The medical terms below are often encountered when dealing with eye diseases and conditions.  Their corresponding meanings should help laymen understand these terms.

Astigmatism:  One of the most common forms of visual impairment where a part of what you see is blurred caused by irregular curvature on the front surface of the eyeball.

Antibiotic:  A chemical compound marketed as a medicinal drug to treat infections caused by pathogens such as bacteria and other microorganisms.  There are natural antibiotics formulated from harmless microorganisms that inhibit the growth of harmful pathogens as well as synthetic antibiotics that are chemically produced in the lab to mimic natural antibiotics.

Bacteria:  Single-celled microorganisms which can be independent self sustaining and reproducing organisms or parasitic, requiring a host to survive.  Also called microbes, they can be harmless or disease causing which are more accurately called pathogens. This is a plural with Bacterium as singular.

Cataract: A condition when the lens of eye gets clouded and develops an opaque white covering to block of the cornea and impair vision which can result in partial or total blindness.

Congenital: Comes at the time of birth.  It is used to describe a medical condition that is present at birth.  Several uses of "congenital" include congenital diseases and abnormalities, to mention some.

Conjunctivitis: A condition where the membranes covering the white of the eye called conjunctiva and the inner linings of the eyelids get inflamed.  The inflammation is caused by the conjunctival membranes irritated by bacteria, viruses, allergy-inducing agents, irritants and toxic or strong chemicals.  Viral and bacterial conjunctivitis are prevalent among children but can attack adults as well. Pinkeye and redeye are vernacular references to conjunctivitis.

Cornea:  The transparent front part of the eyeball that covers the iris and pupil, allowing the clear transmission and fixed focusing of light into the eye.  It accounts for two-thirds of the eye’s optical refraction.

Corneal abrasion: A condition where the otherwise smooth glass-like surface of the cornea has a scratch or scrape which can compromise visual acuity.

Corneal transplant: A surgical process where the cornea or clear front fascia of the eyeball is replaced by a healthy cornea.  Using local anesthesia in an outpatient clinical setting, the transplantation is often indicated for persons with severe scarring of the cornea thrugh infection as in corneal ulcers, injury, and in genetic dysfunctions like keratoconus, an inherited corneal thinning that distorts vision as well as Fuch's dystrophy or corneal clouding with loss of vision.

Glaucoma: An eye disorder where the optic nerve is damaged progressively and permanently impairing vision in the affected eye that could result in complete blindness if untreated.  It is often caused by increased fluid pressure inside the eyes in a condition called intraocular pressure.

Laser:  Stands for Light Amplification by Simulated Emission of Light.  It is a concentrated beam of light which can be focused to produce intense heat. Used in medicine, low power lasers are used to cauterize wounds or cut tissue in microsurgery as well as for diagnostic purposes.

Nearsightedness: Medically termed as Myopia, this is a refractive disorder of the eye that allows it to see near objects (hence, the name) with greater focused clarity than distant objects.

Ophthalmologist: A doctor specialized in and practicing ophthalmology. More commonly referred to as an eye doctor, the ophthalmologist is an M.D.

Optometrist: A healthcare professional licensed to provide primary eye care services which involve diagnosing and treating refractive disorders.  The optometrist can generally do what an ophthalmologist can in terms of diagnosing and treating eye diseases but because he or she is not an M.D., is generally not licensed to prescribe treatment other than for corrective eyeglasses. But some states are allowing them to treat patients diagnosed with cataracts, glaucoma and retinal diseases.

Pupil: Part of the eye which is the opening of the iris directly over the retinal lens. In optics, this is the equivalent of the aperture.  It is the central-most black area surrounded by the colored and determines how much light enters the eye.  It dilates (opens) at night to receive as much light as it could and constrict (closes) in broad daylight to limit the amount of light. See other eye parts.

Refraction:  In ophthalmology, this is the process of bending of light occurring in the human eye that allows an image to be focused on the retina so you can see the object .

Refractive Error:  A condition that reduces visual acuity or loss of the focusing ability that results in blurry perception.  The condition is corrected with the use of eyeglasses or contact lenses as determined or prescribed by an optometrist.