Reverse Geometry Hybrid Contact Lens Fitting in a Case of Donor-Host Misalignment after Keratoplasty

Purpose: To report the successful outcome obtained after fitting a new hybrid contact lens in a cornea with an area of donor-host misalignment and significant levels of irregular astigmatism after penetrating keratoplasty (PKP). Materials and methods: A 41-year-old female with bilateral asymmetric keratoconus underwent PKP in her left eye due to the advanced status of the disease. One year after surgery, the patient referred a poor visual acuity and quality in this eye. The fitting of different types of rigid gas permeable contact lenses was performed, but with an unsuccessful outcome due to contact lens stability problems and uncomfortable wear. Scheimpflug imaging evaluation revealed that a donor-host misalignment was present at the nasal area. Contact lens fitting with a reverse geometry hybrid contact lens (Clearkone, SynergEyes Carlsbad) was then fitted. Visual, refractive, and ocular aberrometric outcomes were evaluated during a 1-year period after the fitting. Results: Uncorrected distance visual acuity improved from a prefitting value of 20/200 to a best corrected postfitting value of 20/20. Prefitting manifest refraction was +5.00 sphere and -5.50 cylinder at 75°, with a corrected distance visual acuity of 20/30. Higher order root mean square (RMS) for a 5 mm pupil changed from a prefitting value of 6.83 µm to a postfitting value of 1.57 µm (5 mm pupil). The contact lens wearing was referred as comfortable, with no anterior segment alterations. Conclusion: The SynergEyes Clearkone contact lens seems to be another potentially useful option for the visual rehabilitation after PKP, especially in cases of donor-host misalignment.

New-Generation Hybrid Contact Lens for the Management of Extreme Irregularity in a Thin Cornea After Unsuccessful Excimer Laser Refractive Surgery

Purpose: To report a very successful outcome obtained with the fitting of a new-generation hybrid contact lens of reverse geometry in a thin cornea with extreme irregularity due to the presence of a central island after unsuccessful myopic excimer laser refractive surgery. Methods: A 32-year-old man attended to our clinic complaining of very poor vision in his right eye after bilateral laser in situ keratomileusis (treatment or surgery) for myopia correction and some additional retreatments afterward. After a comprehensive ocular evaluation, contact lens fitting with a reverse geometry hybrid contact lens (SynergEyes PS, SynergEyes, Carlsbad, CA) was proposed as a solution for this case. Visual, refractive, and ocular aberrometric outcomes with the contact lens were evaluated. Results: Distance visual acuity improved from a prefitting uncorrected value of 20/200 to a postfitting corrected value of 20/16. Prefitting manifest refraction was +6.00 sphere and −3.00 cylinder at 70°, with a corrected distance visual acuity of 20/40. Higher order root mean square for a 5-mm pupil changed from a prefitting value of 1.45 to 0.34 µm with the contact lens. The contact lens wearing was reported as comfortable, and the patient was very satisfied with this solution. Conclusions: The SynergEyes PS contact lens seems to be an excellent option for the visual rehabilitation of corneas with extreme irregularity after myopic excimer laser surgery, minimizing the level of higher order aberrations and providing an excellent visual outcome.

Fixed Mydriatic Pupil Associated with an Intraocular Pressure Rise as a Complication of the Implant of a Phakic Refractive Lens (PRL)

We describe a case report of a patient that was implanted with a posterior chamber phakic intraocular lens (Phakic Refractive Lens, PRL) for the correction of moderate myopia and who developed postoperatively a fixed mydriasis compatible with an Urrets-Zavalia Syndrome (UZS). Specifically, a sudden acute increase of IOP in the left eye was observed in the immediate postoperative period. After IOP stabilization, the refractive result was good, but a fixed and mydriatic pupil appeared. This condition led the patient to experience visual discomfort, halos, and glare associated with high levels of higher-order aberrations in spite of the good visual result. A tinted-contact lens was fitted in order to minimize those symptoms. The UZS should be considered as a possible complication after implantation of posterior chamber phakic intraocular lenses.

