1,721,004 research outputs found
Influence of Apical Clearance on Mini-Scleral Lens Settling, Clinical Performance, and Corneal Thickness Changes
No full textPurpose: The purpose of this work was to define the timing and magnitude of scleral contact lens settling, the factors influencing settling, and to examine whether the amount of apical clearance has an impact on clinical performance or is associated with hypoxia-induced corneal changes. Methods: Eleven patients (22 eyes) with keratoconus were fitted with a mini-scleral lens (Esclera, Brazil). Three different lenses with successively greater sagittal depths were applied to achieve 3 levels of initial apical clearance: 100 to 200 mu m (low), 200 to 300 mu m (medium), and greater than 300 mu m (high). Corneal apical clearance was measured at 15 min, 1, 2, 4, 6, and 8 hr with optical coherence tomography (OCT). Central corneal thickness was measured with OCT and Pentacam, in the morning and immediately after removal of the contact lens. Results: Mean settling was 26.8 +/- 18.8 mu m (42.7%) at 1 hr, 39.5 +/- 26.5 mu m (62.9%) at 2 hr, 50.7 +/- 31.6 mu m (80.8%) at 4 hr, 57.4 +/- 34.6 mu m (91.4%) at 6 hr, and 62.8 +/- 38.4 mu m (100%) at 8 hr. Settling rate was significantly lower in low apical clearance group (P = 0.01). The smaller diameter lenses settled more (P = 0.03). There was a slight statistically significant increase of 1.3% in central corneal thickness measured with OCT (P = 0.03). Central corneal thickness measured with Pentacam at three locations increased slightly (P = 0.001). Settling showed significant intrasubject and intersubject variations. The amount of corneal swelling and comfort scores did not differ significantly according to apical clearance. Conclusions: The average amount of settling was 62.8 mu m after 8 hr, 80% of which occurred during the first 4 hr. Slight corneal swelling (1.3%) occurred after 8 hr of wear
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Takayasu Arteriti’nde göz bulguları ve oküler dolaşımın değerlendirilmesi
No full textAmaç: Takayasu arteriti hastalarında oküler dolaşımdaki bozukluklara veya kullanılan ilaçlara bağlı olarak çeşitli göz komplikasyonları gelişebilmektedir. Bu çalışmanın amacı romatoloji kliniğinde takipli Takayasu arteriti hastalarında oküler komplikasyon durumu ile oküler kan akımı parametrelerini değerlendirmek ve bu parametreler ile klinik bulgular arasındaki ilişkiyi tanımlamaktır. Gereç ve Yöntemler: Marmara Üniversitesi Tıp Fakültesi, Romatoloji Bilim Dalı’nda takipli 65 Takayasu arteriti hastası (60 kadın, 5 erkek, ortalama yaş: 41.8 ±12.9) ve 51 (50 kadın, 1 erkek, ortalama yaş: 37.4 ±12.9) sağlıklı gönüllü çalışmamıza katıldı. Çalışma kapsamında tüm katılımcılara detaylı bir göz muayenesi, optik koherens tomografi (OKT) ile maküla, retina sinir lifi tabakası analizi ve cihazın EDI-OKT modunda koroid görüntülemesi yapıldı. Koroid kalınlığı değerlendirilebilmesi için retina pigment epitelinin dış sınırı ile skleral hiperreflektif bantın iç sınırı arasındaki mesafe manuel olarak ölçüldü. Hastaların sağ gözlerinde renkli Doppler ultrasonografi ile oftalmik arter ve santral retinal arter kan akım parametreleri değerlendirildi. Hastaların göz muayenesine yönlendirildikleri son romatoloji muayenelerindeki kan basıncı ölçümleri, hastalık süreleri istatistiksel analizler için kullanıldı. Hastalık süreleri ile yukarıda belirtilen ölçüm ve muayene bulguları arasında ilişki olup olmadığı incelendi. Bulgular: Hastalarda en sık izlenen oküler komplikasyon hipertansif retinopati (%33.9) olarak saptandı. Dört hastada (%6.2) Takayasu retinopatisi ile uyumlu bulgular izlendi. 