Font effects on reading parameters: comparing Radner Reading Charts printed in Helvetica and Times Roman.

PURPOSE: To investigate the effect of font choice on reading parameters by using the RADNER Reading Charts printed in two fonts (Helvetica vs. Times Roman) equalized in terms of x-height. METHODS: This is a cross-sectional study of 40 participants with healthy eyes (18 to 60 years of age; mean: 42.13 ± 12.28 years). Reading performance was evaluated binocularly with RADNER Reading Charts printed in either Helvetica Neue (T1) Roman sans serif (Adobe) or Times New Roman PS Roman serif (Adobe). The test distance was 40 cm. Reading charts were presented in random order. Reading acuity (RA), mean reading speed of all sentences read (MEAN-ALL RS), mean reading speed from 0.8 logRAD to 0.3 logRAD (MEAN-RS), maximum reading speed (MAX-RS), and critical print size (CPS) were compared. RESULTS: The RA values obtained for the Helvetica and Times Roman fonts (in full logarithmic units of 0.1 logRAD) did not differ between the two fonts (mean for both fonts: - 0.128 ± 0.064 logRAD; 95% CI for both: - 0.148; - 0.107 logRAD). The differences in all other reading parameters between the two fonts were small and not statistically significant. The analyses revealed narrow confidence intervals and good coefficients of reliability. Except for the CPS (r = 0.49) and RA (equal for Helvetica and Times Roman), the correlations for all parameters were high, ranging from r = 0.92 to r = 0.98. CONCLUSION: The equivalent reading performance obtained with Helvetica and Times Roman (when equalized in x-height and layout) makes these font types interchangeable as standards for reading charts.

Towards a standardisation of reading charts: Font effects on reading performance-Times New Roman with serifs versus the sans serif font Helvetica.

PURPOSE: The purpose was to compare systematically the legibility of a font without serifs (Helvetica) and one with serifs (Times New Roman). METHODS: Three paragraphs that were equal in the number of words, syllables, characters, difficulty and reading length were printed at equal size, with equal spacing between the lines and equal layout (paperback style), in either the sans serif typeface Helvetica Neue T1 55 Roman (Adobe) or the serif typeface Times New Roman PS Roman (Adobe). They were also printed in newspaper format in the serif font. The paragraphs were presented in random order (Latin square design) to 36 participants between 18 and 38 years of age (wearing their best-corrected visual acuity). Reading duration was measured with a stopwatch. Reading time, reading speed and the number of reading errors were compared. RESULTS: For the paperback layout, no significant difference in reading time (p = 0.50) or reading speed (p = 0.56) was found between the two fonts. The correlation between the two fonts was high for both reading time and speed (r = 0.93). The mean number of reading errors was the same (0.31 ± 0.58 errors/text) for both fonts. There was a significant difference in reading time and speed between the paperback and the newspaper layout. CONCLUSION: The legibility of Helvetica and Times New Roman is similar when investigated under equivalent conditions. Thus, these two font types can be used as interchangeable standard typefaces.

Age-related course of visual acuity obtained with ETDRS 2000 charts in persons with healthy eyes.

PURPOSE: To investigate the age-related course of best-corrected visual acuity in healthy eyes. METHODS: Two hundred participants (400 eyes) 25 to 74 years of age (114 females, 86 males) were investigated, 20 per 5-year age group. Best-corrected visual acuity was measured monocularly with the ETDRS 2000 charts at a distance of 4 m (Precision Vision, Woodstock, IL, USA). Strict exclusion and termination criteria were used. RESULTS: Visual acuity did not change between ages 25 and 54 years (mean of the better eyes, - 0.18 ± 0.05 logMAR). A significant age-related break-point in visual acuity was found at the ages of 55-59 years. For all age groups, the overall mean visual acuity was - 0.15 ± 0.06 logMAR for the better eyes and - 0.13 ± 0.06 logMAR for the worse eyes. There was no difference between the right and left eyes (- 0.14 ± 0.06 logMAR). The visual acuity was better in the right eye in 29% (n = 58) of the participants, better in the left eye in 32% (n = 64), and the same in both eyes in 39% (n = 78). From ages 25 to 64 years, neither the better nor the worse eye had a visual acuity worse than 0.0 logMAR. CONCLUSION: Best-corrected visual acuity was constantly high until the age of 54 years. An age-related break-point appeared at 55 to 59 years of age. Until age 64, a minimal angle of resolution smaller than 1 min of arc (visual acuity better 0.0 logMAR) can be expected in healthy eyes.

