Patient
Guide
EYE
The eye is one of the most complex organs in the body. Responsible
for taking light signals to the brain, it functions as a natural
camera that is an extension of the brain. It has several layers
that are equivalent to the lens of the camera, the film, and
the lens cover. Remember that any part of the eye can be involved
in the disease process, and may require a subspecialist. to
treat that particular disorder
Cornea
Like the glass on a watch, the cornea is the clear protective
coating on the front of the eye that allows light to pass
through it without distortion. It covers the colored iris.
The lens of the eye focuses the images transmitted through
the cornea to the retina. Therefore, it must be clear and
regularly shaped to give good vision. These images are then
transferred via the optic nerve to the brain, where sight
is interpreted. A "scratched" cornea, when the surface
layer is torn, is extremely painful.
Conjunctiva
The conjunctiva is the clear covering (like cellophane) of
the white part of the eye, the sclera. When it gets irritated
or infected it becomes red, which is called conjunctivitis.
Conjunctivitis can be allergic or infectious; viral conjunctivitis
is often called "pink eye."
Sclera
The sclera is the "white" part of the eye.
Lens
Every camera must have a lens to properly focus the picture.
Your eye has a lens, too, which lies directly behind the pupil
in the sac-like capsule. Your lens, which is about the size
of an "M&M," is normally clear and transparent.
It focuses images onto the retina, which acts as the film
that records the picture. The picture is then transmitted
by the optic nerve to the brain, where the image is interpreted.
It's the brain that does the actual seeing.
Pupil
The dark center of the iris (the colored part of the eye)
is the pupil. The pupil decides how much light is need for
the eye to see properly. It changes sizes to adjust for changes
in light.
Retina
The retina is the light-sensitive part of the eye. It has
one major artery and one major vein, which is called the central
retinal vein. Sometimes, branches of this vein can be blocked.
Uvea
The uvea is the middle section of the eye. It has three parts:
the iris (the colored part of the eye), the ciliary body and
the choroid. Inflammation (or swelling) of any of these parts
or their adjacent tissues is called "uveitis."
Macula
The macula is a part of the eye that contains special light-sensitive
cells which allows us to see fine details clearly. It is located
in the retina. The macula is an important part of the eye
because even small changes can cause severe vision loss.
Vitreous
The vitreous is the clear jelly-like substance that fills
the middle part of the eye.
Optic Nerve
The optic nerve is the pathway that connects the eye to the
brain. It is the means through which images captured by the
retina reach the brain, where those images are interpreted.
Eyelids
The lids of each eye are vital to the preservation of sight.
They maintain vision by keeping moisture inside, and foreign
particles outside of the eye. Without eyelids, our eyes would
quickly dry out from exposure to air, or could be damaged
severely by a cinder, pebble, or some other foreign object.
Think of how fast you blink when something approaches your
eye. There are, however, many ways the lids may be damaged.
They may be cut or burned in an accident, be involved in infections,
or be invaded by many different types of tumors. These tumors
can be benign (not cancerous) or malignant (cancerous). Two
other common lid problems are droopy eye lids (ptosis) and
baggy eyelids (dermatochalasis). Droopy eyelids can be acquired
or congenital. Droopy eyelids are seen most often in children
and baggy eyelids are more common in older people. However,
both can usually be corrected quite successfully.
The Lacrimal System
The lacrimal (tear) system is a miniature drainage network,
which prevents tears from continuously rolling down the cheeks.
From the surface of the eye, the tears flow along the edge
of the lids toward the nose. Just before reaching the corner
of the eye, the tears slide into two tiny drain tubes, and
then into a larger tube which carries the tears into the nose.
This explains why crying often causes one to blow one's nose.
Many problems may cause the tear system to drain poorly. For
instance, an accident may cut one of the two tiny drainage
tubes, a long-standing infection may scar these tubes, or
tumors may invade parts of the tear system. All of these may
lead to poor drainage causing the tears to well up in the
eye and roll down the cheek. Fortunately, surgery or other
kinds of procedures can usually relieve this uncomfortable
situation and restore a functional system. Many infants, about
20 percent, are born with tear ducts or drain tubes that have
not opened. This usually leads to a chronic and ow-grade infection
in the tear drainage system. That causes a mixture of mucus
and pus to accumulate in the inner corner of the eyes, between
the lids. Parents should wipe that away with anything clean,
such as a tissue. The volume of this accumulation can be reduced
by applying antibiotic dropper ointment to the affected eye.
