A glaucoma is a process where the cellsof the optic nerve undergo damage. Due to the sustained damage, thesecells die or start dying. Due to the fact that there are countless ofthese cells present in the optic nerve, only when about 40% of themall are destroyed do we notice first signs of glaucoma, being thevisual field loss.
Once problems of this type startaffecting our vision, we commonly undergo visual field testing forglaucoma, when our doctor directs us to the ophthalmologist. Thefollowing lines will describe this process of testing and provide youwith more information on the subject of this vision problem.
Visual Test for Glaucoma
The process of visual testing forglaucoma encompasses a series of tests which are directed towardsmeasuring all aspects of our eyesight, including side, peripheral andgeneral vision. The testing requires us to sit in front of abowl-shaped device, looking into it, staring at its center.
While you we concentrate on performingthis vision activity, lights flash inside the device and we aresupposed to press a button given to us each time we notice this formof flashing.
Once the testing is done, we receivethe results which inform us about our visual field health, showing usinformation about the times when we did or did not notice theflashing due to visual problems such as glaucoma. If the resultsindicate that our peripheral vision has decreased significantly, themost common suspect behind this state of affairs is glaucoma andfurther tests are done to complete the diagnosis and start thetreatment.
Therefore, visual tests for glaucomaare capable of noticing this condition in its early stages, evenbefore we start noticing our vision loss. Thereby, this form oftesting prevents further decrease of our vision, promoting timelytreatment and recovery.
The whole testing procedure does nottake longer than 45 minutes and does not result in pain. Therefore,all people are advised to do it at some point of their lives, rulingout this condition and preventing further vision loss if it getsdiagnosed early.
Finally, this form of testing is notideal, since it is not 100% accurate, nor is it easy to administerand easy to take. However, it is the most reliable and the fastestpossible form of testing for glaucoma we have come up with yet.
How is Visual Field Testing Done?
Due to the fact that many eye and brainproblems manifest through a decrease in peripheral vision and visionin general, health experts conduct visual field testing in order tonotice these forms of disorder early in their patients, managing totreat them before vision has been irreparably damaged. Namely, apartfrom glaucomas, loss of periphery vision can be caused by braintumors or strokes.
There are several types of visual fieldtests and all of them are carried out in through different routines.Automated perimetry, for example, involves one's responses to objectspresent in different areas of the vision field being tested. Here,the patient needs to keep his/her head absolutely still, resting iton a chin rest, pressing the designated button once he/she noticesthe computer-generated light inside the bowl-like device into whichhe/she is looking.
Alternatively, the patient can undergofrequency doubling perimetry, based on an optical illusion createdthrough the exposure of one's vision to bars which are made out ofcontrasting colors, like black and white per pair, appearing on ascreen that he/she is supposed to watch. Here, if the patient cannotsee the bars, his/her optic nerve is thought to be damaged, resultingin the loss of vision in the retina, due to some disorders affectingthe photosensitive cells in this area.
Finally, electroretinography is a formof visual field testing which is carried out by stimulating theretina of the patient with special strobes of light. The light canalso be emitted in the form of checkerboard. During the testing, theelectrodes that are a part of this device, capture the performance ofthe cornea, creating a graphical record of the entire process. Thisform of testing is most commonly used on individuals who suffer fromretinal damage caused by conditions such as diabetes oratherosclerosis.
All in all, the type of visual fieldtesting conducted on a patient depends on his/her symptoms, medicalhistory and many other factors. Either way, all of these tests arevery important and valuable diagnostic tools, preventing vision lossin thousands of people annually.
Glaucoma is a type of vision problems,taking place due to the cellular damage of the optic nerve, appearingbecause of the exposure of these cells to the pressure inside thisvision organ of ours. Taking into consideration that glaucoma, whennot treated timely, can lead to serious vision impairment, you areadvised to undergo visual field testing, noticing any problems ofthis type before too late.