1,720,984 research outputs found
Management of Type 2 Bubble Formed During Big-Bubble Deep Anterior Lamellar Keratoplasty
No full textCorrispondig letter related to Management of Type 2 Bubble Formed During Big-Bubble Deep Anterior Lamellar Keratoplast
Evaluation of the risk factors associated with conversion of intended deep anterior lamellar keratoplasty to penetrating keratoplasty
No full textBackground/aimsTo identify and evaluate risk factors associated with the need to convert intended deep anterior lamellar keratoplasty (DALK) to penetrating keratoplasty (PK).MethodsRetrospective institutional cohort study including all consecutive eyes undergoing intended DALK between May 2015 and October 2018 at 'Villa Igea' Hospital (Forli, Italy). The indications for surgery were categorised as (1) keratoconus without scarring; (2) keratoconus with scarring; (3) non-keratoconus without scarring; and (4) non-keratoconus with scarring. Multivariate binary logistic regression analysis was performed, introducing, as independent variables, those that reached a significance level of less than 0.05 in univariate analysis. The main outcome measure was whether or not conversion to a PK occurred.Results705 eyes were included, with conversion to PK occurring in 16.2% (n=114) of cases. The factors that remained significant in multivariate analysis were corneal scarring (OR=3.52, p<0.001), manual dissection (OR=42.66, p<0.001), type 2 bubble (OR=90.65, p<0.001) and surgeon inexperience (OR=10.86, p<0.001). A receiver operating characteristic (ROC) curve based on the factors significant in the multivariate binary logistic regression analysis achieved a sensitivity of 89.5% (95% CI 82.3% to 94.4%) and a specificity of 80.2% (95% CI 76.8% to 83.3%) with an area under the ROC curve of 0.91 (95% CI 0.88 to 0.93) (p<0.001)ConclusionOccurrence of a type 2 bubble, the need for manual dissection, the presence of scarring and surgeon inexperience are independent risk factors for the need to convert intended DALK to PK. Correct identification and management of the type of bubble achieved during pneumatic dissection is instrumental in minimising the rate of conversion to PK
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Immunologic Stromal Rejection After Deep Anterior Lamellar Keratoplasty With Grafts of a Larger Size (9 mm) for Various Stromal Diseases
No full textPURPOSE: To evaluate the rate and outcomes of immunologic stromal rejection occurring after large deep anterior lamellar keratoplasty (DALK) and the effect of the underlying disease on the cumulative probability of rejection.METHODS: This was a retrospective chart review of all eyes that underwent a 9-mm DALK at Ospedali Privati Forlì (Forlì, Italy). On the basis of preoperative diagnosis, eyes were assigned to group 1: keratoconus, group 2: stromal disease with a low risk for rejection, or group 3: stromal disease with a high risk for rejection. The cumulative probability of experiencing a rejection episode over time was assessed by Kaplan-Meier analysis and was compared among the 3 groups using the log-rank test. Values of corrected distance visual acuity, central corneal thickness, and endothelial cell density before and 6 months after rejection were compared.RESULTS: Twenty of 377 eyes (5.3%) experienced an episode of stromal rejection [17/265 (6.4%) in group 1, 2/71 (2.8%) in group 2, and 1/41 (2.4%) in group 3]. The mean time interval between DALK and the rejection onset was 11.8 months (range 1-24). The cumulative probability of rejection episodes did not differ significantly among the 3 groups. All episodes resolved within 6 months after the onset, with no significant differences between prerejection and 6-month postrejection values of corrected distance visual acuity, central corneal thickness, and endothelial cell density.CONCLUSIONS: The rate of immunologic stromal rejection after large 9-mm DALK is within the range reported in the literature for conventional DALK, regardless of the indication for surgery
Deep Anterior Lamellar Keratoplasty in Eyes With Intrastromal Corneal Ring Segments
