye clinic. A telephone survey of patients revealed an attack rate of 17% among patients seen during the epidemic period. A case-control study demonstrated that development of EKC was associated with exposure to pneumotonometry and to three caregivers. After controlling for exposure to pneumotonometry, however, only exposure to one caregiver was significantly associated with risk of the disease. On January 19, 1988, after recognition of the outbreak, the eye clinic instituted additional infection control measures. A survey of patients seen the following week showed a substantial decrease in the attack rate (1.9%). Before these control measures were implemented, clinic personnel had followed the manufacturer's recommendations and disinfected pneumotonometer tips with 70% isopropyl alcohol, fearing that other disinfectants would corrode the instrument metal. Isopropyl alcohol, shown to have limited activity against adenovirus in vitro, also was being used to "disinfect" pneumotonometer tips between uses at six other area eye clinics polled by telephone. The results of this study demonstrate the need for changes in the design and manufacture of equipment used in the eye clinic.     

Instant wireless transmission of radiological images using a personal digital assistant phone for emergency teleconsultation

The instant transmission of radiological images may be important for making rapid clinical decisions about emergency patients. We have examined an instant image transfer system based on a personal digital assistant (PDA) phone with a built-in camera. Images displayed on a picture archiving and communication systems (PACS) monitor can be captured by the camera in the PDA phone directly. Images can then be transmitted from an emergency centre to a remote physician via a wireless high-bandwidth network (CDMA 1 x EVDO). We reviewed the radiological lesions in 10 normal and 10 abnormal cases produced by modalities such as computerized tomography (CT), magnetic resonance (MR) and digital angiography. The images were of 24-bit depth and 1,144 x 880, 1,120 x 840, 1,024 x 768, 800 x 600, 640 x 480 and 320 x 240 pixels. Three neurosurgeons found that for satisfactory remote consultation a minimum size of 640 x 480 pixels was required for CT and MR images and 1,024 x 768 pixels for angiography images. Although higher resolution produced higher clinical satisfaction, it also required more transmission time. At the limited bandwidth employed, higher resolutions could not be justified.     

Norwegian version of the Nutritional Form for the Elderly: sufficient psychometric properties for performing institutional screening of elderly patients

The objective of this study was to test if the Norwegian version of the nutritional screening instrument entitled Nutritional Form for the Elderly (NUFFE-NO) demonstrates sufficient evidence of reliability and validity, including sensitivity and specificity, when applied to a select group of elderly hospital patients. The hypothesis was that NUFFE-NO has sufficient psychometric properties to be used as a screening instrument. The model used for the testing procedure was designed to test reliability (homogeneity and stability) and validity (criterion-related, concurrent validity, and construct validity) including sensitivity and specificity in a cross-sectional study. One-hundred fifty-eight patients were interviewed using the nutritional screening instruments NUFFE-NO and Mini Nutritional Assessment (MNA). They were interviewed once again (using NUFFE-NO) 2 to 4 days afterward. Background variables were collected. Data from the patients' records were collected regarding the nutritional screening instrument Nutrition Risk Screening 2002. Anthropometric measurements were performed. A Cronbach α coefficient of .77 was obtained. A majority of the items showed good or very good agreement in a test-retest. A high correlation coefficient (as a measurement of concurrent validity) was estimated between NUFFE-NO and MNA. The NUFFE-NO could separate groups with expected high and low scores, which supported construct validity. Calculated sensitivity and specificity values for NUFFE-NO, with MNA as a criterion and receiver operating characteristic curves with areas 0.79 and 0.80, showed appropriate cutoff points for measuring low, medium, and high risk for undernutrition. In conclusion, NUFFE-NO was shown to have sufficient psychometric properties for performing an institutional screening of elderly hospital patients.