Background: Assessment of visual acuity depends on the optotypes used for measurement. The ability to recognize different optotypes differs even if their critical details appear under the same visual angle. Since opto...Background: Assessment of visual acuity depends on the optotypes used for measurement. The ability to recognize different optotypes differs even if their critical details appear under the same visual angle. Since optotypes are evaluated on individuals with good visual acuity and without eye disorders,differences in the lower visual acuity range cannot be excluded. In this study,visual acuity measured with the Snellen E was compared to the Landolt C acuity. Patients and Methods: 100 patients (age 8-90 years,median 60.5 years) with various eye disorders,among them 39 with amblyopia due to strabismus,and 13 healthy volunteers were tested. Charts with the Snellen E and the Landolt C (PrecisionVision) which mimic the ETDRS charts were used to assess visual acuity. Three out of 5 optotypes per line had to be correctly identified,while wrong answers were monitored. In the group of patients,the eyes with the lower visual acuity,and the right eyes of the healthy subjects,were evaluated. Results: Differences between Landolt Cacuity (LR) and Snellen Eacuity (SE) were small. The mean decimal values for LR and SE were 0.25 and 0.29 in the entire group and 0.14 and 0.16 for the eyes with strabismus amblyopia. The mean difference between LR and SE was 0.55 lines in the entire group and 0.55 lines for the eyes with strabismus amblyopia,with higher values of SE in both groups. The results of the other groups were similar with only small differences between LR and SE. Conclusion: Using the charts described,there was only a slight overestimation of visual acuity by the Snellen E compared to the Landolt C,even in strabismus amblyopia. Small differences in the lower visual acuity range have to be considered.展开更多
Purpose: Positionally induced cyclotorsion could be an important factor concerning correction of astigmatism in refractive surgery. Previous studies have shown no influence of body position on cycloposition in healthy...Purpose: Positionally induced cyclotorsion could be an important factor concerning correction of astigmatism in refractive surgery. Previous studies have shown no influence of body position on cycloposition in healthy subjectswith normal binocular vision. Methods: 10 subjects (median value of age 44.2 years) without binocular vision due to an organic eye disease or to strabismus were examined using three-dimensional videooculography (3D-VOG). This non-invasive method can record changes in the position of both eyes simultaneously in the x-,y-and z-axes. The cycloposition of the eyes was recorded first in a seated position with both eyes open (test 1),then in a supine position with the right eye closed (test 2),then in a supine position with occlusion of both eyes (test 3),and then in a supine position with both eyes open (test 4). In each of these 4 situations,the eyes were recorded for 1 minute. Cyclovergence was calculated as the difference between the right and the left eye positions. Results: The range of cycloposition of the right and left eye in all 4 tests was very small. 95% confidence intervals for cycloposition of the right and left eyes and for cyclovergence: cycloposition right eye/cycloposition left eye/cyclovergence: 0.72;0.76/-0.07;0.01/0.71;0.79 (test 1),0.23;0.29/0.19;0.33/-0.81;-0.63 (test 2),-0.92;0.7/-0.51;-0.37/-0.79;-0.45 (test 3),0.14;0.52/-0.07;0.31/0.59;0.21 (test 4). There was no statistically significant difference of the cycloposition between the 4 test situations. Conclusions: The cycloposition of the eyes does not significantly change between seated and supine positions of the body,either in subjects with,or without binocular vision. This means for refractive surgery that a correction of astigmatism,to be performed in the supine position of the patient,can be based on a measurement of the axis of astigmatism obtained in the seated position.展开更多
Objectives The purpose of this study was to analyze the utility of patient-al ert features in implantable cardioverter defibrillators (ICDs). Background Vario us alert features producing acoustic warning signals have ...Objectives The purpose of this study was to analyze the utility of patient-al ert features in implantable cardioverter defibrillators (ICDs). Background Vario us alert features producing acoustic warning signals have been implemented in ne wer generation ICDs, but their role in early detection of system-related compli cations has not been systematically evaluated. Methods In 240 patients implanted with Medtr-onic ICD devices, the following alert features were routinely activ ated: pacing lead impedance < 200 or > 2,000, high-voltage lead impedance < 10 or >200, low battery voltage (elective replacement indicator), long charge time (>18 s), >3 shocks delivered per episode, and all therapies in a zone delivered. Alert events occurring during follow-up were assessed in relation to actual fi ndings (hospital charts, chest X-rays, ICD printouts including sensing/pacing/d efibrillation threshold tests, episode data) to determine incidence, sensitivity , and specificity of the alert function. Results During 12.2 ±8.9 months, 24 al ert events occurred in the 240 patients (pacing lead impedance, n=4; high-volta ge lead imped-ance, n=7; low battery voltage, n=1; >3 shocks, n=6; all therapie s, n=6). A total of 22 serious complications (necessitating reprogramming or dev ice/lead replacement)were observed, 14 of which were primarily identified throug h a patient alert (lead fracture, n=11; connector defect, n=1; T-wave oversensi ng, n=1; battery depletion, n=1). This reflects a sensitivity of 64%and a speci ficity of 96%of the alert function for serious complications. With 14 of 24 pat ient alerts being caused by serious complications, the positive predictive value reached 58%. Conclusions Patient-alert features are a useful additional tool facilitating early detection of serious ICD complications, but they do not subst itute for regular ICD follow-up, because of their low sensitivity.展开更多
