- Cornea: clear front window of the eye that transmits and focuses light into
the eye
- Iris: colored part of the eye that helps regulate the amount of light that
enters
- Pupil: dark aperture in the iris that allows light to go through into the
back of the eye
- Lens: transparent structure inside the eye that focuses light rays onto the
retina
- Retina: nerve layer that lines the back of the eye, senses light, undergoes
complex chemical changes, and creates electrical impulses that travel through
the optic nerve to the brain
- Macula: small central area in the retina that contains special
light-sensitive cells and allows us to see fine details clearly
- Optic nerve: connects the eye to the brain and carries the electrical
impulses formed by the retina to the visual cortex of the brain
- Vitreous: clear, jelly-like substance that fills the middle of the
eye
Glaucoma
Glaucoma (the sneak thief of sight) refers to a group of eye diseases that
affect the optic nerve and may cause vision loss. Optic nerve damage in glaucoma
is primarily due to elevated intra-ocular pressure (IOP) within the eye.
Glaucoma is classified either as open-angle (the more common chronic condition
which is usually painless) or angle-closure glaucoma (the more unusual type
which often occurs suddenly [acutely] and is associated with pain and redness of
the eye). The elderly, African-Americans, and people with family histories of
the disease are at greatest risk. There are no symptoms in the early stages, and
by the time the patient notices vision changes, visual loss due to glaucoma can
only be halted, not reversed. Glaucoma is usually treated with eyedrops,
although lasers and surgery can also be used. Most cases can be controlled well
with these treatments, thereby preventing further loss of vision. Early
diagnosis and treatment is the key to preserving sight in people with
glaucoma.
Cataracts
Cataract is a painless condition where the normally clear aspirin-sized lens
of the eye starts to become cloudy. The result is much like smearing grease over
the lens of a camera, which impairs normal vision. Causes of cataracts include
cortisone medication, trauma, diabetes, and aging. In fact, cataracts will
affect most people if they live long enough. Diagnosis can be made when a doctor
examines the eyes with a viewing instrument. Symptoms of early cataracts may be
improved with new eyeglasses, brighter lighting, antiglare sunglasses, or
magnifying lenses. If these measures do not help, surgically removing the cloudy
lens and replacing it with an artificial lens is the only effective treatment.
Removal is only necessary when vision loss interferes with your everyday
activities, such as driving, reading, or watching TV. You and your eye-care
professional can discuss the surgery, and once you understand the benefits and
risks, you can make an informed decision about whether cataract surgery is right
for you. In most cases, delaying cataract surgery will not cause long-term
damage to your eye or make the surgery more difficult.
Age-Related Macular Degeneration (AMD)
Age-related macular degeneration is an eye disease with onset usually after
age 60 that progressively destroys the macula, the central portion of the
retina, impairing central vision. It rarely causes blindness because only the
center of vision is affected. There are two types of AMD -- wet and dry --
neither of which causes pain. In wet AMD, abnormal blood vessels behind the
retina start to grow under the macula and leak blood and fluid, causing loss of
central vision, which may occur quickly. Treatment includes laser surgery,
photodynamic therapy, and injections into the eye. None of these will cure the
disease and loss of vision may still progress. In dry AMD, the light-sensitive
cells in the macula slowly break down, causing central vision to diminish over
time. Early stages of dry AMD can be treated with high-dose formulations of
antioxidants and zinc, which may delay and possibly prevent AMD from progressing
to a more advanced stage. Once in the advanced stage, no form of treatment can
restore vision loss.
Retinal Detachment
A retinal detachment is a separation of the retina from its attachments to
its underlying tissue within the eye. Most retinal detachments are a result of a
retinal break, hole, or tear. Once the retina has torn, liquid from the vitreous
gel (clear gel that fills most of the inside of the eye) passes through the tear
and accumulates behind the retina. The buildup of fluid behind the retina is
what separates (detaches) the retina from the back of the eye. Flashing lights,
floaters, or a curtain may be the initial symptoms of a retinal detachment or of
a retinal tear that precedes the detachment itself. Retinal detachments can
occur at any age but occur most commonly in younger adults (age 25 to 50) who
are highly nearsighted and in older people following cataract surgery. Surgical
repair of a retinal detachment is usually successful in reattaching the retina,
although more than one procedure may be necessary. Once the retina is
reattached, vision usually improves and then stabilizes.
