Astigmatism
is an eye disorder that affects the curvature of the eye. This means that the
shape of one's eyes or the eye lens is irregular and this prevents light from
being focused on to the retina properly. It is usually characterized by blurred
vision.
Astigmatism occurs to most people today, but only to different extents.
It can happen to a mild extent, which is not a cause for concern, but it can also
have a negative effect on eye sight, blurring vision at times.
Astigmatism
is a very common eye disorder, and it usually occurs along with other common eye
disorders like Myopia (short-sightedness) and Hyperopia (far-sightedness). Together,
these eye disorders are medically referred to as refractive errors.
Causes
of Astigmatism
Medical research has shown that astigmatism can occur even
at birth, or after an eye injury, disease or surgery. It has also been identified
to be hereditary.
The causes can be known based on the type of Astigmatism
one has.
The two types of Astigmatism are:-
Corneal Astigmatism: This kind of astigmatism occurs when the cornea is
curved improperly or imperfectly. Thus, in this case, the cornea has a distorted
shape that prevents light rays from being refracted properly. Other cornea-related
disorders like Keratoconus - wherein the cornea thins and degenerates gradually
to become more conical in shape.
Lenticular Astigmatism:
The other form of astigmatism deals with an imperfect or an improper eye
lens. With the lens being curved imperfectly, the image that reaches the retina
is imperfect, thus causing blurred vision. Some times lenticular astigmatism is
seen in patients with diabetes. Fortunately, treatment of diabetes can also lead
to reduction in astigmatism.
Symptoms of Astigmatism
- Do you have Astigmatism?
Although diagnosis of the condition of Astigmatism
is done through various eye check-ups and eye tests, astigmatism usually occurs
with the onset of headaches, excessive squinting, fatigue, blurry vision, eyestrain,
distorted vision and photophobia (sensitivity to light).
Diagnosis can be made
with the help of visual acuity tests, regular eye tests, use of a Snellen Chart,
Keratometer, a Keratoscope, or an astigmatic dial.
Treatment
for Astigmatism
Astigmatism can be corrected with the prescription of corrective
lenses (eye glasses or contact lenses) or refractive surgery.
Eyeglasses
are the primary means to correct blurred vision brought upon by astigmatism. Cylindrical
lenses are generally prescribed with a single lens to provide clarity of objects
at all distances.
Contact Lenses and their effects:
- While contact lenses are also prescribed by eye doctors and opticians alike,
it is important to know the pros and cons of using contact lenses to cure astigmatism.
Regular
cleaning and maintenance is required for contact lenses. The delicate nature of
the lenses means that mishandling can lead to other eye disorders as well. However,
it is still recommended as the best way to improve vision and correct astigmatism.
Astigmatism
and Lasik/Laser Surgery: -
Photorefractive Keratectomy (PRK) is
one of the laser surgery techniques used to treat astigmatism. Here, the protective
layer or tissue of the cornea is removed and another laser changes the shape of
the cornea. However, this laser treatment is known to be painful.
Laser
in situ keratectomy (LASIK) is a recent development in the field of eye treatment
technology. It has been favoured largely because it is known to cause the least
amount of pain when compared to other corrective laser surgeries. It involves
using a laser to make a thin cut into the cornea and then shaping the cornea with
the help of an excimer laser.
Other measures include Orthokeratology and LASEK
(Laser epithelial keratomileusis)