No full textPurpose: To evaluate the possibility of using the intrastromal corneal ring segments (ICRSs) previously implanted as a depth reference for performing pneumatic dissection in deep anterior lamellar keratoplasty (DALK). Methods: The depth of placement of 2 symmetrical ICRSs placed in the superior and inferior midperipheral cornea of 4 eyes of 4 patients with keratoconus was measured by means of anterior segment optical coherence tomography. Because of irregular and/or high astigmatism, DALK using pneumatic dissection was performed in all eyes. The standardized procedure included the following: 1) Deep trephination of the recipient cornea outside the ICRSs (9 mm in diameter), aimed at facilitating the insertion and advancement of a dedicated cannula under the ICRS implant, just within its peripheral margin; 2) air injection for pneumatic dissection; 3) removal of about 80% of the anterior stroma; 4) perforation of the "big bubble" ceiling under viscoelastic protection and removal of its central 6 mm; and 5) suturing of a donor lamella of the anterior stroma obtained by microkeratome dissection using a 450-m head and punched to a diameter of 9 mm. Results: In all cases, the site for air injection was selected where the thickness of the stroma underlying the superior ICRS did not exceed 150 m. Pneumatic dissection succeeded uneventfully in all eyes; postoperative best spectacle-corrected visual acuity was 20/20 in 3 of 4 eyes, whereas refractive astigmatism was less than 3 diopters in all cases. Conclusions: The presence of ICRSs facilitates gauging the depth of cannula insertion at the time of DALK, to succeed with pneumatic dissection
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Successful Descemet membrane endothelial keratoplasty in proven herpetic endothelial decompensation requires intensive antiviral therapy
No full textPurpose: To report the outcomes of Descemet membrane endothelial keratoplasty (DMEK) with intensive antiviral therapy for corneal edema secondary to herpes simplex virus type 1 (HSV-1)-mediated endotheliitis. Methods: All eyes with polymerase chain reaction positive for HSV-1 undergoing DMEK for endothelial decompensation between January 2014 and January 2018 were followed up prospectively at our tertiary referral center. All eyes had been free of active inflammation for a minimum of 9 months and were treated prophylactically with high-dose systemic and topical antivirals, which were continued for a prolonged period of time. Primary outcomes were the occurrence of immunological rejection and/or recurrence of endotheliitis, eventually resulting in graft failure. Secondary outcomes were best spectacle-corrected visual acuity and endothelial cell loss. Results: Four consecutive eyes of 4 patients were included with a mean (±SD) patient age of 68.5 ± 15.1 years. The postoperative follow-up averaged 22 months. No eyes exhibited any signs of immunologic rejection, recurrence of endotheliitis, or graft failure. Mean (±SD) decimal best spectacle-corrected visual acuity improved from 0.2 ± 0.1 to 0.7 ± 0.2 (P = 0.007), whereas mean (±SD) endothelial cell loss was 56% ± 10.2% at the final postoperative follow-up. Conclusions: DMEK is an effective option to treat corneal edema secondary to HSV-1-related endotheliitis. Intensive antiviral prophylaxis may reduce the risk of recurrence and subsequent graft failure.Purpose: To report the outcomes of Descemet membrane endothelial keratoplasty (DMEK) with intensive antiviral therapy for corneal edema secondary to herpes simplex virus type 1 (HSV-1)mediated endotheliitis. Methods: All eyes with polymerase chain reaction positive for HSV-1 undergoing DMEK for endothelial decompensation between January 2014 and January 2018 were followed up prospectively at our tertiary referral center. All eyes had been free of active inflammation for a minimum of 9 months and were treated prophylactically with high-dose systemic and topical antivirals, which were continued for a prolonged period of time. Primary outcomes were the occurrence of immunological rejection and/or recurrence of endotheliitis, eventually resulting in graft failure. Secondary outcomes were best spectacle-corrected visual acuity and endothelial cell loss. Results: Four consecutive eyes of 4 patients were included with a mean (6SD) patient age of 68.5 6 15.1 years. The postoperative follow-up averaged 22 months. No eyes exhibited any signs of immunologic rejection, recurrence of endotheliitis, or graft failure. Mean (6SD) decimal best spectacle-corrected visual acuity improved from 0.2 6 0.1 to 0.7 6 0.2 (P = 0.007), whereas mean (6SD) endothelial cell loss was 56% 6 10.2% at the final postoperative follow-up. Conclusions: DMEK is an effective option to treat corneal edema secondary to HSV-1-related endotheliitis. Intensive antiviral prophylaxis may reduce the risk of recurrence and subsequent graft failure
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