A Comparison of the American Society of Cataract and Refractive Surgery post-myopic LASI K/PRK Intraocular Lens (IOL) calculator and the Ocular MD IOL calculator

David L DeMill1, Majid Moshirfar1, Marcus C Neuffer1, Maylon Hsu1, Shameema Sikder21John A Moran Eye Center, University of Utah, Salt Lake City, UT, USA; 2Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USABackground: To compare the average values of the American Society of Cataract and Refractive Surgery (ASCRS) and Ocular MD intraocular lens (IOL) calculators to assess their accuracy in predicting IOL power in patients with prior laser-in-situ keratomileusis (LASIK) or photorefractive keratectomy.Methods: In this retrospective study, data from 21 eyes with previous LASIK or photorefractive keratectomy for myopia and subsequent cataract surgery was used in an IOL calculator comparison. The predicted IOL powers of the Ocular MD SRK/T, Ocular MD Haigis, and ASCRS averages were compared. The Ocular MD average (composed of an average of Ocular MD SRK/T and Ocular MD Haigis) and the all calculator average (composed of an average of Ocular MD SRK/T, Ocular MD Haigis, and ASCRS) were also compared. Primary outcome measures were mean arithmetic and absolute IOL prediction error, variance in mean arithmetic IOL prediction error, and the percentage of eyes within ±0.50 and ±1.00 D.Results: The Ocular MD SRK/T and Ocular MD Haigis averages produced mean arithmetic IOL prediction errors of 0.57 and –0.61 diopters (D), respectively, which were significantly larger than errors from the ASCRS, Ocular MD, and all calculator averages (0.11, –0.02, and 0.02 D, respectively, all P < 0.05). There was no statistically significant difference between the methods in absolute IOL prediction error, variance, or the percentage of eyes with outcomes within ±0.50 and ±1.00 D.Conclusion: The ASCRS average was more accurate in predicting IOL power than the Ocular MD SRK/T and Ocular MD Haigis averages alone. Our methods using combinations of these averages which, when compared with the individual averages, showed a trend of decreased mean arithmetic IOL prediction error, mean absolute upper limit of IOL prediction error, and variance, while increasing the percentage of outcomes within ±0.50 D.Keywords: laser-in-situ keratomileusis, photorefractive keratectomy, intraocular lens calculator, ocular MD, American Society of Cataract and Refractive Surger

Femtosecond-assisted preparation of donor tissue for Boston type 1 keratoprosthesis

We describe a technique for femtosecond laser-assisted preparation of donor tissue for Boston type 1 keratoprosthesis to provide accurate double punching of the donor tissue for optimized alignment in the visual axis. The technique was reproducibly performed in four donor corneas mounted in an artificial anterior chamber. This technique can provide optically centered donor tissue with smooth trephinated edges

The effect of preoperative keratometry on visual outcomes after moderate myopic LASIK

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Prospective, randomized, fellow eye comparison of WaveLight® Allegretto Wave® Eye-Q versus VISX CustomVueTM STAR S4 IRTM in photorefractive keratectomy: analysis of visual outcomes and higher-order aberrations