Bacterial Conjunctivitis (Pink Eye)
Pinkeye, or conjunctivitis, is redness and inflammation of the membranes
(conjunctiva) covering the whites of the eyes and the membranes on the inner
part of the eyelids. The term pinkeye is most commonly used to refer to the
infectious (viral or bacterial) type of conjunctivitis, but it may also result
from allergic reactions or chemical irritants such as air pollution, smoke, or
noxious fumes. The infectious form is very common in children and is highly
contagious. Children and adults who develop infectious pinkeye should see a
doctor to determine whether antibiotic treatment is necessary. Most infectious
cases are caused by viruses and will not respond to antibiotics. In these
instances, the discharge from the eye is clear and watery and symptoms of a cold
may be present. Viral infections last from seven to 10 days. Bacterial pinkeye
generally results in a large amount of discharge that is green to yellow in
color. This discharge can accumulate at night and make opening the eye difficult
in the morning. Bacterial pinkeye usually lasts three to five days and requires
antibiotic eyedrops to help the body remove the bacterial infection. Application
of warm washcloths to the eye area is also effective in removing discharge. To
reduce the chance of spreading infectious pinkeye, those affected should avoid
touching the eye area and wash their hands frequently, particularly before
applying medications to the eye area. Sharing of towels, washcloths, cosmetics,
or eyedrops can also spread the infection.
Uveitis
Uveitis (pronounced you-vee-EYE-tis) is defined as all inflammatory processes
of the middle layers of the eye, also called the uveal tract or uvea. The uvea
is very important because its many veins and arteries transport blood to the
parts of the eye that are critical for vision. Symptoms and signs of uveitis may
include eye redness and irritation, blurred vision, eye pain, increased
sensitivity to light, and floating spots. Potential causes include infection
with a virus, fungus, bacteria or parasite, inflammatory disease affecting other
parts of the body, or injury to the eye. Because uveitis is serious, treatment
needs to begin right away. For uveitis not caused by an infection, your
ophthalmologist may prescribe eyedrops containing steroids to reduce swelling
and drugs to relieve pain. Antibiotics are used in patients with infectious
uveitis. Dark glasses will help with light sensitivity.
Eye Allergies
Severe allergic eye symptoms can be very distressing and are a common reason
for visits to the allergist or ophthalmologist. Occasionally, severe eye
allergies cause serious damage that can threaten eyesight. Eye allergies usually
are associated with other allergic conditions, particularly hay fever (allergic
rhinitis) and atopic eczema (dermatitis). Medications and cosmetics can also
play a significant role in causing eye allergies. Most people with eye allergies
treat themselves and do so quite effectively with OTC products such as eye drops
as well as antihistamines and decongestants. If these remedies don't work or if
there is eye pain, extreme redness, or heavy discharge, you should seek medical
advice.
Sty (Stye)
A sty (sometimes spelled stye) is a tender, painful red bump located at the
base of an eyelash or inside the eyelid. A sty results from an acute infection
of the oil glands of the eyelid that occurs after these glands have become
clogged. A sty also may arise from an infected hair follicle at the base of an
eyelash. Symptoms include redness, tenderness, and pain in the affected area.
The eye may feel irritated or "scratchy." Later symptoms can include swelling,
discomfort during blinking, watering of the eye, and light sensitivity. A common
sign of a sty is a small, yellowish spot at the center of the bump that develops
as pus expands in the area. People of all ages and both genders can develop a
sty. Application of a warm compress or washcloth to the affected area for 10
minutes, four to six times a day, can speed rupture of the sty and aid in the
relief of symptoms. A sty should not be pressed or squeezed to facilitate
drainage. If a sty persists for several days, a doctor may lance (drain) the
infection under local anesthesia.
Keratoconus
We see through the cornea, which is the clear, central part of the front
surface of the eye. Normally, the cornea has a round shape, like a Ping-Pong
ball. Sometimes, however, the structure of the cornea is just not strong enough
to hold this round shape. The normal pressure inside the eye makes the cornea
bulge outward like a cone, causing distorted vision. This condition is called
keratoconus. Often the cause of keratoconus is unknown. The disease usually does
not cause blindness. However, the changes to the cornea will make it impossible
for the eye to focus well even with glasses or soft contact lenses. Rigid
contact lenses or corneal transplantation may be necessary to provide good
vision.
