Laser Eye Surgery Terms Beginning with 'A'

Aberrometer

A diagnostic device that measures the way light waves travel through the eye and any distortion the eyes optical system creates as the light passes through. Used in laser eye surgery to calculate wavefront guided treatments.

Ablation

The removal of tissue using an excimer laser in laser eye surgery to correct a refractive error. Used in LASIK and Epi-LASIK and the treatment of Keratoconus at AccuVision.

Accommodation

In optics this means the capability of the eye to automatically focus from distance to near objects and from near to distance objects.

Accommodation disorder

Where the eyes ability to focus from distance to near ojects and from near to distance does not work correctly. Disorders can be caused by a number of symptoms such as: eye strain, headache, difficulty concentrating (especially reading), blurred vision, double vision. Presbyopia is an example of an Accomodation disorder where near vision is impaired because the lens inside the eye can no longer focus the eye on near objects.

Age Related Macular Degeneration (AMD or ARMD)

Age Related Macular Degeneration is caused by damage to the retinal cones (the part of the eye that transfers images and colour to the brain). A gradual loss of central vision occurs leaving just the peripheral vision for seeing.

Allergy

The body's immune system is programmed to protect the body from foreign bodies e.g. pollen. Allergy symptoms can also affect the eyes, usually showing as redness of the eyes, tears, swollen eyelids or itching.

Amaurosis Fugax

This is sometimes described as an 'Eye Stroke'. It is caused when a blood clot restricts blood flow to the eyes causing temporary vision loss. It usually affects just one eye.

Amblyopia

Also known as Lazy Eye. If the central vision in one eye is less developed than the other, the brain becomes dependent on the information from the good dominant eye. An eye patch is used to help correct Amblyopia at an early age. The two main causes of lazy eye are Strabismus and Anisometroia. It can also be treated in adults using Neurovision.

Aniridia

A condition where the iris in the eye is either absent or partially absent. It is usually a congential defect in the eye and causes photophobia and poor vision.

Anisocoria

A condition where pupils are of unequal size. Causes are various including: a natural event in the population without a known cause, head or eye trauma, previous intraocular surgery, an infection of the membranes around the brain, an intercranial tumor and glaucoma.

Anisometropia

A common condition in people with impaired vision where the prescription needed for good vision is very different for each eye due to the differences in refractive power.

Anterior chamber

The part of the eye located behind the cornea and in front of the iris and lens.

Antibody

This is a specific protien that is initiated by the body's immune system to help fight foreign substances, toxins and infections inside the body.

Antioxidant

A substance that restricts oxidation thereby guarding persons from the effects of 'free radicals'. Free radicals are molecules with one or more unpaired electrons and they can destroy cells and can be part of the cause of various diseases. Antioxidant vitamins include vitamins B, C and beta carotene. Antioxidants may help prevent macular degeneration and eye diseases.

Aqueous humor

This is the clear fluid filling the front of the eye, located between the cornea and the iris. It supplies nutrients to the cornea and the lens. The fluid is created by the ciliary body. If this fluid is not able to drain away freely, pressure builds up and can cause Glaucoma. If this is not overcome, damage to the optic nerve can occur resulting in loss of vision.

Arcus

This describes fatty/oily deposits causing an opaque ring around the periphery of the cornea. It is a condition of elderly people but can also occur in people under the age of forty and is an indication of excessive level of cholesterol in the blood stream.

Aspheric

Meaning not quite a spherical shape. In vision terms people who suffer high perscriptions usually prefer aspheric glasses as they can be produced using thin lenses and lightweight frames and reduce eye magnification. Aspheric contact lenses are designed to overcome astigmatism and can also be used as a multi-focal lens.

Astigmatic Keratotomy

A surgical procedure involving the cutting of the cornea to facilitate making it more spherical after it has healed and thereby reducing astigmatism.

Astigmatism

Where the curvature of the cornea has developed in an asymmetrical shape (shaped like a rugby ball instead of a football). Consequently light entering the eye is focussed on two points on the retina rather than just one, which causes blurred vision. Astigmatism also causes double vision, squinting, eyestrain, distorted vision and shadowing around letters.

Atopy

Used to describe an increase in the antibody immunoglobin E that leads to conditions such as asthma, hay fever, eczema and rhinitis.

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