Twelve-Year Follow-Up of Navigated Computer-Assisted Versus Conventional Total Knee Arthroplasty: A Prospective Randomized Comparative Trial.

BACKGROUND: Navigated computer-assisted total knee arthroplasty (TKA) was introduced to expedite long-term survival based on improved postoperative implantation accuracy. However, long-term outcome data after 10 years or more are rare, even available meta-analyses show controversial study results. METHODS: In a prospective randomized trial, 100 conventional TKAs (group CONV) were compared with 100 computer-assisted TKAs (group NAV) after a mean follow-up of 12 years postoperatively. A long-leg weight-bearing X-ray was performed for measuring mechanical axis of the limb, lateral distal femoral angle, and medial proximal tibial angle. Tibial slope, patella alpha angle, and radiolucent lines were also observed. Clinical investigation included evaluation of 4 different scores: Insall Knee Score, Western Ontario and MacMaster University Index score, Hospital for Special Surgery Knee Score, and visual analog scale. RESULTS: Based on a follow-up rate of at least 75%, no difference in TKA survival was found 12 years postoperatively: 91.5% in group CONV vs 98.2% in group NAV (P = .181). Since 5-year follow-up, no additional TKA revision had been performed in both groups. Group CONV showed a nonsignificant higher inaccuracy of neutral lower limb axis (1.8° ± 1.4°) compared to group NAV (1.6° ± 1.7°, P = .700). All X-ray assessments were not significant different within both study groups (P ≥ .068). Clinical examination showed no differences in evaluations (P ≥ .204). All collected outcome score results were similar (P ≥ .222). CONCLUSION: Twelve years postoperatively, no differences were found in terms of long-term survival, implantation accuracy, clinical outcome or score results.

Implication of femoral stem on performance of articular surface replacement (ASR) XL total hip arthroplasty.

Taper junctions of large diameter metal-on-metal femoral heads and femoral stems were described as metal ion generator due to accelerated wear and corrosion. However, literature about the Articular Surface Replacement (ASR) total hip arthroplasty (THA) invariably deals with stems manufactured by DePuy Orthopedics (Warsaw, IN, USA). Nothing is known whether different stems with common 12/14 mm tapers affect failure rate or ion release. 99 ASR THA (88 patients) implanted with CoxaFit or ARGE Geradschaft stems (K-Implant, Hannover, Germany) were retrospectively analyzed. After a mean follow-up of 3.5 years revision rate was 24.5%, mostly due to adverse reaction to metal debris (ARMD). CT scan revealed component loosening in 10.3% and pseudotumoral lesions in 12.6%. Elevated ion concentrations (>7 µg/l) were found in 38.6%.

Conventional versus computer-assisted technique for total knee arthroplasty: a minimum of 5-year follow-up of 200 patients in a prospective randomized comparative trial.

In the literature, studies of computer-assisted total knee arthroplasty (TKA) after mid-term period are not conclusive and long-term data are rare. In a prospective, randomized, comparative study 100 conventional TKAs (group REG) were compared with 100 computer-assisted TKAs (group NAV). Minimum follow-up was 5years. No difference in implant failure was found with 1.1% in group NAV versus 4.6% in group REG (P=0.368). Group NAV showed a significantly less mean deviation of mechanical limb axis (P=0.015), more TKAs (90% versus 81% in group REG) were within 3° varus/valgus and a higher tibial slope and lateral distal femoral angle (LDFA) accuracy was found (P≤0.034). Clinical investigational parameters showed no differences (P≥0.058). Insall and HSS score total were also higher in group NAV (P≤0.016).

Does single use of an autologous transfusion system in TKA reduce the need for allogenic blood?: a prospective randomized trial.

