How is the PhotoScreener™ used to detect vision disorders?

Using the PhotoScreener™ is a very simple process. The child, seated in a chair, is asked to look directly into the camera lens, and a small light is flashed to attract his or her attention. The camera can play a nursery rhyme to get a child's attention. After the first photograph is taken, the camera automatically realigns its lens and a second photograph is taken. The exposed film, much like a Polaroid photograph, is ejected and develops within two minutes. If the results are not satisfactory, the test can be redone immediately. No eye drops are used, and no physical contact is ever made with the child. This leads to much less stress for small children.

How is the photograph interpreted?

A trained interpreter can review the photographs and detect the possibility of a vision disorder. The test is not a diagnoses-it is a screening device which can effectively detect the presence of an eye disorder. Once a potential problem is noted during the screening interpretation, a parent can be alerted to take their children for further screening by a professional eye doctor who can make the final diagnosis and develop a treatment plan.

What eye disorders does the PhotoScreener™ detect?

The photographs are examined to detect the presence of major pediatric eye problems, including all refractive errors (hyperopia and myopia), amblyopia, anisometropia, media opacities, strabismus, and astigmatism. This is accomplished by observing any reflective crescents that appear in each photographed eye if disorders are present. If a disorder is identified the child can then be referred to an eye doctor for a full eye exam, diagnosis and treatment.

What exactly are childhood eye disorders and how do they affect a child's vision?

Amblyopia can cause blindness and brain damage if not treated. Some of the related conditions include anisometropia, where one eye is very near-sighted or far-sighted; strabismus where the eyes are misaligned or crossed; and media opacities where light is blocked, as in cataracts. Other eye conditions that can be identified with the PhotoScreener™ include hyperopia (far sightedness), myopia (near sightedness) and astigmatism. In some cases, eye problems can disguise themselves in unexpected ways, as in the case of a child with a bent neck who went through months of physical therapy and turned out to be compensating for severe anisometropia. Screening with the PhotoScreener™ offered the first clue as to the reason for the symptoms.

There are several types of Amblyopia :

• Amblyopia , or "lazy eye," is a difference in the images sent to the brain from each eye. The brain "discards" the blurry or unfocused image in favor of the "correct" image. Over time the weaker eye's development slows down. Amblyopia is usually treated with eye patch therapy, glasses, or in some cases eye surgery.

• Anisometropia occurs when a child's eyes have unequal vision, such as when one eye is near-sighted and the other is far-sighted. As a result, the brain receives normal visual input from one eye and blurred images from the other.

• Strabimus , (a.k.a. Suppression Amblyopia) or "crossed eyes," can result in the two eyes crossed inward toward the bridge of the nose, or one pupil crossed upwards, downwards, or to the far edge of the eye ("wall eye.") This leads the brain to routinely suppress the image from the deviating eye. Children with strabismus will often turn their eyes or tilt their head, and may complain of frequent headaches. Strabismus is treated through patching, glasses, or surgery. If left undetected and untreated, Strabismus can result in permanently decreased vision and structural brain damage.

• Deprivation Amblyopia usually results in the most severe loss of vision if left untreated. Certain diseases of the eye, for example cataracts, block light from being focused on the retina (the structure of the back of the eye that acts like the film of a camera). As a result, no clear image is available to be sent to the brain, which is then deprived of visual input.

Refractive Errors include Myopia (near-sightedness), Hyperopia (far-sightedness), and Astigmatism . These conditions occur when there are problems in the way the lens and the cornea focus light on the retina. Light rays bringing images to the brain need to be focused directly on the center of the retina. In myopia, the light rays focus toward the front of the retina, while in hyperopia, they are focused behind. Astigmatism occurs when the cornea's shape is distorted, so that the light reflection to the retina is distorted as well. Refractive errors are most often treated with glasses, contact lenses, or in some cases by flexing the eye muscles inside the eye.

Media Opacity occurs when the cornea, lens, and other clear, refractive areas of the eye become "opaque" leading to blurry vision and/or reduced visual acuity.

Can amblyopia be cured?

A study in Survey of Ophthalmology (Vol. 40 No. 1 July-August 1995) observed that "the best approach to managing amblyopia is to detect amblyogenic factors before the age of two years and prevent it through eliminating the causes of visual deprivation." The review concluded that when amblyopia exists, "it can be cured if adequately treated in children less that six to seven years of age," but also pointed out that amblyopia is often still diagnosed too late for treatment to be effective, in both industrialized and developing countries, alike.

What advantages does the PhotoScreener™ have over other vision testing methods?

Most current vision screening methodologies are not effective in screening preverbal children. With the PhotoScreener™ , however, doctors can reliably screen children as young as six months for conditions that could lead to amblyopia. The methodology is extremely simple: a flash photograph of the subject's eye is taken. The light reflected from the retina is analyzed to detect refractive errors, strabismus and/or media opacities.

Is the photoscreening process uncomfortable for the child?

The PhotoScreener™ operates very much like any other camera; it takes an instant Polaroid® photograph of the child's eyes - safely and painlessly - without dilation. The entire process takes less than five minutes. The camera uses a combination of flashing lights and a musical tune to help capture the child's attention.

How does the PhotoScreener™ work?

The PhotoScreener™ takes two pictures of the child's eyes. The Polaroid® snapshots allow for immediate interpretation of disorders that might otherwise be missed. Refractive errors are evident if white crescents appear in the photograph. Strabismus and cataracts are also clearly visible in the photographs. It is very easy to use, weighs only six pounds and uses a special high speed 667 Polaroid® film. For a more detailed description of how the camera works, click here.