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Femtosecond laser-assisted Descemeta??s stripping endothelial keratoplasty: a prospective study of 6-month visual outcomes, corneal thickness and endothelial cell loss
摘要： Purpose To report 6-month outcomes of visual acuity, the corneal thickness and endothelial cell density (ECD) in patients undergoing femtosecond laser-assisted Descemet’s stripping endothelial keratoplasty (FS-DSEK). Methods This prospective, consecutive, interventional series examined 25 eyes of 25 patients who underwent FS-DSEK for Fuchs endothelial dystrophy and bullous keratopathy. The pre-cut endothelial graft thickness (CET) was 150 lm. Best-corrected visual acuity (BCVA), central corneal thickness (CCT), donor CET, recipient corneal stromal thickness (CST) and ECD were assessed at 1 week and 1, 2, 3 and 6 months postoperatively. Results The mean BCVA at 6 months was 0.76 ± 0.35 logMAR units, improving from 1.54 ± 0.52 logMAR. CCT decreased significantly, from 759.8 ± 152.4 lm at 1 week to 631.7 ± 79.7 lm at 6 months postoperatively (P = 0.001). CET recovered to 153.4 ± 33.7 lm (P = 0.076) at 6 months as pre-cut status. The CST decreased from 561.5 ± 96.3 lm at 1 week to 479.7 ± 57.9 lm at 6 months (P < 0.001). Preoperatively, the donor ECD was 2747.6 ± 255.4 cells/mm2, and the ECD decreased to 1729.1 ± 562.9 cells/mm2 at 6 months, for a peak ECD loss of 36.86%. A greater decrease in CST observed from 1 week to 6 months postoperatively correlated with a lower ECD loss (P = 0.019) and a lower preoperative ECD (P = 0.012). However, a thinner CET correlated with a higher preoperative ECD (P = 0.028). Conclusions FS-DSEK is a safe and effective surgical alternative for corneal endothelial decompensation. The donor ECD and its changes could be used as predictive factors for the improvement of CST and CET.
关键词： Visual acuity,Corneal endothelial cell density,Graft thickness,Femtosecond laser,Descemet’s stripping endothelial keratoplasty
更新于2025-09-23 15:19:57
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Optoelectronic Properties of Electron Beam-Deposited NiOx Thin Films for Solar Cell Application
摘要： The fabrication of highly efficient nickel oxide (NiOx) thin film for optoelectronic devices is a challenging task because optoelectronic properties are considerably influenced by deposition technique and film thickness. The effect of thickness on the film properties of electron beam–physical vapour-deposited NiOx thin film has been investigated in this work. The influence of post-annealing treatment on the optoelectronic properties of the film was compared with that of the as-deposited one. Optical transparency gradually decreased upon the successive increment in thickness of the as-deposited and annealed films. The surface roughness of as-deposited films increased linearly with the increase in film thickness, but this behaviour was altered in post-annealed films. Spherical grains with high packing density were observed on the as-deposited films, but the grain size was altered substantially on the post-annealed films. The annealed films presented a higher work function than their corresponding as-deposited films. This work presents important insights into the design of photovoltaic devices with an effective deposition process, including a high material utilisation.
关键词： thickness,work function,NiOx,electron beam vapour deposition,annealing,opto-electronic
更新于2025-09-23 15:19:57
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[IEEE 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Effect of Ni thickness on the IMC and reliability of ultrathin ENEPIG
摘要： Electroless Ni(P)/electroless Pd/immersion Au （ ENEPIG ） is a common surface finish featured by good solderability, wide application and reliable mechanical properties. With the miniaturization and high integration of the integrated circuits, high thickness of Ni-P will affect the signal integrity because of the gigantic resistance. This study focused on the effect of the Ni layer thickness on the morphology and evolution of IMC and the reliability of ENEPIG. Commercial SAC305 solders were reflowed on different thicknesses of Ni (0.3um and 3um) to study the Cu/Ni IMC evolution while OSP sample was used as a control sample. Aged experiments were conducted at 150°C to evaluate the long term thermal stabilization and After every aging stage, we conducted high speed shear test to estimate the mechanical strength of the IMCs and analysis of fracture morphology. After aging, scallop-shaped IMCs of (Cu,Ni)6Sn5 was formed and its thickness increased with aging as well. Brittle IMC (Cu,Ni)3Sn first began to appear in ultrathin ENEPIG and the shear strength dropped slightly. After 256 h aging, ultrathin Ni layer had been completely consumed and a large number of (Cu,Ni)3Sn formed while 5um ENEPIG still had a good barrier effect. Even if Ni layer had been consumed, ultrathin ENEPIG still had a certain inhibitory effect on IMC growth compared with OSP, probably because of the formation of NiSnP layer. Further drop tests and temperature cycle tests will be conducted and the failure models together with cause will be also presented combined with previous results of IMC evolution.