Majid Moshirfar1, Daniel S Churgin2, Brent S Betts3, Maylon Hsu1, Shameema Sikder4, Marcus Neuffer1, Dane Church5, Mark D Mifflin11University of Utah, John A Moran Eye Center, Department of Ophthalmology and Visual Sciences, Salt Lake City, UT, USA; 2University of Arizona College of Medicine, Phoenix, AZ; 3Temple University School of Medicine, Philadelphia, PA, USA; 4Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA; 5Virginia Commonwealth University School of Medicine, Richmond, VA, USABackground: The purpose of this study was to compare differences in visual outcomes, higher-order aberrations, contrast sensitivity, and dry eye in patients undergoing photorefractive keratectomy using wavefront-guided VISX CustomVue™ and wavefront-optimized WaveLight® Allegretto platforms.Methods: In this randomized, prospective, single-masked, fellow-eye study, photorefractive keratectomy was performed on 46 eyes from 23 patients, with one eye randomized to WaveLight Allegretto, and the fellow eye receiving VISX CustomVue. Three-month postoperative outcome measures included uncorrected distance visual acuity, corrected distance visual acuity, refractive error, root mean square of total and grouped higher-order aberrations, contrast sensitivity, and Schirmer’s testing.Results: Mean values for uncorrected distance visual acuity (logMAR) were —0.03 ± 0.07 and —0.06 ± 0.09 in the wavefront-optimized and wavefront-guided groups, respectively (P = 0.121). Uncorrected distance visual acuity of 20/20 or better was achieved in 91% of eyes receiving wavefront-guided photorefractive keratectomy, and 87% of eyes receiving wavefront-optimized photorefractive keratectomy, whereas uncorrected distance visual acuity of 20/15 was achieved in 35% of the wavefront-optimized group and 64% of the wavefront-guided group (P ≥ 0.296). While root mean square of total higher-order aberration, coma, and trefoil tended to increase in the wavefront-optimized group (P = 0.091, P = 0.115, P = 0.459, respectively), only spherical aberration increased significantly (P = 0.014). Similar increases were found in wavefront-guided root mean square of total higher-order aberration (P = 0.113), coma (P = 0.403), trefoil (P = 0.603), and spherical aberration (P = 0.014). There was no significant difference in spherical aberration change when comparing the two platforms. The wavefront-guided group showed an increase in contrast sensitivity at 12 cycles per degree (P = 0.013).Conclusion: Both VISX CustomVue and WaveLight Allegretto platforms performed equally in terms of visual acuity, safety, and predictability in photorefractive keratectomy. The wavefront-guided group showed slightly improved contrast sensitivity. Both lasers induced a comparable degree of statistically significant spherical aberration, and tended to increase other higher-order aberration measures as well.Keywords: wavefront-guided, wavefront-optimized, photorefractive keratectom

Strategien und Technologien einer pluralistischen Fern- und Nahwärmeversorgung in einem liberalisierten Energiemarkt unter besonderer Berücksichtigung der Kraft-Wärme-Kopplung und regenerativer Energien : Kurztitel: Pluralistische Wärmeversorgung ; AGFW-Hauptstudie - erster Bearbeitungsabschnitt. Band 1, Grundlagen der Kraft-Wärme-Kopplung, Zertifizierungsverfahren und Fördermodelle

Die im vorliegenden Band 1 vorgestellten Ergebnisse sollen der Begleitung der anstehenden KWK-Gesetzgebung in technischer und wirtschaftlicher Hinsicht dienen. Das derzeitige KWK-(Vorschalt-)Gesetz, welches durch ein neues mit klareren Kriterien verbundenes Gesetz ersetzt werden soll, ist in mehrfacher Hinsicht problematisch, da es Regelungen zum Auffangen von Stranded Investments mit Regelungen zur Förderung von KWK vermischt, keine klare Definition von KWK enthält, industrielle KWK ausgegrenzt und durch die intransparente Förderstruktur das Mittelaufkommen und die Mittelverwendung nicht nachvollziehbar macht. Ein KWK-Ausbau wird sich in der gegenwärtigen Situation des Strommarktes nur auf der Basis einer Förderung entwickeln können (vgl. Vorstudie). Obwohl neue KWK-Anlagen im Vergleich zu neuen Anlagen der ungekoppelten Erzeugung unter Vollkostenbedingungen meist günstiger abschneiden, benötigen sie vor dem Hintergrund des aktuell auf dem Niveau kurzfristiger Grenzkosten geführten Preiskampfes zusätzliche Deckungsbeiträge. Die Analyse der Vielzahl vorgeschlagener Zertifizierungskriterien hat ergeben, dass definierter KWK-Strom eine geeignete Messgröße darstellt. Ausführliche Analysen zeigen, dass die Bestimmung dieses Stromanteils mit Hilfe einer einmaligen Anlagenzertifizierung relativ unproblematisch ist. Eine weitere Differenzierung des so definierten KWK-Stroms, z. B. hinsichtlich der CO2-Effizienz, birgt dagegen die Gefahr so krasser Fördergegensätze zwischen alten und neuen Anlagen sowie zwischen gas- und kohlegefeuerten Anlagen, dass dadurch vorhandene, für zukünftige Anwendungen prädestinierte Standorte verloren gehen könnten und die sinnvolle Auskopplung großer Wärmemengen aus Steinkohlekraftwerken unterbleibt. Die Bewertung verschiedener Fördermodelle ergibt kein eindeutiges Bild, welches Fördermodell zu bevorzugen wäre. Andererseits zeigt sich, dass sich aus allen Bausteinen von Förderinstrumenten ein sinnvolles Instrumentenmix konstruieren lässt