Implantation of a diffractive trifocal intraocular lens: One-year follow-up

Purpose: To evaluate the visual, refractive, contrast-sensitivity, and aberrometric outcomes during a 1-year follow-up after implantation of a trifocal intraocular lens (IOL). Setting: Premium Clinic, Teplice, Czech Republic. Design: Prospective case series. Methods: This study included eyes of patients having cataract surgery with implantation of the trifocal IOL model AT Lisa tri 839MP. Distance, intermediate (66 and 80 cm), and near (33 and 40 cm) vision; contrast sensitivity; aberrometric outcomes; and the defocus curve were evaluated during a 12-month follow-up. The level of posterior capsule opacification (PCO) was also evaluated. Results: In 120 eyes (60 patients), 1 month postoperatively, an improvement was observed in all visual parameters (P ≤ .03) except corrected near and intermediate visual acuities (both P ≥ .05). From 1 month to 12 months postoperatively, small but statistically significant changes were observed in uncorrected and corrected distance and near visual acuities (all P ≤ .03) and in uncorrected intermediate visual acuity (P = .01). In the defocus curve, no significant differences were found between visual acuities corresponding to defocus levels of −1.0 diopter (D) and −2.0 D (P = .22). The level of ocular spherical aberration decreased statistically significantly at 6 months (P < .001). Ocular and internal higher-order aberrations increased minimally but significantly from 6 to 12 months postoperatively (P < .001). The mean 12-month PCO score was 0.32 ± 0.44 (SD). Four eyes (3.3%) required neodymium:YAG capsulotomy. Conclusion: The trifocal IOL provided complete and stable visual restoration after cataract surgery during a 12-month follow-up, with good levels of visual quality.

Wavefront-Guided Laser Treatment Using a High-Resolution Aberrometer to Measure Irregular Corneas: A Pilot Study

PURPOSE: To evaluate in a pilot study the visual, refractive, corneal topographic, and aberrometric changes after wavefront-guided LASIK or photorefractive keratectomy (PRK) using a high-resolution aberrometer to calculate the treatment for aberrated eyes. METHODS: Twenty aberrated eyes of 18 patients undergoing wavefront-guided LASIK or PRK using the VISX STARS4IR excimer laser and the iDesign aberrometer (Abbott Medical Optics, Inc., Santa Ana, CA) were enrolled in this prospective study. Three groups were differentiated: keratoconus post-CXL group including 11 keratoconic eyes (10 patients), post-LASIK group including 5 eyes (5 patients) with previous decentered LASIK treatments, and post-RK group including 4 eyes (3 patients) with previous radial keratotomy. Visual, refractive, contrast sensitivity, corneal topographic, and ocular aberrometric changes were evaluated during a 6-month follow-up. RESULTS: An improvement in uncorrected (UDVA) and corrected visual acuity (CDVA) associated with a reduction in the spherical equivalent was observed in the three groups, but was only statistically significant in the keratoconus post-CXL and post-LASIK groups (P ≤ .04). All eyes gained one or more lines of CDVA after surgery. Improvements in contrast sensitivity were observed in the three groups, but they were only statistically significant in the keratoconus post-CXL and post-LASIK groups (P ≤ .04). Regarding aberrations, a reduction was observed in trefoil aberrations in the keratoconus post-CXL group (P = .05) and significant reductions in higher-order and primary coma aberrations in the post-LASIK group (P = .04). CONCLUSIONS: Wavefront-guided laser enhancements using the evaluated platform seem to be safe and effective to restore the visual function in aberrated eyes.

Cortical Abnormalities in Adults and Adolescents with Major Depression based on Brain Scans from 20 Cohorts Worldwide in the ENIGMA Major Depressive Disorder Working Group

The neuro-anatomical substrates of major depressive disorder (MDD) are still not well understood, despite many neuroimaging studies over the past few decades. Here we present the largest ever worldwide study by the ENIGMA (Enhancing Neuro Imaging Genetics through Meta-Analysis) Major Depressive Disorder Working Group on cortical structural alterations in MDD. Structural T1-weighted brain magnetic resonance imaging (MRI) scans from 2148 MDD patients and 7957 healthy controls were analysed with harmonized protocols at 20 sites around the world. To detect consistent effects of MDD and its modulators on cortical thickness and surface area estimates derived from MRI, statistical effects from sites were meta-analysed separately for adults and adolescents. Adults with MDD had thinner cortical gray matter than controls in the orbitofrontal cortex (OFC), anterior and posterior cingulate, insula and temporal lobes (Cohen’s d effect sizes: −0.10 to −0.14). These effects were most pronounced in first episode and adult-onset patients (>21 years). Compared to matched controls, adolescents with MDD had lower total surface area (but no differences in cortical thickness) and regional reductions in frontal regions (medial OFC and superior frontal gyrus) and primary and higher-order visual, somatosensory and motor areas (d: −0.26 to −0.57). The strongest effects were found in recurrent adolescent patients. This highly powered global effort to identify consistent brain abnormalities showed widespread cortical alterations in MDD patients as compared to controls and suggests that MDD may impact brain structure in a highly dynamic way, with different patterns of alterations at different stages of life.

