A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

O

Ocular Albinism

A form of albinism in which only the eyes are affected. The genes fail to make the usual amounts of a pigment called melanin. The typical reddish or violet eyes associated with albinism may not be present and instead, the eyes may be blue, green or even brown and physically appear to be normal. However, on examination by your eye doctor, it may show that there is very little pigment in the iris of the eye.

The hallmark of ocular albinism is in the fovea, the small area of the retina which affords acute vision. In ocular albinism, the fovea does not develop completely due to an absence of melanin pigment needed during pre-natal development. The eye cannot process sharp light images. Because the fovea does not develop well, it is difficult to correct vision completely with glasses.

Another problem present in ocular albinism is that nerves from the back of the eye to the brain do not follow the usual pattern of routing. A test called a visually evoked potential, which is performed like an EEG or brain wave test, can show this condition.

What causes it?
Albinism is an inherited genetic disorder. It affects one in 17,000 in the United States alone and affects people of all races.

What are the symptoms?
Light and glare sensitivity (photophobia), crossed eyes, lazy eye, and visual acuity problems. Albinos often have low vision problems and some are legally blind. Nystagmus (erratic rapid movement of the eyes back and forth) may also be present.

Eye problems often result from the lack of pigment. The iris, the colored part of the eye, lacks pigment in the albinic eye and therefore allows stray light to enter the eye where it normally wouldn't. This results in an exaggerated sensitivity to light and glare. In addition, the retina (the part of the eye that receives incoming light) does not develop normally in utero or process correctly after birth.

What can be done?
Because there is no way to correct the lack of pigment, treatment of the associated conditions is necessary. Surgery to correct Strabismus or Esotropia can correct crossed or lazy eyes, vision therapy can help improve the strength of the eye muscles, and optical aids can be prescribed to aid in daily activities. Bifocals, reading glasses, contact lenses, and bioptics can all help with low vision problems.

Additional keywords and misspellings:
albino

Ocular Allergies

Definition:
Allergic reactions to the eye and eyelid are quite common. More than half of all cases of conjunctivitis is allergic; eyes are sensitive to irritants such as soap, cosmetics, detergents or fabric softener, or simply airborne allergens that have come in direct contact with the eye (usually during high pollen seasons). Pollen and dust can trigger a histamine release which causes burning, itching, watering of the eye, and can also be accompanied by nasal discharge.

Types of ocular allergies include:

  • Eczema
  • Dermatoconjunctivitis
  • Vernal Conjunctivitis
  • Contact Lens Conjunctivitis (also known as Giant Papillary Conjunctivitis, or GPC)
  • Blepharitis

What are the symptoms?
Symptoms of an allergic reaction include redness, tearing, oozing, crusting, and itching.

What is the treatment?
Treatment of the symptoms depends on the type of allergic reaction. For more information, click on the underlined words to learn more about symptoms and treatment options.

Additional keywords and misspellings:
eye allergies , tearing, allergic lid edema, eczema, excema, blepharitis, blefaritis, inflammation, itchy eyes

Ocular Anterior Segment
The anterior portion of the globe (cornea, iris and anterior sclera).
Ocular Hypertension
High intraocular pressure, a reading greater than 21 mm Hg. High pressure can be indicative of Glaucoma.
Ocular Posterior Segment
That portion of the eye posterior to the iris.
Oculist
Opthalmologist
Oculocutaneous Albinism

ock' kew loh kuh TAY' nee us AL' buh nizm

A form of albinism in which the eyes, skin and hair are affected. The genes fail to make the usual amounts of a pigment called melanin, resulting in white hair, skin, and reddish or violet eyes.

Oculocutaneous Albinism

What causes it?
Albinism is an inherited genetic disorder. It affects one in 17,000 in the United States alone and affects people of all races.

What are the symptoms?
Pale, cream-colored skin and hair; reddish eyes, extreme light sensitivity, crossed eyes, lazy eye, and visual acuity problems. Nystagmus (erratic rapid movement of the eyes back and forth) may also be present.

Eye problems often result from the lack of pigment. The iris, the colored part of the eye, lacks pigment in the albinic eye and therefore allows stray light to enter the eye where it normally wouldn't. This results in an exaggerated sensitivity to light and glare. In addition, the retina (the part of the eye that receives incoming light) does not develop normally in utero or process correctly after birth.

