Parametric modeling of wideband piezoelectric polymer sensors: Design for optoacoustic applications.

In this work, we present a three-dimensional model for the design of wideband piezoelectric polymer sensors which includes the geometry and the properties of the transducer materials. The model uses FFT and numerical integration techniques in an explicit, semi-analytical approach. To validate the model, we made electrical and mechanical measurements on homemade sensors for optoacoustic applications. Each device was implemented using a polyvinylidene fluoride thin film piezoelectric polymer with a thickness of 25 µm. The sensors had detection areas in the range between 0.5 mm2 and 35 mm2 and were excited by acoustic pressure pulses of 5 ns (FWHM) from a source with a diameter around 10 µm. The experimental data obtained from the measurements agree well with the model results. We discuss the relative importance of the sensor design parameters for optoacoustic applications and we provide guidelines for the optimization of devices.

[Comparing central corneal thickness measured using ultrasound pachymetry and the Pentacam in healthy subjects and patients with primary open-angle glaucoma]. / Comparaison de l'épaisseur cornéenne centrale mesurée par pachymétrie ultrasonore et par Pentacam chez les patients sains et les patients avec glaucome primaire à angle ouvert.

PURPOSE: To determine the capacity for measurement of central corneal thickness by ultrasound pachymetry and by Pentacam (pachymetry at the pupillary axis and minimum corneal pachymetry) to discriminate between healthy controls and patients with primary open-angle glaucoma. METHODS: Measurements of the left eyes of 123 control subjects and 128 glaucomatous patients were taken. Differences between the two data sets for each variable were identified using a t-test for independent samples. Three univariate binary logistic regression models (to discriminate between glaucoma and controls) were constructed, in which the predictive variables were the determinations of corneal thickness. RESULTS: All variables showed a normal distribution. Controls and patients failed to differ significantly in terms of ultrasound pachymetry but did differ in terms of pupillary axis thickness (mean difference 22.01µm in favour of controls; 95% CI: 5.61-34.15) and minimum corneal thickness (mean difference 21.65µm in favour of controls; 95% CI: 3.05-32.25). The logistic regression model for ultrasound pachymetry was not significant (P=0.051) but significant discriminatory capacity was shown for pupillary axis thickness (expB=0.987; 95% CI: 0.99-0.993; sensitivity: 58.5%; specificity: 64.8%) and minimum corneal thickness (expB=0.987; 95% CI: 0.981-0.994; sensitivity: 61.9%; specificity: 63.1%). CONCLUSIONS: Central corneal thickness measurement by Pentacam, while not an ad hoc diagnostic test for glaucoma, showed a similar yet not inappreciable capacity to discriminate between glaucoma patients and controls.

[Comparison of Goldmann applanation and dynamic contour tonometry measurements: effects of corneal morphometry]. / Concordancia entre la tonometría de aplanación de Goldmann y la tonometría de contorno dinámico: efectos de la morfometría corneal.

OBJECTIVES: To compare intraocular pressure (IOP) measurements made by Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT). METHODS: IOPs were measured by GAT and DCT in 63 eyes of 63 healthy subjects. A comparison was made by intraclass correlation coefficient. Passing-Bablok plot was constructed to establish the existence of systematic and/or proportional biases. Multivariate regression analysis was used to examine whether the measurements of both instruments were affected by the power of the steepest and flattest corneal axes, their orientation, age or central corneal thickness (CCT). RESULTS: The intra-class correlations (ICCs) were 0.57 (95% confidence interval (95% CI): 0.29-0.74). Mean differences were 1.68 (DCT minus GAT) (95% CI: 0.92-2.44). Passing-Bablok analysis (X=DCT, Y=GAT) revealed a systematic bias (A=-14.35, 95% CI: -24.51-[-9.14]) and a proportional bias (B=1.74, 95% CI: 1.43-2.26). Multivariate regression analysis revealed that the DCT was independent of the corneal characteristics analysed while GAT was biased by CCT (B=0.042, 95% CI: 0.002-0.082). CONCLUSIONS: While GAT was biased by corneal CCT; DCT readings were independent of corneal morphometry.

