Influencia de la longitud axial ocular en el grosor de la capa de fibras nerviosas peripapilar medido con tomografía de coherencia óptica / Ocular axial length influence on peripapillary retinal nerve fiber layer thickness measurement with optical coherence tomography

Antecedentes La tomografía de coherencia óptica (OCT) permite la medición del grosor de la capa de fibras del nervio óptico (CFNR) peripapilar. El efecto de la longitud axial ocular (LA) sobre el grosor de la CFNR puede ser relevante en la interpretación de los resultados de OCT en el diagnóstico de enfermedades del nervio óptico. Objetivos Evaluar la influencia de la longitud axial ocular en el grosor de la CFNR y en los parámetros topográficos del disco óptico (área del disco óptico, área del anillo neurorretiniano y volumen de la excavación papilar) medidos por OCT en individuos sanos. Método Se estudió una muestra de 109 ojos sanos clasificados en 3 grupos según la LA (A: LA<22mm; B: LA 22-24,5mm; C: LA>24,5mm). La medición del grosor de la CFNR y de los parámetros topográficos del disco óptico se realizó mediante Swept-Source OCT Triton (Topcon Corporation, Tokio, Japón), y se compararon entre grupos mediante análisis de la varianza. La correlación entre la longitud axial y las variables de estudio se realizó mediante correlación de Pearson. Resultados El grosor de la CFNR fue menor en ojos con longitud axial más alta en el cuadrante superior (r=−0,41; p<0,001), inferior (r=−0,58; p<0,001) y nasal (r=−0,43; p<0,001), en el valor medio de la CFNR (r=−0,49; p<0,001), área del disco óptico (r=−0,40;p<0,001) y área del anillo neurorretiniano (r=−0,25; p=0,01). Conclusión La LA se correlaciona negativamente con el grosor de la CFNR y los parámetros topográficos del disco óptico medidos mediante Swept-Source OCT Triton (Topcon) (AU)

Background Optical coherence tomography (OCT) allows the measurement of the peripapillary optic nerve fiber layer (RNFL) thickness. The effect of ocular axial length (AL) on RNFL thickness measurement may be relevant in the interpretation of OCT results in diagnosing optic nerve diseases. Purposes To assess the influence of ocular AL on RNFL thickness and on optic disc topographic parameters (optic disc area, rim area and cup volume) measured by OCT, in healthy individuals. Method A sample of 109 healthy eyes classified into three groups according to AL (A: AL <22mm; B: AL 22–24.5mm; C: AL >24.5mm) was studied. RNFL thickness and optic disc topographic parameters were measured using Swept-Source OCT Triton (Topcon Corporation, Tokyo, Japan) and were compared between groups using a variance analysis. Correlation between the AL and the study variables was performed using a Pearson's correlation coefficient test. Results The RNFL thickness was lower in eyes with higher AL in the superior (r=−0.41; p<0.001), inferior (r=0.58; p<0.001) and nasal (r=−0.43; p<0.001) quadrants, in the mean value of the RNFL (r=−0.49; p<0.001), optic disc area (r=−0.40; p<0.001) and rim area (r=−0.25; p=0.01). Conclusion AL is negatively correlated with RNFL thickness and optic disc topographic parameters measured by Swept-Source OCT Triton (Topcon) (AU)

Ocular axial length influence on peripapillary retinal nerve fiber layer thickness measurement with optical coherence tomography.

BACKGROUND: Optical coherence tomography (OCT) allows the measurement of the peripapillary optic nerve fiber layer (RNFL) thickness. The effect of ocular axial length (AL) on RNFL thickness measurement may be relevant in the interpretation of OCT results in diagnosing optic nerve diseases. PURPOSE: To assess the influence of ocular AL on RNFL thickness and on optic disc topographic parameters (optic disc area, rim area and cup volume) measured by OCT, in healthy individuals. METHODS: A sample of 109 healthy eyes classified into 3 groups according to AL (A: AL<22mm; B: AL 22-24.5mm; C: AL>24.5mm) was studied. RNFL thickness and optic disc topographic parameters were measured using Swept-Source OCT Triton (Topcon) and were compared between groups using a variance analysis. Correlation between the AL and the study variables was performed using a Pearson's correlation coefficient test. RESULTS: The RNFL thickness was lower in eyes with higher AL in the superior (r=-0.41; p<0.001), inferior (r=0.58; p<0.001) and nasal (r=-0.43; p<0.001) quadrants, in the mean value of the RNFL (r=-0.49; p<0.001), optic disc area (r=-0.40; p<0.001) and rim area (r=-0.25; p=0.01). CONCLUSIONS: AL is negatively correlated with RNFL thickness and optic disc topographic parameters measured by Swept-Source OCT Triton (Topcon).

Could a patient with SMC1A duplication be classified as a human cohesinopathy?

The disorders caused by mutations in genes encoding subunits and accessory proteins of cohesin complex are collectively termed as cohesinopathies. The best known cohesinopathy is Cornelia de Lange Syndrome (CdLS), which is a multisystem developmental disorder characterized by facial dysmorphism, limb malformations, growth and cognitive impairment. Mutations in five genes, encoding subunits of the cohesin complex (SMC1A, SMC3, RAD21) and its regulators (NIPBL, HDAC8), are responsible for ∼ 70% of CdLS cases. We describe a 16-year-old boy with facial dysmorphism, growth retardation, intellectual disability, hirsutism and small hands, who has a small Supernumerary Marker Chromosome (sSMC) present in mosaic form. sSMC is composed of two duplicated segments encompassing 17 genes including SMC1A gene, at the regions Xp11.22 and Xp11.21q11.1. Clinical comparison between our patient with a previously reported individual with a SMC1A duplication and four male carriers of similar sSMC reported in databases, suggest that they all share clinical features related to cohesinopathies. Although our patient does not have the classical CdLS craniofacial phenotype, he has pre and postnatal growth retardation, intellectual disability and mild musculoskeletal anomalies, features commonly seen in patients with cohesinopathies.

Inhibition of the two-photon absorption response exhibited by a bilayer TiO2 film with embedded Au nanoparticles.

We use two different synthesis approaches for the preparation of TiO(2) films in order to study their resulting third order optical nonlinearity, and its modification by the inclusion of Au nanoparticles in one of the samples. An ultrasonic spray pyrolysis method was used for preparing a TiO(2) film in which we found two-photon absorption as a dominant nonlinear effect for 532 nm and 26 ps pulses; and a purely electronic nonlinearity at 830 nm for 80 fs pulses. A strong optical Kerr effect and the inhibition of the nonlinear optical absorption in 532 nm can be obtained for the first sample if Au nanoparticles embedded in a second TiO(2) film prepared by a sol-gel technique are added to it. We used an optical Kerr gate, z-scan, a multi-wave mixing experiment and an input-output transmittance experiment for measuring the optical nonlinearities.