Actualización de la utilidad de la tomografía de coherencia óptica para el estudio del ángulo iridocorneal / Update on the usefulness of optical coherence tomography in assessing the iridocorneal angle

El ángulo iridocorneal por sus implicaciones en la fisiopatología del drenaje del humor acuoso es una estructura fundamental de la cámara anterior. La tomografía de coherencia óptica de segmento anterior es una técnica rápida y no invasiva que obtiene imágenes de los tejidos vivos con una alta resolución permitiendo conocer la anatomía normal del ángulo, sus alteraciones y los cambios que se producen en el mismo tras diferentes intervenciones terapéuticas. La tecnología de la tomografía de coherencia óptica de segmento anterior ha ido evolucionando hasta ofrecer imágenes que permiten identificar y cuantificar estructuras angulares claves en sujetos sanos y en pacientes con glaucoma, especialmente la malla trabecular y el canal de Schlemm, lo que puede contribuir a ampliar el conocimiento de la fisiopatología del glaucoma. Además, permite cuantificar la abertura angular con unos parámetros objetivos descritos en los últimos años, entre los que destacan el ángulo iridotrabecular, la distancia de abertura angular y el área iridotrabecular. La tomografía de coherencia óptica de segmento anterior presenta múltiples utilidades en el estudio de los distintos mecanismos del cierre angular, la evaluación de los cambios angulares tras la realización de una iridotomía láser o iridoplastia, cirugía de la catarata o el implante de lentes fáquicas

The iridocorneal angle, due to its implications in the physiopathology of aqueous humour drainage, is a fundamental structure of the anterior chamber. Anterior segment optical coherence tomography is a rapid and non-invasive technique that obtains images in vivo. The high resolution allows it to analyse the normal anatomy of the angle, any alterations, and the changes that occur after different therapeutic interventions. Anterior segment optical coherence tomography technology has evolved to provide images that allow the identification and quantification of the angular structures in healthy subjects and in glaucoma patients, and especially the trabecular meshwork and the Schlemm's canal. It also enables the angle width to be quantified, with some objective parameters that have been standardised in recent years, such as the trabecular-iris angle, the angle opening distance, and the trabecular-iris area. This technique has multiple uses in the study of the different mechanisms of angle closure, the evaluation of changes after a laser peripheral iridotomy or iridoplasty after cataract surgery, as well as after the implantation of phakic lenses

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.

Combined spatial, contrast, and temporal functions perimetry in mild glaucoma and ocular hypertension.

PURPOSE: To evaluate the diagnostic ability of a new perimetric procedure in glaucoma. METHODS: Pulsar perimeter shows white circular sinusoidal grating patterns with decreasing amplitude, 5 in diameter, 500 msec in duration in 66 locations. The stimuli scale combines spatial resolution and contrast. The stimuli were shown with centrifugal wave motion at 8 cyl/deg (K6W) or pulse at 30 Hz (T30W). Fifty-six normal eyes and 82 eyes with ocular hypertension and mild glaucoma were included. These 82 cases were classified into four levels of diagnostic certainty, from 0 (ocular hypertension) to 3 (mild glaucoma). RESULTS: Mean examination time was 3:49 min. Specificity was 96.4% (T30W) and 94.6% (K6W). Sensitivities for levels 0 and 3 were 34.5% to 100% (T30W) and 24.1% to 75% (K6W). The receiver operating characteristic (ROC) curve areas for T30W at levels 1, 2, and 3 were 0.88, 0.94, and 0.99. The ROC areas for K6W were 0.83, 0.91, and 0.97. There was good correlation between both Pulsar perimetries (r=0.88), but it was lower with conventional perimetry (r=0.58 for T30W and r=0.59 for K6W). CONCLUSIONS: The novel Pulsar T30W perimetry may be helpful for the study of mild glaucoma and ocular hypertension. (Eur J Ophthalmol 2004; 14: 514-22).