Age-related macular degeneration: choroidal ischaemia?

Aim: Our aim is to use ultrasound to non-invasively detect differences in choroidal microarchitecture possibly related to ischaemia among normal eyes and those with wet and dry age-related macular degeneration (AMD).

Design: Prospective case series of subjects with dry AMD, wet AMD and age-matched controls.

Methods: Digitised 20 MHz B-scan radiofrequency ultrasound data of the region of the macula were segmented to extract the signal from the retina and choroid.

Correlation of anterior chamber angle and ciliary sulcus diameters with white-to-white corneal diameter in high myopes using artemis VHF digital ultrasound.

Purpose: To determine whether horizontal angle diameter and sulcus diameter can be accurately estimated by conventional external measurements in high myopic eyes.

Methods: Ten horizontal anterior segment scans were obtained with the Artemis 1 very high-frequency (VHF) digital ultrasound arc-scanner in 40 eyes of 20 patients. Angle and sulcus diameters were measured and descriptive statistics and within-eye repeatability were calculated.

Explaining The Current Role Of High Frequency Ultrasound In Ophthalmic Diagnosis (Ophthalmic Ultrasound).

Ultrasound has become as indispensable as indirect ophthalmoscopy or slit lamp in evaluation of the eye. It is an important adjuvant for the clinical assessment of a variety of ocular and orbital diseases. Advances in instrumentation, higher frequencies and more sensitivity and resolution have resulted in continuous improvement in image quality.

Very high frequency ultrasound biometry of the anterior and posterior chamber diameter.

Purpose: To measure the largest diameter of the anterior chamber (AC) and posterior chamber (PC) dimension and its orientation and determine the relationship with the principal keratometric meridians.

Methods: Twenty-eight eyes of 14 subjects were scanned with high frequency (50 MHz) ultrasound in sequential meridional scan planes at 30 degrees increments. Observer identified angle and ciliary sulcus recess boundaries in each patient scan set were fit with an elliptical model to obtain the ellipse semi-major axis corresponding to the largest diameter and its meridional orientation.

High-resolution ultrasonic imaging of the posterior segment.

Purpose: Conventional ophthalmic ultrasonography is performed using 10-megahertz (MHz) transducers. Our aim was to explore the use of higher frequency ultrasound to provide improved resolution of the posterior pole.

Design: Prospective case series.

Noninvasive in vivo detection of prognostic indicators for high-risk uveal melanoma: ultrasound parameter imaging.

Purpose: Primary malignant melanoma of the choroid and ciliary body has traditionally been treated without histologic staging, using purely clinical indicators. The presence of extravascular matrix patterns (EMP) in histologic sections of uveal melanoma has been shown to be an independent indicator of metastatic risk. These patterns are of a dimension and physical composition that are likely to be detected with ultrasound backscatter analysis.

Ultrasound measurement of the effect of temperature on microperfusion in the eye.

Recent developments in ultrasound (US) technology have allowed the study of microperfusion in the anterior segment of the eye. Our aim was to determine the effect of the thermal environment on blood flow in the anterior segment. We measured blood flow in the major arterial circle of five rabbits.