How does scanning laser polarimetry work?
It projects a polarized beam of a light into the eye. As this light passes through the NFL tissue, it changes and slow. The detectors measure the change and convert it into thickness units that are graphically displayed.
What is corneal compensation?
Purpose: : Variable corneal compensation (VCC) is a method for removing the anterior segment birefringence component from the scanning laser polarimetry (SLP) signal in order to isolate the retinal nerve fiber layer component, improving the accuracy of the technique for diagnosing glaucoma.
What is GDx test for glaucoma?
The GDx (short for Glaucoma Diagnosis) is a type of scanning laser polarimeter. The GDx uses a diode laser in the near infrared region to measure nerve fiber layer thickness and 65,536 retinal points. The polarized light passes through the retinal nerve fiber layer.
What is GDx VCC?
The Zeiss Glaucoma Detection with Variable Corneal Compensation (or GDx VCC) is a diagnostic instrument that performs a non-obtrusive retinal scan to measure the thickness of the retinal nerve fiber layer without dilation.
What is confocal scanning laser ophthalmoscopy?
Confocal scanning laser ophthalmoscopy is a non–invasive investigation that has been used initially to receive three–dimensional images of the retinal surface in vivo. The commercial name of the device is Heidelberg Retina Tomograph (HRT).
What are OCT images?
Optical coherence tomography (OCT) is a non-invasive imaging test. OCT uses light waves to take cross-section pictures of your retina. With OCT, your ophthalmologist can see each of the retina’s distinctive layers. This allows your ophthalmologist to map and measure their thickness.
What is corneal compensated IOP?
The Corneal-compensated IOP (IOPcc) is a pressure measurement that uses the CH to determine an IOP value that is less affected by corneal properties, such as CCT. Corneal Resistance Factor (CRF) is calculated using a proprietary algorithm and is an indicator of the overall cornea resistance [3].
What is normal endothelial cell count?
Estimation of Corneal Endothelial Reserve Estimation of the endothelial reserve is made by compar- ing a cornea’s endothelial cell count to the normal range of 1500 to 3500 cells/mm2 (age, 40-90).
What is HRT in glaucoma?
Heidelberg Retinal Tomography is a diagnostic procedure used for precise observation and documentation of the optic nerve head, essential for the diagnosis and management of glaucoma. The HRT uses a special laser to take 3-dimensional photographs of the optic nerve and surrounding retina.
What is HRT in ophthalmology?
The Heidelberg Retina Tomograph (HRT) is a non-invasive confocal scanning laser microscope that is used to obtain a three-dimensional, computerized scan (like a CAT scan) of your optic nerve head and retina in the posterior segment.
How does scanning laser ophthalmoscopy work?
Confocal scanning laser ophthalmoscopy (SLO) [84] scans the retina with a point of light moving in a raster pattern and detects the reflected light in a confocal process that allows the reconstruction of a three-dimensional image of the retina.
How does a scanning laser ophthalmoscope work?
SLO utilizes horizontal and vertical scanning mirrors to scan a specific region of the retina and create raster images viewable on a television monitor. While it is able to image the retina in real time, it has issues with reflections from eye astigmatism and the cornea.