What can be done?
Because there is no way to correct the lack of pigment, treatment of the associated conditions is necessary. Surgery to correct Strabismus or Esotropia can correct crossed or lazy eyes, vision therapy can help improve the strength of the eye muscles, and optical aids can be prescribed to aid in daily activities. Bifocals, reading glasses, contact lenses, and bioptics can all help with low vision problems.

Additional keywords and misspellings:
albino albinism white red eyes

OD
Abbreviation for the right eye (oculus dexter, Latin)
Ophthalmologist

off thal moll' oh jist

An Ophthalmologist is a medical doctor who specializes in eye and vision care and has an M.D.designation on their name. Ophthalmologists are specially trained to provide the full spectrum of eye care, from prescribing glasses and contact lenses to complex and delicate eye surgery.

Ophthalmology

off thal moll' oh jee

The branch of medicine dealing with the science of the structures, functions and diseases of the eye.

For more information about Ophthalmology, visit the American Academy of Ophthalmology website at www.aao.org

Ophthalmoscopy

off-thal-MOSS-koh-pee

A safe, non-contact examination of the inside of the eye and retina. The ophthalmoscope is a small handheld device. The head of this tool contains many lenses and projects light through a variably sized aperture, and is attached to a handle which serves as the power source. To perform the examination, lights in the exam room are dimmed, allowing the pupil to maximally dilate. If the pupil is still not dilated sufficiently, a topical solution may be used to aid in dilation. The patient is then asked to fixate on a target. By varying the lenses, the distance and aperture size, the doctor can survey the iris, lens, vitreous, retina and optic disc.

Optic Disc

The optic disk is the visible part of the optic nerve. This is where the images we see are transmitted to the brain.

Optic Disc

Optic Nerve
A bundle of nerve fibers located at the back of the eye, responsible for taking the information from the retina as electrical signals and delivering it to the brain where this information is interpreted as a visual image.
Optometrist

Doctors of optometry are independent primary health care providers who examine, diagnose, treat and manage diseases and disorders of the visual system, the eye and associated structures as well as diagnose related systemic conditions. Optometrists examine the internal and external structure of the eyes to diagnose eye diseases like glaucoma, cataracts and retinal disorders; systemic diseases like hypertension and diabetes; and vision conditions like nearsightedness, farsightedness, astigmatism and presbyopia. Optometrists also do testing to determine the patient's ability to focus and coordinate the eyes, and to judge depth and see colors accurately. They prescribe eyeglasses and contact lenses, low vision aids, vision therapy and medicines to treat eye diseases.

As primary eye care providers, optometrists are an integral part of the health care team and an entry point into the health care system. They are skilled in the co-management of care that affects the eye health and vision of their patients and an excellent source of referral to other health care professionals.

The optometrist has completed pre-professional undergraduate education in a college or university and four years of professional education at a college of optometry, leading to the doctor of optometry (O.D.) degree. Some optometrists complete a residency.

Definition courtesy of the American Optometric Association

Optometry

Optometry is the science that deals with studying the eye and related structures for visual difficulties and eye disorders. Optometry is also concerned with vision testing, vision training, eye exercises, and the prescription of corrective devices such as eyeglasses and contact lenses, all for the purpose of making someone's vision the best it can possibly be. Someone who studies optometry is known as an optometrist.

Additional keywords and misspellings:
optometer opto eyedoctor doctor optometric physician eyecare

Ortho Keratology
Also known as Ortho-K, it is the use of contact lenses to change the shape of the cornea in order to correct refractive error.
OS
Abbreviation for the left eye (oculus sinister, Latin).
OU
Abbreviation for both eyes or each eye (oculus uterque, Latin).
Outer
Relative to an imaginary point centrally located within the eye; further from this imaginary point.
The Eye Encyclopedia is a collection of eye care terminology created by practicing optometrists and ophthalmologists. The information provided is not intended to be a substitute for regular medical care or to diagnose or treat any medical condition, and should be used only as a supplemental source of information. Please consult your doctor if you have any questions or concerns about your eye health.