How Does Sightline Work?

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SIGHTLINE is designed to achieve three objectives:

1. Enable the Patient to Learn to See Better by Using a Different Location on the Eye
2. Adapt the Patient's Home Environment to Increase Productivity, Safety & Independence
3. Teach the Patient proper ergonomics with regard to lighting, magnification, glare and ALD techniques

The first objective involves a wonderful technique called Eccentric Viewing.

The human visual system works in the following way:

• When a beam of light reflects off an object, if the eye is pointed toward that object, the beam enters the eye, where it passes to the back to an area called the Macula.
• At the center of the macula is a second, smaller area called the Fovea. The greatest concentration of photoreceptor cells is located on the fovea. It is this area where detail or central vision occurs. The fovea converts light into electromagnetic impulses and transmits them, via the optic nerve, to the brain, which forms an image of the object.
• We call this process - seeing or sight.

In the normal process of creating sight, a waste product called drusen is generated. The healthy macula simply disposes of the drusen and no consequences are felt. However, when macular degeneration strikes, this waste removal process is compromised. The drusen accumulates, infects other cells and causes scarring called scotomas. As these scotomas increase, they progressively interfere with the ability of the fovea to receive light and transmit impulses to the brain where images can be formed. The result is the progressive loss of central vision and the ability to differentiate color, contrast, size and shape.

The bad news is, of course, that this happens in the first place. The worse news is that there are no medical or surgical remedies to stop or reverse this process. Injectible drugs are being used in some cases to control the seepage associated with "wet" AMD, so that helps. But, otherwise there are no options for curing the degeneration of central vision at this time.

There is, however, some really good news.

Most individuals, who reach the point where the fovea is no longer usable for fixation, typically have other islands of healthy tissue on the retina, which be developed for use as a kind of "substitute macula". Even though there is usually more than one healthy island, typically, one is more sensitive than the others. This location is called the preferred retinal locus. The human visual system is already aware of the PRL, but it's not accustomed to using it and, consequently, unable to use it in a stable and sustainable manner.

This is where eccentric viewing comes in.

Eccentric Viewing is a series of techniques whereby the patient learns to use the preferred retinal locus in place of the damaged macula to perform the functions of central vision. With proper education, training and practice, the majority of those, who suffer from moderate to profound macular impairment can use eccentric viewing to achieve dramatic increases in visual abilities. It is not uncommon for those patients, who master EV, to increase visual functionality by 30-60% in just 8 weeks.

The SIGHTLINE program has a second, equally important component, which is just as critical as eccentric viewing. We call it "home ergonomics". Ergonomics refers to the adaptation of one's environment to the functions they are trying to perform. This concept is vitally important to those who are coping with low vision. The importance of proper lighting, glare reduction, use of magnification, reading & writing stations and countless other ADL techniques cannot be underestimated. In 90% of the homes where we treat SIGHTLINE patients, we find inadequate lighting, excessive glare, failure to use critical assistive devices like CCTVs and telemicroscopes and poorly set up reading & writing locations - each of which compromises reading effectiveness and ADL functionality by up to 80%.

Thus, the second stage of each SIGHTLINE intervention is to reengineer the home environment to make sure that basic activities, like reading, writing, meal preparation, grooming and walking safely can be performed as efficiently and safely as possible. We call this the Home Ergonomics Phase.

Under SIGHTLINE, the effective integration of eccentric viewing training with home ergonomics is enabling low vision patients to make huge improvements in the quality of their life. They are reading faster and more accurately, they are back performing functions like grooming, light housekeeping, meal preparation and others, which they haven't been able to do for years. They are playing cards, reading prayer books & seeing faces. They feel safer, more productive and more independent.

Is their vision back to normal? No, sadly it is not, but the range of activities they can now enjoy has been broadened tremendously.