Blepharitis
Blepharitis is an inflammation of the eyelids and occurs in two forms,
anterior (outside of the eyelid) and posterior (inner eyelid). Both types of
blepharitis can cause a burning or foreign body sensation, excessive tearing,
itching, sensitivity to light, red and swollen eyelids, redness of the eye,
blurred vision, frothy tears, dry eye, flaking at the base of the lashes, or
crusting of the eyelashes upon awakening. Common causes for anterior blepharitis
are bacteria (Staphylococcus) and scalp dandruff while posterior forms
are caused by problems with the oil glands in the eyelid. Treatment for both
forms involves keeping eyelids clean and free of crusts. Warm compresses should
be applied to loosen crusts, followed by a light scrubbing with a cotton swab
and a mixture of water and baby shampoo. Because blepharitis rarely goes away
completely, most patients must maintain an eyelid hygiene routine for life. If
the blepharitis is severe, an eye-care professional may also prescribe
antibiotics or steroid eyedrops.
Chalazion (Eyelid Cyst)
A chalazion is a tiny lump of the upper or lower eyelid caused by
inflammation of a gland of the lid. It may be soft and fluid-filled or firmer. A
chalazion is also referred to as a meibomian cyst, tarsal cyst, or conjunctival
granuloma. The narrow opening through which a meibomian gland secretes its
material can become clogged from narrowing of the opening or hardening of the
sebaceous liquid near the opening. If this occurs, the gland will have a backup
of the material it secretes and it will swell. Most chalazions are treated with
warm compresses to the eyelid to promote healing and circulation of blood to the
inflamed area. Doctors may prescribe an antibiotic drop or ointment to be used
immediately after the compresses. If the chalazion persists and is causing an
unsightly lump, it can be removed surgically through the inside of the lid.
Corneal Ulcer
Most corneal ulcers are caused by infections and can be bacterial (common in
people who wear contact lenses), viral (herpes simplex virus and varicella
virus), or fungal (improper care of contact lenses or overuse of eyedrops that
contain steroids). Symptoms include red eyes, pain, feeling like something is in
the eye, tearing, pus/thick discharge, blurry vision, pain from bright lights,
swollen eyelids, or a white or gray round spot on the cornea. Self-treatment
consists of removing contact lenses, applying a cool compress to the affected
eye, washing hands often, and OTC pain medications such as Tylenol or Motrin.
Anyone with a corneal ulcer should be seen immediately by an ophthalmologist,
who will do testing and most likely prescribe antibiotic and other eyedrops. If
the ulcer persists or worsens, a surgical procedure known as corneal
transplantation may be performed.
Diabetic retinopathy
Diabetic retinopathy, a common complication of diabetes, affects the blood
vessels in the retina (the thin light-sensitive membrane that covers the back of
the eye). It is due to the retina not receiving enough oxygen. If untreated, it
may lead to blindness. If diagnosed and treated promptly, blindness is usually
preventable. There are two types: nonproliferative and proliferative
retinopathy. Nonproliferative retinopathy is the less severe type in which there
may be hemorrhages (bleeding) in the retina and leakage of blood or serum
causing a "wet retina." As a consequence vision may be diminished. Proliferative
retinopathy is a more severe type of diabetic retinopathy. New abnormal fragile
vessels develop on the surface of the retina and may grow toward the center of
the eye. These vessels frequently bleed into the vitreous (the clear jelly in
the center of the eye). Such bleeding episodes cause severe visual problems.
Treatment is by laser surgery or surgery on the vitreous. These techniques can
slow the progression of diabetic retinopathy and sometimes will reverse visual
loss. However, damage done may be permanent. Diabetic retinopathy can often be
prevented by lifestyle modification, including weight loss, dietary changes, and
exercise. In addition, better control of high blood sugar decreases the
incidence and the progression of diabetic retinopathy.
Strabismus (crossed eyes)
Strabismus, also known as crossed eyes, is a condition in which the eyes
don't look toward an object together. One of the eyes may look in or out or turn
up or down. The danger with strabismus in young children is that the brain may
come to rely more on one eye than the other and the less-favored eye fails to
develop its relationship to the brain properly, leading to decreased vision
(amblyopia) in that eye. The classic treatment for mild to moderate strabismus
has long been an eye patch covering the stronger eye, which forces the weaker
eye to do enough work to catch up. Severe strabismus may require surgery.
Floaters
"Eye floaters" are deposits or condensation in the vitreous jelly of the eye.
People use the term eye floaters to describe seeing floating spots within their
vision when they look around. People describe eye floaters as spots, straight
and curved lines, strings, or "O" or "C" shaped blobs. Some see a single floater
while others may think they see hundreds. Floaters may be present in one or both
eyes. The majority of eye floaters are caused by normal aging changes within the
eye. However, a person developing symptoms of eye floaters should be checked by
an ophthalmologist to make certain that there is no associated eye abnormality
which requires treatment. Most floaters will fade over time and become less
annoying or noticeable. Herbs, vitamins, and iodine-containing products have
been touted as effective in decreasing eye floaters. However, none of these have
been proven effective in clinical trials.
