414 research outputs found
Short-term angiographic changes after transpupillary thermotherapy of choroidal neovascularization.
No full textCombined clear corneal phacoemulsification and ab interno trabeculectomy: three-year case series.
No full textPURPOSE: To evaluate the efficacy and safety of a novel surgical approach, ab interno trabeculectomy, in a combined procedure (clear corneal phacoemulsification + ab interno trabeculectomy) for the management of concurrent cataract and glaucoma with prognostic factors for filtration failure. SETTING: Department of Ophthalmology, Palmanova Hospital, Udine, Italy. METHODS: A prospective noncomparative case series of 11 eyes of 11 consecutive cataract patients with medically uncontrolled primary open-angle glaucoma or pseudoexfoliation glaucoma was performed. Each patient had phacoemulsification + intraocular lens implantation + ab interno trabeculectomy, which consisted of a gonioscopically controlled ab interno removal of a quadrant (3 clock hours) of the trabecular meshwork. The main outcome measures were intraocular pressure (IOP), the number of antiglaucomatous medications used, and complications. RESULTS: Ten patients completed a 3-year follow-up. One patient had further surgery because of poor IOP control; in this case, the last valid observation was carried forward for IOP calculation. Mean preoperative IOP and IOPs measured 1, 3, 6,12, 24, and 36 months after surgery were 25.0,15.8,15.4,15.4, 15.2, 15.0, and 15.3 (-38.56%) mm Hg respectively. The number of medications averaged 2.4 before surgery and dropped to 0.8 at the end of follow-up. No major complications occurred during the follow-up period. CONCLUSIONS: The new surgical procedure combining phacoemulsification with ab interno trabeculectomy can induce a clinically relevant decrease in IOP in eyes with cataract and glaucoma with poor prognosis for filtering surgery. However, a randomized controlled clinical trial with a more extended follow-up and a larger series of patients is needed to ascertain the actual effectiveness and safety of this procedure
Optical coherence tomography versus stereoscopic fundus photography or biomicroscopy for diagnosing diabetic macular edema: a systematic review
No full textPURPOSE. To review systematically the sensitivity and specificity of optical coherence tomography ( OCT) for diagnosing macular edema attributable to diabetic retinopathy compared with well-established gold standard tests such as fundus stereophotography or contact and noncontact fundus biomicroscopy. METHODS. Medline and Embase were searched electronically and six major ophthalmic journals from 1998 to 2006 were hand searched. Two reviewers independently assessed trial searches, studied quality with the QUADAS ( Quality Assessment of Diagnostic Accuracy Studies) checklist, and extracted data. The target disease was clinically significant macular edema ( CSME) according to Early Treatment of Diabetic Retinopathy Study ( ETDRS) criteria. A bivariate model was used to obtain summary estimates of sensitivity and specificity and fit a summary receiver operating characteristic ( ROC) curve. RESULTS. Fifteen studies were considered eligible. These studies were of good quality for most items of the QUADAS checklist, but most studies did not report masking of examiners and did not describe how withdrawals and undetermined results were treated. Seven studies included healthy control subjects, which could have artificially enhanced OCT diagnostic performance. All but one study included both eyes of the patients without taking into account the within-subject correlation in statistical analyses. Sensitivity and specificity data could be extracted from only 6 of 15 studies, because appropriate cross tabulations of index and reference tests were not reported by the others. In five of these studies, central retinal thickness cutoffs between 230 and 300 mu m were adopted to define abnormal OCT results and considered the central type of CSME only, whereas in one study a complex algorithm accounting for extrafoveal CSME was used. The design of one study was case-control and was excluded from the meta-analysis. The expected operating point on the summary ROC, a pooled estimate of all studies, corresponded to a sensitivity of 0.79 ( 95% CI: 0.71 - 0.86), a specificity of 0.88 ( 95% CI: 0.80 - 0.93), a positive likelihood ratio of 6.5 ( 95% CI: 4.0 - 10.7), and a negative likelihood ratio of 0.24 ( 95% CI: 0.17 - 0.32). These values suggest a good overall performance of OCT for diagnosing CSME. CONCLUSIONS. OCT performs well compared with fundus stereophotography or biomicroscopy to diagnose diabetic macular edema. The quality of reporting of such studies should be improved, and authors should present cross tabulations of index and reference test results. Data adjusted for within-subject correlation should also be provided, although this issue represents a challenge for systematic reviewers
Episcleral repair of retinal detachment with the operating microscope and a contact wide-field lens. Pilot study.
No full textNarrow-band multi-filter radiometer for total ozone content measurements: Mario Zucchelli Station (Antarctica) campaign
No full textThe importance of ground-based measurements of ultraviolet radiation has increased since the discovery of the stratospheric ozone layer depletion. Spectroradiometers are the most widely used class of instruments, although the requirement to work in attended stations is sometimes limiting. In this work we present a filter radiometer, named F-RAD, with good optical stability, very short sampling time (1 min), and proven reliability. The instrument is based on a stand-alone functioning, making it suitable for operation in hostile environments. The total ozone column (TOC) was estimated by the irradiance ratio at wavelengths where the ozone absorbs the solar radiation and where the radiation is not absorbed. Direct correlation between the TOC values estimated by F-RAD and by the Ozone Monitoring Instrument (OMI) was found, and the standard deviations of the ratios between such values were calculated. Three wavelength ratios were identified to take into account the dependence of the measurements from the Solar Zenith Angle, AF-RAD (306.0 nm/325.3 nm) for SZA < 50°, BF-RAD (309.9 nm/325.3 nm) and CF-RAD (317.5 nm/325.3 nm) for SZA > 50°. Considering the OMI ozone data as the reference values, the accuracy of the filter radiometer is estimated to be ±4%. The data collected during the calibration campaign in Lampedusa (June-July 2009, Italy) and during the first Antarctica winter of the 2009-2013 measurement campaign at Mario Zucchelli Station (MZS) are reported. The TOC measured by the F-RAD instrument, by the OMI on board of EOS-Aura satellite (NASA), and by the NOAA UV Monitoring Station in McMurdo (USA) are compared to assess the appropriateness of F-RAD for a long-term measurement campaign. © 2017 Optical Society of America
Control of F-2 color centers spontaneous emission in LiF thin films inside optical microcavities
No full textAn experimental investigation on spontaneous emission properties of Fabry-Perot microcavities consisting of quarter-wavelength ZnS/Cryolite Bragg mirrors and a lithium fluoride (LiF) thin film colored with low-energy electron beam lithography is reported for the first time. Angular-resolved photoluminescence measurements show the modifications of F-2 color centers visible spontaneous emission. The resonator induces a narrowing of the emission spectrum and a related increase in the directionality and intensity of the emission along the cavity axis. (C) 2001 Elsevier Science B.V. All rights reserved
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