What is nerve fiber analyzer?
The Nerve Fiber Analyzer (NFA; Laser Diagnostic Technologies, San Diego, CA) is a scanning laser polarimeter that was developed to measure the thickness of the human retinal nerve fiber layer (NFL) in vivo.
What is GDx and where it is use in glaucoma?
The GDx maps the nerve fibers and compares them to a database of healthy, glaucoma-free patients. A thinning of the fibers indicates glaucoma. This information is then made available to your healthcare provider in the form of pictures, graphs and statistical data that indicate the probability of glaucoma.
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.
How is optic nerve damage measured?
MEASUREMENT OF DISC SIZE The average vertical diameter of the optic disc around 1.8 mm; a disc that is measured to be less than 1.5 mm is likely a small disc while one greater than 2.2 mm can be considered abnormally large. A correction factor must be used depending on the indirect lens that is used.
What is a good RNFL thickness?
RNFL Thickness Values, TSNIT Profile The mean value for RNFL thickness in the general population is 92.9 +/- 9.4 microns. Typically, a normal, nonglaucomatous eye has an RNFL thickness of 80 microns or greater. An eye with an average RNFL thickness of 70 to 79 is suspicious for glaucoma.
What is nerve fiber in the eye?
In the mature eye, the optic nerve fiber layer of the retina consists of the axonal processes of ganglion cells that are directed toward the optic papilla and emerge from the eye as the optic nerve.
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 normal RNFL thickness on OCT?
Average RNFL thickness indicates a patient’s overall RNFL health. The mean value for RNFL thickness in the general population is 92.9 +/- 9.4 microns. Typically, a normal, nonglaucomatous eye has an RNFL thickness of 80 microns or greater.
What is the normal RNFL thickness?
What is normal RNFL symmetry?
Mean RNFL thickness between the 2 eyes of normal individuals should not differ by more than approximately 9 to 12 μm, depending on which scanning algorithm of OCT3 is used and which eye measures thicker.
What is RNFL in ophthalmology?
Glaucoma is generally described as a loss of retinal ganglion cell axons. This loss is routinely diagnosed by the presence of thinning of the optic nerve neuroretinal rim, peripapillary retinal nerve fiber layer (RNFL), and/or inner layers of the macula.
Which of the following laser is used in detecting the retina?
Scanning laser ophthalmoscopy (SLO) is a method of examination of the eye. It uses the technique of confocal laser scanning microscopy for diagnostic imaging of the retina or cornea of the human eye.
What is the GDX test used to diagnose?
View All. The GDx is a test that has proved its usefulness in the diagnosis and management of glaucoma. The GDx uses laser to determine the thickness of the nerve fiber layer. Older glaucoma tests have centered around measuring eye pressure or measuring the effect that glaucoma has on your overall visual field.
How does the GDX work?
The GDx uses a laser to determine the thickness of the nerve fiber layer in the back of the eye. Older glaucoma tests have centered around measuring eye pressure or measuring the effect that glaucoma has on your overall visual field.
How does The GDx measure the optic nerve?
The optic nerve is responsible for carrying images to the brain. Glaucoma is known as the “sneak thief of sight,” because many people are not aware they have a problem until significant vision has been lost. The GDx uses a type of scanning laser polarimeter to measure the thickness of the nerve fiber layer.