13 gözde (%10) posteriyor subkapsüler katarakt saptandı ve 7 gözün psödofakik olduğu izlendi. Hiçbir hastada iskemik neovasküler komplikasyonlara bağlı görme azalması izlenmedi. Takayasu arteriti ile sağlıklı kontroller arasından santral maküla kalınlığı, fovea hacmi, retina sinir lifi tabakası kalınlığı ve subfoveal koroid kalınlığı açısından istatistiksel anlamlı farklılık izlenmedi. Takayasu arteriti hastalarının Doppler ile yapılan kan akımı analizlerinde rezistivite indeksinin oftalmik arterde (0.75 vs. 0.66, p=0.002) ve santral retinal arterde (0.75 vs. 0.67, p=0.001) daha yüksek olduğu izlendi. Hipertansif retinopati gelişen hastaların hastalık süreleri gelişmeyen hastalara kıyasla anlamlı olarak daha uzun bulunurken (7.9 yıl vs. 4.7 yıl, p=0.016), üst ekstemite kan basınçları arasında anlamlı bir fark saptanmadı. Radiyal arterede nabızsızlık bulgusu olan hastaların aynı gözlerindeki oftalmik arter rezisitivite indeksi, radiyal arterde nabızsızlık olmayan hastalara kıyasla daha yüksek bulunurken (0.77 vs. 0.68, p=0.031), karotis üfürümü olan veya olmayan hastaların oküler kan akım parametreleri arasında anlamlı bir fark saptanmadı. Hastalık süresi 5 yıldan uzun olan veya 5 yıldan kısa olan olguların oküler kan akımı parametreleri arasında anlamlı bir fark izlenmedi. Katılımcıların subfoveal koroid kalınlıkları ile oküler kan akımı parametreleri arasında anlamlı bir korelasyon saptanmadı. Sonuç: Marmara Üniversitesi Tıp Fakültesi Hastanesi’nde takipli hastalarda Takayasu retinopatisi gelişme oranı literatüre göre daha düşük bulunmuştur. Hiçbir hastada görme ile ilgili şikayet izlenmezken, Doppler bulguları oküler kan akımında subklinik bir azalmaya işaret etmektedir. ler kan akımı, oküler komplikasyon, renkli Doppler ultrasonografi, retinopati, Takayasu arteritiOcular Findings and Ocular Blood Flow Changes in Takayasu Arteritis Purpose: Ocular involvement in Takayasu arteritis mainly arises due to complications related with altered ocular blood flow or side effects of the treatments. In this study, we aimed to document ocular complication rate, ocular blood flow status and the association of ocular blood flow parameters with clinical outcome of the Takayasu arteritis patients followed in the rheumatology clinic. Material and Methods: We have included 65 Takayasu arteritis patients followed at Marmara University Medical School, Rheumatology Division (60 female, 5 male, mean age: 41.8 ±12.9) and 51 healthy subjects (50 female, 1 male, mean age: 37.4 ±12.9) in this study. All of the participants had a detailed ophthalmological examination, optical coherence tomography scan of the macula, retinal nerve fiber layer and choroid. Ocular blood flow in ophthalmic artery and central retinal artery was evaluated with Color Doppler ultrasonography. The rheumatology examination data was reached from the last rheumatology visit at which the patients were referred to the ophthalmology clinic. Results: The most common ocular complication was hypertensive retinopathy (33.9%). Four patients had retinal findings related with Takayasu retinopathy (6.2%). Thirteen eyes had posteriyor subcapsular cataract (%10) and 7 eyes were pseudophacic (5.4%). None of the patients suffered a loss in visual acuity due to ischemic and/ or neovascular complications. There was no statistically significant difference between the Takayasu arteritis patients and healthy subjects for the central macular thickness, foveal volume, retinal nerve fiber layer thickness and subfoveal choroideal thickness. Takayasu arteritis patients had increased resistivity index in ophthalmic artery (0.75 vs. 0.66, p=0.002) and central retinal artery (0.75 vs. 0.67, p=0.001). The patients with hypertensive retinopathy had a significantly longer disease duration compared to the no retinopathy group (7.9 years vs. 4.7 years, p=0.016), while there was no statistically significant difference between the groups for upper extremity blood pressure values. The resistivity index of the ophthalmic artery was higher in patients with ipsilateral radial artery pulselessness compared to the patients who had no pulselessness (0.77 vs. 0.68, p=0.031). The patients with carotid artery bruits did not have a significant change in the ocular blood flow parameters compared to the patients who did not have carotid artery bruits. There was no significant difference for ocular blood flow parameters between the patients with long disease duration (>5 years) and short disease duration (<5 years). There was no correlation between the subfoveal choroideal thickness values and ocular blood flow parameters of the participants. Conclusion: The prevalence of Takayasu arteritis was lower in our study compared with previous studies. While none of the patients complained about visual disturbances, Doppler findings indicate a subclinical reduction in ocular blood flow in Takayasu arteritis. Key words: color Doppler ultrasonography, ocular blood flow, ocular complication, retinopathy, Takayasu arteriti
