August 2, 2012 | POSTED BY | Articles, Clinical Optometry
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Imagine if you lost the ability to see; how would you be able to tell the time when you can’t even see the clock? How would you read the newspaper, navigate through your phone, or read your e-mail? How would you cook dinner, when you cannot see the dials on the stove, follow the instructions to the recipe, or accurately measure your ingredients? The effects of losing sight can completely turn your world upside down. Some people face this problem on a daily basis, and this loss of their acuity can completely disable a person of his or her functions, independence, and well-being.

We can carry out a major awareness of the problems faced by this type visual of anomaly. The field of low vision in the clinical setting can greatly benefit the needs of people who have experienced this loss of acuity, and loss of function of their sight. With the hard work of the optometrist, opthalmologist, occupational therapists, and eye care professionals, those who have had some visual loss can take full advantage of their remaining ability to see.  With the use of magnifiers, telescopes, and low vision technology, one can regain this independence once lost with the inability to see. With a change in lifestyle, there will be a significant amount of time for a person to learn and understand how to use tools, their condition and to utilize it as much as they can to remain independent and secure with their low vision.  

Low vision, or visual impairment, is defined as functional limitation of the eye or visual system and can manifest as reduced visual acuity or contrast sensitivity, visual field loss, photophobia, diplopia, visual distortion, visual perceptual difficulties, or any combination of the above. The loss of central vision, but still being able to see in the periphery of their field of vision can be a visual impairment caused from macular degeneration, which can easily affect their daily life. This is a loss of visual perception, but not all of the vision is at loss. Low vision specialists come into the picture as they learn to take this information about the patients visual boundaries, and allow for the patient to easily learn to use what vision they have left.

The evaluation of the low vision patient is a very detailed procedure. The goal of low vision is to evaluate the functional status of the eye and the visual system, to assess ocular health and related systemic health conditions and the impact of disease or abnormal conditions on visual function, to educate patients regarding their visual impairment and ocular and related systemic health status, management, and future care. The optometrist makes an assessment of the visual boundaries with the use of refraction, visual field testing, the patient’s ocular health, and the management of the progression of the disease. Also non-conventional tests such as contrast sensitivity tests, glare testing, and electrodiagnostic tests are ways to assess the processes of a patient’s eyes. All of these different tests are taken by the optometrist, and evaluated to accurately approach the patient’s visual needs.

To understand all of these requirements and to be fully aware of the function of low vision, optometrists must take full advantage of the functional requirements a patient needs. Each patient will face a different impairment to his or her vision. That is why it is important to understand the different types of low vision systems, tools, and equipment and to understand the adjustment to living with these types of visual anomalies. The patients will not be disabled by these conditions, but yet limited to what they can visually perceive. Daily activities, such as reading the newspaper, navigating through a room, or driving can be remediated with low vision devices. Education, time, and rehabilitation will ultimately determine the success of the patient.

The usual solution to low vision would be to prescribe low vision glasses. This has changed with the course of invention and understanding of low vision rehabilitation and the need for many other factors to evaluate the patient’s needs. These glasses are made from the strongest type of Rx prescribed by an optometrist (usually the result of a subjective refraction), reaching from -20.00 to +20.00 diopters. Some variety of these glasses can change depending on the need for more magnification or a larger field of view. The use of hand magnifiers to enlarge print into a viewing medium, such as a viewing window, will allow the patient to see the newspaper and enlarge print such as email, letters, and books. 

A Closed Circuit Television (CCTV) is a form of electronic video magnification. This form of magnification has radically changed low vision rehabilitation by maximizing what a visually impaired patient can do. By the use of a camera mounted above the viewed material, a television monitor projects the image and enlarges the image of the print. This is the easiest low vision aid for patients who need 3 x magnification. It is a very useful tool, because it builds confidence with patients who have suffered once before with low vision aids. The magnifier itself can enlarge the image 75x magnification. This tool has been perfect for working distance tasks, such as working on papers, cutting nails, and reading the cookbook. The use of this tool is universal when it comes to magnification settings and to adjust all of the paitent’s low vision needs. 

One way a person with low vision can see at a distance is to mount a telescope on a pair of suitable eyewear. This involves taking a pair of eyeglasses and mounting a device onto the frame, taking advantage of any vision that the person has to see at a distance and giving the ability to magnify the field of view. One of the most well-known of these types of devices is the bioptic system, which in turn has allowed those who have had low vision to actually drive. These devices have been pioneered and made legal for persons deemed unable to drive, to once again sit behind a steering wheel. This feat could not have been possible without the development of the bioptic system by Dr. William Feinbloom, the father of low vision care in the United States. 

Dr. Feinbloom established the first the first low vision rehabilitation center. After having a rich background in the field of optometry while being in his father’s clinic, he became an OD and started a clinic in Bufalo, NY. One day he had a low vision patient, and was frustrated that he could not help this patient see. He then started developing a telescope, designed like a telescope similar to what astronomers used to view the stars. This telescope was small enough that he was able to mount the device onto a pair of frames and have 3 x magnification. After helping a total of 500 patients with low vision, and reporting on his findings, he became the leading expert of the field, getting a degree in physiological optics, and began developing many more low vision aids.  

This use of the bioptic system has allowed many to get behind the wheel of a car. For those who were told they could not drive with their current eye condition, this gave many people a phenomenal opportunity to once again regain control of their lives by being able to drive. The first person to get fully licensed to drive with the use of bioptic system is Dennis Kelleher, a patient who was struck by albinism, that resulted in some visual loss. Kelleher was a leading advocate, demonstrating that a person who has been struck with low vision can actually drive. 

The field of low vision is still expanding in its use in the real world, because each patient will be faced with several different types of visual loss. But it is the understanding of a persons’ visual need, restrictions to their vision, and the way they interact with the world are all factors that will determine the success of the person with low vision.