Geochemistry of basalts from ODP Leg 49, North Atlantic Ocean

The geochemistry of basalts recovered from seven sites in the North Atlantic is described with particular reference to minor elements. Three sites (407, 408, and 409) along the same mantle flow line, transverse to the Reykjanes Ridge at about 63°N, provide information on the composition of basalts erupted over a 34-m.y. interval between 2.3 and 36 m.y. ago. At Site 410, at 45°N, penetration into 10 m.y.-old crust west of the ridge axis permits comparisons with young basalts dredged from the median valley at 45°N. Three sites in the FAMOUS area at about 36°N provided material from very young (1 m.y.) basaltic crust (Site 411), and material to test the geochemical coherence of basalts of different ages (1.5 and 3.5 m.y.) on either side of a fracture zone (Sites 412 and 413). These sites complement earlier data from dredged and drilled sites (Leg 37) in the FAMOUS area. At Site 407, four geochemically distinct basalt units occur, with different normative and rare-earth element (REE) characteristics, and there is a clear correlation with magnetic stratigraphy. Yet there is a remarkable consistency in incompatible element ratios between these units, indicating derivation from an essentially similar mantle source. The basalts from the younger sites, 408 and 409, show a similar range of normative and REE variation, but incompatible element ratios are identical to those at Site 407, indicating that basalts at all three sites were produced from a mantle source which was geochemically relatively uniform. Rare-earth differences between the basalts can be interpreted in terms of variations in the degree and depth of partial melting causing HREE (+Y) retention in the source, although there may be some inter-site differences with respect to REE. A similar picture is presented at 45°N. Apparently a range of tholeiitic, transitional, and alkalic basalts were being erupted 10 m.y. ago, which have almost identical geochemical characteristics to those recently erupted in the median valley at 45°N. Incompatible element ratios are markedly different from those recorded at the Reykjanes Ridge. Basalts recovered from the FAMOUS sites are geochemically similar to previous samples recovered from the FAMOUS area, and their incompatible element ratios are similar, but not identical, to those at 45°N. However, total trace element levels are consistently lower than in 45°N basalts, which might imply smaller degrees of partial melting and/or greater depths of magma generation at 45°N, or higher trace element levels in the mantle source at 45°N. Few of the basalts recovered on Leg 49 have the geochemical characteristics of typical "MORB" (e.g., Nazca Plate, Leg 34). The data strongly support models invoking geochemical inhomogeneity in the source regions of basalts produced at the Mid-Atlantic Ridge. However, the data also introduce an additional time factor into such models and demonstrate the uniformity of the mantle source at a particular ridge sector (over periods in excess of 30 m.y.), while emphasizing the marked differences along the ridge. Mixing models invoking "depleted" and "enriched" mantle sources would seem to be inadequate to account for the observed variations.

Gut filling, gut content and fatty acid composition of demersal fish species sampled during POLARSTERN cruise ANT-XXIV/2

The gut contents and fatty acid composition of 49 fish belonging to five Antarctic demersal families (Nototheniidae, Macrouridae, Channichtyidae, Bathydraconidae and Artedidraconidae) sampled at two stations at the Southern Ocean shelf and deep sea (600 and 2150 m) were analysed in order to identify their main food resource by linking trophic biomarkers with the dietary items found in the fish guts. Main food items of most fish analysed were amphipod crustaceans (e.g. in 63% of Trematomus bernachii guts) and polychaetes (e.g. in 80% of Bathydraco sp. guts), but other food items including fish, other crustaceans and gastropods were also ingested. The most prominent fatty acids found were 20:5(n-3), 16:0, 22:6(n-3) and 18:1(n-9). The results of gut content and fatty acid analyses indicate that all fish except the Channichthyidae share similar food resources irrespective of their depth distribution, i.e. benthic amphipods and polychaetes. A difference of the dietary spectrum can be observed with ontogenetic phases rather than between species, as high values of typical calanoid copepod marker fatty acids as 22:1(n-11) indicate that younger (smaller) specimens include more zooplankton in their diet.

