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Pinholes Glasses
- The Solution to Common Eye Complaints
Myopia (Near Sightedness)
Myopia or near sightedness is a refractive eye disorder that affects our
eyes' long distance vision. People with myopia have no difficulty focusing
their eyes on close-up objects, but have varying degrees of difficulty
focusing on more distant objects. It often first appears during childhood
and gradually worsens with age - this is known as myopic creep.
The major cause of myopia is an abnormal elongation of the eyeball, where
it becomes stretched from front to back, or the curvature of the cornea is
greater than usual. The distance between the retina - the light sensitive
part of the eye on the back wall of the eyeball - and the cornea at the
front of the eye increases, and so light rays entering the eye come to focus
in front of the retina. This leaves a 'blur circle' on the retina itself as
the light rays cross paths and begin to diverge beyond the focal point.
Recent studies have revealed that although myopia can be hereditary, it
is also accentuated by chronic use of the eyes for short-distance focusing,
such as when working at a computer screen. Evolution has programmed our eyes
to naturally focus in the middle to long-distance when our eyes are at rest.
To focus on close-up work our eye muscles must tense, thickening the eye
lens, in order to focus the light rays upon the retina. Persistent or
prolonged short-distance focusing causes pressure to increase in the
vitreous chamber of the eye, thus elongating the eyeball.
Pinhole glasses offer instant relief as the 'stopped down' aperture
produces a greater focal range. Combined with the 'narrower than normal'
beam of light entering the eye, pinhole glasses reduce the the blur circle
on the retina, so enabling the eyes to see more clearly.
Hyperopia (Far Sightedness)
Hyperopia or far sightedness is a refractive eye disorder caused by a
shorter than normal eyeball or a flatter than usual cornea. Light entering
the unaided eye comes to focus behind the retina, thus casting a blur circle
on the retina itself. People suffering from hyperopia find it difficult to
focus in the short-distance, whilst have fewer problems focusing in the
middle to long-distance.
Young people with this condition can naturally improve their vision by
working the focusing accommodation of their eyes. By continuously trying to
focus in the short-distance their eye muscles will become stronger, enabling
the eye lens to shorten the focal length of the light rays, and therefore
decrease the blur circle on the retina.
Pinhole glasses, whilst not suitable for the hyperopic young, can be used
for far sightedness in later life when the eye muscles weaken with ageing.
They offer instant relief as the 'stopped down' aperture produces a greater
focal range. Combined with the 'narrower than normal' beam of light entering
the eye, the blur circle on the retina is decreased, so enabling the eyes to
see more clearly.
Presbyopia
Presbyopia is a condition that affects many people from their mid-40s
onwards. As we age our eye lenses become less flexible, making it more
difficult for us to focus in the short-distance. The weaker eye lenses
gradually becomes less able to focus divergent light rays onto the retina,
moving the focal point backwards beyond the retina. As with hyperopia, a
gradually expanding blur circle is cast upon the retina itself, blurring our
vision.
Pinhole glasses offer relief in the short-term, as the 'stopped down'
aperture produces a greater focal range. Combined with the 'narrower than
normal' beam of light entering the eye, the blur circle on the retina is
decreased, so enabling the eyes to see more clearly. It is recommended
however, that pinhole glasses should be used in conjunction with eye muscle
strengthening exercises, so the eye muscles themselves are better equipped
to keep the eye lenses more flexible.
Astigmatism
Astigmatism is a refractive eye disorder caused by a misshapen cornea at
the front of the eye. A normal cornea is spherical in shape, but some people
are born with a more oblong shaped cornea that projects two points of light
on to the retina at the back of the eye. The resultant image processed by
the brain is blurred, the degree of blur determined by the distance between
the two points on the retina. The closer the points are the less blurred the
image appears.
Pinhole glasses reduce the blur of astigmatism by limiting the distance
between the two points of light on the retina, thus helping sufferers to see
more clearly.
Cataracts
Cataracts are opacities that form on the lens of the eye, often in later
life as dead cells in the eye lens accumulate. Cataracts are seen as white
cloudy areas within the pupil - a projection of the cataract on the lens
which is located immediately behind the pupil. People with cataracts suffer
from blurred vision, as the cataract scatters light entering the eye, so
preventing it from focusing on the retina. The amount of light scatter is
worse when the pupil size is larger.
Pinhole glasses help to reduce light scatter by stopping down the pupil
to the size of the pinhole. Less light scatter occurs, and vision is
improved.
Computer Vision Syndrome (CVS)
More and more people now spend their days working at computer screens.
Many experience eye strain, headaches, fatigue, dry eyes or blurred vision
when using a computer for lengthy periods of time. These complaints
constitute Computer Vision Syndrome, and businesses lose thousands of
dollars every month due to time off or sickness because of it.
Computer Vision Syndrome is attributed to the often harsh light of the
computer screen, the need of the user to constantly focus on the screen, and
the glare of office lighting or lighting in the surrounding environment.
Anti-radiation screens, prescription 'computer glasses' and ergonomically
designed work environments are all solutions to the problem, with varying
cost implications and results.
Pinhole glasses offer an alternative solution that is extremely
affordable by comparison. The pinholes reduce glare by blocking out
extraneous light rays, and reduce the incidence of eye strain by increasing
the depth of field without the need for stressful focusing accommodation.
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