文摘Background: Assessment of visual acuity depends on the optotypes used for measurement. The ability to recognize different optotypes differs even if their critical details appear under the same visual angle. Since optotypes are evaluated on individuals with good visual acuity and without eye disorders,differences in the lower visual acuity range cannot be excluded. In this study,visual acuity measured with the Snellen E was compared to the Landolt C acuity. Patients and Methods: 100 patients (age 8-90 years,median 60.5 years) with various eye disorders,among them 39 with amblyopia due to strabismus,and 13 healthy volunteers were tested. Charts with the Snellen E and the Landolt C (PrecisionVision) which mimic the ETDRS charts were used to assess visual acuity. Three out of 5 optotypes per line had to be correctly identified,while wrong answers were monitored. In the group of patients,the eyes with the lower visual acuity,and the right eyes of the healthy subjects,were evaluated. Results: Differences between Landolt Cacuity (LR) and Snellen Eacuity (SE) were small. The mean decimal values for LR and SE were 0.25 and 0.29 in the entire group and 0.14 and 0.16 for the eyes with strabismus amblyopia. The mean difference between LR and SE was 0.55 lines in the entire group and 0.55 lines for the eyes with strabismus amblyopia,with higher values of SE in both groups. The results of the other groups were similar with only small differences between LR and SE. Conclusion: Using the charts described,there was only a slight overestimation of visual acuity by the Snellen E compared to the Landolt C,even in strabismus amblyopia. Small differences in the lower visual acuity range have to be considered.
文摘Purpose: Positionally induced cyclotorsion could be an important factor concerning correction of astigmatism in refractive surgery. Previous studies have shown no influence of body position on cycloposition in healthy subjectswith normal binocular vision. Methods: 10 subjects (median value of age 44.2 years) without binocular vision due to an organic eye disease or to strabismus were examined using three-dimensional videooculography (3D-VOG). This non-invasive method can record changes in the position of both eyes simultaneously in the x-,y-and z-axes. The cycloposition of the eyes was recorded first in a seated position with both eyes open (test 1),then in a supine position with the right eye closed (test 2),then in a supine position with occlusion of both eyes (test 3),and then in a supine position with both eyes open (test 4). In each of these 4 situations,the eyes were recorded for 1 minute. Cyclovergence was calculated as the difference between the right and the left eye positions. Results: The range of cycloposition of the right and left eye in all 4 tests was very small. 95% confidence intervals for cycloposition of the right and left eyes and for cyclovergence: cycloposition right eye/cycloposition left eye/cyclovergence: 0.72;0.76/-0.07;0.01/0.71;0.79 (test 1),0.23;0.29/0.19;0.33/-0.81;-0.63 (test 2),-0.92;0.7/-0.51;-0.37/-0.79;-0.45 (test 3),0.14;0.52/-0.07;0.31/0.59;0.21 (test 4). There was no statistically significant difference of the cycloposition between the 4 test situations. Conclusions: The cycloposition of the eyes does not significantly change between seated and supine positions of the body,either in subjects with,or without binocular vision. This means for refractive surgery that a correction of astigmatism,to be performed in the supine position of the patient,can be based on a measurement of the axis of astigmatism obtained in the seated position.
文摘Objectives The purpose of this study was to analyze the utility of patient-al ert features in implantable cardioverter defibrillators (ICDs). Background Vario us alert features producing acoustic warning signals have been implemented in ne wer generation ICDs, but their role in early detection of system-related compli cations has not been systematically evaluated. Methods In 240 patients implanted with Medtr-onic ICD devices, the following alert features were routinely activ ated: pacing lead impedance < 200 or > 2,000, high-voltage lead impedance < 10 or >200, low battery voltage (elective replacement indicator), long charge time (>18 s), >3 shocks delivered per episode, and all therapies in a zone delivered. Alert events occurring during follow-up were assessed in relation to actual fi ndings (hospital charts, chest X-rays, ICD printouts including sensing/pacing/d efibrillation threshold tests, episode data) to determine incidence, sensitivity , and specificity of the alert function. Results During 12.2 ±8.9 months, 24 al ert events occurred in the 240 patients (pacing lead impedance, n=4; high-volta ge lead imped-ance, n=7; low battery voltage, n=1; >3 shocks, n=6; all therapie s, n=6). A total of 22 serious complications (necessitating reprogramming or dev ice/lead replacement)were observed, 14 of which were primarily identified throug h a patient alert (lead fracture, n=11; connector defect, n=1; T-wave oversensi ng, n=1; battery depletion, n=1). This reflects a sensitivity of 64%and a speci ficity of 96%of the alert function for serious complications. With 14 of 24 pat ient alerts being caused by serious complications, the positive predictive value reached 58%. Conclusions Patient-alert features are a useful additional tool facilitating early detection of serious ICD complications, but they do not subst itute for regular ICD follow-up, because of their low sensitivity.