Concordancia entre la tonometría de aplanación de Goldmann y la tonometría de contorno dinámico: efectos de la morfometría corneal / Comparison of Goldmann applanation and dynamic contour tonometry measurements: effects of corneal morphometry

Objetivos: Determinar la concordancia entre la presión intraocular (PIO) medida mediante tonometría de aplanación de Goldmann (TAG) y tonometría de contorno dinámico (TCD).MétodosLa PIO se midió mediante TAG y TCD en 63 ojos de 63 voluntarios sanos. La concordancia se determinó mediante coeficiente de correlación intraclase (CCI). Se empleó el método de Passing-Bablok para establecer la presencia de sesgos proporcionales y/o sistemáticos. El análisis de regresión multvariable se empleó para determinar si las diferencias estaban condicionadas por la potencia de los ejes mayor y menor de la córnea, por su orientación, por el grosor corneal central (GCC) y por la edad.ResultadosEl CCI fue 0,57 (intervalo de confianza [IC] al 95%: 0,29-0,74). La diferencia media entre los dos instrumentos fue 1,68mmHg (TCD menos TAG) (IC 95%: 0,92-2,44). El análisis de Passing-Bablok (X=DCT, Y=GAT) reveló la presencia de un sesgo sistemático (A=-14,35, IC 95%: -24,51-[-9,14]) y otro proporcional (B=1,74, IC 95%: 1,43-2,26). El análisis de regresión multivariable mostró una total independencia del TCD de las características corneales mientras que la TAG estaba afectada por el GCC (B=0,042 CI 95%: 0,002-0,082).ConclusionesLa TCD se mostró independiente de las características morfométricas de la córnea mientras que la TAG se afectó por el GCC (AU)

Objectives: To compare intraocular pressure (IOP) measurements made by Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT).MethodsIOPs were measured by GAT and DCT in 63 eyes of 63 healthy subjects. A comparison was made by intraclass correlation coefficient. Passing-Bablok plot was constructed to establish the existence of systematic and/or proportional biases. Multivariate regression analysis was used to examine whether the measurements of both instruments were affected by the power of the steepest and flattest corneal axes, their orientation, age or central corneal thickness (CCT).ResultsThe intra-class correlations (ICCs) were 0.57 (95% confidence interval (95% CI): 0.29-0.74). Mean differences were 1.68 (DCT minus GAT) (95% CI: 0.92-2.44). Passing-Bablok analysis (X=DCT, Y=GAT) revealed a systematic bias (A=-14.35, 95% CI: -24.51-[-9.14]) and a proportional bias (B=1.74, 95% CI: 1.43-2.26). Multivariate regression analysis revealed that the DCT was independent of the corneal characteristics analysed while GAT was biased by CCT (B=0.042, 95% CI: 0.002-0.082).ConclusionsWhile GAT was biased by corneal CCT; DCT readings were independent of corneal morphometry (AU)

A caspase-dependent cleavage of CDC25A generates an active fragment activating cyclin-dependent kinase 2 during apoptosis.

The cellular level of the CDC25A phosphatase is tightly regulated during both the normal and genotoxic-perturbed cell cycle. Here, we describe a caspase-dependent cleavage of this protein at residue D223 in non-genotoxic apoptotic conditions. This specific proteolysis generates a catalytically active C-terminal fragment that localizes to the nuclear compartment. Accumulation of this active CDC25A fragment leads to reduced inhibitory phosphorylation of the CDC25A substrate cyclin-dependent kinase 2 (CDK2) on Tyr15. Moreover, CDK2 was found stably associated with this fragment, as well as with an ectopically expressed CDC25A224-525 truncation mutant that mimicks the cleavage product. Ectopic expression of this mutant induced CDK2 Tyr15 dephosphorylation, whereas its catalytically inactive version did not. Finally, this 224-525 mutant initiated apoptosis when transfected into HeLa cells, whereas its catalytic inactive form did not. Altogether, this study demonstrates for the first time that caspase-dependent cleavage of CDC25A is a central step linking CDK2 activation with non-genotoxic apoptotic induction.

