The ability of the eye to focus on different distances using muscles to adjust the shape of the lens within the eye.
Amblyopia (Lazy Eye):
Children do not have a fully developed visual system until the approximate age of 8. Some children suppress one eye to overcome high amounts of blur or double vision thus not giving that eye a chance to develop properly. This results in a loss of vision that cannot initially be improved by glasses alone. In most cases the eye appears normal. The problem can be corrected if caught before the age of 8; however, it is difficult if not impossible to correct afterwards.
B
Blepharitis:
Blepharitis is inflammation of the eyelids usually caused by blocked oil glands that lie within the eyelids. Severe cases can result in bacterial infections, styes, corneal inflammation (keratitis) and conjunctivitis.
Biomicroscope with Digital Camera:
An instrument used by the optometrist to assess the ocular health on both the surface and within the eye at high magnifications. This instrument may be equipped with a camera to provide a digital record that can be referred back to at future assessments.
Colour vision:
The ability of the brain to perceive different types (wavelengths) of light as different hues. Most individuals are able to see the full colour palette or spectrum but some have difficulty seeing certain colours since they perceive colours differently. These individuals may be colour deficient or colour blind. It is important to know that true complete colour blindness is very rare and most patients who have issues with colour are colour deficient.
Comprehensive exam:
A full and complete eye exam that will determine your prescription and assess your ocular health. A comprehensive exam is recommended for all children and seniors on a yearly basis and adults every two years.
Conjunctivitis:
An inflammation of the surface tissue over the white of the eye. This inflammation can be caused by allergies, infection, or injury.
Contact Lens:
A medical device which is placed on the eye to help correct a patients prescription. Contact lenses can be either hard or soft. They can be very flexible in wearing time, replacement schedules and care regimes. All contact lenses are fit by the Doctors at Optometrists clinic so you can be assured that you will get the best for your health and lifestyle.
Contact Lens Overwear:
When not enough oxygen gets to the cornea as a result of wearing contact lenses longer than the recommended amount, irritation, redness and loss of vision can occur. This may lead to bacterial infections or corneal ulcers if it is not dealt with promptly. Contact lenses are a medical device and must be treated as such.
Corneal Ulcer:
An ulcer results from bacteria infiltrating a damaged or compromised cornea. The bacteria create a small divot on the cornea comparable to a pothole on a road. Corneal ulcers can be extremely painful and permanent loss of vision can occur. Contact lens wearers are at highest risk if they do not maintain proper cleaning, handling and disinfection of their lenses and cases.
Cataract:
As we age, the lens within the eye can become yellowed or cloudy. They are also common in diseases like diabetes or can be caused by certain medications. Cataracts tend to obscure vision much like a dirty windshield on a car. For most, it is a natural part of the aging process and is correctable with surgery.
Cycloplegic Refraction:
A secondary test done to better determine a patients refraction. Some patients, most often those with farsightedness, can use their eye muscles to help focus through their refraction in order to see better. This can lead to problems like fluctuating vision and headaches. Cycloplegia refers to the relaxation of the muscles responsible for focusing thereby allowing the doctor to determine how much refraction is actually present.
D
Diabetic Eye Disease:
Increased blood sugars affect the blood circulation system in the eye causing blood vessels to weaken and leak. This leads to swelling of the retina which causes loss of vision. Other conditions more likely to develop as a result of diabetes include cataracts, glaucoma and retinal detachments.
Dilation:
The process involving the relaxation of the papillary muscles to allow the pupil to become enlarged.
Dry Eye:
The tear film is responsible to keep the eye's surface well lubricated. Inconsistencies or insufficiencies within the tear film can cause symptoms such as stinging, burning, and scratchiness.
E
F
Farsightedness
(Hyperopia):
Farsightedness is caused by a shorter than normal eye or flatter than normal cornea. This causes the light entering the eye to focus behind the retina rather than directly on it. People with farsightedness tend to have difficulty seeing up close with associated eye strain yet may still have difficulty with distance tasks.
F.D.T. - Frequency Doubling Technology:
This instrument detects and measures peripheral vision loss that can occur in diseases like glaucoma or diabetes. This quick test is useful for screening purposes.
G
GDx:
This instrument measures and analyzes the nerve fiber layer inside the eye which is useful in the early detection of glaucoma.A retinal nerve fiber layer analyser. This state of the art tool objectively measures the nerve fibers density and its configuration.