BACKGROUND: Mechanical autotransfusion systems for washed shed blood (WSB) were introduced to reduce the need for postoperative allogenic blood transfusions (ABTs). Although some authors have postulated decreased requirements for ABT by using autologous retransfusion devices, other trials, mostly evaluating retransfusion devices for unwashed shed blood (USB), verified a small or no benefit in reducing the need for postoperative ABT. Because of these contradictory findings it is still unclear whether autologous retransfusion systems for WSB can reduce transfusion requirements. QUESTIONS/PURPOSES: We therefore asked whether one such autologous transfusion system for WSB can reduce the requirements for postoperative ABT. METHODS: In a prospective, randomized, controlled study, we enrolled 151 patients undergoing TKA. In Group A (n=76 patients), the autotransfusion system was used for a total of 6 hours (intraoperatively and postoperatively) and the WSB was retransfused after processing. In Control Group B (n=75 patients), a regular drain without suction was used. We used signs of anemia and/or a hemoglobin value less than 8 g/dL as indications for transfusion. If necessary, we administered one or two units of allogenic blood. RESULTS: Twenty-three patients (33%) in Group A, who received an average of 283 mL (range, 160-406 mL) of salvaged blood, needed a mean of 2.1 units of allogenic blood, compared with 23 patients (33%) in Control Group B who needed a mean of 2.1 units of allogenic blood. CONCLUSIONS: We found the use of an autotransfusion system did not reduce the rate of postoperative ABTs. LEVEL OF EVIDENCE: Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Retinal thickness and volume measurements in diabetic macular edema: a comparison of four optical coherence tomography systems.

PURPOSE: To compare different spectral domain optical coherence tomography devices regarding retinal thickness values in patients with diabetic macular edema and to correlate the results with conventional time domain Stratus OCT data. METHODS: Thirty eyes of 30 consecutive patients with diabetic macular edema were included into a prospective study. The macula was examined by Spectralis HRA+OCT, Cirrus HD-OCT, 3D OCT-1000, and Stratus OCT. The procedures' sequence was performed by a single experienced technician in a randomized fashion according to a computer-generated list. In each eye, foveal thickness, foveal volume, and total macular volume were measured automatically. Intraclass correlation, coefficients of variance, and coefficients of repeatability were calculated. RESULTS: Foveal thickness differed between the particular devices with a mean ± SD ranging from 359.97 ± 105.84 µm to 437.70 ± 115.84 µm. Correlation between the different OCT devices resulted in r > 0.7 (Pearson), and intraclass correlation was >0.9. Agreement of measurements was assessed showing a mean difference of foveal thickness values ranging from 19.2 µm to 77.7 µm (P < 0.05) and coefficients of repeatability ranging from 37.7 µm to 87.4 µm. CONCLUSION: While intradevice reproducibility is satisfactory, retinal thickness and volume measurements should not be used interchangeably because measurements differed significantly between systems. The lack of interdevice agreement seems to be related to the different segmentation algorithm of thickness measurement and should be considered because it may strongly influence treatment decisions and conclusions.

Spectral-domain optical coherence tomography for monitoring epiretinal membrane surgery.

