Using a modern direct ophthalmoscope gives a view of the optic disc using the principle of reversibility of light. Inspection of the optic disc by ophthalmoscopy or biomicroscopy can give an indication of the health of the optic nerve. In particular, the eye care physician notes the colour, cupping size as a cup-to-disc ratio , sharpness of edge, swelling, hemorrhages, notching in the optic disc and any other unusual anomalies.
It is useful for finding evidence corroborating the diagnosis of glaucoma and other optic neuropathies, optic neuritis , anterior ischemic optic neuropathy or papilledema i.
Women in advanced stage of pregnancy with pre-eclampsia should be screened by an ophthalmoscopic examination of the optic disc for early evidence of rise in intracranial pressure. Traditional colour-film camera images are the gold standard in imaging, requiring an expert ophthalmic photographer, ophthalmic technician, optometrist or an ophthalmologist for taking standardised pictures of the optic disc.
Stereoscopic images offer an excellent investigative tool for serial follow-up of suspected changes in the hands of an expert optometrist or ophthalmologist. However, since not everybody can be trained so well, automated techniques have been devised to supplant or replace the human expertise.
They quantitate the nerve fiber layer of disc and surrounding retina and statistically correlate the findings with a database of previously screened population of normals.
List of Partners vendors. The human eye is pretty good at accurately detecting an enormous array of information about the world around us, but it does have its limitations. One example of this is a blind spot or a small portion of the visual field that corresponds to the location of the optic disk located at the back of the eye. The blind spot is the location on the retina known as the optic disk where the optic nerve fiber exit the back of the eye.
The optic disk is approximately 1. In addition to being the point where the optic nerve exits the eye, it is also where the major blood vessels enter to provide blood flow to the eye. Because there are no cones or rods at this point on the retina, there is a very small gap in the visual field. You literally have a very tiny gap in your vision where you are essentially blind.
While there are ways to force yourself to notice this blind spot, we typically do not notice this visual gap in our day to day lives. Researchers have proposed a number of different explanations as to why we do not notice this blind spot. Some suggest that the opposite eye compensates for the missing visual information. One of the most commonly accepted theories is that the brain actually fills in the missing information using visual cues in the environment.
Even if you close one eye, the blind spot is almost impossible to detect. This is because your brain is so adept at providing the missing visual information so that you never notice that small gap in your visual field. Surprisingly, researchers have found that you might actually be able to shrink your blind spot by using certain eye training exercises. In a small study involving just 10 participants, researchers found that using specific eye exercises could shrink the blind spot by as much as 10 percent.
The exercises used in the study involved placing an image of a small ring directly in a person's blind spot and displaying waves of light and dark bands moving through the ring. The participants were asked to determine which way the bands were moving as well as the color of the ring.
The size of the ring was manipulated so that at the beginning of the study, it was detectable about 70 percent of the time, then the researchers modified the size so that it was eventually so small it was completely hidden by the blind spot. Over time, the participants were better able to detect the smaller image in their blind spot as well as judge the color of the ring and direction of the moving bands.
This reduction in the size of the blind spot represents a very small improvement in vision. The research suggests that this improvement would be so small that people would not even notice it, partly because most people don't even notice their blind spot anyways.
As you have learned, the blind spot is an area on your retina that has no visual receptors. Because of this, there is a tiny gap in your visual field. The optic disk is the part of the retina where the optic nerve leaves the eye and heads to the brain. In the optic disk, there are no receptor cells. Axons of the retinal ganglion cells gather at the optic disk and form the optic nerve, which carries the neural signal into the brain.
Because there are no receptors at the site of the optic disk, this location is also called the blind spot. Because the blind spot on the left eye does not correspond to the same region in space as the blind spot on the right eye, humans really do not have a blind spot in their visual field. Even when viewing the world with only one eye, we are not aware of our blind spot. In this demonstration, you can find your own optic disk and experience this filling in.
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