bluuebunny/crossref_metadata_2025 huggingface dataset:
Borneo vortex and mesoscale convective rainfall
Authors: Koseki S. , Koh T.-Y. , Teo C.-K.
Published: May 2014

Abstract. We have investigated how the Borneo vortex develops over the equatorial South China Sea under cold surge conditions in December during the Asian winter monsoon. Composite analysis using reanalysis and satellite data sets has revealed that absolute vorticity and water vapour are transported by strong cold surges from upstream of the South China Sea to around the Equator. Rainfall is correspondingly enhanced over the equatorial South China Sea. A semi-idealized experiment reproduced the Borneo vortex over the equatorial South China Sea during a "perpetual" cold surge. The Borneo vortex is manifested as a meso-α cyclone with a comma-shaped rainband in the northeast sector of the cyclone. Vorticity budget analysis showed that the growth/maintenance of the meso-α cyclone was achieved mainly by the vortex stretching. This vortex stretching is due to the upward motion forced by the latent heat release around the cyclone centre. The comma-shaped rainband consists of clusters of meso-β-scale rainfall cells. The intense rainfall in the comma head (comma tail) is generated by the confluence of the warmer and wetter cyclonic easterly flow (cyclonic southeasterly flow) and the cooler and drier northeasterly surge in the northwestern (northeastern) sector of the cyclone. Intense upward motion and heavy rainfall resulted due to the low-level convergence and the favourable thermodynamic profile at the confluence zone. In particular, the convergence in the northwestern sector is responsible for maintenance of the meso-α cyclone system. At both meso-α and meso-β scales, the convergence is ultimately caused by the deviatoric strain in the confluence wind pattern but is significantly self-enhanced by the nonlinear dynamics.
Airborne characterization of smoke marker ratios from prescribed burning
Authors: Sullivan A. P. , May A. A. , Lee T. , McMeeking G. R. , Kreidenweis S. M. , Akagi S. K. , Yokelson R. J. , Urbanski S. P. , Collett J. L.
Published: May 2014

Abstract. A Particle-into-Liquid Sampler – Total Organic Carbon and fraction collector system was flown aboard aTwin Otter aircraft sampling prescribed burning emissions in South Carolina in November2011 to obtain smoke marker measurements. The fraction collector provided 2 min time-integrated off-line samples for carbohydrate (i.e., smoke markers levoglucosan, mannosan, galactosan) analysis by high-performance anion-exchange chromatography with pulsed amperometric detection. Each fire location appeared to have aunique Δ levoglucosan / Δ water-soluble organic carbon (WSOC) ratio (RF01/RF02/RF03/RF05 = 0.163 ± 0.007 μg C μg C−1, RF08 = 0.115 ± 0.011 μg C μg C−1, RF09A = 0.072 ± 0.028 μg C μg C−1, RF09B = 0.042 ± 0.008 μg C μg C−1). These ratios were comparable to those obtained from controlled laboratory burns and suggested that the emissions sampled during RF01/RF02/RF03/RF05 were dominated by the burning of grasses, RF08 by leaves, RF09A by needles, and RF09B by marsh grasses. These findings were further supported by the Δ galactosan / Δ levoglucosan ratios (RF01/RF02/RF03/RF05 = 0.067 ± 0.004 μg μg−1, RF08 = 0.085 ± 0.009 μg μg−1, RF09A = 0.101 ± 0.029 μg μg−1) obtained as well as by the ground-based fuel and filter sample analyses during RF01/RF02/RF03/RF05. Differences between Δ potassium / Δ levoglucosan ratios obtained for these prescribed fires vs. laboratory-scale measurements suggest that some laboratory burns may not accurately represent potassium emissions from prescribed burns. The Δ levoglucosan / Δ WSOC ratio had no clear dependence on smoke age or fire dynamics suggesting that this ratio is more dependent on the type of fuel being burned. Levoglucosan was stable over a timescale of at least 1.5 h and could be useful to help estimate the air quality impacts of biomass burning.
Impact of solar versus volcanic activity variations on tropospheric temperatures and precipitation during the Dalton Minimum
Authors: Anet J. G. , Muthers S. , Rozanov E. V. , Raible C. C. , Stenke A. , Shapiro A. I. , Brönnimann S. , Arfeuille F. , Brugnara Y. , Beer J. , Steinhilber F. , Schmutz W. , Peter T.
Published: May 2014

Abstract. The aim of this work is to elucidate the impact of changes in solar irradiance and energetic particles versus volcanic eruptions on tropospheric global climate during the Dalton Minimum (DM, AD 1780–1840). Separate variations in the (i) solar irradiance in the UV-C with wavelengths λ < 250 nm, (ii) irradiance at wavelengths λ > 250 nm, (iii) in energetic particle spectrum, and (iv) volcanic aerosol forcing were analyzed separately, and (v) in combination, by means of small ensemble calculations using a coupled atmosphere–ocean chemistry–climate model. Global and hemispheric mean surface temperatures show a significant dependence on solar irradiance at λ > 250 nm. Also, powerful volcanic eruptions in 1809, 1815, 1831 and 1835 significantly decreased global mean temperature by up to 0.5 K for 2–3 years after the eruption. However, while the volcanic effect is clearly discernible in the Southern Hemispheric mean temperature, it is less significant in the Northern Hemisphere, partly because the two largest volcanic eruptions occurred in the SH tropics and during seasons when the aerosols were mainly transported southward, partly because of the higher northern internal variability. In the simulation including all forcings, temperatures are in reasonable agreement with the tree ring-based temperature anomalies of the Northern Hemisphere. Interestingly, the model suggests that solar irradiance changes at λ < 250 nm and in energetic particle spectra have only an insignificant impact on the climate during the Dalton Minimum. This downscales the importance of top–down processes (stemming from changes at λ < 250 nm) relative to bottom–up processes (from λ > 250 nm). Reduction of irradiance at λ > 250 nm leads to a significant (up to 2%) decrease in the ocean heat content (OHC) between 0 and 300 m in depth, whereas the changes in irradiance at λ < 250 nm or in energetic particles have virtually no effect. Also, volcanic aerosol yields a very strong response, reducing the OHC of the upper ocean by up to 1.5%. In the simulation with all forcings, the OHC of the uppermost levels recovers after 8–15 years after volcanic eruption, while the solar signal and the different volcanic eruptions dominate the OHC changes in the deeper ocean and prevent its recovery during the DM. Finally, the simulations suggest that the volcanic eruptions during the DM had a significant impact on the precipitation patterns caused by a widening of the Hadley cell and a shift in the intertropical convergence zone.
Non-orthogonal version of the arbitrary polygonal C-grid and a new diamond grid
Authors: Weller H.
Published: May 2014

