scholarly journals Συσχέτιση κεντρικού πάχους κερατοειδούς με πάχος οπτικών ινών και των παραμέτρων της οπτικής θηλής με HRT II στην οφθαλμική υπερτονία και στους διαφόρους τύπους γλαυκώματος

2013 ◽  
Author(s):  
Χρήστος Πίτσας
Keyword(s):  
Standard Deviation ◽  
Mean Deviation ◽  
Pattern Standard Deviation

ΣΚΟΠΟΣ: Να συγκρίνουμε και να συσχετίσουμε τις παραμέτρους τηςκεφαλής του οπτικού νεύρου που λαμβάνονται με το HRT με ταελλείμματα (σκοτώματα) που εντοπίστηκαν από την short-wavelengthautomatic perimetry (SWAP) σε οφθαλμούς με οφθαλμική υπερτονία(OHT).ΜΕΘΟΟΣ: Η μελέτη περιελάμβανε με τυχαία επιλογή τον έναοφθαλμό από 146 διαδοχικούς ασθενείς με οφθαλμική υπερτονία. Όλοι οιασθενείς που περιελήφθησαν στην μελέτη είχαν αξιόπιστα οπτικά πεδία,SWAP και μετρήσεις HRT που πραγματοποιήθηκαν εντός 2 εβδομάδων.Οι οφθαλμοί κατηγοριοποιήθηκαν ως φυσιολογικοί ή παθολογικοί,σύμφωνα με τα κριτήρια του οπτικού πεδίου και του Moorfieldsregression analysis MRA για το HRT.ΑΠΟΤΕΛΕΣΜΑΤΑ: Η ανάλυση της συσχέτισης μεταξύ των δεικτώντου οπτικού πεδίου { mean deviation (MD), pattern standard deviation(PSD) και corrected pattern standard deviation (CPSD)} και τωνπαραμέτρων του HRT έγινε με τη χρήση του Spearman correlationcoefficient (r) και η συμφωνία μεταξύ των εξετάσεων, για τονχαρακτηρισμό των οφθαλμών, υπολογίστηκε με την τιμή k.Αποτελέσματα: Η μέση ηλικία των ασθενών ήταν 53 ± 10,5 χρόνια καιτο μέσο πάχους του κεντρικού κερατοειδούς (CCT) ήταν 559 ± 37 μm.Είκοσι-εννέα οφθαλμοί (19,9%) είχαν σκοτώματα στην SWAP. Είκοσιεννέα οφθαλμοί (19,9%) είχαν φυσιολογικό HRT. Έξι οφθαλμοί (4,1%)είχαν φυσιολογικό HRT και σκοτώματα στην SWAP. Άλλοι εννέαοφθαλμοί (6,2%) είχαν "οριακό" HRT και σκοτώματα στη SWAP .Το k statistic είναι 0,116 (ρ = 0,12), και έτσι υπάρχει μια πολύ χαμηλήσυμφωνία μεταξύ των δύο μεθόδων. εν ανιχνεύθηκε στατιστικάσημαντική συσχέτιση μεταξύ των παραμέτρων της HRT και τωνπαραμέτρων της SWAP.ΣΥΜΠΕΡΑΣΜΑΤΑ: Τα σκοτώματα στην SWAP μπορεί να συνυπάρχουν με βλάβες του οπτικού δίσκου που ανιχνεύει το HRT σεοφθαλμούς με οφθαλμική υπερτονία. Στους περισσότερους οφθαλμούς,ωστόσο, οι δύο μέθοδοι ανιχνεύουν διαφορετικές χαρακτηριστικά τουγλαυκώματος.

scholarly journals Changes in Frequency-Doubling Perimetry in Patients with Type I Diabetes prior to Retinopathy

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Isabel Pinilla ◽  
Antonio Ferreras ◽  
Miriam Idoipe ◽  
Ana I. Sanchez-Cano ◽  
Diana Perez-Garcia ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Type I Diabetes ◽  
Frequency Doubling ◽  
Diabetic Group ◽  
Control Group ◽  
Mean Deviation ◽  
Diabetic Patients ◽  
Type I ◽  
Pattern Standard Deviation ◽  
The Mean