Farsightedness (hyperopia)
About one in four people in the U.S. have hyperopia or farsightedness, in
which people have difficulty focusing on close objects. The occurrence of
hyperopia increases with age; at least half of all people over the age of 65
have some degree of farsightedness. The condition occurs when light entering the
eye focuses behind the retina instead of directly on it. An abnormally flat
cornea or short eye can cause the light to be focused in this fashion. To
correct hyperopia you must change the way the light rays bend when entering your
eye. Glasses, contact lenses, or refractive surgery can all be used to correct
farsightedness.
Nearsightedness (Myopia)
Nearsightedness affects 20%-30% of the population, but this eye disorder is
easily corrected with eyeglasses, contact lenses, or surgery. People who have
myopia or nearsightedness have difficulty seeing distant objects but can see
objects that are near clearly. In people with myopia, the eyeball is too long or
the cornea has too much curvature, so the light entering the eye is not focused
correctly. Light rays of images focus in front of the retina, the
light-sensitive part of the eye, rather than directly on the retina, causing
blurred vision at distance.
Astigmatism
Astigmatism is a common form of visual impairment in which an image is
blurred due to an irregularity in the curvature of the front surface of the eye,
the cornea. In astigmatism, the curve of the cornea is shaped more like an
American football rather than a normal spherical basketball. Astigmatism occurs
in nearly everybody to some degree. Astigmatism can be hereditary and is often
present at birth. It can also result from pressure from the eyelids on the
cornea. Almost all degrees of astigmatism can be corrected with properly
prescribed eyeglasses or contact lenses. For a person with only a slight degree
of astigmatism, corrective lenses may not be needed at all, as long as other
conditions such as nearsightedness or farsightedness are not present. Another
method for correcting astigmatism is by changing the shape of the cornea through
refractive laser eye surgery.
Color Blindness
When we see different colors, we are perceiving differences in the light that
is reaching our eyes. The way we see different colors is something like the way
we hear different sounds as being low or high. The colors of every rainbow
always appear in the same order: red, orange, yellow, green, blue, indigo, and
violet. The different colors in each part of the rainbow correspond to a
different wavelength of light. Color blindness results from an absence or
malfunction of certain color-sensitive cells in the retina. The retina is the
nerve layer at the back of the eye that converts light into nerve signals that
are sent to the brain. A person with color blindness has trouble seeing red,
green, blue, or mixtures of these colors. Most color vision problems are
inherited (genetic) and are present at birth. Other color vision problems are
caused by aging, disease, injury to the eye (acquired color vision problems),
optic nerve problems, or side effects of some medicines. Tests are used to
measure the ability to recognize different colors with the most common test
being the pseudoisochromatic plate test (also known as the Ishihara color test).
The type of color vision problem you have can often be determined by which
patterns you can and can't see in the various plates used for the test.
Inherited color vision problems cannot be treated or corrected. Some acquired
color vision problems can be treated, depending on the cause.
Proactive Eye Health
Good eye health and eye care are crucial to the value of sight. Be proactive
in your eye health by taking a role in maintaining and protecting your sight,
avoiding eye injuries, preventing common eye disorders, and treating problems
early. Eye-care professionals, including ophthalmologists (medical doctors
specializing in diseases and surgery of the eye) and optometrists recommend that
everyone with visual or other eye signs or symptoms have their eyes checked. In
people who have no symptoms, it is recommended that people over 40 have their
eyes checked every two years and people over 60 have their eyes checked
annually.
After this, start visualizing your big toe of right foot in your mind. Visualize all the toes of that foot one by one. In the same way, get the picture of all the toes of the left foot starting from its big toe. Slowly move from the toes to calves, and then knee joints. Then mentally visualize thighs, trunk, inner parts of stomach, chest, shoulder joints, hands, neck, throat, chin, mouth, nose, ears, eyes, mid point of eyebrows, fore head and finally imagine the top mid point on your head. This location is called the seat of God. Do this visualization slowly and one by one from bottom to top of head. Then proceed in the same way but in reverse order from head to toes of your legs. When you do this, you will often feel a sort of tingling sensation in your body parts. Do this for at least 3 times a day. This observation leads your mind to forget the external world and increases your concentration. You will feel tranquility of mind.