Abstract. Quasi-uniform grids of the sphere have become popular recently since they avoid parallel scaling bottlenecks associated with the poles of latitude–longitude grids. However quasi-uniform grids of the sphere are often non-orthogonal. A version of the C-grid for arbitrary non-orthogonal grids is presented which gives some of the mimetic properties of the orthogonal C-grid. Exact energy conservation is sacrificed for improved accuracy and the resulting scheme numerically conserves energy and potential enstrophy well. The non-orthogonal nature means that the scheme can be used on a cubed sphere. The advantage of the cubed sphere is that it does not admit the computational modes of the hexagonal or triangular C-grids. On various shallow-water test cases, the non-orthogonal scheme on a cubed sphere has accuracy less than or equal to the orthogonal scheme on an orthogonal hexagonal icosahedron. A new diamond grid is presented consisting of quasi-uniform quadrilaterals which is more nearly orthogonal than the equal-angle cubed sphere but with otherwise similar properties. It performs better than the cubed sphere in every way and should be used instead in codes which allow a flexible grid structure.
Predicting streamflows in snowmelt-driven watersheds using the flow duration curve method
Authors: Kim D. , Kaluarachchi J.
Published: May 2014

Abstract. Predicting streamflows in snow-fed watersheds in the Western United States is important for water allocation. Since many of these watersheds are heavily regulated through canal networks and reservoirs, predicting expected natural flows and therefore water availability under limited data is always a challenge. This study investigates the applicability of the flow duration curve (FDC) method for predicting natural flows in gauged and regulated snow-fed watersheds. Point snow observations, air temperature, precipitation, and snow water equivalent were used to simulate the snowmelt process with the SNOW-17 model, and extended to streamflow simulation using the FDC method with a modified current precipitation index. For regulated watersheds, a parametric regional FDC method was applied to reconstruct natural flow. For comparison, a simplified tank model was used considering both lumped and semi-distributed approaches. The proximity regionalization method was used to simulate streamflows in the regulated watersheds with the tank model. The results showed that the FDC method is capable of producing satisfactory natural flow estimates in gauged watersheds when high correlation exists between current precipitation index and streamflow. For regulated watersheds, the regional FDC method produced acceptable river diversion estimates, but it seemed to have more uncertainty due to less robustness of the FDC method. In spite of its simplicity, the FDC method is a practical approach with less computational burden for studies with minimal data availability.
Towards predictive data-driven simulations of wildfire spread – Part I: Reduced-cost Ensemble Kalman Filter based on a Polynomial Chaos surrogate model for parameter estimation
Authors: Rochoux M. C. , Ricci S. , Lucor D. , Cuenot B. , Trouvé A.
Published: May 2014

Abstract. This paper is the first part in a series of two articles and presents a data-driven wildfire simulator for forecasting wildfire spread scenarios, at a reduced computational cost that is consistent with operational systems. The prototype simulator features the following components: a level-set-based fire propagation solver FIREFLY that adopts a regional-scale modeling viewpoint, treats wildfires as surface propagating fronts, and uses a description of the local rate of fire spread (ROS) as a function of environmental conditions based on Rothermel's model; a series of airborne-like observations of the fire front positions; and a data assimilation algorithm based on an ensemble Kalman filter (EnKF) for parameter estimation. This stochastic algorithm partly accounts for the non-linearities between the input parameters of the semi-empirical ROS model and the fire front position, and is sequentially applied to provide a spatially-uniform correction to wind and biomass fuel parameters as observations become available. A wildfire spread simulator combined with an ensemble-based data assimilation algorithm is therefore a promising approach to reduce uncertainties in the forecast position of the fire front and to introduce a paradigm-shift in the wildfire emergency response. In order to reduce the computational cost of the EnKF algorithm, a surrogate model based on a polynomial chaos (PC) expansion is used in place of the forward model FIREFLY in the resulting hybrid PC-EnKF algorithm. The performance of EnKF and PC-EnKF is assessed on synthetically-generated simple configurations of fire spread to provide valuable information and insight on the benefits of the PC-EnKF approach as well as on a controlled grassland fire experiment. The results indicate that the proposed PC-EnKF algorithm features similar performance to the standard EnKF algorithm, but at a much reduced computational cost. In particular, the re-analysis and forecast skills of data assimilation strongly relate to the spatial and temporal variability of the errors in the ROS model parameters.
Adapting to life: ocean biogeochemical modelling and adaptive remeshing
Authors: Hill J. , Popova E. E. , Ham D. A. , Piggott M. D. , Srokosz M.
Published: May 2014