PURPOSE: To assess prognostic factors in epiretinal membrane (ERM) surgery using spectral-domain (SD) optical coherence tomography (OCT). DESIGN: Prospective, interventional case series. PARTICIPANTS: Forty-one patients. METHODS: Patients with a diagnosis of ERM were examined with spectral-domain and time-domain (TD) OCT before and after surgery. MAIN OUTCOME MEASURES: Main outcome measures were functional results and predefined OCT patterns. Cofactors analyzed were the type of ERM, the duration and grading of subjective metamorphopsia, simultaneous cataract surgery, the type of dyes used, the duration of surgery, gender, and age. A multivariate regression analysis was performed. RESULTS: Thirty-nine patients (95%) showed an improved or stable best-corrected distance visual acuity (DVA) at 3 months, whereas 36 patients (88%) showed an improved or stable best-corrected near visual acuity (NVA) at 3 months. Significant correlations (P>0.4) were found between the course of central retinal thickness (CRT) assessed using SD OCT and TD OCT (P<0.02). No clinically relevant correlations (P<0.3) were seen between CRT and VA (P>0.1). Baseline DVA and NVA were found to be significant prognostic values for the postoperative decrease in CRT in both OCT systems (P<0.04) as well as for the visual outcomes (P<0.007) at 3 months. In addition, the integrity of the junction between the photoreceptor inner segment and outer segment (IS/OS) significantly influenced the visual outcomes at 3 months (P<0.038). The baseline profile of the internal limiting membrane (ILM) significantly influenced the NVA at 3 months (P<0.009), whereas the postoperative foveal contour significantly influenced the DVA at 3 months (P<0.025). The type of ERM, subjective metamorphopsia, simultaneous cataract surgery, the type of dyes used, the duration of surgery, gender, or age had no significant influence on patient outcome (P>0.05). Compared with TD OCT, SD OCT allowed for a more precise differentiation between the ERM and the retinal surface and for a better evaluation of the IS/OS line. CONCLUSIONS: Besides the baseline VA, the integrity of the IS/OS line, better visualized by SD OCT, can be used to predict the functional outcomes after surgery. Additionally, analyzing the ILM profile and the foveal contour may help to understand limited visual outcomes after surgery. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Cinacalcet decreases bone formation rate in hypercalcemic hyperparathyroidism after kidney transplantation.

BACKGROUND/AIMS: Cinacalcet reduces serum calcium in kidney transplant recipients with hypercalcemic hyperparathyroidism. Its effect on bone, however, has not been investigated in this population. METHODS: We prospectively examined bone turnover, histomorphometry and density as well as serum bone biomarkers in 10 transplant recipients before and after treatment with cinacalcet. RESULTS: After 18-24 months of treatment with cinacalcet, bone formation decreased in 7, increased in 2, and remained zero in 1 patient (p = 0.11). Trabecular bone volume was maintained. Trabecular number decreased (p = 0.03), but trabecular thickness was unchanged (p = 0.17). Osteoid decreased (p = 0.02) and osteoblast surface increased (p = 0.02). Bone mineral density of the femur remained stable in 1 patient, decreased in 2 patients, but increased in 7 patients (p = 0.153). Serum calcium concentration (p = 0.005), iPTH (p = 0.01) and calcitonin concentration decreased (p = 0.03), while 25(OH) vitamin D(3) increased (p = 0.02). No fractures were reported. Graft function remained stable. CONCLUSION: While cinacalcet might decrease bone formation rate, it did not change bone volume, and bone mineral density of the femur increased. Therefore, the use of cinacalcet in hypercalcemic hyperparathyroidism might be safe with regard to the bone disease present after kidney transplantation.

Angiogenic and inflammatory markers in the intraocular fluid of eyes with diabetic macular edema and influence of therapy with bevacizumab.

PURPOSE: The purpose of this study was to determine the concentrations of angiogenic and inflammatory markers in human eyes with diffuse diabetic macular edema before and during therapy with intravitreal bevacizumab and their association with disease activity. METHODS: In a prospective clinical trial, 10 eyes of 10 consecutive patients with vision loss because of diabetic macular edema were compared with 10 eyes of 10 age-matched controls. Bevacizumab was administered at baseline; retreatments were given monthly according to disease activity. During a follow-up of 6 months, aqueous humor samples were taken each time intravitreal therapy was administered. A multiplex assay was used for measurement of 12 different growth factors and cytokines. RESULTS: Aqueous humor of eyes with diabetic macular edema demonstrated a significantly increased expression of monocyte chemoattractant protein-1 and interleukin-8 and higher, but not significant, levels of interleukin-6 and vascular endothelial growth factor. Intravitreal therapy with bevacizumab resulted in a significant decrease of vascular endothelial growth factor below physiologic levels. This change was not associated with clinical disease activity as measured by visual acuity and central retinal thickness. CONCLUSION: Eyes with diabetic macular edema showed a different profile of monocyte chemoattractant protein-1 and interleukin-8 as compared with controls. The intraocular vascular endothelial growth factor expression decreased significantly after the first intravitreal injection of bevacizumab; this reduction was prolonged by consecutive monthly retreatment.

