|
Home
Contacts
Acuvue Contact Lenses
Freshlook Contacts
Focus Daily
Discount Contacts
Bifocals
Toric
Color Contacts
Manufacturers
Bausch and Lomb
Ciba Vision
Coopervision
Accessories
Contact Lens Cases
Contact Lens
Solutions
Vision
Eye
Exams
Computer Vision
Sports Vision
Vision and Nutrition
Contact
Lens Prescriptions
LASIK & Vision
Surgery
Eye Illnesses
Astigmatism
Macular
Degeneration
Myopia
Presbyopia
Hyperopia
Cataracts
Diabetic
Retinopathy
Glaucoma
Retinal Detachment
|
Eye Exams
A comprehensive eye exams involves a number of different tests, each of
which is designed to provide information about vision limitations and
physical eye health. There are a few different kinds of eye doctors who
can carry out eye exams, but each also has a different, more defined
function.
1) Ophthalmologists
Ophthalmologists hold a doctorate of medicine (M.D.). These doctors have
an intimate knowledge of all types of eye conditions and diseases, and can
perform eye surgery when required.
2) Optometrists
Optometrists hold a doctor of optometry degree (O.D.). Optometrists
typically diagnose vision limitations, prescribe corrective lenses, and
when vision disorders are present, refer patients to ophthalmologists.
3) Opticians
Opticians specialize in prescription eyeglasses. In certain geographical
locations, they can distribute and fit contact lenses as well.
The American Academy of Ophthalmology suggests that the following time
frames for comprehensive eye exams be followed;
Individuals with healthy eyes and no signs of vision impairment should
undergo eye exams once between the ages of 20-40, every two years between
the ages of 40 and 65, and annually after age 65.
Kids and teens should have an eye test prior to 3 months of age, again
between 6 months and one year of age, at three years, and at 5 years. At
young ages, eye tests can be performed by the child's pediatrician, or
another eye doctor. A child who shows signs of vision impairment, who has
been diagnosed with an eye condition, or who has a disease that puts their
vision at risk, such as
diabetes, should have routine eye exams annually.
About Eye Exams
A comprehensive eye exam involves several different tests measuring
peripheral vision, depth perception, visual acuity, color vision, and the
ability to focus close up. Different kinds of instruments and lenses are
employed to test vision and eye health. Every part of the eye is examined
for any role it may play in various eye disorders.
Eye Tests
Several tests exist to examine both the physical characteristics of the
eye itself, as well as aspects of vision. These tests include:
1) Visual Acuity Test
This is the eye test most people are familiar with. Using a Smellen chart
containing various letters, numbers and/or symbols, a patient's ability to
read the chart indicates how clearly one can see from a distance. The
results of a visual acuity test are expressed as a fraction, for example
20/20 vision. The top 20 indicates the distance from the chart at which
the patient can read accurately (20 feet with normal vision), whereas the
bottom number indicates the distance that one with normal eyesight can
accurately read the chart.
2) External Eye Examination
Only light is used in this physical examination of the eye itself. The
doctor assesses how the pupil responds to light, both the movement and
position of the eyes, corneal health, and the clarity of the iris.
3) Slit-Lamp Exam
This exam allows the doctor to assess the cornea, iris, lens and anterior
chamber of the eye under intense magnification. An intense light is beamed
through a slit lamp so that the doctor can see a cross section of the
front areas of the eye and check for any abnormalities. The doctor may
choose to use a dye to check for corneal problems such as tears, scrapes,
cuts, or infections. The doctor uses blue light, making the dye appear
yellow as it spreads across the eyes.
4) Retinal Exam
An ophthalmoscope or slit lamp is used to diagnose any irregularities in
the retina, vitreous fluid, choroid or optic nerve. Dilating eye drops are
placed in the eye, widening the pupils and proving a better view into the
back potion of the eye. A retinal exam can be used to detect signs of
diseases such as high blood pressure or diabetes.
5) Perimetry (Visual Field Test)
Visual field refers to the area in front of an individual that they are
able to see without moving the eyes. The Perimetry test uses a
computerized machine that flashes spots of light at varying brightness
onto different locations of a screen. Each time the patient can see a
spot, they press a button that records the results, providing a map of
where vision is strong or weak. Eye disorders such as
macular degeneration or
glaucoma cause characteristic patterns of holes in a patient's visual
field, allowing the doctor to diagnose the disorder long before a patient
even notices vision loss. The Amsler grid is another test used to assess a
patient's visual field. A grid with a black dot at the center is used to
test each eye's ability to focus clearly. Each eye is tested to assess
whether the grid can be seen clearly as the eye focuses on the dot.
Distortion of the graph can indicate retinal damage.
6) Refraction Assessment
Crisp vision relies heavily on the eyes ability to correctly focus light
waves that pass through the cornea and lens onto the center of the retina.
The ability to assess a patient's refraction helps a doctor determine the
lens prescription best suited to a patient's vision needs. Both a
computerized refractor, or Retinoscopy can be used to test for refractive
errors. Then, an instrument called a Phoroptor is used to fine tune the
exact lens best able to correct the error.
7) Tonometry (Glaucoma test)
Glaucoma is an eye disease that causes damage to the optic nerve, usually
due to increased pressure within the eye. The deterioration of the optic
nerve hampers peripheral (side) vision. When left untreated, glaucoma can
lead to blindness; however, with treatment, it is a manageable eye
disease. Tonometry measures internal eye pressure. Tonometry measures the
amount of force required to briefly flatten the cornea. When internal eye
pressure is high, glaucoma is typically diagnosed.
8) Fluorescein Angiography
This test is used to diagnose diseases present in the retina or choroid. A
dye is injected into a vein in the arm, causing the blood vessels in the
choroid and retina to appear yellow when the dye reaches and circulates
through the eye. A camera is used to take pictures every couple of
minutes, allowing a doctor to see whether any abnormalities in the blood
vessels exist. This exam is typically used to detect the presence of
macular degeneration and
diabetic retinopathy.
There is no reason why an individual should not undergo eye tests at the
suggested intervals proposed by the Academy of Ophthalmology. If a patient
isn't experiencing any vision problems, corrective lenses are not required
and vision will not worsen without them. Understanding any irregularities
or abnormalities present in the eyes and early diagnosis of such problems
is critical to planning successful treatment of a number of eye diseases.
Resources: Learn more about
pediatric eye exams. Learn if you qualify
for the National Eye Care Project's free
eye exams for seniors. |