关键词： ENEPIG,Ni thickness,Reliability,Ultrathin,IMC
更新于2025-09-23 15:19:57
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Tunable Work Function of MgxZn1-xO as a Viable Friction Material for Triboelectric Nanogenerator
摘要： Since the invention of triboelectric nanogenerators (TENGs), their output performance has been improved through various approaches such as material surface modification, device structure optimization and so on, but rarely through the development of new friction materials. In this work, magnetron sputtered MgxZn1-xO film is developed as a viable friction material, that rubs against polydimethylsiloxane (PDMS) in TENG. The work function, measured by Kelvin probe microscopy, of the MgxZn1-xO films can be effectively tuned by varying Mg composition, x, and exposed surface facets, which are shown to dominate the charge transfer behavior. In addition, film thickness also plays an important role, affecting the output performance. The output voltage and total charge of a TENG with MgxZn1-xO film are demonstrated to be tremendously enhanced by 55 and 90 times, respectively, compared to that of a TENG with ZnO film. Even more intriguingly, the tribo-output polarity can be reversed by adjusting the relative work function through varying the preferred growth orientation of the MgxZn1-xO film, for a given value of Mg content.
关键词： surface facet,triboelectric nanogenerator,work function,ZnO,MgxZn1-xO,thickness effect
更新于2025-09-23 15:19:57
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Relationship between macular thickness measurement and signal strength using Stratus optical coherence tomography
摘要： Purpose: To examine the relationship between signal strength and macular thickness as measured by Stratus optical coherence tomography (OCT)'s fast macular thickness protocol in healthy subjects. Methods: In this prospective cross-sectional study 79 eyes of 42 healthy subjects were enrolled. The age, gender, and eye (right vs left) of each subject were recorded. The Stratus OCT fast macular thickness scan protocol was used and the macular thickness was measured with retinal thickness map analysis. Each eye was imaged at least six times to acquire images with signal strengths of 4, 5, 6, 7, 8, and 9 out of 10 via adjustment of the focusing knob. The OCT parameters included in the analysis were thickness in the central 1 mm and in the different quadrants in the 3-mm area. Results: Overall 79 eyes of 42 patients with a mean age of 38.4±12.4 were included. There was no significant difference between the signal strength measurements obtained with different signal strengths in the central thickness (P=0.20). In the superior, nasal, inferior, and temporal quadrants, a signal strength of 8 demonstrated up to 3 μm thicker measurements than a signal strength of 5 (P<0.05). In general linear regression analysis, after accounting for age and gender, signal strength did not remain a significant predictor of thickness in any quadrant. Conclusions: When using fast map macular measurements, a signal strength of 5 is clinically as efficient as a signal strength of 8 in measuring macular thickness in all quadrants. Insisting on higher signal strength may not be necessary.