Angle-closure glaucoma after piggyback intraocular lens implantation.

PURPOSE: To report a case of angle closure glaucoma after piggyback intraocular lens implantation and its treatment. METHODS: The authors present the case of a 75-year-old woman who was seen in the emergency department with angle closure glaucoma. Two years before she had undergone piggyback intraocular lens (IOL) implantation in order to correct a refractive error after cataract surgery. Ultrasound biomicroscopy revealed a closed angle with synechiae in 360 degrees as well as the presence of two IOLs: one in the capsular bag and the other in the ciliary sulcus. Extraction of the anterior IOL was precluded due to the poor endothelial count. Peripheral iridotomy and trabeculectomy were ineffective to lower the intraocular pressure (IOP); the authors decided to implant with an Ahmed valve and to place the valve's tube between the two IOLs to protect the endothelium. RESULTS: After Ahmed valve implantation, IOP maintains stable around 10-12 mmHg without medical treatment. CONCLUSIONS: Ahmed valve implantation is a good option in angle closure glaucoma due to piggyback. The placement of the valve's tube between the two IOLs is a good option to protect corneal endothelium.

Ocular inflammatory signs observed in a cohort of Spanish patients with Behçet disease and ocular inflammation.

PURPOSE: To study the clinical characteristics of a cohort of Spanish patients diagnosed with Behcet disease and who also presented ocular inflammation. METHODS: Thirty cases of Behçet disease were studied retrospectively. The authors studied age distribution, distribution by sex, clinical course, laterality, type of uveitis, secondary glaucoma, corneal involvement, hypopyon, iris-lens synechiae, secondary cataract, cystoid macular edema (CME), and papillitis (optic neuritis). RESULTS: Fourteen of the patients were men and 16 were women (ratio 0.875:1). The mean age of the patients was 35.24 years (+/-10.917; 21-61 years). In 23 patients, the disease course was recurrent. In 9 patients, the disease manifested unilaterally. In 5 patients showing unilateral onset, the contralateral eye became affected. In 2 of the 30 patients, uveitis exclusively affected the anterior segment. In 8 patients, uveitis was solely posterior. There was one case of intermediate uveitis. The remaining 19 patients showed panuveitis. Three had focal chorioretinitis. One had diffuse chorioretinitis. Fifteen showed signs of diffuse vasculitis. Eight patients showed focal vasculitis. CONCLUSIONS: Women were slightly more affected than men, although the authors found no significant correlation between sex and the clinical variables examined. Apart from one unexpected case of intermediate uveitis, the observations are similar to those reported for other patient series.

Agreement between slit lamp examination and optical coherence tomography in estimating cup-disc ratios.

PURPOSE: To compare optical coherence tomography (OCT) cup-disc ratio measurements with those estimated by two independent examiners using the slit lamp in an evaluation of the optic nerve head (ONH). METHODS: In 47 eyes each of 47 patients with glaucoma and 47 healthy subjects, the ONH was examined using the slit lamp with a 78 D lens. Two examiners subjectively determined the cup-disc area ratio (A-CDR), the horizontal cup-disc ratio (H-CDR), and the vertical cup-disc ratio (V-CDR). These measurements were compared to objective OCT readings obtained by a third examiner blind to the slit lamp results. RESULTS: For the three variables determined, correlation indices between the OCT readings and the two sets of slit lamp measurements were significantly higher for the glaucoma group than the control group. In the patients with glaucoma, the OCT tended to underestimate A-CDR and overestimate H-CDR. For both these variables, Bland-Altmann analysis revealed significant differences between the two methods that persisted across the whole range of CDRs examined. In contrast, differences in V-CDR varied with disc size. CONCLUSIONS: The OCT is a diagnostic tool that provides a complete automatic evaluation of the ONH. However, its measurements vary significantly from those obtained in subjective evaluations performed by experienced ophthalmologists.

