Glossary

Here you will find the most common terms used in and around an optometric office.

 

Age-related macular degeneration (AMD, ARMD) –Group of conditions that include deterioration of the macula, resulting in loss of sharp central vision. Two general types: “dry,” which is more common, and “wet,” in which abnormal new blood vessels grow under the retina and leak fluid and blood further disturbing macular function. Most common cause of decreased vision after age 60.

Amblyopia,“lazy eye“ -Decreased vision in one or both eyes without detectable anatomic damage in the eye or visual pathways. Usually uncorrectable by eyeglasses or contact lenses.

Astigmatism- Optical defect in which refractive power is not uniform in all directions. Light rays entering the eye are bent unequally by different meridians, which prevents formation of a sharp image focus on the retina. Slight uncorrected astigmatism may not cause symptoms, but a large amount may result in significant blurring and headache.

Blepharitis – Inflammation of the eyelids, usually with redness, swelling, and itching

Cataract- cloudiness of the crystalline lens which may prevent a clear image from forming on the retina. Surgical removal of the lens may be necessary if visual loss becomes significant, with lost optical power replaced with an intraocular lens, contact lens, or aphakic spectacles. May be congenital or caused by trauma, disease, or age.

Chalazion – Inflammed lump in a meibomian gland (in the eyelid). Inflammation usually subsides, but may need surgical removal

Color blindness- Reduced ability to discriminate between colors, especially shades of red and green. Usually hereditary.

Cone- Light-sensitive retinal receptor cell that provides sharp visual acuity and color discrimination.

Conjunctiva- Transparent muccous membrane covering the outer surface of the eyeball except the cornea, and lining the inner surfaces of the eyelids.

Conjunctivitis, “pink eye“ -Inflammation of the conjunctiva. Characterized by discharge, grittiness, redness and swelling. Usually viral in origin, but may be bacterial or allergic; may be contageous.

Cornea- The transparent front part of the eye that covers the iris, pupil, and anterior chamber.

Edema – An abnormal accumulation of fluid which causes swelling.

Eye lens – A transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina. By changing shape, the lens functions to change the focal distance of the eye so that it can focus on objects at various distances, thus allowing a sharp image of the object of interest to be formed on the retina.

Diabetic retinopathy -Spectrum of retinal changes accompanying long-standing diabetes mellitus. Early stage is background retinopathy. May advance to proliferative retinopathy, which includes the growth of abnormal new blood vessels (neovascularization) and fibrous tissue.

Dilated pupil- Enlarged pupil, resulting from contraction of the dilator muscle or relaxation of the iris sphincter. Occurs normally in dim illumination, or may be produced by certain drugs (mydriatics, cycloplegics) or result from blunt trauma.

Diopter – Unit to designate the refractive power of a lens.

Dry eye syndrome-Corneal and conjunctival dryness due to deficient tear production, predominantly in menopausal and post-menopausal women. Can cause foreign body sensation, burning eyes, filamentary keratitis, and erosion of conjunctival and corneal epithelium.

Enucleation- Is the surgical removal of the eye.

Fundus photographs -Provide views of the interior of the eye, including the retina and macula, and are taken by a special camera attached to a low power microscope.

Iris – A thin, circular structure in the eye responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina.

Macula – The central area of the retina is called the macula. The macula is responsible for sharp, central vision. Good central vision is critical for activities such as reading, driving, and sewing. If the macula is damaged by disease, the “straight ahead” vision is affected. The rest of the retina is responsible for peripheral vision.

Optic nerve – Also called cranial nerve 2, transmits visual information from the retina to the brain. Derived from the embryonic retinal ganglion cell, a diverticulum located in the diencephalon, the optic nerve doesn’t regenerate after transection.

Retina – In a manner similar to a camera, light enters the front of your eye through the cornea and lens and is brought to focus on the back of your eye on the tissue called the retina. In a sense, the retina functions like the film in a camera. From there, the signals are transmitted to the brain, thereby creating sight.

Sclera – Also known as the white or white of the eye, is the opaque, fibrous, protective, outer layer of the eye containing collagen and elastic fiber.

Vitreous – The clear gel that fills the central cavity of the eye.