关键词： retinal thickness,macular thickness,Stratus OCT,fast map macular measurement,signal strength
更新于2025-09-19 17:15:36
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Evaluation of Corneal Epithelial Thickness Imaged by High Definition Optical Coherence Tomography in Healthy Eyes
摘要： Purpose: To evaluate corneal epithelial thickness (CET) and corneal thickness (CT) in healthy eyes using spectral domain optical coherence tomography. Methods: Thirty-six healthy eyes were imaged using the Cirrus high-definition (HD)-optical coherence tomography device. The average CET and CT were assessed using Cirrus Review Software within predefined concentric corneal ring-shaped zones. Specific regions of CET (superior, inferior, temporal, nasal, superonasal, inferotemporal, superotemporal, and inferonasal) were also assessed. The difference between zones was compared between males and females. Results: The average CET was 48.3, 47.1, 46.1, and 45.8 mm in the 4 concentric zones (0–2, 2–5, 5–7, and 7–9 mm), respectively (P < 0.001). The average CT was 533.5, 550.8, and 579.4 mm in the 3 zones (0–2, 2–5, and 5–7 mm), respectively (P < 0.001). There was no statistically significant correlation between CET and CT in any of the measured zones. Males had thicker corneas than did females in each of the 3 CT zones (P < 0.05), but CET did not differ significantly. The CET superonasal–inferotemporal in 2.0 to 5.0 mm and CET superotemporal–inferonasal in 5.0- to 7.0-mm zones were significantly thinner in males than in females (?1.15 vs. 0.9 mm, ?3.5 vs. ?1.9 mm), respectively (P < 0.05). Conclusions: Optical coherence tomography-based analysis of CET reveals that it is thinner in the periphery, whereas the total corneal thickness is greater. Although total CT seems to be influenced by sex, CET is not. Regional and sex-based variations in CT may need to be considered when assessing corneal and epithelial alterations in the setting of disease.
关键词： corneal thickness,optical coherency tomography,imaging,corneal epithelial thickness
更新于2025-09-19 17:15:36
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Outcomes of intravitreal bevacizumab and macular photocoagulation for treatment of diabetic macular edema in a tertiary care eye hospital at Karachi
摘要： Objective: To study the outcomes of intravitreal injection of Bevacizumab and laser photocoagulation in the treatment of diabetic macular edema (DME). Methods: Seventy-two eyes of 59 patients with diabetic macular edema were divided into two groups of 41 eyes (Group-A) and 31 eyes (Group-B). Subjects in group-A were treated with three intravitreal injections of Bevacizumab (IVB), and that of group-B with macular photocoagulation. Duration of study was 9 months. Follow up pattern for both groups was 1, 2, 3 and 6 months. Best Corrected Visual acuity on log MAR (BCVA) for distance as well as near in each visitwas recorded. Retinal OCT for central macular thickness (CMT) was performed on baseline. SPSS version 20.0 was used to analyze the data. Results: Mean age of the patients was 53.76 ± 8.82 ranging to 36-71 years. Out of 59 patients, 40 (67.8%) were male and 19 (32.2%) female. It was observed that the difference of results among both groups was not significant. Fig.2 documents visual acuity recorded as Improved; Stable and Worse. Conclusion: The improvement in BCVA was significant at 6 months in both treatments. The final improvements in BCVA has been almost similar between both the treatment groups although it was noted that IVB group showed early improvement in BCVA at follow-ups of 1 and 3 months. A long term follow-up is required in these cases to see the effect of both these treatment strategies.
关键词： Diabetic Macular edema,Anti-VEGF,Central macular thickness
更新于2025-09-19 17:15:36
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Comparison of optic coherence tomography results in patients with diagnosed epilepsy: Findings in favor of neurodegeneration
摘要： Background: Epilepsy is a chronic neurological disease characterized with recurrent seizures. Progressive neuronal degeneration is a common consequence of long-term and/or recurrent seizure activity in epilepsy. Optical coherence tomography (OCT) is a new medical imaging technique that displays biological tissue layers as high-resolution tomographic sections. The aim of our study was to evaluate OCT findings in patients with epilepsy and to compare OCT findings in terms of disease duration, presence of status, seizure frequency, and drug use. Methods: Forty-three patients who had epilepsy according to the Commission on Classification and Terminology of the International League Against Epilepsy (ILAE) in 2010 and 40 healthy controls were recruited for the study. Disease duration, seizure frequency, status history, and multiple drug use were noted. Retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner-plexiform layer (IPL), and choroid thinning were analyzed by using spectral OCT. Results: The mean RNFL values are 101.48 ± 11.33 in the patient group and 108.76 ± 8.37 in the control group (p = 0.001). The mean GCL thickness values in the patient and control groups are 1.14 ± 0.12 and 1.22 ± 0.05, (p < 0.001). The mean IPL thickness is 0.93 ± 0.09 in the patient group and 0.97 ± 0.05 in the control group (p = 0.02). Choroid thickness is significantly increased in the patient group (p < 0.001). Conclusions: Demonstration of RNFL, IPL, and GCL thinning might indicate neurodegeneration, and choroid thickening indicates neuroinflammation. We found no association between disease duration, seizure frequency, status history, and multiple drug use and OCT parameters. Further studies with larger patient groups should clarify the matter.