Herpetic optic neuritis associated with herpetic keratitis.

PURPOSE: To report a case of herpetic optic neuritis associated with herpetic keratitis. METHODS: A 65 year old woman presented with oedema in the nasal sector of his right papilla. Blood biochemistry, a haemogram, erythrocyte sedimentation rate and C-reactive protein were all normal. The patient was diagnosed as having a non-arteritic anterior ischaemic optic neuropathy. One week later slit lamp examination showed diffuse stromal corneal oedema and a dendritic lesion in the nasal zone of the corneal epithelium. RESULTS: Serology for varicela-zoster virus was positive. Treatment was started with valacyclovir given orally and topical acyclovir ointment. A week later, the optic disc swelling and corneal lesions had resolved. CONCLUSIONS: The precise mechanism through which the papilla and cornea were successively affected in our patient is unclear but the sensitive innervation of both these structures is provided by the nasal branch of the nasociliary nerve and the spread of herpes via this nerve could affect both sites.

Circadian IOP-lowering efficacy of travoprost 0.004% ophthalmic solution compared to latanoprost 0.005%.

PURPOSE: The primary objective of this study was to determine the intraocular pressure- (IOP) lowering efficacy over two consecutive 24-h periods of travoprost 0.004% ophthalmic solution (Travatan) compared to latanoprost 0.005% (Xalatan) dosed once daily in patients with primary open-angle glaucoma or ocular hypertension. METHODS: This was a double-masked trial conducted at the Hospital Clínico San Carlos, Madrid, Spain. The primary objective of this study was to determine the IOP lowering efficacy of travoprost and latanoprost. During the eligibility visit, patients' IOP was measured throughout two consecutive 24-h periods every 4 h. Patients were then randomized to travoprost or latanoprost (one drop at 8 p.m. daily for 2 weeks). Sixty-two patients were randomized (travoprost n = 32; latanoprost n = 30). IOP was measured at week 2 every 4 h throughout two 24-h periods. All measurements were taken in both supine and sitting positions with the aid of Perkins applanation tonometry. Limitations of the study include a small sample size (due to the difficulty in recruiting patients in a study of this type) which enrolled only Caucasian patients and a short study duration. However, with 25 subjects per group, there was at least 90% power to detect a mean IOP change from baseline of 2.9 mmHg and 80% power to detect a difference of 2.5 mmHg between treatments. RESULTS: Patients on travoprost therapy showed lower mean IOP levels than those on latanoprost. This difference was statistically significant (p < 0.05) at 12, 16, 20, 24, 36, 40, and 48 h after the last dose for the supine position. The mean IOPs in the supine position throughout the first and the second 24-h period of the week 2 visit as well as for the 48-h visit were statistically lower (p < 0.05) for the travoprost group. Adverse events were mild and included hyperemia and corneal staining. Travoprost and latanoprost were both well tolerated. CONCLUSION: Mean IOP values were significantly lower for patients on travoprost for the majority of time points in the supine position.

Concomitant administration of travoprost and brinzolamide versus fixed latanoprost/timolol combined therapy: three-month comparison of efficacy and safety.