Geochemistry at DSDP Sites 69-505, 69-504 and 70-504

Deep basement penetration during Legs 69 and 70 at Hole 504B in the Panama Basin allowed the recovery of a 561.5-meter sequence of basaltic pillows, thin flows, and breccias interspersed with thick massive flows. The lavas, which are aphyric to moderately plagioclase-olivine-clinopyroxene phyric, are petrologically indistinguishable from typical mid-ocean-ridge basalts (MORB). Some units are distinctive in that they carry accessory chrome-spinel microphenocrysts or emerald green clinopyroxene phenocrysts. Major and trace element analyses were carried out on 67 samples using X-ray fluorescence techniques. The basalts resemble normal MORB in terms of major elements. However, the trace element analyses show that most of the basalts are characterized by very strong depletion in the more incompatible elements compared with, for instance, normal (N type) MORB from the Atlantic at 22°N. Interdigitated with these units are one or two units that have distinctly higher incompatible element concentrations similar to those in basalts of the transitional (T) type from the Reykjanes Ridge (63°N in the Mid-Atlantic Ridge). All the basalts appear to have undergone some high-level crystal fractionation, although this has not proceeded to the extent of yielding ferrobasalts as it has at the adjacent Galapagos Spreading Center or along the East Pacific Rise. The magnetic anomalies are of lower amplitude than in the latter two regions, which suggests that the absence of ferrobasalts may be a general feature of the ocean crust generated at the Costa Rica Rift. The presence of two distinct magma types, one strongly depleted and the other moderately enriched in incompatible elements, suggests that magma chambers at the spreading center are discontinuous rather than continuous and that there is some chemical heterogeneity in the underlying mantle source. Observed variations in incompatible element ratios of basalts from the more depleted group could, however, reflect mixing between these two magma types. In general it would appear that the mantle feeding the Costa Rica Rift is significantly more depleted in incompatible trace elements than that feeding the Mid-Atlantic Ridge.

Can parents and teachers provide a reliable and valid report of behavioral inhibition?

Reliability and validity of parent and teacher report of behavioral inhibition (BI) was examined among children aged 3 to 5 years. Confirmatory factor analysis supported 6 correlated factors reflecting specific BI contexts, each loading on a single, higher order factor of BI. Internal consistency was acceptable, with moderate stability over 1 year and strong correlation with a brief inhibition subscale from a temperament questionnaire. Children who were rated by mothers and teachers as high BI took longer to initiate contact with a stranger, spoke less often and for shorter periods, and required more prompting to elicit speech compared with low-BI peers in a simulated stranger interaction task. Father report of BI was significantly associated with mean duration of speech and eye gaze.

A new analytical solution for water table fluctuations in coastal aquifers with sloping beaches

The Boussinesq equation appears as the zeroth-order term in the shallow water flow expansion of the non-linear equation describing the flow of fluid in an unconfined aquifer. One-dimensional models based on the Boussinesq equation have been used to analyse tide-induced water table fluctuations in coastal aquifers. Previous analytical solutions for a sloping beach are based on the perturbation parameter, epsilon(N) = alphaepsilon cot beta (in which beta is the beach slope, alpha is the amplitude parameter and epsilon is the shallow water parameter) and are limited to tan(-1) (alphaepsilon) much less than beta less than or equal to pi/2. In this paper, a new higher-order solution to the non-linear boundary value problem is derived. The results demonstrate the significant influence of the higher-order components and beach slope on the water table fluctuations. The relative difference between the linear solution and the present solution increases as 6 and a increase, and reaches 7% of the linear solution. (C) 2003 Elsevier Ltd. All rights reserved.

