Exploring the precision of femtosecond laser-assisted descemetorhexis in Descemet membrane endothelial keratoplasty

Objective Descemet membrane endothelial keratoplasty (DMEK) remains a challenging technique. We compare the precision of femtosecond laser-assisted DMEK to manual DMEK. Methods and Analysis A manual descemetorhexis (DR) of 8 mm diameter was compared with a femtosecond laser-assisted DR of the same diameter (femto-DR) in 22 pseudophakic patients requiring DMEK. We used OCT images with a centred xy-diagram to measure the postoperative precision of the DR and the amount of endothelial denuded area. Endothelial cell loss (ECL) and best corrected visual acuity were measured 3 months after surgery. Results In the manual group, the median error of the DR was 7% (range 3%-16%) in the x-diameter and 8% (range 2%-17%) in the y-diameter. In the femto group, the median error in the respective x and y-diameters was 1% (range 0.4%-3%) and 1% (range 0.006%-2.5%), smaller than in the manual group (p=0.001). Endothelial denuded areas were larger in the manual group (11.6 mm(2), range 7.6-18 mm(2)) than in the femto group (2.5 mm(2), range 1.25.9 mm(2)) (p<0.001). The ECL was 21% (range 5%-78%) in the manual DR and 17% (range 6%-38%) in the femto-DR group (p=0.351). The median visual acuity increased from 0.4 logMAR (range 0.6-0.4 logMAR) in both groups to 0.1 logMAR (range 0.4-0 logMAR) in the manual group and to 0.1 logMAR (range 0.3-0 logMAR) in the femto group (p=0.461). Three rebubblings were required in the manual group, whereas the femto group required only one. Conclusion The higher precision of the femto-DR bears the potential to improve DMEK surgery

Performance of the optimized Post-Zel'dovich approximation for CDM models in arbitrary FLRW cosmologies

We investigate the performance of the optimized Post-Zel'dovich approximation in three cold dark matter cosmologies. We consider two flat models with $\Omega_0=1$ (SCDM) and with $\Omega_0=0.3$ ($\Lambda$CDM) and an open model with $\Omega_0=0.3$ (OCDM). We find that the optimization scheme proposed by Wei{\ss}, Gottl\"ober & Buchert (1996), in which the performance of the Lagrangian perturbation theory was optimized only for the Einstein-de Sitter cosmology, shows the excellent performances not only for SCDM model but also for both OCDM and $\Lambda$CDM models. This universality of the excellent performance of the optimized Post-Zel'dovich approximation is explained by the fact that a relation between the Post-Zel'dovich order's growth factor $E(a)$ and Zel'dovich order's one $D(a)$, $E(a)/D^2(a)$, is insensitive to the background cosmologies.Comment: 8 pages, 3 figures, LaTex using aaspp4.sty and epsf.sty, Accepted for publication in ApJ Letter

Visual outcomes and complications following posterior iris-claw aphakic intraocular lens implantation combined with penetrating keratoplasty

Abstract Background To evaluate the indication, visual outcome, and complication rate after implantation of a posterior iris-claw aphakic intraocular lens (IOL) during penetrating keratoplasty. Methods This retrospective study comprised 23 eyes (23 patients) without adequate capsule support undergoing posterior iris-claw aphakic IOL implantation (Verisyse™/ Artisan®) during penetrating keratoplasty between 2005 and 2010. Mean follow-up was 18 months (range from 12 to 37 months). Results The IOLs were inserted during an IOL exchange in 17 eyes and as a secondary procedure in six aphakic eyes. Pseudophakic bullous keratopathy with corneal scar after anterior chamber intraocular lens (ACIOL) was the main indication for penetrating keratoplasty in 16 eyes (69.6 %). The final corrected distance visual acuity (CDVA) in logMAR (mean 1.0 ± 0.46) improved significantly (p &lt; 0.05) compared to the preoperative CDVA (mean 1.8± 0.73). Twenty eyes (86.9 %) had a final visual acuity in logMAR better than the pre-operative CDVA. The mean postoperative IOP 16.3 mmHg±4.0 was not significantly (p &gt; 0.05) higher compared to the preoperative IOP 15.6 mmHg±5.1. Complications included slight temporary pupil ovalization in three eyes (13.0 %) and iris-claw IOL sublocation in three eyes (13.0 %); all IOLs could be easily repositioned. Cystoid macular edema occured in one eye (4.3 %) 8 weeks after primary surgery. All grafts remained clear without any sign of graft rejection. Conclusions Retropupillar iris-claw IOL during penetrating keratoplasty provides good visual outcomes with a favorable complication rate, and can be used for a wide range of indications in eyes without adequate capsule support