关键词： Retinal nerve fiber layer,Optic coherence tomography,Choroidal thickness,Ganglion cell layer,Epilepsy
更新于2025-09-19 17:15:36
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Trends in MODIS and AERONET derived aerosol optical thickness over Northern Europe
摘要： Long-term Aqua and Terra MODIS (MODerate resolution Imaging Spectroradiometer) Collections 5.1 and 6.1 (c051 and c061, respectively) aerosol data have been combined with AERONET (AERosol RObotic NETwork) ground-based sun photometer observations to examine trends in aerosol optical thickness (AOT, at 550 nm) over Northern Europe for the months April to September. For the 1927 and 1559 daily coincident measurements that were obtained for c051 and c061, respectively, MODIS AOT varied by 86 and 90%, respectively, within the predicted uncertainty of one standard deviation of the retrieval over land (DAOT ? ±0.05 ± 0.15(cid:3)AOT). For the coastal AERONET site Gustav Dalen Tower (GDT), Sweden, larger deviations were found for MODIS c051 and c061 (79% and 75%, respectively, within predicted uncertainty). The Baltic Sea provides substantially better statistical representation of AOT than the surrounding land areas and therefore favours the investigations of trends in AOT over the region. Negative trends of 1.5% and 1.2% per year in AOT, based on daily averaging, were found for the southwestern Baltic Sea from MODIS c051 and c061, respectively. This is in line with a decrease of 1.2% per year in AOT at the AERONET station Hamburg. For the western Gotland Basin area, Sweden, negative trends of 1.5%, 1.1% and 1.6% per year in AOT have been found for MODIS c051, MODIS c061 and AERONET GDT, respectively. The strongest trend of –1.8% per year in AOT was found for AERONET Belsk, Poland, which can be compared to –1.5% per day obtained from MODIS c051 over central Poland. The trends in MODIS and AERONET AOT are nearly all statistically significant at the 95% confidence level. The strongest aerosol sources are suggested to be located southwest, south and southeast of the investigation area, although the highest prevalence of pollution events is associated with air mass transport from southwest.
关键词： satellite observations,atmospheric transport,aerosol optical thickness,anthropogenic aerosol
更新于2025-09-19 17:15:36
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Diffuse Retinal Nerve Fiber Layer Defects Identification and Quantification in Thickness Maps
摘要： PURPOSE. To report retinal nerve fiber layer (RNFL) defect identification and quantification in RNFL thickness maps according to the structural RNFL loss, and to evaluate diffuse RNFL defects. METHODS. A total of 170 patients with glaucoma and 186 normal subjects were consecutively enrolled. We defined RNFL defects in an RNFL thickness map by the degree of RNFL loss. The reference level for RNFL defect determination was set as a 20% to 70% degree of RNFL loss with a 1% interval. To identify RNFL defects, each individual RNFL thickness map was compared to the normative database map by using MATLAB software, and the region below the reference level was detected. The area, volume, location, and angular width of each RNFL defect were measured. Diffuse RNFL defects were defined as having an angular width > 30°. RESULTS. The optimal reference level for glaucomatous RNFL defects identification was 42% loss of RNFL. Retinal nerve fiber layer defects were identified in all (100%) of the 170 glaucoma patients and false-positive RNFL defects were detected in 16 (8.16%) cases among the 186 normal subjects. In all, 64.1% of glaucoma patients had diffuse RNFL defects, and 47.7% of diffuse RNFL defects were associated with mild glaucoma patients. The volume of diffuse RNFL defects was significantly associated with the severity of glaucomatous damage (P = 0.009). Diffuse RNFL defects were located closer to the center of the optic disc than localized RNFL defects (P < 0.001). CONCLUSIONS. Retinal nerve fiber layer thickness map analysis is an effective method for analyzing RNFL defects. Quantitative measurements (area, volume, location, and width) were useful to understanding diffuse RNFL defects.
关键词： OCT,diffuse RNFL defect,RNFL thickness map,retinal nerve fiber layer
更新于2025-09-19 17:15:36