Comparison of two minimally invasive implantation instrument-sets for total knee arthroplasty.

Several choices of instrument systems are available for minimally invasive surgical approaches. There are reports that one alternative, the quadriceps sparing, side-cutting instrumentation, results in diminished implantation accuracy. A total of 108 patients were randomized to undergo TKA either using side-cutting implant instrumentation (Group A) or anterior-posterior mini-incision instrumentation (Group B). All TKAs were operated on with a minimal invasive, mini-midvastus surgical approach. 50% of the TKAs were performed with computer-assistance in each cohort. The radiographic parameters, clinical outcomes and knee scores were evaluated preoperatively and 3 months postoperative. In Group B, we found significantly higher accuracy for the mechanical axis of the limb (range +/-3 degrees: Group A 54% versus Group B 89%, p = <0.001), medial proximal tibial angle (range +/-3 degrees: Group A 85% versus Group B 98%, p = <0.027) and tibial slope (range +/-3 degrees: Group A 59% versus Group B 85%, p = <0.007). The application of the navigation system could only significantly reduce outliers (accuracy >3 degrees) in Group B. Clinical outcomes and knee scores were similar in both groups and were not influenced by computer-assistance. Using the anterior-posterior, mini-incision instruments for minimally invasive TKA will lead to higher implantation accuracy when compared to the quadriceps sparing side-cutting instrumentation. The navigation technique could not compensate for shortcomings of the side-cutting instrumentation. The clinical relevance of this study is that the quadriceps sparing side-cutting instrumentation should not be used for TKA because of unacceptable reduced implantation accuracy.

Association of retinal sensitivity and morphology during antiangiogenic treatment of retinal vein occlusion over one year.

PURPOSE: Evaluation of the association between functional and anatomic retinal changes during anti-vascular endothelial growth factor (VEGF) therapy with bevacizumab (Avastin) in patients with cystoid macular edema secondary to retinal vein occlusion (RVO) using microperimetry and spectral domain optical coherence tomography (SD-OCT). DESIGN: Prospective, uncontrolled study (EUDRACT NR-2005-003288-21). PARTICIPANTS: Twenty-eight patients with cystoid macular edema secondary to RVO. METHODS: Patients initially received 3 consecutive intravitreal injections of 1.25 mg bevacizumab at 4-week intervals. Further treatment was based on morphologic (OCT) and functional best-corrected visual acuity (BCVA) findings. During the 1-year follow-up, a rigorous standardized evaluation was performed monthly. Macular function was documented by microperimetry (Nidek, MP1 Microperimeter) and BCVA based on the Early Treatment in Diabetic Retinopathy Study (ETDRS). Morphologic parameters included central retinal thickness (CRT) as measured by conventional OCT (Stratus), and central subfield thickness (CST), mean retinal thickness (MRT), and retinal volume (RV) measured by SD-OCT. MAIN OUTCOME MEASURES: Imaging of retinal morphology using OCT and SD-OCT and evaluation of retinal function assessed with microperimetry and ETDRS charts during 12 months of anti-VEGF treatment. RESULTS: Within 6 months, the mean area of absolute scotoma was reduced from 21.4% of the central visual field to 6.4% and remained at this level until month 12 (7.4%). Mean BCVA improved from 51 to 66 letters on ETDRS charts. The CRT, CST, and MRT decreased significantly (P<0.002) and remained stable during the follow-up. The RV values did not improve significantly under therapy. Statistical analysis using a linear effects model revealed significant associations between the functional and morphologic outcomes, most notably between BCVA, macular sensitivity, CRT (Stratus OCT), CST, and MRT (Cirrus OCT) values. CONCLUSIONS: Central retinal morphology, especially CRT and CST measured by conventional and SD-OCT, and retinal function improved significantly during treatment of RVO with a flexible dosing regimen of intravitreal bevacizumab. Functional (central visual acuity and visual field) and morphologic parameters (retinal thickness) were significantly related. These associations highlight the value of OCT imaging for assessing this disease entity.