Abstract. An outstanding problem in biogeochemical modelling of the ocean is that many of the key processes occur intermittently at small scales, such as the sub-mesoscale, that are not well represented in global ocean models. This is partly due to their failure to resolve sub-mesoscale phenomena, which play a significant role in vertical nutrient supply. Simply increasing the resolution of the models may be an inefficient computational solution to this problem. An approach based on recent advances in adaptive mesh computational techniques may offer an alternative. Here the first steps in such an approach are described, using the example of a simple vertical column (quasi-1-D) ocean biogeochemical model. We present a novel method of simulating ocean biogeochemical behaviour on a vertically adaptive computational mesh, where the mesh changes in response to the biogeochemical and physical state of the system throughout the simulation. We show that the model reproduces the general physical and biological behaviour at three ocean stations (India, Papa and Bermuda) as compared to a high-resolution fixed mesh simulation and to observations. The use of an adaptive mesh does not increase the computational error, but reduces the number of mesh elements by a factor of 2–3. Unlike previous work the adaptivity metric used is flexible and we show that capturing the physical behaviour of the model is paramount to achieving a reasonable solution. Adding biological quantities to the adaptivity metric further refines the solution. We then show the potential of this method in two case studies where we change the adaptivity metric used to determine the varying mesh sizes in order to capture the dynamics of chlorophyll at Bermuda and sinking detritus at Papa. We therefore demonstrate that adaptive meshes may provide a suitable numerical technique for simulating seasonal or transient biogeochemical behaviour at high vertical resolution whilst minimising the number of elements in the mesh. More work is required to move this to fully 3-D simulations.
Knowledge Management Implementation at the Women’s Branch of the Institute of Public Administration in Saudi Arabia: A Proposed Model
Authors: Abokhodiar Eiman Saud
Published: May 2014

This article aims to introduce a proposed model of knowledge management implementation at the Women’s Branch of the Institute of Public Administration (WIPA). The model was built after a review and analysis of literature related to knowledge management implementation in higher education institutions. The research includes three sections. The first section deals with a theoretical framework of knowledge management, including a knowledge management definition, components of knowledge management systems, an academic knowledge framework, an organizational knowledge framework, and processes of knowledge management. The second section reviews and discusses the proposed model of knowledge management implementation at WIPA. Finally, the article concludes with a discussion of the success factors and expected barriers to the proposed model.
Front Matter
Authors: Jacob W. James
Published: May 2014

This is the second issue of Volume 4, with articles that examine higher education and/or action research projects in Indonesia, Saudi Arabia, the United States, Zambia, and other contexts.
The University of Zambia School Teaching Experience: Is It Effective?
Authors: Manchishi Peter Chomba , Mwanza David Sani
Published: May 2014

Teaching practice exercises serve the purpose of orienting the teacher into real classroom situations where the novice puts his or her skills into practice. Education students at the University of Zambia (UNZA) go through the school teaching experience after their third year of study. This comes after they have arguably completed enough content and methodology courses to teach. The purpose of this study was to establish the effectiveness of the UNZA school teaching experience. The research instruments used were interview guides, observation checklists, and focus group discussions. The respondents included 80 serving teachers, 80 student teachers, and 10 head teachers drawn from 10 high schools in the Lusaka District. In addition, 10 lecturers from UNZA were also sampled. The findings revealed that the design and delivery of the UNZA student teaching experience was not effective.
Comparison of Visual Performance after Implantation of 3 Types of Intraocular Lenses: Accommodative, Multifocal, and Monofocal
Authors: Tan Nian , Zheng Dengyi , Ye Jian
Published: May 2014

Purpose

To compare the performance of accommodative, multifocal, and monofocal intraocular lenses (IOLs).

Methods

In this clinical control study, 3 types of IOL were implanted in 128 eyes of 86 patients with age-related cataract who underwent phacoemulsification. Accommodative (Tetraflex), multifocal (ZMA00), and monofocal (Akreos Advanced Optics [AO]) IOLs were implanted into 43, 40, and 45 eyes, respectively. The uncorrected, best-corrected distance, contrast sensitivity, and distance-corrected intermediate and near visual acuity (UCDVA, BCDVA, CSVA, DCIVA, and DCNVA, respectively), amplitude of pseudoaccommodation, and patient satisfaction were measured at 1, 3, and 12 months after surgery.

Results

Differences in CSVA at all contrast degrees, UCDVA, and BCDVA among the 3 groups were not significant. Patients in the Akreos AO group exhibited a poorer DCIVA and DCNVA and experienced less pseudoaccommodation compared to patients in the other 2 groups at 3 and 12 months after surgery (p<0.01). Patients in the ZMA00 group exhibited a better DCIVA and experienced more pseudoaccommodation than patients in the Tetraflex group (3 months: p<0.05, 12 months: p<0.01 for both outcomes). Three months after surgery, total spectacle independence was achieved by 84.4%, 60.7%, and 17.2% of the ZMA00, Tetraflex, and Akreos AO group patients, respectively.

Conclusions

All 3 types of IOLs allowed greater distance visual acuity; however, multifocal IOLs produced better DCIVA and DCNVA and more pseudoaccommodation and spectacle independence. Accommodative IOLs ranked second. Neither accommodative nor multifocal IOLs reduced CSVA.
Plasma Homocysteine in Patients with Retinal Vein Occlusion
Authors: Minniti Giuseppe , Calevo Maria Grazia , Giannattasio Alessandro , Camicione Paola , Armani Ugo , Lorini Renata , Piana Gianna
Published: May 2014

Purpose

To evaluate total plasma homocysteine (HCY) during fasting and post methionine load test (MLT), serum folate, serum vitamin B12, and methylenetetrahydrofolate reductase (MTHFR) mutation in patients with retinal vein occlusion (RVO) and to examine the association between these risk factors and 2 subtypes of RVO: central (CRVO) and branch (BRVO).