Purpose. To evaluate the ability of frequency-doubling technology (FDT) perimetry in detecting visual field defects in young adults with type I diabetes prior to retinopathy or with minor retinovascular changes.Methods. This comparative cross-sectional study included 30 healthy subjects and 73 age-matched patients with type I diabetes mellitus. All subjects underwent a full ocular examination including an FDT with the threshold C-20-5 strategy. Only one eye per subject was randomly included in the statistical analysis. FDT results and time to perform the test were compared between the groups.Results. The mean age was 27.1 years in the control group and 26.6 years in the diabetic group (P=0.875). The mean period from the onset of diabetes was12.6±6.7years, while minimal retinovascular changes were observed in 18 eyes. Mean deviation of FDT did not differ between the groups. Although global indices of FDT were within normal limits, pattern standard deviation of FDT was higher in the diabetic group (P=0.035). The area under the receiver operating characteristic curve was 0.647 for pattern standard deviation of FDT (standard error = 0.052;P=0.017).Conclusion. FDT can detect retinal dysfunctions in diabetic patients prior to the onset of significant vascular complications.

scholarly journals Comparison of imo and Humphrey field analyzer perimeters in glaucomatous eyes

2021 ◽  
Vol 14 (12) ◽  
pp. 1882-1887
Author(s):  
Yoshinori Nakai ◽  
◽  
Yuko Shono ◽  
Kaori Taoka ◽  
Yoshihide Nakai ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Visual Field ◽  
Mean Deviation ◽  
Diagnostic Ability ◽  
Visual Field Index ◽  
Pattern Standard Deviation ◽  
Humphrey Field Analyzer ◽  
The Difference ◽  
Field Disturbance ◽  
Sensitivity Specificity

AIM: To compare the imo perimeter, a new portable head-mounted perimeter unit that enables both eyes to be examined quickly and simultaneously, with the Humphrey field analyzer (HFA) perimeter to investigate correlations and their diagnostic ability in glaucomatous eyes. METHODS: The performance of the equipment in 128 glaucomatous eyes and 40 normal eyes were tested. We investigated the correlations of mean deviation, pattern standard deviation, visual field index, and the sensitivity. RESULTS: Measurements of mean deviation (r=0.886, P<0.001), pattern standard deviation (r=0.814, P<0.001), and visual field index (r=0.871, P<0.001) in both perimeters were strongly and positively correlated. The sensitivities in the imo perimeter were 80.5% for mean deviation, 81.2% for pattern standard deviation, and 80.5% in visual field index; those in the HFA were 63.3% for mean deviation, 74.5% for pattern standard deviation, and 80.5% for visual field index. Both perimeters demonstrated high diagnostic ability. CONCLUSION: The parameters by the imo and HFA in glaucomatous eyes show strong positive correlations with favorable sensitivity, specificity, and diagnostic ability. However, the difference between imo and HFA results increases with the increase in visual field disturbance.

Eye Movements Simultaneously Recorded by Electrooculographic and Photoelectric Methods

1979 ◽  
Vol 48 (2) ◽  
pp. 619-624 ◽  
Author(s):  
Jin Ong ◽  
Gene A. Harman
Keyword(s):  
Eye Movements ◽  
Standard Deviation ◽  
Mean Amplitude ◽  
Mean Deviation ◽  
Deviation Index ◽  
Velocity Peak ◽  
The Mean

Three types of eye movements, saccadic, reading, and pursuit, were recorded from 6 college subjects, two in each by the electrooculographic and photoelectric methods simultaneously. A deviation index (DI), which is the standard deviation divided by the mean, was devised to compare the precision of recording amplitude deflection, and a proportion index (PI), which is M1 divided by M2, was devised to compare the mean amplitude indirectly between these two methods. Results showed that the proportion indexes of three types of eye movements were comparable, and the mean index of 0.54 indicated that the amplification in the electrooculographic method was about half as much as that in the photoelectric. The mean deviation index of 0.132 vs 0.135 was, again, comparable, meaning that these two methods of recording amplitude deflections are of about the same degree of magnitude and precision. Certain qualitative differences regarding the amplitude and velocity peak deflection between these two methods were also noted.

scholarly journals Classification and Statistical Trend Analysis in Detecting Glaucomatous Visual Field Progression

2019 ◽  
Vol 2019 ◽  
pp. 1-5
Author(s):  
Cristiana Valente ◽  
Elisa D’Alessandro ◽  
Michele Iester
Keyword(s):  
Statistical Analysis ◽  
Standard Deviation ◽  
Visual Field ◽  
Trend Analysis ◽  
Open Angle Glaucoma ◽  
Mean Deviation ◽  
Threshold Strategy ◽  
Visual Field Progression ◽  
The Mean