Neovascular age-related macular degeneration: intraocular cytokines and growth factors and the influence of therapy with ranibizumab.

PURPOSE: To investigate concentrations of growth factors and inflammatory cytokines in eyes with neovascular age-related macular degeneration (AMD) before and during therapy with intravitreal ranibizumab and to identify associations with disease activity. DESIGN: Prospective clinical trial. PARTICIPANTS AND CONTROLS: Twenty-eight eyes of patients with neovascular AMD were compared with 28 eyes of age-matched patients with cataract as control. METHODS: Ranibizumab was administered intravitreously once at baseline, and retreatments were given at monthly visits if optical coherence tomography (OCT) revealed macular edema or vision loss had occurred. Aqueous humor samples were taken each time intravitreal interventions were performed. Follow-up was 12 months. Luminex (Luminex Inc., Austin, TX) multiplex assays were used for measurement of 29 different growth factors and cytokines, including vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF). MAIN OUTCOME MEASURES: Differences in the concentrations of growth factors and inflammatory cytokines in eyes with neovascular AMD compared with control eyes and the influence of therapy with intravitreal ranibizumab. RESULTS: A significantly increased expression of VEGF (P = 0.033) and a significantly decreased expression of PDGF (P = 0.038) were measured in the aqueous humor of eyes with neovascular AMD. Furthermore, a significant decrease of VEGF (P<0.001) was observed after intravitreal injection of ranibizumab along with significant changes in visual acuity and central retinal thickness (P = 0.039 and P<0.001). During follow-up with a flexible regimen, a correlation was identified between increased VEGF levels and persistent or recurrent macular edema. Changes in PDGF levels were strongly associated with alterations in VEGF concentration. CONCLUSIONS: Vascular endothelial growth factor and PDGF-AA seemed to be associated with disease activity of neovascular AMD. Intravitreal anti-angiogenic treatment with ranibizumab resulted in significantly decreased intraocular VEGF expression below physiologic levels compared with controls. This effect was measurable as long as 4 weeks after each injection and was prolonged by consecutive retreatment. With recurrence after discontinuation of treatment, VEGF levels increased again.

Ventricular interaction in children after repair of tetralogy of Fallot: a longitudinal echocardiographic study.

AIMS: Progressive right ventricular (RV) dilation due to pulmonary regurgitation (PR) after repair of tetralogy of Fallot (TOF) may impair left ventricular (LV) filling. Our aim was to analyse long-term time courses of M-mode LV and RV measurements and to relate these to the degree of PR. METHODS AND RESULTS: Retrospective longitudinal cohort of children (n = 88) after repair of TOF followed by serial echocardiography over 9 years. LV and RV diameters were expressed by z-scores based on normal paediatric reference values. Time courses of LV and RV diameter z-scores, degree of PR, and influence of co-variables were analysed using mixed regression models. LV diameter z-scores were significantly lowered before repair, increased after surgery, but fell again over time; thus, mean LV diameters were significantly lower than normal population means at all times. LV diameter z-scores correlated negatively with RV dilation and degree of PR. Notably, they were significantly higher in patients with previous shunts. After pulmonary valve replacement, LV diameter z-scores recovered to normal, whereas RV diameter z-scores remained abnormal. CONCLUSION: Our results confirm progressive adverse RV-LV interaction in the long-term post-operative follow-up of TOF. The use of z-scores facilitated the analysis of time courses of LV and RV diameters.

Intravitreal triamcinolone for persistent cystoid macular oedema in eyes with quiescent uveitis.