On the dimensionality of the Attachment Style Questionnaire in Italian clinical and nonclinical participants

This study examined the utility of the Attachment Style Questionnaire (ASQ) in an Italian sample of 487 consecutively admitted psychiatric participants and an independent sample of 605 nonclinical participants. Minimum average partial analysis of data from the psychiatric sample supported the hypothesized five-factor structure of the items; furthermore, multiple-group component analysis showed that this five-factor structure was not an artifact of differences in item distributions. The five-factor structure of the ASQ was largely replicated in the nonclinical sample. Furthermore, in both psychiatric and nonclinical samples, a two-factor higher order structure of the ASQ scales was observed. The higher order factors of Avoidance and Anxious Attachment showed meaningful relations with scales assessing parental bonding, but were not redundant with these scales. Multivariate normal mixture analysis supported the hypothesis that adult attachment patterns, as measured by the ASQ, are best considered as dimensional constructs.

A genetic investigation of the covariation among Inspection Time, Choice Reaction Time, and IQ subtest scores

Information processing speed, as measured by elementary cognitive tasks, is correlated with higher order cognitive ability so that increased speed relates to improved cognitive performance. The question of whether the genetic variation in Inspection Time (IT) and Choice Reaction Time (CRT) is associated with IQ through a unitary factor was addressed in this multivariate genetic study of IT, CRT, and IQ subtest scores. The sample included 184 MZ and 206 DZ twin pairs with a mean age of 16.2 years (range 15-18 years). They were administered a visual (pi-figure) IT task, a two-choice RT task, five computerized subtests of the Multidimensional Aptitude Battery, and the digit symbol substitution subtest from the WAIS-R. The data supported a factor model comprising a general, three group (verbal ability, visuospatial ability, broad speediness), and specific genetic factor structure, a shared environmental factor influencing all tests but IT, plus unique environmental factors that were largely specific to individual measures. The general genetic factor displayed factor loadings ranging between 0.35 and 0.66 for the IQ subtests, with IT and CRT loadings of -0.47 and -0.24, respectively. Results indicate that a unitary factor is insufficient to describe the entire relationship between cognitive speed measures and all IQ subtests, with independent genetic effects explaining further covariation between processing speed (especially CRT) and Digit Symbol.

On the role of magnesium and nitrogen in the infiltration of aluminium by aluminium for rapid prototyping applications

Selective laser sintering has been used to fabricate an aluminium alloy powder preform which is subsequently debound and infiltrated with a second aluminium alloy. This represents a new rapid manufacturing system for aluminium that can be used to fabricate large, intricate parts. The base powder is an alloy such as AA6061. The infiltrant is a binary or higher-order eutectic based on either Al-Cu or At-Si. To ensure that infiltration occurs without loss of dimensional precision, it is important that a rigid skeleton forms prior to infiltration. This can be achieved by the partial transformation of the aluminium to aluminium nitride. In order for this to occur throughout the component, magnesium powder must be added to the alumina support powder which surrounds the part in the furnace. The magnesium scavenges the oxygen and thereby creates a microclimate in which aluminium nitride can form. The replacement of the ionocovalent Al2O3 with the covalent AlN on the surface of the aluminium powders also facilitates wetting and thus spontaneous and complete infiltration. (C) 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Semi-analytical solution for nonlinear vibration of laminated FGM plates with geometric imperfections

This paper investigates the nonlinear vibration of imperfect shear deformable laminated rectangular plates comprising a homogeneous substrate and two layers of functionally graded materials (FGMs). A theoretical formulation based on Reddy's higher-order shear deformation plate theory is presented in terms of deflection, mid-plane rotations, and the stress function. A semi-analytical method, which makes use of the one-dimensional differential quadrature method, the Galerkin technique, and an iteration process, is used to obtain the vibration frequencies for plates with various boundary conditions. Material properties are assumed to be temperature-dependent. Special attention is given to the effects of sine type imperfection, localized imperfection, and global imperfection on linear and nonlinear vibration behavior. Numerical results are presented in both dimensionless tabular and graphical forms for laminated plates with graded silicon nitride/stainless steel layers. It is shown that the vibration frequencies are very much dependent on the vibration amplitude and the imperfection mode and its magnitude. While most of the imperfect laminated plates show the well-known hard-spring vibration, those with free edges can display soft-spring vibration behavior at certain imperfection levels. The influences of material composition, temperature-dependence of material properties and side-to-thickness ratio are also discussed. (C) 2004 Elsevier Ltd. All rights reserved.