Glaucoma:
An eye disease resulting in peripheral vision loss and eventual blindness as a result of nerve fiber death within the eye caused by high intraocular pressures. Other risk factors include family history and ethnicity. Early detection of glaucoma is paramount as there are generally no symptoms of the disease until it is in a late stage. Glaucoma is routinely screened at every comprehensive eye exam.
H
I
Intraocular hypertension:
A higher than normal pressure within the eye (> 21 mmHg) which is not related to eye disease. See glaucoma.
Iris:
The coloured part of the eye. This structure controls the amount of light entering the eye by adjusting the size of the pupil.
J
K
Keratoconus:
This degenerative disease results in a progressive thinning and bulging of the cornea into a volcano-like shape. This gradually causes the vision to become blurred and distorted which may not be correctable with glasses alone. People with keratoconus tend to have high amounts of nearsightedness and astigmatism as a result of the cornea's irregular shape.
L
Lens:
This clear structure within the eye helps to focus light on the retina. It is also responsible for accommodation by changing shape as we look at different distances.
M
Macular Degeneration:
Behind the retina there is another tissue layer which is partly responsible for feeding the retina. Over time this layer can weaken and develop holes and cracks which starves the portions of the retina directly in front of it. This starved retina eventually loses its sensitivity to light and central vision slowly deteriorates. This is known as the 'dry' form of macular degeneration. As time goes on, weak blood vessels grow through these cracks and bleed causing large areas of scaring in the retina. This is known as the 'wet' form of macular degeneration. Genetics, age, nutrition, smoking and exposure to the sun may cause this condition.
N
Nearsightedness (Myopia):
Nearsightedness is caused by a longer than normal eye or steeper than normal cornea. This causes the light entering the eye to focus in front of the retina rather than directly on it. People with nearsightedness have difficulty seeing at far distances but have little problems with near tasks.
O
Ocular Hypertension:
High (greater than 21 mm
Hg) intraocular pressure.
Ocular Motility:
The range of motion of the eyes and their ability to work together.
Ocular Health:
The overall health of structures in and around the eyes. It is very important to have your ocular health checked and is done at all complete eye exams.
P
Presbyopia:
Around the age of 40, the lens within the eye loses its flexibility and our ability to accommodate is lost. Accommodation refers to when the lens changes shape and thus changes our point of focus from distance to near. This condition is also known as 'short arm syndrome' which everyone experiences at some point in their lives.
Posterior Viteous Detachment (PVD):
PVD occurs in most individuals over the age of 65. As we age, the gelatinous vitreous loses its consistency so that the central core becomes more liquid and the outer layers peel from the retina. This does not cause vision loss.
Pink Eye:
This is caused by a viral or bacterial infection of the conjunctiva (the layer above the white of the eye or sclera). Viral infections are usually associated with a cold or sore throat. Bacterial conjunctivitis varies in severity which is dependent on the type of bacteria involved. Bacteria most often involved are staphylococcus and streptococcus (Staph. and Strep.)
Pupil:
The black spot surrounded by the iris. The spot is actually a hole which acts as a window to allow light to pass into the eye which allows us to see.
Q
R
Refraction
A clinical procedure performed to determine the type and strength of correction a patient requires for the clearest possible vision. The refraction is used to determine a prescription for different eye wear.
Retinal Detachment:
The retina is a thin tissue layer that can develop holes or even tears from numerous causes. These gaps allow fluid to seep underneath and separate the retina from the rest of the eye much like wallpaper peeling off a damp wall. When the retina has detached, vision is lost.
S
Stereopsis:
The ability of a patient to see in three dimensions. Some may recognise the test as “the fly test” when being examined. Recreational activities that require stereopsis include magic eye pictures and 3D movies.
Strabismus (Crossed eye):
Most eyes focus at the same spot sending slightly different perspectives to the brain so that we can judge depth and the three dimensions. Strabismus occurs when eye muscles cannot maintain both eyes on the same spot causing misalignment of the eyes or 'turned eyes'.
T
Tonometry:
A test to measure intraocular
pressure It is one of the tests that is used to screen for glaucoma.
Tonometer:
An instrument that measures the pressure within the eye. A common one is the non-contact tonometer which is commonly called the “puff of air” test.
U
V
Visual Field Test (Perimetry):
An instrument used to detect and closely monitor visual field loss that can occur with glaucoma or other neurological diseases. .
