Common Eye Problems:
What are refractive errors?
For our eyes to be
able to see, light rays must be bent or "refracted"
so they can focus on the retina, the nerve layer that
lines the back of the eye. The cornea and the lens
refract light rays. The retina receives the picture
formed by these light rays and sends the image to the
brain through the optic nerve. A refractive error
means that the shape of your eye doesn't refract the
light properly, so that the image you see is blurred.
While refractive errors are called eye disorders,
they are not diseases. In a normal eye, the cornea
and lens focus light rays precisely on the retina. |
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What are the different types of
refractive errors?
MYOPIA (nearsightedness): A myopic eye is longer than normal or the
cornea has too much focusing power, so that the light
rays are focused in front of the retina. Close
objects look clear but distant objects appear blurred.
This condition affects over 25% of all people in the
United States. |
Myopia |
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|
HYPEROPIA (farsightedness): The opposite of myopia. The eye is shorter
than normal or the cornea lacks refractive power.
Light rays are focused behind the retina and close
objects are blurry. |
Hyperopia |
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|
ASTIGMATISM: This condition blurs and distorts both
distance and near objects. A normal cornea is round
and smooth (like a basketball). With astigmatism,
your cornea is curved more in one direction than in
the other (like an egg or football). You can have
astigmatism in combination with myopia or hyperopia. |
|
PRESBYOPIA
(aging eyes): When you
are young, the lens in your eye is soft and flexible.
The lens of the eye changes its shape easily,
allowing you to focus on objects both close and far
away. After the age of 40, the lens becomes more
rigid. Because the lens can't change shape as easily
as it once did, it is more difficult to read at close
range. This normal condition is called presbyopia.
You can also have presbyopia in combination with
myopia, hyperopia, or astigmatism. No exercise or
medication can reverse presbyopia. |
|
How are refractive errors corrected?
Eyeglasses: Glasses are an easy method to correct
refractive errors. They can also help protect your
eyes from harmful light rays, such as ultraviolet (UV)
light rays. A special coating that screens out UV
light is available when you order your glasses.
Bifocals are glasses that are used to correct
presbyopia. They have correction for reading on the
bottom half of the lens and another for seeing
distance on the top. Trifocals are lenses with three
different lens corrections in on set of eyeglassses.
If you don't need correction for seeing distance, you
can buy over-the-counter reading glasses to correct
presbyopia. |
|
Contact
Lenses: There are
now a wide variety of contact lenses available. The
type that is best for you depends on your refractive
error and your lifestyle. If you want to wear contact
lenses, discuss the various options with your
ophthalmologist. |
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Refractive
Surgery: Many people rely on glasses and/or contact lenses to
correct their vision. Some find these methods
inconvenient, uncomfortable or unattractive. Others suffer from
dryness or are otherwise unable to tolerate contact lenses. Refractive eye surgery is a general term for surgical
procedures that can improve or correct the eye's
focus by permanently changing the shape of the cornea.
The cornea is the clear, front surface of the eye
which, along with the lens, focuses light rays onto
the retina. Sierra Eye Associates offer Laser Refractive
Surgery (LASIK) to reduce
dependence on eyeglasses or contact lenses. |
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Cataracts
A
cataract is a clouding of the normally clear lens in the eye. This is a
normal aging process which blocks light from entering the eye, and causes vision
problems such as glare, halos, and difficulty reading. Please read more
about cataracts by clicking <HERE>
|
This is a 'mature' cataract. Note the opacities in the the
normally black pupil. |
Glaucoma
When
pressure within the eye increases and damage to the optic nerve (in the back of
the eye) results, this is called Glaucoma. There are several types of
glaucoma and several ways to treat it. If discovered in time, vision loss
usually can be prevented. Sierra Eye Associates is proud to have the only
Glaucoma Subspecialist in all of Northern Nevada in Dr.
Michael Stanko. Please visit our Glaucoma Page to learn more.
Pediatrics
Pediatric
ophthalmology is a subspecialty area of ophthalmology which concentrates
on diagnosis, management, and treatment of ocular disorders frequently
encountered in childhood. Some of these conditions include Amblyopia (lazy eye), Strabismus (crossed-eye),
prematurity, and genetic/inherited disorders (such as retinitis pigmentosa). Sierra Eye Associates is the only practice to have two Pediatric
Ophthalmologists on staff to serve the Northern Nevada community with Dr.
L. Alan Johnson, and Dr. Pauline Hong. Please visit our Pediatric section for more information.
Diabetes mellitus is a condition which interferes with the
body's ability to regulate sugar metabolism. As a result, medium to small
blood vessels throughout the body become damaged. One common area of blood
vessel damage is in the retina of the eye. Diabetic retinopathy,
as it is called, can lead to severe vision loss and even blindness if not
diagnosed and treated correctly. Please visit our web page on diabetic
retinopathy for more information.
Age Related Macular Degeneration (ARMD) is a
disease that affects the retina of the eye. This condition is probably
hereditary in nature, but the only known association is advancing age. The
retina is the inner lining of the back of the eye, like the inside of the wall
of a basketball. The retina works like film in a camera. The central
part of the vision, that part used for reading, is served by a portion of the
retina called the macula. This is the area involved in ARMD.
Please visit our web page for more information <HERE>.
Floaters and Flashes of
Light:
This is a common condition frequently seen after the age of
50, although it can occur earlier in life. It results from a change in the
jelly (vitreous) in the back of your eye. The jelly liquefies and can pull
on the retina as it does so. This 'vitreous detachment' from the retina can
cause flashes of light and subsequent floaters.
Sometimes, however, this normal occurrence can cause a tear in
the retina or even a detachment of the retina. It is therefore recommended that
a complete ophthalmic examination with pupil dilation be performed if flashes
and floaters are noted, to rule out retinal problems. Please visit our web page
on Floaters and Flashes.
DISCLAIMER: Sierra Eye Associates
provides online information on the Internet for communication and
review purposes only. Such information is not intended to be
complete, nor to replace the importance of proper, thorough
medical advice from an experienced and trained ophthalmologist
who is familiar with a particular patient. Sierra Eye Associates
and its doctors disclaims any and all liability for any injury or
other damages which may be directly or indirectly associated with
the communication or review of information contained herein.Materials produced here are not intended to provide medical
information. Rather, the materials are presented for
informational purposes only. None of the material presented here
should be relied upon by any person for purposes other than
informational. Sierra Eye Associates encourages any patient
reviewing these material to obtain individual medical advice and
answers to specific medical questions by a qualified
ophthalmologist.
Please call (775) 329-0286 if you would like
to schedule an appointment.
