Low Vision Literature Review The impact of low vision on a person's quality of life can be devastating… people with low vision can improve their quality of life through rehabilitation services to teach them how to use their remaining vision more effectively. Using a variety of visual aids may bring them back or help them keep their independence (Kupfer, 1999 as cited in Windsor & Windsor, 2001).

Low vision or vision loss has been operationally defined most commonly as that associated with macular degeneration due to age that accounts for more than half of all reported cases of visual impairment. There are other known causes of vision loss that include but may not be limited to corneal degeneration, eye injuries, traumatic brain injury, brain tumors, stroke, toxoplasmosis, optic atrophy, glaucoma, retinal dystrophies, retinal detachment, retinopathy of prematurity, achormatopsia and histoplasmosis (Windsor & Windsor, 2001). Moreover, visual impairment is described as having the ability to significantly impact every facet of a persons' life including the ability to work, recreationally as well as educationally. Additionally, all age brackets suffer in different aspects of their lives because of the impairment of low vision which can significantly impact independence for the elderly, career choices for adults, and potential educational and developmental delays for children.

Literature review

Windsor and Windsor in their 2001 article, "Low Vision Rehabilitation: An Introduction" posit the importance of utilizing all available and qualifying resources to aid those who are suffering with this condition. According to the most recent statistics quoted by the authors, there are approximately 135 million individuals worldwide who suffer with low vision and more than 14 million reside in the United States of America. In essence, one out of every 20 individuals is considered to be visually impaired, with approximately 120,000 who have light perception only or are completely blind (American Optometric Association, 1997). As such, the authors posit that given the aforementioned numbers, there are many individuals who have a great deal of residual vision and are therefore in the position to benefit from what has been termed low vision rehabilitation (Windsor & Windsor, 2001).

Low vision rehabilitation for those who are visually impaired can involve any number of rehabilitative tools and techniques as well as a host of treatment modalities to include optical devices, prescription eye glasses, adaptive computer software, electronic aids, modification of the individual's environment, glare control, counseling as well as education of not only the patient but their family members as well regarding independent living aids, skills building and training, mobility training, driver rehabilitation, mental health intervention and occupational therapy (Windsor & Windsor, 2001). Subsequent to a careful examination by an ophthalmologist or optometrist that has proven skills in low vision rehabilitation, low vision rehabilitation can take place. Part of the examination is determining what the underlying causes of the symptomology are related to whether injury or disease (Windsor & Windsor, 2001). According to the authors, each disease or injury has specific functional characteristics and need to be understood within that contextual frame of reference. Conversely, those individuals with central retinal disorders that may manifest as histoplasmosis maculopathy, age related macular degeneration or Stargardt's may present to the specialist with central vision loss and photophobia but still maintain peripheral vision. Mobility of the patient may be substantial in that they are able to ambulate but have difficulty with facial recognition. The functional and physical limitations associated with low vision are then needed to be determined by an ophthalmologist or optometrist (Windsor & Windsor, 2001).

Patient's visual acuity and refractive status can be more accurately measured with low vision refractive techniques (Windsor & Windsor, 2001). This kind of examination or testing purportedly employs control of illumination, larger testing charts, techniques that facilitate eccentric viewing and the use of trial frame refraction. These special techniques used for testing may not be the same in the patients home as when conducted by a special...

For those patients that are non-verbal, special tools and techniques have been developed to ensure examinations can be performed in the most accurate way possible (Scott, et al., 1999; Windsor & Windsor, 2001).
Understanding the individuals functioning vision level is most often secured through the use of a grid referred to as Amsler, laser scanning opthalmoscope, contrast sensitivity electroretinogram and visual evoked potential. With contrast sensitivity examinations, the eye's ability to discern subtleties vs. issues black and white visual acuity are measured (van Rens, Chmielowski & Lemmens, 1991). The Behavioral Inattention Test, according to experts, is an assistive screening tool for those individuals who suffer with right brain injury and have unilateral or hemified neglect and may then experience mimic hemianoptic field loss. Another significant portion of the low vision examination is also the dilated internal examination wherein the intraocular pressures as well as the health of the external eye are examined (Windsor & Windsor, 2001).

At present, there are many low vision systems that are used as a part of the low vision rehabilitation process. For example, magnification through magnifiers, strong bifocals, and telescopes are frequently used to aid those suffering with low vision. New techniques such as the auto focus and closed circuit television are all new technologies designed to assist those with low vision (Windsor & Windsor, 2001). There are also tools readily available as part of low vision rehabilitation that address the issue of glare and light control. Most often, some form of filtering system is institute to reduce shorter wavelength light transmission. Windsor ad Windsor maintain the importance of taking into consideration issues with glare and light both internally and externally with the use of visors and hats aiding in the reduction of these two issues when light and glare are an issue out of doors.

With the advent of computer technology and with the increased use of computers in many individuals' daily lives, a new set of challenges has been established for individuals who suffer with low vision. As such, new adaptive technologies are being developed that include large letter keyboards, larger monitors, software for screen enlargement, voice activated systems, dedicated computer eyewear as well as new telescopic systems (Windsor & Windsor, 2001). However, authors do warn that in order for these systems to be most effective, they must be integrated in a comprehensive way to garner the greatest level of benefit.

Conclusion

Low vision or vision loss has been operationally defined most commonly as that associated with macular degeneration due to age that accounts for more than half of all reported cases of visual impairment. Visual impairment is described as having the ability to significantly impact every facet of a persons' life including the ability to work, recreationally as well as educationally. Additionally, all age brackets suffer in different aspects of their lives because of the impairment of low vision which can significantly impact independence for the elderly, career choices for adults and potential educational and developmental delays for children.

Low vision rehabilitation for those who are visually impaired can involve any number of rehabilitative tools and techniques as well as a host of treatment modalities to include optical devices, prescription eye glasses, adaptive computer software, electronic aids, modification of the individual's environment, glare control, counseling as well as education of not only the patient but their family members as well regarding independent living aids, skills building and training, mobility training, driver rehabilitation, mental health intervention and occupational therapy (Windsor & Windsor, 2001). The low vision rehabilitation plan includes the individual patients' history, a physical examination, a test of their current level of vision and functionality and a determination as to which low vision aids may be the most effective and in combination garner the greatest benefit for the client.

According to Massof with the Wilmer Eye Institute, reduction in the level of difficulty with regard to the performance of specific goals or objectives as well as the reduction in the…