Methods

This case-control study included 91 Italian patients presenting a first RVO and 71 healthy subjects, matched by age, without history of thromboembolic diseases, glaucoma, or malignancy. Homocysteine fasting and after MLT, serum folate level, serum vitamin B12 level, and other laboratory tests were assessed. Genetic analysis for the C677T MTHFR mutation was performed.

Results

Multivariate logistic regression analysis indicated that hypertension (odds ratio [OR] 2.63; 95% confidence interval [CI] 1.30-5.30; p = 0.007), higher values of fasting HCY (OR 1.16; 95% CI 1.01-1.33; p = 0.03), and low concentrations of vitamin B12 (OR 0.99; 95% CI 0.995-0.999; p = 0.01) were independently correlated with RVO. Moreover, the main determinants for CRVO risk were hypertension (OR 2.46; 95% CI 1.06-5.72; p = 0.04), high values of fasting HCY (OR 1.20; 95% CI 1.02-1.41; p = 0.03), and low concentrations of vitamin B12 (OR 0.99; 95% CI 0.994-0.999; p = 0.008), whereas for BRVO risk only hypertension was significant (OR 2.74; 95% CI 1.24-6.03; p = 0.01). Genotype distribution of the MTHFR C677T mutation did not reveal any significant difference between patients and controls.

Conclusions

These results suggest that elevated fasting HCY levels, low vitamin B12 levels, and hypertension are associated with a risk of RVO, especially for CRVO. Moreover, our data suggest that only hypertension is associated with BRVO risk.
Complement C3, C2, and factor B Gene Polymorphisms and Age-Related Macular Degeneration in a Greek Cohort Study
Authors: Havvas Ioannis , Marioli Dimitra I. , Deli Angeliki , Zarkadis Ioannis K. , Pharmakakis Nikolaos
Published: May 2014

Purpose

To elucidate whether polymorphisms of C2, C3, and CFB genes are major genetic determinants of age-related macular degeneration (AMD) in a Greek population.

Methods

This was a case-control association study comprising 120 Greek patients with early and late-stage AMD and 140 independent controls of Caucasian origin. All participants were genotyped for rs547154, rs2230199, rs641153, and rs12614 polymorphisms by a combination of PCR and direct DNA sequencing assays.

Results

The frequency of the rs2230199 G allele (minor allele) was significantly higher in patients with AMD in comparison with controls (0.34 vs 0.22, p = 0.0031) and similar to the frequency of other reported populations. There was a significant difference in the frequencies of the rs2230199 genotypes among cases and controls (p = 0.0055). rs2230199 was found to be a significant predictor of advanced AMD status (odds ratio 6.41, confidence interval [CI] 2.72-15.09, p<0.0001; area under the curve 0.706, CI 0.61-0.78, p<0.0001]). For the other single nucleotide polymorphism (SNP) loci, the allele and genotype frequencies did not reach statistical significance. The minor allele frequencies in controls and cases were similar and still much lower than the frequencies reported in other populations.

Conclusions

The rs547154, rs641153, and rs12614 SNPs were not associated with AMD development in Greek patients. However, this finding should be viewed with caution as the particular polymorphisms presented with very low frequencies in the Greek population. Finally, the replication of the reported associations of C3 with AMD suggests that the presence of the C3 G allele could serve as a high-risk genetic marker for the development of AMD and the progression of the disease to the advanced clinical stage.
Health-Related Quality of Life in Children Operated for Pediatric Cataracts
Authors: Uzun Aslihan , Atilla Huban
Published: May 2014

Purpose

To evaluate health-related quality of life (HRQOL) in children who had surgery for pediatric cataracts.

Methods

Twenty-five children were divided into 2 groups according to the age at the time of survey (younger than 6 years in group A and 7 years and older in group B). A questionnaire that had 1 part appraising the child's perception and 3 parts evaluating the functional, social, and surgical apprehensions of parents was given to the participants. The questions in the first part were answered by parents in group A (proxy test) and by children in group B (self test). The correlations between the results and patient characteristics were evaluated statistically.

Results

Mean (range) score for the first part was 79.5 (58-97) in group A and 70 (56-86) in group B. Functional, social, and surgical scores were 42.5 (0-80), 45 (5-100), and 63 (12.5-100) in group A and 40 (10-90), 70 (40-85), and 75 (25-100) in group B. Functional, social, or surgical scores were not significantly different between groups. Social apprehensions were significantly higher in parents of patients with preoperative strabismus in group B. Functional, social, surgical apprehensions, and children's thoughts were not correlated significantly with age, sex, family history, laterality, associated nystagmus, aphakia or pseudophakia, postoperative optical rehabilitation, or the need for additional surgery in the groups.

Conclusions

Although pediatric cataracts are known to have a great impact on children's life socially and functionally, there was no significant relationship between patient characteristics and HRQOL. The associated preoperative strabismus causes more social concern in the parents.
Amniotic Membrane Transplantation in Acute Toxic Epidermal Necrolysis: Histopathologic Changes and Ocular Surface Features after 1-Year follow-up
Authors: López-García José Santiago , Rivas Luis , García-Lozano Isabel , Conesa Eduardo , Elosua Isabel , Murube Juan
Published: May 2014

Purpose

To evaluate ocular features and histopathologic changes in patients with toxic epidermal necrolysis (TEN) treated with amniotic membrane transplantation (AMT) in the acute phase.