Methods of assessment of patients for Nd:YAG laser capsulotomy that correlate with final visual improvement

BACKGROUND: This paper attempts to clarify the usefulness of various simple pre-operative measures in estimating the potential for a visually successful capsulotomy. METHODS: 24 patients attending for capsulotomy had pre-operative measures of glare with BAT tester, visibility of posterior pole and grading of posterior capsular pearls and fibrosis seen at slit lamp. Visual function was measured before and after standardised capsulotomy. Correlations of the various preoperative measures with eventual visual function improvements were calculated. RESULTS: Pearls at slit lamp and poor posterior pole visualisation were all correlated with improvements in visual acuity and contrast sensitivity after capsulotomy. Amount of fibrosis visible at slit lamp and glare assessment were not correlated with vision improvements after laser. CONCLUSION: Of the various measures that are taken prior to Nd : YAG capsulotomy, some correlate with eventual visual improvement but for others no clinical utility was found. Practitioners should note these findings as they are especially of use in more questionable or high-risk cases to help determine whether referral for PCO treatment by Nd: YAG capsulotomy is likely to benefit the patient

The summertime Boreal forest field measurement intensive (HUMPPA-COPEC-2010): an overview of meteorological and chemical influences

This paper describes the background, instrumentation, goals, and the regional influences on the HUMPPA-COPEC intensive field measurement campaign, conducted at the Boreal forest research station SMEAR II (Station for Measuring Ecosystem-Atmosphere Relation) in Hyytiälä, Finland from 12 July–12 August 2010. The prevailing meteorological conditions during the campaign are examined and contrasted with those of the past six years. Back trajectory analyses show that meteorological conditions at the site in 2010 were characterized by a higher proportion of southerly flow than in the other years studied. As a result the summer of 2010 was anomalously warm and high in ozone making the campaign relevant for the analysis of possible future climates. A comprehensive land use analysis, provided on both 5 and 50 km scales, shows that the main vegetation types surrounding the site on both the regional and local scales are: coniferous forest (Scots pine and/or Norway spruce); mixed forest (Birch and conifers); and woodland scrub (e.g. Willows, Aspen); indicating that the campaign results can be taken as representative of the Boreal forest ecosystem. In addition to the influence of biogenic emissions, the measurement site was occasionally impacted by sources other than vegetation. Specific tracers have been used here to identify the time periods when such sources have impacted the site namely: biomass burning (acetonitrile and CO), urban anthropogenic pollution (pentane and SO&lt;sub&gt;2&lt;/sub&gt;) and the nearby Korkeakoski sawmill (enantiomeric ratio of chiral monoterpenes). None of these sources dominated the study period, allowing the Boreal forest summertime emissions to be assessed and contrasted with various other source signatures

Tier, Maschine, Avatar

Die postmoderne Identitätssuche setzt, anknüpfend an die europäische Tradition, weiterhin das Tier als Figur der Alterität und zugleich als integratives Element des menschlichen Wesens. Neben dem Tier ist die Maschine ein konstitutiver Teil der Identität des Menschen. Mit der katastrophalen Erfahrung des Holocaust wird jedoch die bis dahin in die geschlossene Figur des Kreises eingebundene Wechselwirkung dieser Elemente aufgebrochen. Dazu tritt in der Postmoderne der Avatar als Figur der Virtualität. In einem offenen Kreislauf von Dehumanisierung, Reanimalisierung und Rehumanisierung, der in der Dissertation an exemplarischen französischen und italienischen Romanen der zweiten Hälfte des 20. Jahrhunderts nachgezeichnet wird, artikuliert sich die postmoderne Identitätssuche in Form einer offenen Spirale