Efficacy and safety of low-concentration, bisulphite-containing, intracameral epinephrine and topical atropine treatments for the prevention of intraoperative floppy iris syndrome
No full textPurpose: The aim of this study was to evaluate the efficacy and safety of topical atropine and topical atropine combined with intracameral low-concentration, bisulphite-containing epinephrine treatment for the prophylaxis of intraoperative floppy iris syndrome.Materials and methods: Seventy-two eyes of 55 male patients who were treated with alpha-adrenergic antagonist medications for benign prostatic hyperplasia were included in this study. Standard premedication with topical cyclopentolate, phenylephrine, tropicamide and ketorolac was applied to all of the patients. In 22 cases no further prophylactic method was used (Group-NP), while in 29 cases topical atropine drops was instilled 12h and 30min before surgery (Group-A) and in 21 cases 1:16000 epinephrine was injected to the anterior chamber at the beginning of surgery (Group-EA) in addition to topical atropine prophylaxis.Results: In Group-NP, 62.8% of the cases developed IFIS, while development of IFIS was significantly lower in Group-A (17.2%, p=0.0004) and Group-EA (9.5%, p<0.0001). Posterior capsule rupture was observed in two cases (9.1%) in Group-NP, in one case (3.4%) in Group-A and was not observed in Group-EA. There was no statistically significant difference between the groups for the development of surgical complications. We did not observe any adverse events or significant endothelial cell loss (p=0.462).Conclusions: Our results indicate that preoperative use of topical atropine reduces the incidence of IFIS. Use of low-concentration, bisulphite-containing epinephrine is more effective in the prevention of IFIS and does not cause preservative related endothelial damage. This prophylaxis may be preferred when preservative free epinephrine is not available
Variations on the Author
Get PDF“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
Get PDFWe 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
Peripapillary retinal leukemic infiltration associated with papilledema in a T-ALL patient without cranial or optic nerve involvement
No full textPurpose: To present a rare case of bilateral peripapillary retinal leukemic infiltration associated with papilledema without retrobulbar optic nerve involvement in a patient with acute lymphoblastic leukemia (ALL). Methods: This was a retrospective case report. Results: A 24-year-old man with T-cell ALL and 2-month history of papilledema presented to our department with reduction of visual acuity in the left eye. Visual acuity was 20/60 in the right eye and hand movements in the left eye. Fundus examination revealed grade 3 papilledema, bilateral peripapillary leukemic infiltration, and intraretinal hemorrhages. Cranial magnetic resonance imaging did not show any sign of cranial mass or optic nerve involvement. Pulse steroid therapy and oral acetazolamide was started. At day 18, visual acuity improved to 20/40 in the right eye and 20/60 in the left eye, while papilledema improved to grade 1 and hemorrhages regressed. Conclusions: To our knowledge, there is no other report of peripapillary leukemic infiltration in the absence of retrobulbar optic nerve involvement. We suspect that papilledema might have facilitated peripapillary retinal infiltration due to altered vascular permeability. The reverse could also be possible: leukemic infiltration leading to increase in vascular permeability may also contribute to papilledema
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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