818 research outputs found

    Clinical outcomes at one year following keratoconus treatment with accelerated transepithelial cross-linking

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    This study evaluated the clinical outcomes in keratoconus corneas following accelerated transepithelial corneal collagen cross-linking (CXL) (Avedro KXLÂź system, Waltham, MA, USA) over one year of follow-up. The mean depth of the demarcation line measured by optical coherence tomography (OCT) was 205.19 ÎŒm. One month after surgery, a non-statistically significant change was noted in sphere (P=0.18) and in spherical equivalent (P=0.17), whereas a significant improvement was observed in corrected distance visual acuity (P=0.04). A significant change was observed in topographic astigmatism (P=0.03) and posterior corneal a sphericity (P=0.04). Accelerated transepithelial CXL may be a useful technique for the management of progressive keratoconus

    Efficacy of Perceptual Learning-Based Vision Training as an Adjuvant to Occlusion Therapy in the Management of Amblyopia: A Pilot Study

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    A retrospective study was conducted to evaluate preliminarily the efficacy of perceptual learning (PL) visual training in medium-term follow-up with a specific software (Amblyopia iNET, Home Therapy Systems Inc., Gold Canyon, AZ, USA) for visual acuity (VA) and contrast sensitivity (CS) recovering in a sample of 14 moderate to severe amblyopic subjects with a previously unsuccessful outcome or failure with patching (PL Group). This efficacy was compared with that achieved in a patching control group (13 subjects, Patching 2). At one-month follow-up, a significant VA improvement in the amblyopic eye (AE) was observed in both groups, with no significant differences between them. Additionally, CS was measured in PL Group and exhibited a significant improvement in the AE one month after the beginning of treatment for 3, 6, 12, and 18 cycles/Âș (p = 0.003). Both groups showed long-lasting retention of visual improvements. A combined therapy of PL-based visual training and patching seems to be effective for improving VA in children with amblyopia who did not recover vision with patching alone or had a poor patching compliance. This preliminary outcome should be confirmed in future clinical trials.The author David P Piñero has been supported by the Ministry of Economy, Industry and Competitiveness of Spain within the program RamĂłn y Cajal, RYC-2016-20471

    AnĂĄlisis retrospectivo de cambios en las vergencias fusionales en pacientes con exotropia intermitente tras realizar terapia visual

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    La exotropia es un tipo de estrabismo caracterizado por una desviación divergente de los ejes oculares que imposibilita la visión binocular. Una de las opciones de tratamiento de la exotropia es la terapia visual (TV) sola o en combinación con la cirugía de estrabismo. Sin embargo, la evidencia todavía es limitada en cuanto a la eficacia de la TV en estos casos. Por ello, se realizó un estudio retrospectivo donde se analizaron el cover test, el punto próximo de convergencia y las reservas fusionales positivas {RFP) y negativas (RFN) de dos grupos de pacientes con exotropia antes y después de realizar TV en la Unidad de Optometría Clínica Avanzada del Hospital Vithas Medimar de Alicante. Tras la TV, ambos grupos mostraron una mejora de la RFP, aunque este incremento sólo fue estadísticamente significativo en el grupo que no había sido operado previamente

    Interchangeability of corneal curvature and asphericity measurements provided by three different devices