PURPOSE: To compare the efficacy and safety of the concomitant administration of travoprost 0.004% once daily and brinzolamide 0.1% twice daily with those of a fixed combination of latanoprost 0.005%/timolol 0.5% once daily. RESEARCH, DESIGN AND METHODS: Forty-four patients with primary open-angle glaucoma or ocular hypertension with elevated IOP insufficiently responsive to monotherapy were randomly assigned to one of the two treatment groups: concomitant administration of travoprost 0.004% once daily and brinzolamide 0.1% twice daily (TB group: 22 patients) or latanoprost 0.005% plus timolol 0.5% once daily (LT group: 22 patients). Visits were undertaken at screening (current ocular hypotensive therapy was discontinued), baseline (randomization), and after 2 weeks, 1 month, 2 months and 3 months of therapy. MAIN OUTCOME MEASURES: IOP was determined at 9 a.m., 12 p.m. and 4 p.m. at each study visit, and diurnal IOP was calculated as the mean of these recordings. Adverse events were recorded at each visit. RESULTS: IOP at the baseline visit was similar in both groups. Overall mean IOP was significantly lower in the TB as compared to the LT group after 1 month, 2 month and 3 month follow-up; only 9 a.m. measurements were significantly different, reaching a maximum difference (16.9 +/- 0.9 mmHg vs 18.4 +/- 1.8 mmHg, p < 0.001) at the 3 month check. The percentage of responders (IOP decrease > or = 30%) was higher in the TB group. Both treatments were well tolerated and there were no cases of withdrawal from treatment. CONCLUSIONS: Travoprost 0.004% and brinzolamide 0.1% concomitant therapy showed a greater efficacy than the fixed latanoprost 0.005%/timolol 0.5% combination in terms of absolute IOP decreases. Travoprost/brinzolamide therapy also offered the advantages of a greater percentage of responders.

[Development of an automatic discrimination system for glaucomatous visual fields based on neuro-fuzzy nets]. / Desarrollo de un sistema automático de discriminación del campo visual glaucomatoso basado en un clasificador neuro-fuzzy.

PURPOSE: To provide a useful tool in the diagnosis of glaucoma by developing an automatic system for visual field classification based on neuro-fuzzy rules. METHOD: A total of 212 visual fields (OCTOPUS 123 program G1X), from 198 patients, were analysed: 61 normal (controls) and 151 with glaucomatous damage (49% with incipient damage, 29.1% with moderate damage, and 21.9% advanced). Inclusion criteria for glaucomatous patients were: Visual acuity >0.5, IOP < 20 mm Hg (with treatment), refraction <5 Dp and previous perimetric experience. EXCLUSION CRITERIA: miotics, other ocular pathologies which could interfere with visual field examination, and for control subjects: visual acuity >0.5, no ocular pathologies and refraction < 5 Dp. A neuro-fuzzy classifier (NEFCLASS) is a system consisting in a series of fuzzy rules, obtained after a learning process, which attempts to assign to each piece of data input its corresponding output. Initially, the characteristics of each data input are established (input units). Then, based on previous knowledge, a set of rules are defined, and finally, the learning process allows the optimisation of the classifier parameters to generate an output. RESULTS: Input units were defined by using the mean defects calculated at specific areas of the visual field; five rules were then created which generated sensitivity and specificity values of 96.0% and 93.4% respectively. CONCLUSIONS: The use of neuro-fuzzy rules for visual field classification in normal vs glaucomatous can provide results which can match the quality of those obtained with other techniques such as discriminatory analysis or neural networks.

Desarrollo de un sistema automático de discriminación del campo visual glaucomatoso basado en un clasificador neuro-fuzzy / Development of an automatic discrimination system for glaucomatous visual fields based on neuro-fuzzy nets

Objetivo: Construir un sistema automático de clasificación del campo visual (CV), basado en reglas fuzzy, como herramienta de ayuda al diagnóstico de glaucoma. Método: Se analizaron 212 perimetrías blanco-blanco (OCTUPUS 123 programa G1X) correspondientes a 61 controles y 151 glaucomatosos (incipientes 49,0 por ciento, moderados 29,1 por ciento y avanzados 21,9 por ciento) de 198 pacientes. Criterios de inclusión (glaucomatosos): Agudeza visual >0,5, PIO 0,5 sin patología ocular salvo defectos de refracción (refracción (5D). Un clasificador neuro-fuzzy (NEFCLASS) es un sistema formado por un conjunto de reglas fuzzy, obtenidas a partir de un proceso de aprendizaje, que pretende asignar a una entrada dada la clase de salida correspondiente. Inicialmente, se seleccionan las características de entrada, seguidamente, se construye una base de reglas a partir del conocimiento a priori existente y, finalmente, la etapa de aprendizaje, permite optimizar los parámetros del clasificador. Resultados: Utilizando como características de entrada los defectos medios, calculados en áreas específicas del CV, se obtuvieron cinco reglas que arrojaron unos valores de sensibilidad y especificidad del 96,0 por ciento y 93,4 por ciento, respectivamente. Conclusiones: La aplicación de técnicas neuro-fuzzy en la discriminación de campos visuales normales y glaucomatosos ofrece resultados muy competitivos frente a técnicas ya utilizadas en esta tarea (análisis discriminante y redes neuronales) (AU)

