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
Background: A causative therapy for Duane’ s retraction syndrome,which is the most prominent example of connatal ocular misinnervation,does not exist. Eye muscle surgery is indicated in cases with manifest strabismus...Background: A causative therapy for Duane’ s retraction syndrome,which is the most prominent example of connatal ocular misinnervation,does not exist. Eye muscle surgery is indicated in cases with manifest strabismus in primary position and an annoying compensatory head posture to maintain binocular single vision. Different surgical approaches to the different types of Duane’ s retraction syndrome,mostly on the affected eye but also on the fellow eye,are described in the literature. Method: We retrospectively analyzed the pre-and postoperative findings of 55 patients in whom we performed surgery because of Duane’ s retraction syndrome during the years 1999 to 2004. The type of retraction syndrome,the angle reduction in primary position and the reduction of head posture were evaluated in regard to the surgical procedure chosen. Results: In 37 cases surgery was primary. In 25 cases a single recession of the medial rectus (16 cases) or the lateral rectus (9 cases) muscle of the affected eye was performed. For a dose-response relationship of the one-muscle recessions,the mean angle reduction in the primary position was 2 pdpt (cm/m) per mm recession. The mean reduction of head posture was 1.5 per mm recession. In 10 cases combined surgery on the affected eyewas performed. The correlation between themean angle reduction and the recession was 3 pdpt (cm/m) per 1 mm. Conclusion: Depending on the type of retraction syndrome,the angle in primary position,the head posture and the globe retraction,different surgical options exist which aim at rehabilitation of the patient suffering from Duane’ s retraction syndrome.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Background: A causative therapy for Duane’ s retraction syndrome,which is the most prominent example of connatal ocular misinnervation,does not exist. Eye muscle surgery is indicated in cases with manifest strabismus in primary position and an annoying compensatory head posture to maintain binocular single vision. Different surgical approaches to the different types of Duane’ s retraction syndrome,mostly on the affected eye but also on the fellow eye,are described in the literature. Method: We retrospectively analyzed the pre-and postoperative findings of 55 patients in whom we performed surgery because of Duane’ s retraction syndrome during the years 1999 to 2004. The type of retraction syndrome,the angle reduction in primary position and the reduction of head posture were evaluated in regard to the surgical procedure chosen. Results: In 37 cases surgery was primary. In 25 cases a single recession of the medial rectus (16 cases) or the lateral rectus (9 cases) muscle of the affected eye was performed. For a dose-response relationship of the one-muscle recessions,the mean angle reduction in the primary position was 2 pdpt (cm/m) per mm recession. The mean reduction of head posture was 1.5 per mm recession. In 10 cases combined surgery on the affected eyewas performed. The correlation between themean angle reduction and the recession was 3 pdpt (cm/m) per 1 mm. Conclusion: Depending on the type of retraction syndrome,the angle in primary position,the head posture and the globe retraction,different surgical options exist which aim at rehabilitation of the patient suffering from Duane’ s retraction syndrome.