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    AIM: To evaluate the interchangeability of keratometric and asphericity measurements provided by three measurement systems based on different optical principles. METHODS: A total of 40 eyes of 40 patients with a mean age of 34.1y were included. In all cases, a corneal curvature analysis was performed with IOL-Master (IOLM), iDesign 2 (ID2), and Sirius systems (SIR). Differences between instruments for flattest (K1) and steepest (K2) keratometric readings, as well as for magnitude and axis of corneal astigmatism were analyzed. Likewise, differences in asphericity (Q) between SIR and ID2 were also evaluated. RESULTS: Mean differences between devices for K1 were 0.20±0.21 (P<0.001), -0.12±0.36 (P=0.046) and -0.32±0.36 D (P<0.001) for the comparisons IOLM-SIR, IOLM-ID2 and SIR-ID2, respectively. The ranges of agreement for these comparisons between instruments were 0.41, 0.70, and 0.70 D. For K2, mean differences were 0.31±0.33 (P<0.001), -0.08±0.43 (P=0.265) and -0.39±0.38 D (P<0.001), with ranges of agreement of 0.65, 0.84, and 0.74 D. Concerning magnitude of astigmatism, ranges of agreement were in the limit of clinical relevance (0.49 D, P=0.011; 0.55 D, P=0.386; 0.43 D, P=0.05). In contrast, ranges of agreement were clinically relevant for astigmatic axis (26.68o, 33.83o and 18.37o, P≄0.121) and for Q between SIR and ID2 (0.16, P<0.001). CONCLUSION: The keratometric corneal power, astigmatic axis and asphericity measurements provide by the three systems evaluated cannot be considered as interchangeable, whereas measurements of corneal astigmatism obtained with SIR and ID2 can be considered as interchangeable for clinical purposes.The author David P. Piñero has been supported by the Ministry of Economy, Industry and Competitiveness of Spain within the program RamĂłn y Cajal, RYC-2016-20471. Additionally he received an unrestricted grant from Johnson and Johnson Vision for the performance of this research

    Differences in corneo-scleral topographic profile between healthy and keratoconus corneas

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    Purpose: To evaluate the differences in corneo-scleral topographic profile between healthy and keratoconus eyes, and their potential diagnostic ability for keratoconus detection. Methods: Prospective comparative study including 21 keratoconic eyes (11 patients) and 88 healthy eyes (88 patients). In all cases, a complete eye exam was performed including an evaluation of the corneo-scleral profile. The diagnostic ability of corneo-scleral topographic parameters to detect keratoconus was evaluated using the receiver operating characteristic (ROC) curve. Results: A significant lower inferior tangent angle at limbus (ITA) was found in the keratoconic group compared to the control group (p = 0.024). Regarding sagittal heights, significant differences between groups were found in temporal sagittal height (TSH) for 11 mm (p = 0.040), 12 mm (p = 0.041) and 13 mm corneal chords (p = 0.040), difference between temporal and nasal sagittal heights (T-NSH) for 12 mm (p = 0.025) and 13 mm (p = 0.034), and maximum sagittal height (MaxSH) for 12 mm (p = 0.043), with higher values in keratoconus. In bilateral cases, these differences were not found when comparing with the least severe keratoconus eye. Statistical significance for the ROC curve was only found for ITA (p = 0.025), 12-mm (p = 0.048) and 13-mm TSH (p = 0.042), and 13-mm T-NSH (p = 0.037), with cutoff values associated to limited values of sensitivity and specificity. Conclusions: The corneo-scleral profile in keratoconus presents higher levels of asymmetry compared to healthy eyes, especially in eyes with moderate and advanced stages of the disease. The diagnostic accuracy of corneo-scleral topographic data alone for keratoconus detection is limited and must be used in conjunction with other clinical parameters

    Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

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    A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

    Probing effective field theory operators in the associated production of top quarks with a Z boson in multilepton final states at root s=13 TeV

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    Measurement of the Higgs boson production rate in association with top quarks in final states with electrons, muons, and hadronically decaying tau leptons at s√=13TeV

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    The rate for Higgs (H) bosons production in association with either one (tH) or two (ttÂŻH) top quarks is measured in final states containing multiple electrons, muons, or tau leptons decaying to hadrons and a neutrino, using proton–proton collisions recorded at a center-of-mass energy of 13TeV by the CMS experiment. The analyzed data correspond to an integrated luminosity of 137fb−1. The analysis is aimed at events that contain H→WW, H→ττ, or H→ZZ decays and each of the top quark(s) decays either to lepton+jets or all-jet channels. Sensitivity to signal is maximized by including ten signatures in the analysis, depending on the lepton multiplicity. The separation among tH, ttÂŻH, and the backgrounds is enhanced through machine-learning techniques and matrix-element methods. The measured production rates for the ttÂŻH and tH signals correspond to 0.92±0.19(stat)+0.17−0.13(syst) and 5.7±2.7(stat)±3.0(syst) of their respective standard model (SM) expectations. The corresponding observed (expected) significance amounts to 4.7 (5.2) standard deviations for ttÂŻH, and to 1.4 (0.3) for tH production. Assuming that the Higgs boson coupling to the tau lepton is equal in strength to its expectation in the SM, the coupling yt of the Higgs boson to the top quark divided by its SM expectation, Îșt=yt/ySMt, is constrained to be within −0.9<Îșt<−0.7 or 0.7<Îșt<1.1, at 95% confidence level. This result is the most sensitive measurement of the ttÂŻH production rate to date.SCOAP