Aim. To evaluate the agreement between different methods in detection of glaucomatous visual field progression using two classification-based methods and four statistical approaches based on trend analysis. Methods. This is a retrospective and longitudinal study. Twenty Caucasian patients (mean age 73.8 ± 13.43 years) with open-angle glaucoma were recruited in the study. Each visual field was assessed by Humphrey Field Analyzer, program SITA standard 30-2 or 24-2 (Carl Zeiss Meditec, Inc., Dublin, CA). Full threshold strategy was also accepted for baseline tests. Progression was analyzed by using Hodapp–Parrish–Anderson classification and the Advanced Glaucoma Intervention Study visual field defect score. For the statistical analysis, linear regression (r2) was calculated for mean deviation (MD), pattern standard deviation (PSD), and visual field index (VFI), and when it was significant, each series of visual field was considered progressive. We also used Progressor to look for a significant progression of each visual field series. The agreement between methods, based on statistical analysis and classification, was evaluated using a weighted kappa statistic. Results. Thirty-eight visual field series were analyzed. The mean follow-up time was 6.2 ± 1.53 years (mean ± standard deviation). At baseline, the mean MD was −7.34 ± 7.18 dB; at the end of the follow-up, the mean MD was −9.25 ± 8.65 dB; this difference was statistically significant (p<0.001). The agreement to detect progression was fair between all methods based on statistical analysis and classification except for PSD r2. A substantial agreement (κ = 0.698 ± 0.126) was found between MD r2 and VFI r2. With the use of all the statistical analysis, there was a better time-saving. Conclusions. The best agreement to detect progression was found between MD r2 and VFI r2. VFI r2 showed the best agreement with all the other methods. GPA2 can help ophthalmologists to detect glaucoma progression and to help in treatment decisions. PSD r2 was the worse method to detect progression.

scholarly journals SAMPLE STANDARD DEVIATION(s) CHART UNDER THE ASSUMPTION OF MODERATENESS AND ITS PERFORMANCE ANALYSIS

2017 ◽  
Vol 5 (6) ◽  
pp. 368-377
Author(s):  
Kalpesh S. Tailor
Keyword(s):  
Standard Deviation ◽  
Performance Analysis ◽  
Normal Distribution ◽  
Control Chart ◽  
Control Charts ◽  
Curve Analysis ◽  
Mean Deviation ◽  
Sample Standard Deviation ◽  
Underlying Distribution ◽  
Control Limits

Moderate distribution proposed by Naik V.D and Desai J.M., is a sound alternative of normal distribution, which has mean and mean deviation as pivotal parameters and which has properties similar to normal distribution. Mean deviation (δ) is a very good alternative of standard deviation (σ) as mean deviation is considered to be the most intuitively and rationally defined measure of dispersion. This fact can be very useful in the field of quality control to construct the control limits of the control charts. On the basis of this fact Naik V.D. and Tailor K.S. have proposed 3δ control limits. In 3δ control limits, the upper and lower control limits are set at 3δ distance from the central line where δ is the mean deviation of sampling distribution of the statistic being used for constructing the control chart. In this paper assuming that the underlying distribution of the variable of interest follows moderate distribution proposed by Naik V.D and Desai J.M, 3δ control limits of sample standard deviation(s) chart are derived. Also the performance analysis of the control chart is carried out with the help of OC curve analysis and ARL curve analysis.

scholarly journals Zero-Shot Pipeline Detection for Sub-Bottom Profiler Data Based on Imaging Principles

2021 ◽  
Vol 13 (21) ◽  
pp. 4401
Author(s):  
Gen Zheng ◽  
Jianhu Zhao ◽  
Shaobo Li ◽  
Jie Feng
Keyword(s):  
Standard Deviation ◽  
Object Detection ◽  
Real Time ◽  
Synthesis Method ◽  
Vertical Direction ◽  
Mean Deviation ◽  
The Real ◽  
Detection Algorithms ◽  
Underwater Pipeline ◽  
Time Requirements

With the increasing number of underwater pipeline investigation activities, the research on automatic pipeline detection is of great significance. At this stage, object detection algorithms based on Deep Learning (DL) are widely used due to their abilities to deal with various complex scenarios. However, DL algorithms require massive representative samples, which are difficult to obtain for pipeline detection with sub-bottom profiler (SBP) data. In this paper, a zero-shot pipeline detection method is proposed. First, an efficient sample synthesis method based on SBP imaging principles is proposed to generate samples. Then, the generated samples are used to train the YOLOv5s network and a pipeline detection strategy is developed to meet the real-time requirements. Finally, the trained model is tested with the measured data. In the experiment, the trained model achieved a [email protected] of 0.962, and the mean deviation of the predicted pipeline position is 0.23 pixels with a standard deviation of 1.94 pixels in the horizontal direction and 0.34 pixels with a standard deviation of 2.69 pixels in the vertical direction. In addition, the object detection speed also met the real-time requirements. The above results show that the proposed method has the potential to completely replace the manual interpretation and has very high application value.