Nearly all of the time, the blockage of this drainage system
will open by one year of age. If the duct has not opened by
the child's first birthday, an ophthalmologist may open the
blocked naso-lacrimal duct by a simple procedure called probing
of the naso-lacrimal system. This brief procedure requires
a brief period of general anesthesia and a short outpatient
stay in the hospital. Some ophthalmologists probe in the office,
without general anesthesia, but usually before the child is
one year old.
The Orbit
The orbit is the bony housing in which the eyeball sits. If
you place your finger on your brow and press down, you will
feel the edge of the orbit. By continuing to move your finger
around in a circle, you can feel the orbit protection provided
the eyeball on all sides, except in the front where the lids
protect the eye. Between the bony housing and the eyeball
are other structures such as fat, muscle, blood vessels and
glands. These are known as the orbital contents. The orbital
contents may develop a tumor, causing the eye to protrude.
Often, these tumors have to be removed to help maintain normal
eye function. The orbit can also suffer fractures during trauma
to the eye. Therefore, it is always wise to use certified,
shatterproof eyewear whenever engaging in sports.
Uvea
The uvea is the middle layer of the wall of the eye. It has
three parts: the iris, the ciliary body and the choroid. Inflammation
(or swelling) of any part of the uvea is called uveitis It
has many causes, but they are hard to identify.
The symptoms of uveitis depend upon the area that is inflamed
and the duration of inflammation. Acute iritis may cause a
red eye with pain and sensitivity to light. Chronic and posterior
inflammation may be painless but may cause symptoms such as
floaters or decreased vision. These symptoms should alert
you to seek expert medical attention promptly.
A careful medical history, including family, social and sexual
history, is important in the uveitis patient. Evaluation of
uveitis is directed toward the diagnosis and identification
of possible underlying causes of the disease. Bacteria, fungi,
viruses, protozoa or other agents along with abnormalities
of the immune system can cause uveitis. Testing may involve
blood tests, X-rays, special ocular studies or evaluation
by other skilled medical consultants beyond ophthalmology.
A full medical evaluation may reveal an inflammatory disease
that has involved other organs besides the eye. Examples of
this include sarcoidosis, rheumatoid arthritis, syphilis,
and related conditions. For these types of conditions, treatment
for the underlying cause of the uveitis helps all parts of
the body, including the eye.
In most cases, no obvious underlying cause is found for the
uveitis. Treatment then is directed to the eye inflammation
alone. Treatment may include drops or injections of cortisone
medication around the eye. Sometimes it may be necessary to
use oral drugs that suppress inflammation, such as prednisone
or cytotoxic (chemotherapeutic) agents. Treatment may be prolonged
for uveitis. Therefore, close follow-up with an ophthalmologist
is important to keep the eye functional and to detect occasional
side effects from the treatments.
Procedure for examination
After
you register with the reception, you will be given a card
with your unique number which you can quote in all your future
visits and correspondence. In case you lose the card- please
inform the staff- they can retrieve your number from the computer
records
Your
vision and number will be checked using the autorefractometer
( Or computerised eye testing in lay terms)
The pressure of your eye will be recorded using the Pneumo
Tonometer or air puff tonometer. You will feel a small puff
of air on your cornea during this test so do not get alarmed.
If your pressure is abnormal or if you have glaucoma , the
pressure will be rechecked using the Applanation Tonometer
The front part of your eye will be checked using the Slit
Lamp. In this test a bright light will be focused using a
special instrument
Drops will then be instilled in your eyes to dilate the pupils
to enable us to see the retina or the inside part of the eye.
Please inform if you have any allergy to any drops at this
stage. Dilating drops blur the near vision and give you glare
, so please inform if you have to drive back home and would
like to do it some other time.
After dilating – your retina will be examined using the Indirect
Ophthalmoscope which focuses a bright light on to your eye
Some special tests for crossed eyes may be carried out in
certain cases
After the whole examination , you will be explained about
your eye condition and if necessary – certain special tests
such as Fundus Fluorescein Angiography( FFA) , Ultrasonography,
Perimetry, Corneal Topography may be advised
You may be advised treatment in the form of drops, glasses
or in certain cases Laser treatment for retinal diseases,
for some forms of Glaucoma and for myopia . You may be advised
surgery , the procedure of which will be explained to you
in detail
Do
not hesitate to clear any doubts you have regarding any form
of examination or treatment carried out or advised.
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