    Anterior Eye Profilometry-guided Scleral Contact Lens Fitting in Keratoconus

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    We report the case of a 35-year-old woman diagnosed with keratoconus since she was 18 years old and wearer of corneal rigid contact lenses (CLs). We refitted the case with the fully scleral CL ICD16.5 (Paragon Vision Sciences) for obtaining not only a successful visual restoration, but also a comfortable wear. We initiated the fitting with the spherical model of the CL, but it failed due to instability of the lens. We confirmed the presence of a clear asymmetry in the anterior scleral geometry in both eyes by using the profilometer eye surface profiler (ESP, Eaglet Eye), with a difference between nasal and temporal sagittal heights of 470 and 170 ÎŒm in right and left eyes respectively. Although this profile suggested the need for the fitting of a CL with significant peripheral toricity, we followed the manufacturer’s guidelines and performed a trial with a CL of moderate peripheral toricity (125 ÎŒm of difference between steep and flat meridian). The stability of the CL failed again and finally a CL with a peripheral toricity close to that measured with the profilometer was fitted. With this lens, good visual performance, lens stability, and comfort was obtained and maintained during a 1-year follow-up. This case suggests that fully scleral CLs fitting might be optimized with the use of corneo-scleral profilometers, minimizing potentially the number of trials. This potential benefit should be investigated further in future studies

    Clinical utility of ocular residual astigmatism and topographic disparity vector indexes in subclinical and clinical keratoconus

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    Purpose. We aimed to characterize the distribution of the vector parameters ocular residual astigmatism (ORA) and topography disparity (TD) in a sample of clinical and subclinical keratoconus eyes, and to evaluate their diagnostic value to discriminate between these conditions and healthy corneas. Methods. This study comprised a total of 43 keratoconic eyes (27 patients, 17–73 years) (keratoconus group), 11 subclinical keratoconus eyes (eight patients, 11–54 years) (subclinical keratoconus group) and 101 healthy eyes (101 patients, 15–64 years) (control group). In all cases, a complete corneal analysis was performed using a Scheimpflug photography-based topography system. Anterior corneal topographic data was imported from it to the iASSORT software (ASSORT Pty. Ltd), which allowed the calculation of ORA and TD. Results. Mean magnitude of the ORA was 3.23 ± 2.38, 1.16 ± 0.50 and 0.79 ± 0.43 D in the keratoconus, subclinical keratoconus and control groups, respectively (p < 0.001). Mean magnitude of the TD was 9.04 ± 8.08, 2.69 ± 2.42 and 0.89 ± 0.50 D in the keratoconus, subclinical keratoconus and control groups, respectively (p < 0.001). Good diagnostic performance of ORA (cutoff point: 1.21 D, sensitivity 83.7 %, specificity 87.1 %) and TD (cutoff point: 1.64 D, sensitivity 93.3 %, specificity 92.1 %) was found for the detection of keratoconus. The diagnostic ability of these parameters for the detection of subclinical keratoconus was more limited (ORA: cutoff 1.17 D, sensitivity 60.0 %, specificity 84.2 %; TD: cutoff 1.29 D, sensitivity 80.0 %, specificity 80.2 %). Conclusion. The vector parameters ORA and TD are able to discriminate with good levels of precision between keratoconus and healthy corneas. For the detection of subclinical keratoconus, only TD seems to be valid
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