Purpose: To provide a useful tool in the diagnosis of glaucoma by developing an automatic system for visual field classification based on neuro-fuzzy rules. Method: A total of 212 visual fields (OCTOPUS 123 program G1X), from 198 patients, were analysed: 61 normal (controls) and 151 with glaucomatous damage (49% with incipient damage, 29.1% with moderate damage, and 21.9% advanced). Inclusion criteria for glaucomatous patients were: Visual acuity >0.5, IOP < 20 mm Hg (with treatment), refraction <5 Dp and previous perimetric experience. Exclusion criteria: miotics, other ocular pathologies which could interfere with visual field examination, and for control subjects: visual acuity >0.5, no ocular pathologies and refraction < 5 Dp. A neuro-fuzzy classifier (NEFCLASS) is a system consisting in a series of fuzzy rules, obtained after a learning process, which attempts to assign to each piece of data input its corresponding output. Initially, the characteristics of each data input are established (input units). Then, based on previous knowledge, a set of rules are defined, and finally, the learning process allows the optimisation of the classifier parameters to generate an output. Results: Input units were defined by using the mean defects calculated at specific areas of the visual field; five rules were then created which generated sensitivity and specificity values of 96.0% and 93.4% respectively. Conclusions: The use of neuro-fuzzy rules for visual field classification in normal vs glaucomatous can provide results which can match the quality of those obtained with other techniques such as discriminatory analysis or neural networks (Arch Soc Esp Oftalmol 2002; 77: 669-676) (AU)

Primeros hallazgos con perimetría pulsar en pacientes hipertensos oculares / Initial findings with pulsar perimetry in patients with ocular hypertension

Objetivo: Evaluar los primeros resultados de la perimetría Pulsar en pacientes hipertensos oculares (HTO) y compararlos con la población normal. Método: Se estudiaron 34 ojos (edad media 57,29 D.E. 10,55) de pacientes hipertensos oculares y 41 ojos (edad media 48,34 D.E. 13,71) de pacientes normales con perimetría convencional blanco- blanco Octopus G1 normal. A todos se les realizó una exploración oftalmológica completa incluyendo perimetría PULSAR con estrategia TOP del Prof. González de la Rosa. Criterios de exclusión: AV 3 dp esféricas y 1,5 dp de astigmatismo, pupila < 3 mm, cirugía o patología ocular, diabetes o enfermedades neurológicas. Todos tenían experiencia perimétrica previa. Se utilizó la t de Student para el análisis de los resultados. Resultados: Con perimetría PULSAR la sensibilidad media (SM) en los pacientes normales fue de 21,25 src ('spatial resolution and contrast units') D.E. 2,70; el defecto medio (DM) de 0,93 src D.E. 1,80; y la varianza de pérdida (VP) de 6,11 src D.E. 4,30. En HTO la SM fue de 18,65 src D.E. 2,79; el DM de 2,73 src D.E. 2,30; y la VP de 8,46 src D.E. 5,01. Hay diferencias estadísticamente significativas con p<0,01 entre los dos grupos para la SM y el DM con un intervalo de confianza de (+0,92; +4,28) y de (-3,05; -0,54) respectivamente y con p<0,05 para la VP con un intervalo de confianza de (-4,49; -0,20). Conclusiones: La perimetría Pulsar parece tener una mayor sensibilidad para la detección precoz de daño en pacientes HTO que la perimetría convencional blanco-blanco (AU)