Methods

A prospective study of 5 eyes (3 patients) with severe ocular involvement and 4 eyes (2 patients) with moderate involvement treated with AMT in the acute phase of TEN was performed. Patients underwent a complete ophthalmic assessment before the intervention and 3, 6, 9, and 12 months postoperatively. Tear film break-up time (BUT), Schirmer test, fluorescein_staining, corneal and conjunctival epithelial squamous metaplasia, ocular sequelae, and conjunctival retraction were measured.

Results

In patients with severe involvement, 2 eyes (40%) showed mild symblepharon and peripheral corneal neovascularization, and corneal epithelial defects, lid margin malposition, and trichiasis was found in 20% of the eyes; only 1 eye (20%) required surgery for structural defects. We did not find ocular sequelae after 1-year follow-up in the patients with moderate involvement. Only 1 eye (25%) developed mild symblepharon that did not require specific treatment. Amniotic membrane transplantation significantly improved the squamous metaplasia in corneal and conjunctival nonsecretory epithelial cells, and significantly improved the goblet cells density after 1-year follow-up.

Conclusions

Amniotic membrane transplantation performed for acute TEN reduced inflammation and ocular surface scarring, improved dry eye and squamous metaplasia. and decreased ocular sequelae in the chronic stage. Although further and prospective studies are needed, AMT may be the optimal treatment for acute TEN with severe or moderate ocular involvement.
Reproducibility of Disc and Macula Optical Coherence Tomography using the Canon OCT-HS100 as Compared with the Zeiss Cirrus HD-OCT
Authors: Brautaset Rune , Birkeldh Ulrika , Rosén Rebecka , Ramsay Marika Wahlberg , Nilsson Maria
Published: May 2014

Purpose

In a clinical setting, the usefulness of optical coherence tomography (OCT) is strongly dependent on reproducibility of the measurement. The aim of the present study was to evaluate macula and optic disc measurement reproducibility with the new spectral-domain OCT (SD-OCT) from Canon (Canon OCT-HS100) and to compare reproducibility and obtained measurements with the Zeiss Cirrus HD-OCT.

Methods

Macula and optic disc parameters from the right eyes of 31 subjects were obtained twice with both instruments. Interoperator reproducibility was evaluated by use of the coefficient of repeatability (CR), and the obtained measurements were compared between the instruments.

Results

No difference in interoperator reproducibility could be found when comparing the 2 instruments and reproducibility ranged from 3.94% to 12.77% for optic disc parameters and from 1.19% to 3.54% for macula parameters. The lowest reproducibility was found for cup volume and vertical cup/disc ratio with both instruments. For all macula and retinal nerve fiber layer (RNFL) thickness measurements, there was a statistical difference when comparing the 2 instruments, except for RFNL measurements of the superior quadrant, with the Canon OCT-HS100 always evaluating the thickness to be thicker; however, the 2 instruments correlated well.

Conclusions

The Canon OCT-HS100 is a reproducible instrument that matches the Zeiss Cirrus HD-OCT well. It remains to be evaluated how sensitive the Canon OCT-HS100 is to detect small subtle changes in optic disc parameters and macular nerve fiber layer thickness. Furthermore, due to the differences in thickness estimation, it is important to emphasize that SD-OCTs are not interchangeable.
Reasons for Early Ocular Hypertension after Uneventful Cataract Surgery
Authors: Fan Fan , Luo Yi , Lu Yi , Liu Xin
Published: May 2014

Purpose

To discuss the reasons for and measurements of early ocular hypertension after uneventful phacoemulsification and intraocular lens (IOL) implantation.

Methods

This was a retrospective review of patients who had early ocular hypertension after cataract surgery from a single-surgeon practice that medications failed to control or required additional surgery from September 2011 to January 2013.

Results

Of the 1270 eyes that had cataract surgery by one surgeon in our department in 16 months, 12 (9.4‰) eyes of 12 patients met the inclusion criteria. The mean postoperative intraocular pressure (IOP) peak was 41 (range 32-62) mm Hg. The median time of initial onset after cataract surgery was 3.5 days (range 1-60 days). Six eyes had antiglaucoma surgery history. Ahmed valve implantation with mitomycin C (MMC) was applied to 4 eyes. Two eyes underwent 5-fluorouracil needling revision with MMC. The IOP dropped in 3 eyes only in the case that the conventional topical corticosteroid agent was stopped, diagnosed as steroid responders. One eye of a patient with diabetes mellitus (DM) developed pseudophakic pupillary block angle-closure glaucoma due to the plasma glucose fluctuations. The IOP was controlled after Nd:YAG laser iridotomies. Residual cortex caused ocular hypertension in 2 eyes and surgical aspirations were performed. Following monitoring of IOP for 6 to 24 months, all eyes were within the normal range.

Conclusions

Patients with history of glaucoma surgery; high myopia, especially in young age; and DM merit particular observation and treatment for possible IOP elevation following cataract surgery.
Mortality in Primary Open-Angle Glaucoma and Exfoliative Glaucoma
Authors: Tarkkanen Ahti H.A. , Kivelä Tero T.
Published: May 2014

Purpose

To study mortality among unselected Finnish patients with either primary open-angle glaucoma (POAG) or exfoliative glaucoma (EG) after a minimum follow-up of 7 years after enrollment.

