Cataracts
A cataract is a clouding of the eye’s natural lens, which lies behind the iris and the
pupil.
Cataracts are the most common cause of vision loss
in people over age 40 and are the principal cause of
blindness in the world. In fact, there are more cases
of cataracts worldwide than there are of glaucoma,
macular degeneration and diabetic retinopathy
combined, according to studies. Today, cataracts affect are affecting millions of people
The type of cataract you have will affect exactly
which symptoms you experience and how soon
they will occur. When a nuclear cataract first deTypes of cataracts include:
velops, it can bring about a temporary improvement in your near vision, called “second sight.”
• A subcapsular cataract occurs at the back of the
lens. People with diabetes or those taking high
doses of steroid medications have a greater risk of Unfortunately, the improved vision is short-lived
and will disappear as the cataract worsens. On
developing a subcapsular cataract.
the other hand, a subcapsular cataract may not
• A nuclear cataract forms deep in the central zone produce any symptoms until it’s well-developed.
(nucleus) of the lens. Nuclear cataracts usually are If you think you have a cataract, see an eye doctor for an exam to find out for sure.
associated with aging.
• A cortical cataract is characterized by white,
wedge-like opacities that start in the periphery
of the lens and work their way to the center in a
spoke-like fashion. This type of cataract occurs in
the lens cortex, which is the part of the lens that
surrounds the central nucleus.
Cataract Symptoms and Signs
A cataract starts out small and at first has little
effect on your vision. You may notice that your
vision is blurred a little, like looking through a
cloudy piece of glass or viewing an impressionist
painting.
A cataract may make light from the sun or a lamp
seem too bright or glaring. Or you may notice
when you drive at night that the oncoming headlights cause more glare than before. Colours may
not appear as bright as they once did.
What Causes Cataracts?
The lens inside the eye works much like a camera
lens, focusing light onto the retina for clear vision. It also adjusts the eye’s focus, letting us see
things clearly both up close and far away.
The lens is mostly made of water and protein.
The protein is arranged in a precise way that
keeps the lens clear and lets light pass through it.
But as we age, some of the protein may clump
together and start to cloud a small area of the
lens. This is a cataract, and over time, it may
grow larger and cloud more of the lens, making
it harder to see.