1,721,014 research outputs found
Long-term complications of bilateral posterior chamber phakic intraocular lens implantation.
No full textA 34-year-old woman had posterior chamber phakic intraocular lens (PCP IOL) implantation to correct high myopia in both eyes. Five years postoperatively, the patient presented with a decrease in visual acuity from central anterior subcapsular cataract formation in both eyes and IOL dislocation in the left eye. In vivo confocal microscopy of the cornea showed markedly decreased endothelial cell density in both eyes and the presence of bright endothelial microdeposits possibly related to pigmentary dispersion. Gonioscopy showed angle pigmentary deposits with no intraocular pressure increase. The patient was successfully treated by removing the PCP IOLs and performing phacoemulsification with in-the-bag IOL implantation in both eyes. This led to a recovery of visual acuity. This case report presents the rare occurrence and surgical management of cataract formation, IOL dislocation, and severe endothelial cell loss as a late complication of PCP IOL implantatio
In vivo confocal microscopy in primary congenital glaucoma with megalocornea.
No full textTo report the microscopic findings of congenital glaucoma-related megalocornea using in vivo confocal microscopy.
PATIENTS AND METHODS: Two consecutive adult patients presenting the typical features of glaucomatous megalocornea underwent a complete ophthalmologic examination. The first patient presented with progressive glaucoma with bilateral megalocornea. The second patient's left eye was affected by megalocornea without actual evidence of glaucoma, whereas the right eye was healthy. Both patients were examined using a new-generation scanning slit corneal confocal microscope.
RESULTS: In both patients, confocal microscopy revealed a mild reduction of keratocyte density in the mid and rear stroma, a particular abnormal "clew-shaped" morphology of stromal nerves, and the presence of discontinuous hyperreflective structures overhanging the endothelial layer at the level of the Descemet membrane. The endothelium showed severe polymegethism, pleomorphism, and a markedly decreased cell density, and focal cellular lesions were noted.
CONCLUSION: Confocal microscopy is a diagnostic tool used to evaluate microscopic aspects of Haab striae and endothelial morphologic changes in glaucomatous megalocornea. Unsuspected alterations, such as nerves abnormalities and focal endothelial tractions by scar tissue, were observed
Prospective randomized comparison of wavefront-guided and conventional photorefractive keratectomy for myopia with the meditec MEL 70 laser.
No full textPURPOSE: To study refractive results and aberrometric changes in myopic patients treated with wavefront-guided photorefractive keratectomy (PRK) in comparison with standard PRK.
METHODS: Sixty eyes of 60 patients with myopic astigmatism were randomly divided into two groups. Group 1 included 30 eyes (mean spherical equivalent refraction -4.39 +/- 1.31 D; range -2.50 to -6.50 D) treated with wavefront-guided PRK using the WASCA workstation and the Asclepion Meditec flying spot MEL 70 excimer laser. Group 2 had 30 eyes (mean spherical equivalent refraction -4.33 +/- 1.22 D; range -2.50 to -6.50 D) that underwent conventional PRK using the same laser, and served as the control group. Wavefront analysis of high order aberrations was performed before and 6 months after surgery.
RESULTS: Postoperatively, wavefront error increased in both groups (5.0-mm wavefront aperture diameter). Six months after surgery, the eyes that received the WASCA ablation had a smaller increase in root-mean-square (RMS; 70% of increment) compared to the conventional PRK group (139% of increment) (P<.001). In the standard PRK group, all aberrations notably increased; in the wavefront-guided PRK group there was a smaller increase of trefoil and spherical aberrations (P<.001) and a decrease of coma aberrations (P<.001). The smaller increase of wavefront error in the wavefront-guided PRK group compared to the standard PRK group was more evident when preoperative RMS values were higher than 0.4 microm (P<.01). The visual parameters (spherical equivalent refraction, uncorrected and best spectacle-corrected visual acuity) did not show significant differences between the two groups.
CONCLUSION: Wavefront-guided PRK induced a smaller increase of postoperative wavefront-error compared to conventional PRK, particularly in patients with higher preoperative higher order aberrations
Femtosecond Laser-Assisted Stromal Lenticule Addition Keratoplasty for the Treatment of Advanced Keratoconus: A Preliminary Study
No full textPURPOSE: To investigate the in vivo effect of a novel femtosecond laser-assisted procedure termed stromal lenticule addition keratoplasty for advanced keratoconus.
METHODS:
Ten patients with stage III and IV stable keratoconus were included. Negative meniscus-shaped stromal lenticules were produced from corneoscleral eye bank buttons with a refractive lenticule extraction procedure with a 500-kHz VisuMax femtosecond laser (Carl Zeiss Meditec, Jena, Germany). Recipient corneas underwent a modified femtosecond laser flap-cut procedure to produce an intrastromal pocket and lenticules were implanted. Patients were followed up for 6 months after surgery with determination of uncorrected (UDVA) and corrected (CDVA) distance visual acuity, subjective refraction and topographic corneal curvature changes, anterior segment optical coherence tomography (AS-OCT), and in vivo confocal microscopy.
RESULTS:
Comparison of preoperative and 6-month postoperative UDVA and CDVA showed statistically significant improvements (P = .024 and .007, respectively) from 1.58 ± 0.36 to 1.22 ± 0.37 and from 1.07 ± 0.17 to 0.70 ± 0.23 logMAR. Eight of 10 eyes showed an improvement in UDVA (P < .001) that ranged between one and three lines, whereas all but one eye presented improved CDVA. Corneal topography documented a decrease between preoperative and 6-month postoperative anterior mean curvature (AVG-K at 3 mm) and anterior Q values (P = .005). AS-OCT showed a significant increase in thickness of the central and mid-peripheral cornea produced by the lenticule implantation (P = .005).
CONCLUSIONS:
The stromal lenticule addition keratoplasty procedure was clinically efficient in improving the corneal shape and vision in patients with keratoconus. Negative meniscus-shaped lenticule addition induced a flattening of the cone while increasing corneal thickness
Management of scleral rupture during retinal detachment surgery: a case report.
No full textPURPOSE: Rupture of the sclera occurring during retinal detachment surgery is generally associated with unfavourable anatomic and visual outcomes. Re-operation after a failed scleral buckle procedure and pre-existing scleral thinning are considered the main risk factors for scleral rupture.
CASE REPORT: We describe the management and the favourable outcome of a case of scleral rupture in a 71-year-old woman during re-operation for retinal detachment.
CONCLUSIONS: We managed this case of scleral rupture in accordance with current indications concerning the anatomical recovery, by scleral suture and patch graft, restoring IOP by gas tamponade. The positive outcome was partly related to the prompt closure of the retinal hole which led to reattachment, and partly to favourable events such as the moderate intensity of vitreous hemorrhage and the lack of any more serious intraoperative and postoperative complications
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
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
Bevacizumab collirio nel trattamento delle neovascolarizzazioni corneali: nuova opzione terapeutica?
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