Methods

A total of 344 patients with POAG and 155 patients with EG had received free medication for the treatment of glaucoma from the Finnish National Social Insurance Institution (FSII). The FSII operates national health insurance, which is compulsory for all Finnish citizens. To be granted free medication, the patient has to file an application with a certificate from an ophthalmologist. If the predefined criteria for glaucoma specified by the Finnish Parliament are met, full reimbursement for glaucoma medications is granted and the patient is listed in the registry of FSII. We reviewed the records of 519 consecutive patients who had been diagnosed with glaucoma and to whom free medication had been granted between June 2004 and December 2005. Patients with acute glaucoma or secondary glaucoma were excluded. Those with open angles were classified into POAG or EG. The quality of the ophthalmologists’ records was high. The Finnish Population Registry, a governmental institute, provided information on those patients who had died before January 2013.

Results

At enrollment, the groups with POAG and EG were comparable as regards sex: 66% female with POAG and 68% with EG. The patients with POAG were younger (median 68 years) than those with EG (median 74 years). By January 2013, 59 patients with POAG and 48 with EG had died. At death, the patients with POAG were younger (median 81.8 years) than those with EG (87.9 years). In both groups, the women lived longer than the men, but among patients with POAG, women and men died at a younger age than those with EG.

Conclusions

As has been reported previously, life expectancy of patients with EG was longer when compared to those with POAG. Higher death rate among patients with EG is explained by higher median age at baseline.
Comparison of Visual Quality between Aspheric and Spherical IOLs
Authors: Yağcı Ramazan , Uzun Feyza , Acer Semra , Hepşen Ibrahim F.
Published: May 2014

Purpose

To determine if aspheric intraocular lens (IOL) implantation produces the same degree of postoperative ocular aberration and contrast sensitivity as spherical IOL implantation.

Methods

In this randomized prospective comparative study, 60 eyes of 30 cataract surgery patients were randomly assigned to receive a spherical IOL (Rayner 620H) in one eye and an aspheric IOL (Rayner 920H) in the contralateral eye. All patients were examined at 1 month postoperatively. Primary outcomes of contrast sensitivity and ocular wavefront higher order aberrations (HOAs) were assessed.

Results

Aspheric IOLs (median total HOAs 0.26 root mean square [RMS]; range 0.13-0.82 RMS) produced significantly lower total HOAs than spherical IOLs (median total HOAs 0.34 RMS; range 0.18-1.08 RMS; p<0.05). Contrast sensitivity was significantly better with aspheric IOLs (median contrast sensitivity 1.8 log units; range 1.35-1.8 log units) than with spherical IOLs (median contrast sensitivity 1.65 log units; range 1.35-1.8 log units; p<0.05).

Conclusions

When compared with a structurally (platform and material) similar spherical IOL (Rayner 620H), aspheric IOLs (Rayner 920H) appear to significantly reduce HOAs and yield better levels of contrast sensitivity under photopic conditions.
Reposition of a Misaligned Zeiss AT TORBI 709M® Intraocular Lens 15 Months after Implantation
Authors: Brandlhuber Ulrich , Haritoglou Christos , Kreutzer Thomas C. , Kook Daniel
Published: May 2014

Purpose

To report the treatment of a patient with a misaligned intraocular lens (IOL).

Methods

We describe a case of a misaligned bitoric single-piece, plate haptic IOL (AT TORBI 709M®, Carl Zeiss Meditec AG, Jena, Germany) 15 months after uneventful phacoemulsification and IOL implantation in the capsular bag. Keratoconus with partly regular astigmatism was preexisting.

Results

Thorough examination showed a misalignment of the bitoric IOL of 25 degrees, explaining the patient's symptoms (monocular diplopia). Despite capsular fibrosis, surgical revision with IOL rotation was advised and could be performed without major difficulty. A follow-up visit showed a corrected distance visual acuity of 16/20 and a correctly aligned toric IOL.

Conclusions

A long preceding operation should not detain the surgical revision of a misaligned toric IOL in the capsular bag.
Effect of Prophylactic Medication and Influence of Vitreous Reflux in Pressure Rise after Intravitreal Injections of Anti-VEGF Drugs
Authors: Carnota-Méndez Pablo , Méndez-Vázquez Carlos , Otero-Villar Jaime , Saavedra-Pazos José Antonio
Published: May 2014

Purpose

To assess the efficacy of a hypotensive prophylactic medication in preventing intraocular pressure (IOP) changes after intravitreal injections, and the effect of occurrence of vitreous reflux on the variation of IOP.

Methods

A total of 141 intravitreal injections of anti-vascular endothelial growth factor drugs (0.05 mL) were randomly distributed into 2 groups: in group 1 (n = 77), no prophylactic IOP-lowering medication was used; in group 2 (n = 64), a fixed combination of brimonidine and timolol was instilled 5 minutes before the injection. The IOP was measured before and 1, 15, and 30 minutes after the injection. The presence of vitreous reflux was recorded.

Results

Despite significantly reducing the IOP by ~3 mm Hg, prophylactic medication did not prevent a transient IOP rise. A total of 22.7% of injections showed vitreous reflux, and those patients experienced much lower initial spikes. Indeed, only 6.5% out of 77 injections above 30 mm Hg within 1 minute after injection showed vitreous reflux. Only one case showed an IOP >30 mm Hg at 15 minutes, and none at 30 minutes postinjection. The IOP normalization rates over time were similar in all groups within 15 minutes.

