Aqueous Fluid/Aqueous Humor: A clear fluid that fills the front part of the eye providing oxygen and nourishment.

Astigmatism: A refractive error that prevents the light rays from forming a single focus on the retina.

Blepharitis: Inflammation of the margins of the eyelids.

Blepharoplasty: Plastic surgery of the eyelids.

Cataract: A condition in which the crystalline lens of the eye, the capsule surrounding the lens, or both, lose clarity causing loss of visual acuity.

Chalazion: Inflammatory enlargement of the meibomian gland of the eyelid.

CO 2 Laser: Carbon dioxide laser used extensively for laser skin resurfacing and plastic surgery.

Conjunctiva: A thin mucous membrane that lines the white part of the eye (sclera) and the inside of the eyelids.

Cornea: The clear, transparent portion of the front of the eye.

Erbium Laser: Laser used for laser facial peels and laser skin resurfacing.

Excimer Laser: Laser used to precisely reshape the cornea for laser vision correction (LASIK and PRK.)

Farsightedness: See Hyperopia

Hyperopia: A condition of the eye causing the image to focus beyond the retina. In our youth the innate accommodating (focusing) power of the eyes often compensates for farsightedness; as we age, our eyes become less able to make this accommodation.

LASIK: Laser Vision Correction

Lens:

A piece of glass or plastic used to refract (bend) light rays to correct the effects of myopia, hyperopia or astigmatism.

The elastic crystalline lens of the eye that lies directly behind the pupil and is held in place by zonules (fibers that are attached to the ciliary body). This lens is responsible for fine-tuning visual images.

Myopia: A condition of the eye, usually due to the cornea being too curved or the eye being too long, whereby the focal image is formed in front of the retina (also known as Nearsightedness).

Nearsightedness: See Myopia

Optic Nerve: The second cranial nerve. The optic nerve transmits signals from the retina to the brain.

PRK: An acronym for Photo Refractive Keratectomy

Refractive Error: A condition of the optical system of the eye whereby images are not focused clearly on the retina. Glasses, contact lenses or refractive surgery can usually correct the condition.

Refraction: The sum of steps performed in arriving at a decision as to what lens (if any) will most benefit the patient. The steps include refractometry, measurement of visual activity, and exercise of clinical judgment.

Refractive Surgery: Eye surgery to change the way the structures of the eye bend light rays in order to focus the light rays on the retina. The surgery is usually performed on the cornea.

Retina: The region at the post-exterior chamber of the eye that contains all the sensor receptors for the transmission of light. These receptors consist of two main types--rods and cones. Cones function best under daylight conditions. Rods function best in dim light and allow us to see at night and with good vision.

RK; Radial Keratomy: Incisional surgery of the cornea to flatten the cornea and correct nearsightedness.

Sclera: The "white" coating of the eye. This outer layer maintains the integrity of the eye.

Uveal Tract: The inner coating of the sclera that provides much of the blood supply to the retina.

Vitreous humor: The jelly-like fluid inside the eyeball