Eye & Contact Lens Factsheets
PRESBYOPIA
The literal translation of presbyopia
is 'old sight' however this does seem a little
cruel as this is a condition which affects everybody
from as young as the age of 40.
The lens inside the eye is responsible
for our ability to focus on near objects. To do
this it has to change in shape and become steeper
in form, to provide the extra power for near vision;
when we look up again into the distance the mechanism
is reversed and the lens returns to normal.
Unfortunately, the ability of
the lens to be able to provide this extra power,
which is called accommodation, reduces with age
almost from birth but it is not until we reach
about 40 something that we begin to notice and
have difficulty with near vision.
Occasionally the onset of presbyopia
can appear to happen almost overnight, but more
usually it is a gradual decline starting with
difficulty in reading small print or threading
a needle, and then finding that even normal print
has to be held further away from the eyes in order
to focus. At this stage the eyes often feel tired
and strained after periods of close work and a
headache is not unlikely.
Overcoming this problem is essentially
very easy. To compensate for the loss of power
in the lens of the eye all that is required is
to add a little bit of positive power by means
of a spectacle lens. Unfortunately this is not
just a case of buying a pair of ready made reading
glasses off the shelf, as other factors such as
existing prescription, astigmatism, lens centration
and ocular balance must be considered. Existing
spectacle wearers can choose between the options
of having a separate pair for reading or a single
pair of bifocal or varifocal lenses. Today the
varifocal lens is the most widely used. For contact
lens wearers there are also a number of options,
the most simple being a pair of reading spectacles
to wear over the contact lenses, however bifocal
and varifocal contact lenses are available and
there are also other less known methods of correction
such as monovision. As always we are
readily available to discuss any problems with
you and to advise on the type of correction we
feel would be most suitable for your day to day
needs.
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