Conclusions

Prophylactic medication instilled 5 minutes before the injection was not effective in preventing a pressure rise after intravitreal injections. Vitreous reflux decreased significantly the spike figures compared to injections with no reflux.
Homozygous c.1937+1G>A Splice-Site Variant of the ABCA4 gene is Associated with Stargardt Disease
Authors: Eandi Chiara M. , Grignolo Federico M. , Passerini Ilaria , Marchese Cristiana
Published: May 2014

Purpose

To report the phenotype of homozygous ABCA4 c.1937+1G>A splice-site variant associated with Stargardt disease.

Methods

Two siblings, a 10-year-old boy and a 32-year-old woman, born from consanguineous parents, presented with central vision loss and macular pigmentary atrophic changes suggestive of Stargardt disease. After genetic counselling, ABCA4 gene analysis was performed.

Results

The 2 siblings affected were shown to be homozygous for the c.1937+1G>A splice junction variant of the ABCA4 gene. Both parents were heterozygous for the same mutation; they were asymptomatic and the fundus examination revealed a normal appearance.

Conclusions

Thus far, ABCA4 c.1937+1G>A splice-site variant was shown to cause retinitis pigmentosa when in hemizygosity and Stargardt disease when present on one allele. In this family two sibs homozygous for the ABCA4 c.1937+1G>A splice-site variant have a less severe phenotype of Stargardt disease. This observation provides useful information for the diagnosis and counseling of patients with this ABCA4 variant.
Management of Recurrent Corneal Ulcers: Use of Amniotic Membrane
Authors: Ricciardelli Gabriella , Ceccuzzi Roberto , Raneri Marco , Scalisi Antonino , Bianchi Paolo E.
Published: May 2014

Purpose

Amniotic membrane (AM), or amnion, is a thin membrane on the inner side of the fetal placenta; it completely surrounds the embryo/fetus and delimits the amniotic cavity, which is filled by amniotic liquid. In recent years, the structure and function of the amnion have been investigated due to its pluripotent properties, which are an attractive source for tissue transplantation and reconstructive surgery. The pioneering use of AM in skin transplantation by Davis dates back to 1910; in 1913, Sabella and Stern employed it in the treatment of burns and superficial scars. Certain characteristics make the AM ideally suited to its application in ocular surface reconstruction. It can be easily obtained and its availability is nearly unlimited. We report a case of AM transplantation to treat ocular surface abnormality.

Methods

A 28-year-old man came to our attention for persistent foreign body feeling and pain in his right eye. Because of progressive clinical worsening, we decided to perform surgical apposition of AM.

Results

Clinical and instrumental follow-up was conducted with periodic complete checkups. At 1 year follow-up, best-corrected visual acuity was 4/10.

Conclusions

Characteristics of AM make it potentially useful to treat ocular surface abnormalities.
Optical Coherence Tomography Characteristics of the Iris in Cogan-Reese Syndrome
Authors: Holló Gábor , Naghizadeh Farzaneh
Published: May 2014

Purpose

To describe the characteristic optical coherence tomography (OCT) findings of the iris in Cogan-Reese syndrome.

Methods

A 63-year-old woman was referred for consultation due to diffuse pigmentation of the iris and elevated intraocular pressure (IOP) in the left eye. The clinical examination revealed Cogan-Reese syndrome with pedunculated iris outcroppings on the entire iris surface, and no peripheral anterior synechia. The right eye was normal with normal IOP.

Results

Imaging the left iris with the CAM-L cornea lens adapter of the Optovue Fourier-domain OCT (RTVue-OCT) showed a folded iris surface, an increased total iris thickness, and an increased distance between the anterior and posterior iris layers, compared to those of the healthy right eye.

Conclusions

Traction by the pathological endothelial cell layer that covers the iris surface in Cogan-Reese syndrome causes characteristic OCT signs in the iris. Detection of the folded iris surface, increase of iris thickness, and increase of the distance between the anterior and posterior iris layers with RTVue-OCT anterior segment examination may promote the correct diagnosis and may help the clinician to discriminate Cogan-Reese syndrome from true iris nevi or iris melanoma.
Vascularization of Conjunctival Autografts in Pterygium Surgery: Comparison of Fibrin Glue with Sutures
Authors: Küçükerdönmez Cem , Karalezli Aylin , Zengin Mehmet Ozgur , Akova Yonca Aydin
Published: May 2014

Purpose

To monitor the development of graft vascularization after pterygium excision with conjunctival autograft transplantation (CAT) using indocyanine green angiography (ICGA) and to compare the graft vascularization between 2 different fixation techniques (fibrin glue and sutures).

Methods

A total of 26 eyes of 26 patients with primary pterygium were randomly assigned after pterygium excision as having either fibrin glue (13 eyes) or Vicryl sutures (13 eyes) for CAT. Anterior segment ICGA findings were evaluated postoperatively at 1, 7, and 15 days and the percentages of graft vascularization in both groups were compared using pixel analysis software program.

Results

The mean ± SD age of patients in the suture and fibrin glue groups was 52.1 ± 12.7 years and 57.1 ± 9.82 years, respectively. There was no statistically significant difference between the groups regarding age, sex, or follow-up (p<0.05 for all). Also, the mean intraoperative defect size was not significantly different between the groups, which was measured as 20.11 ± 10.44 mm2 in the suture group and 23.44 ± 12.34 mm2 in the fibrin glue group (p = 0.343). The mean percentage of vascularized graft area at postoperative day 1 and 7 was 18.1 ± 7.8% and 25.3 ± 8.6% in the suture group and 34.8 ± 10.2% and 66.1 ± 17.8% in the fibrin glue group. The difference between the groups was statistically significant (p<0.01 for both). At postoperative day 15, all grafts were 100% perfused in both groups.

