| Know
about Contact Lens
What
is Contact Lens?
A corrective lens for particular type of
refractive error that can be worn directly
over the eye or over the cornea i.e. a front
portion of the eye.
Advantages:
Here are some of the advantages contact
lenses offer:
- They provide unobstructed wider peripheral
vision.
- Since contact lenses move with your
eye, you’re always looking through
the optical centre of the lens, where
vision is best.
- They don’t fog up or smudge,
get splattered with rain, get in your
way, or slide down your nose resulting
no weight and discomfort.
- They allow the world to see the natural
you!
- They now come in a variety of tints
and opaque colors to enhance or change
the color of your eye
Types
of contact lens:
Contact Lenses are mainly of two
types:
- Soft Contact Lens
- Semi-soft or Rigid Gas Permeable
Lens
Soft
Contact Lens:
These are made of flexible polymers with significant
water content. They are larger than the cornea
(12-14mm) and mould to the front of the eye
with a lens life of 12 months approximately.
They are comfortable even on first fitting
and stable on the eye for sporting activities
but they are unable to correct much astigmatism.
For more than 0.75 D astigmatism or cylindrical
spectacle power there are special lenses in
soft, which is known as Soft toric lenses.
Semi
Soft or Rigid Gas Permeable Lens
It can be used in all types of refractive
errors. Lenses are made of polymers that do
not absorb water but have a high permeability
to oxygen. They are smaller in diameter than
the cornea (8-10mm). The good oxygen transmission
maintains corneal health and there is a lower
incidence of eye infections and allergic reactions
than with soft contact lenses. It works best
in Irregular astigmatism where spectacles
can not provide optimal vision e.g. Post trauma,
post penetrating keratoplasty, post refractive
surgeries, conditions such as keratoconus,
Keratoglobus, Pellucid Marginal Degeneration
etc. |