BACKGROUND: To determine the outcome following injections of triamcinolone acetate (IVTA) in the treatment of persistent cystoid macular oedema (CMO) in quiescent, non-infectious uveitis. METHODS: Retrospective analysis of patients with inactive uveitis requiring/not requiring immunosuppressive therapy who received IVTA because of chronic CMO refractory to previous systemic steroids. Number of IVTA (re-)treatments, distance visual acuity, near visual acuity, mean foveal thickness, intraocular pressure, duration of CMO, type of uveitis and systemic therapy were assessed previous to and 1, 4, 12 weeks following each IVTA treatment. RESULTS: Between March 2003 and May 2006, 24 eyes of 18 patients received between one and three IVTA injections. A resolution of chronic CMO was observed in 7/24 eyes (29.2%, 5 eyes after single injection of IVTA, 1 eye each after two and three injections of IVTA), a significant increase in distance visual acuity in 9/24 eyes (37.5%; 5 eyes with resolution of CMO, 4 eyes despite persistent CMO) and in near visual acuity in 13/24 eyes (54.6%; 6 eyes with resolution of CMO, 7 eyes despite persistent CMO). CONCLUSIONS: IVTA might be considered as a treatment for patients with chronic CMO when persistent despite previous systemic steroid therapy. Even patients without sustained resolution of CMO after IVTA might benefit in terms of transiently increasing visual acuity, but progression of cataract and rise in intraocular pressure limit repeatability.

Biomechanical comparison of modified Kessler and running suture repair in 3 different animal tendons and in human flexor tendons.

PURPOSE: To establish the animal flexor tendon that best mimics the biomechanical performance of human flexor tendons. We investigated the biomechanical behavior of core and running sutures in 3 different animal flexor tendons and in human flexor tendons. Additionally, we attempted to help standardize future flexor tendon studies. To that purpose, nearly all variables occurring in the test setup have been highlighted. METHODS: The species selected were pig, calf, sheep, and human. Two groups were formed. In the first group we tested 3-0 core sutures (Ticron; Tyco Healthcare, Vienna, Austria), and in the second group we tested 5-0 running sutures (Ethilon; Ethicon, Vienna, Austria). In each group, 10 tendons of each specimen were tested, which yielded a total of 80 tendons. In each group, the repaired tendons were subjected to 3,000 linear load cycles at a load of 15 N. At the end of this procedure, final gap values were recorded. In the next step, ultimate load-to-failure data were obtained from each specimen. RESULTS: Core sutures behaved similarly in the human, sheep, and pig tendons with respect to ultimate loads. With respect to gap formation, core sutures behaved similarly in the human, sheep, and calf tendons. Deep running sutures behaved similarly in the human, sheep, and pig tendons in terms of ultimate load to failure. CONCLUSIONS: In this study, sheep tendons were found to best mimic the biomechanical behavior of human tendons. Calf tendons seem to be unsuitable. There is a strong need for consistency in biomechanical test setups.

Age-related changes in baseline reading acuity and speed as measured using RADNER Reading Charts in healthy eyes with best corrected ETDRS distance acuity.

PURPOSE: To assess age-related differences in baseline measures of reading performance obtained from the RADNER Reading Charts in healthy eyes with best corrected (ETDRS) distance acuity. METHODS: Cross-sectional study of participants (n=200) aged 25-74 years (n=20 per 5 years age group). Best corrected distance visual acuity was measured monocularly with ETDRS 2000 Charts. Reading performance was evaluated binocularly with the RADNER Reading Charts. Reading acuity (RA), reading acuity score (RA score), mean reading speed (MEAN-RS), maximum reading speed, reading speed with a long paragraph, critical print size (CPS) and the logMAR/logRAD ratio were analysed. RESULTS: RA, RA score, CPS-1 (last logRAD with normal reading speed) and ETDRS acuity did not change significantly between age 25 and 54 years. Overall, the mean RA was -0.091±0.07 logRAD, and the RA score was -0.069±0.07 logRAD. The mean difference between the RA and best ETDRS acuity was 0.0603±0.055 logMAR (r=0.62; p<0.05). The logMAR/logRAD ratio was 87.75%±11.23%. The MEAN-RS ranged from 189±21.9 words per minute (wpm) for the group aged 70-74 years to 236±22.5 wpm for the group aged 40-44 years and correlated well with the long paragraph results (r=0.87). CONCLUSION: Best corrected RA, reading speed and ETDRS distance acuity were constant until the age of 54 years. An age-related break point was found between the groups aged 50-54 years and 55-59 years; for reading speed, the break point can be assumed to be within the age range of 50-54 years.