Conclusions

Fibrin glue fixation of conjunctival autografts led to more vascularization in the early postoperative period than suture fixated grafts, which in turn may have significance in terms of graft health and pterygium recurrence.
Comparison of Intralesional Corticosteroid and Propranolol Treatment of Periorbital Infantile Hemangiomas: An Outcome Study of 61 Cases
Authors: Hoornweg Marije J. , Saeed Peerooz , Tanck Michael W.T. , Hage J. Joris , Coumou Adriaan D. , Van Der Horst Chantal M.A.M.
Published: May 2014

Purpose

To compare intralesional corticosteroid (IC) injections with oral propranolol in children with periorbital infantile hemangioma (IH).

Methods

Children were diagnosed with IH and treated with IC (n = 29) or propranolol (n = 14). In cases in which no further improvement was seen, treatment was stopped and the outcome measured. Type, duration, and complications of treatment and supportive or additional therapies were scored, along with outcomes of visual measurements, at the start and end of therapy.

Results

Twenty-one of the 29 children (72%) treated with IC injections were given a second injection and 16 (55%) were given more than two. Median duration of IC therapy was 15.9 months (interquartile range (IQR) 10.28), compared with 6.5 months (IQR 4.87) for propranolol (p<0.001). The complications reported after IC injections were bleeding (n = 9) and ulceration (n = 7). No complications were noted in the propranolol group. Additional therapy consisting of oral prednisolone therapy was applied in one child from the steroid-treated group. The levels of amblyopia and the median absolute improvement did not significantly differ between the groups.

Conclusions

The IC injections and oral propranolol medication equally improved amblyopia in children with IH of the periorbital and cheek region; however, propranolol was associated with fewer complications and additional or supportive treatment was not indicated. We prefer oral propranolol medication over IC injections in cases in which IH threatens to hamper visual acuity.
Open-Globe Injuries at An Emergency Department in Porto, Portugal: Clinical Features and Prognostic Factors
Authors: Teixeira Sérgio M. , Bastos Ricardo R. , Falcão Manuel S. , Falcão-Reis Fernando M. , Rocha-Sousa Amândio A.
Published: May 2014

Purpose

To describe the epidemiology, characteristics, surgical management, functional outcome, and prognostic factors of open-globe injuries requiring surgical treatment.

Methods

A retrospective review of 180 patients who underwent surgical repair of an open-globe injury at the ophthalmology emergency department of the Hospital S. João (Porto-Portugal) was performed. Prognostic factors for no light perception and for poor vision (visual acuity < 3/10) in patients who retained vision after surgical treatment were determined.

Results

We observed a different age distribution between male and female ocular trauma (143 patients were men, with a mean age of 46.4 years, while the mean age for women was 70.9 years). Domestic accidents were the most frequent context of trauma (44.4%). However, work accidents constituted the principal context of trauma among men. Initial visual acuity, concomitant adnexa lesion, associated nonocular trauma, and intentionally caused trauma were predictors of no vision at the end of the follow-up. Older age, lens damage, and retinal detachment were predictors of poor vision in patients with retained visual acuity. Vitreous hemorrhage, posterior segment lesion, and simultaneous lesion of anterior and posterior segment anticipated both no vision and poor vision. Isolated anterior segment lesion was associated with vision survival and good vision (≥ 3/10).

Conclusions

The prognostic factors identified in this study may aid the process of decision-making in 2 crucial moments: at the initial approach and during the follow-up of patients with vision survival after open-globe injuries.
Changes in the Etiology of Endophthalmitis from 2003 to 2010 in a Large Tertiary Medical Center
Authors: Kessner Rivka , Golan Shani , Barak Adiel
Published: May 2014

Purpose

To ascertain the leading causes of endophthalmitis at the Tel Aviv Medical Center between 2003 and 2010.

Methods

The design of the study is retrospective chart review. The medical records of all patients diagnosed with endophthalmitis in our center between 2003 and 2010 were reviewed for visual acuity and results of ophthalmologic examination at admission, treatment, complications, laboratory investigations, and final visual results. The etiologies of endophthalmitis after cataract surgery were compared for each year from 2003 to 2010, and after intravitreal (IVT) injection from 2006 to 2010.

Results

Eighty patients were diagnosed with endophthalmitis between 2003 and 2010: 46 male and 34 female, average age 70.7 years. A total of 27.5% were treated with IVT antibiotic injection only and 68.8% needed pars plana vitrectomy. Final visual acuity was better than counting fingers in 56.3% of cases. Surgery was almost the sole cause of endophthalmitis until 2005, when IVT injection became an important etiology. The incidence of postcataract endophthalmitis decreased significantly after 2007 and that following IVT injection decreased significantly after 2008.

Conclusions

The leading etiology of endophthalmitis changed from postoperative endophthalmitis to endophthalmitis after IVT injection from 2003 to 2010, and the incidence of the infection as a complication of those procedures decreased.
Accidental Foveal Photocoagulation Secondary to Alexandrite Laser
Authors: Anaya-Alaminos Roberto , Muñoz-Ávila José I. , González-Gallardo María C. , Mora-Horna Eduardo R. , García-Serrano José L. , Ramírez-Garrido María V.
Published: May 2014

Purpose

In recent years, we have seen an increase in the use of laser systems in the field of aesthetics (mainly depigmentation and hair removal). Alexandrite laser is the most widely used.

Methods

Case report.

Results

We describe a case of retinal injury (foveal photocoagulation) directly related to an alexandrite laser hair removal procedure.

Conclusions

Hair removal by laser systems is a fast and efficient method. The use of lasers without adequate protective measures or by unqualified personnel increases the risk of ocular adverse effects.