scholarly journals Comparison of Perimetric Outcomes from Melbourne Rapid Fields Tablet Perimeter Software and Humphrey Field Analyzer in Glaucoma Patients

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Harsh Kumar ◽  
Mithun Thulasidas
Keyword(s):  
Standard Deviation ◽  
Visual Field ◽  
Rural Areas ◽  
Visual Fields ◽  
Test Time ◽  
Mean Deviation ◽  
Time Saving ◽  
Humphrey Field Analyzer ◽  
Probability Plot ◽  
The Mean

Purpose. To compare visual field results obtained using Melbourne Rapid Fields (MRF) iPad-based perimeter software and Humphrey Field Analyzer (HFA) 24-2 Swedish Interactive Threshold Algorithm (SITA) standard program in glaucoma patients. Design. A cross-sectional observational study. Methods. In this single-centre study involving patients diagnosed with glaucoma, the perimetric outcomes of MRF were compared against those returned from the HFA 24-2 SITA standard. Outcomes included mean deviation (MD), pattern standard deviation (PSD), visual field index (VFI)/visual capacity (VC), foveal threshold, test time, number of points depressed at P<5% on PSD probability plot, and glaucoma hemifield test/color coded indicator. Results. The study included 28 eyes of 28 glaucoma patients. Mean (standard deviation) test times were 342.07 (56.70) seconds for MRF and 375.11 (88.95) for HFA 24-2 SITA standard P=0.046. Mean MD was significantly lower for MRF (Δ = 3.09, P<0.001), and mean PSD was significantly higher for MRF (Δ = 1.40, P=0.005) compared with HFA. The mean foveal threshold for the MRF was significantly lower than the mean HFA foveal threshold ((Δ = 9.25, P<0.001). The number of points depressed at P<5% on the PSD probability plot was significantly less for MRF P<0.001. Other perimetric outcomes showed no significant differences between both. Bland–Altman plots showed that considerable variability existed between the programs. Conclusion. MRF is a good cost-effective, time-saving, user-friendly tool for monitoring visual fields in settings where access to traditional perimetry is limited. The lack of Internet strength in rural areas and questionable detection of early cases may be two points in MRF fields requiring an upgrade.

scholarly journals Validation of refractivity profiles derived from GRAS raw-sampling data

2011 ◽  
Vol 4 (7) ◽  
pp. 1541-1550 ◽  
Author(s):  
F. Zus ◽  
G. Beyerle ◽  
S. Heise ◽  
T. Schmidt ◽  
J. Wickert ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Penetration Depth ◽  
Radio Occultation ◽  
Lower Troposphere ◽  
Research Centre ◽  
Mean Deviation ◽  
Negative Bias ◽  
Altitude Range ◽  
Full Spectrum ◽  
The Mean

Abstract. Results from GRAS (GNSS Receiver for Atmospheric Sounding) RO (Radio Occultation) data recorded in RS (Raw Sampling) mode processed at the GFZ (German Research Centre for Geoscience) Potsdam are presented. The experimental processing software POCS-X includes FSI (Full Spectrum Inversion) in order to cope with multi-path regions and enables in connection with RS data to retrieve atmospheric refractivity profiles down to the Earths surface. Radio occultation events observed between 30 September and 30 October 2007 are processed and the retrievals are validated against co-located ECMWF (European Centre for Medium-Range Weather Forecasts) profiles. The intercomparison indicates good quality of the retrieved profiles. In the altitude range 8 to 25 km the standard deviation is below 1 %. The mean deviation in this altitude range tends to be negative. At 30 km the negative bias reaches about −0.4 %. Below 8 km the standard deviation increases, reaching 2.5 % at 2 km. Below 2 km the mean deviation tends to be negative, reaching −1.9 % close to the ground. The negative bias mainly stems from the tropical lower troposphere; there, the negative bias reaches −3 %. The tropospheric penetration depth obtained from RS data shows a vast improvement compared to the tropospheric penetration depth typically obtained from CL (Closed Loop) data; 50 % of all retrieved profiles reach 720 m.

Sign in / Sign up

Export Citation Format

Share Document