Bard Optical Vision Glossary


Progressive Lenses: Progressive lenses offer a full range of vision correction, from up-close objects to those at a distance. Instead of dealing with multiple pairs of glasses or a set of bifocals, progressive lenses create a seamless progression of lens strength, allowing you to see your world better from any distance. These lenses can be particularly helpful to those suffering from presbyopia – a common condition for people over the age of forty, often noted through difficulty reading, particularly in low-light
Sola HDv (manufactured by Carl Zeiss) generic info on Hi-def lenses: Digital HD (high-definition) lenses, or “free form” lenses, offer unprecedented visual quality. The process puts this lens design on the back surface of the lens, resulting in less peripheral distortion. This offers you a 20-40% wider viewing area across your visual field. They provide sharper vision and increased clarity, so colors are more defined and details are more vivid. They can be customized for your prescription and frame choice.
Anti-Reflective Lenses: Anti-Reflective lenses work to eliminate reflections on either side of your glasses. With Anti-Reflective lenses, you can improve the efficiency of your glasses since less light is lost. Your vision will improve, as well as the appearance of your lenses. The coating also helps to repel water and grease, making them easier to clean. These lenses appear nearly invisible in your frames, and they reduce annoying glare. This can significantly improve your night driving or viewing of screens.
Polarized Lenses: Polarized lenses work as a filter, eliminating light from reflective surfaces. There are many common sources, including roads, water, snow, car hoods, and even water vapor in the air. Using polarized lenses results in increased visual clarity and comfort outdoors. Colors will appear more vibrant, details will be more precise, and they eliminate UVA/UVB rays.
Polycarbonate Lenses: Polycarbonate lenses are up to 30% thinner than plastic and are 10 times stronger than plastic, making them impact resistant and virtually unbreakable. These lightweight frames provide 100% protection from UV rays. They are an excellent choice for children, people who regularly participate in sports, or are in environments where their eyeglasses may be easily broken.
CR-39 Lenses: CR-39 lenses (or hard resin lenses), a plastic lens, are the most common lens sold. They are lightweight and very affordable. These frames are lighter than glass, making them a comfortable fit for any individual. They are available in many styles, and easy to tint.


age-related macular degeneration: often called AMD or ARMD, is the leading cause of vision loss and blindness among Americans who are age 65 and older. Because people in this group are an increasingly larger percentage of the general population, vision loss from macular degeneration is a growing problem.
amblyopia: also known as lazy eye, is a vision development disorder in which an eye fails to achieve normal visual acuity, even with prescription eyeglasses or contact lenses. Particularly if lazy eye is detected early in life and promptly treated, reduced vision can be avoided. But if left untreated, lazy eye can cause severe visual disability in the affected eye, including legal blindness. It’s estimated that about 2 to 3 percent of the U.S. population has some degree of amblyopia.
astigmatism: a condition caused by an irregularly shaped cornea. Instead of the cornea having a symmetrically round shape (like a baseball), it is shaped more like a football, with one meridian being significantly more curved than the meridian perpendicular to it. There are three types of astigmatism, Myopic, Hyperopic and mixed. Astigmatism is detected during a routine eye exam with the same instruments and techniques used for the detection of nearsightedness and farsightedness. Astigmatism, like nearsightedness and farsightedness, usually can be corrected with eyeglasses, contact lenses or refractive surgery.


bifocal: a lens that is designed with two different prescription areas to correct for both near and distance vision.
bridge: the part of a spectacle frame that extends across the nose.


cataract: is a clouding of the eye’s natural lens, which lies behind the iris and the pupil. Cataracts are the most common cause of vision loss in people over age 40 and is the principal cause of blindness in the world. There are three types of cataracts, Subcapsular, Nuclear and Cortical. Cataract surgery is very successful in restoring vision. In fact, it is the most frequently performed surgery in the United States, with more than 3 million Americans undergoing cataract surgery each year, according to PBA. Nine out of 10 people who have cataract surgery regain very good vision, somewhere between 20/20 and 20/40.
color blindness: an inability to distinguish between certain colors such as red and green (most common form – colors would appear as yellow). This condition is an inherited trait that occurs almost exclusively in males, but the recessive gene that causes the condition is carried by the female.
cone: nerve cells of the retina (along with rods) that transmit impulses along the optic nerve to the brain. Cones provide color vision and respond best to bright light.
conjunctivitis: commonly referred to as “pinkeye”; an infection of the mucosal membrane that both covers the eye and lines the eyelid and is caused by bacterium, viruses, or allergies. Symptoms include redness, itching, and discharge. Treatment is often performed with antibiotics or cortisone. This infection was a major cause of blindness in infants prior to the use of silver nitrate eye drops for newborns.
cornea: transparent layers of cells and proteins that cover the front of the eye and serve to both control and focus light into the eye. Most common problems with visual acuity, including hyperopia (farsightedness), myopia (nearsightedness), and astigmatism, are due irregularities in the shape of the cornea.
corneal abrasion: a cut or scratch within the cornea. This may be caused by foreign objects such as dirt, sand, wood or metal shavings, dust, fingernails, etc. that come in contact with the surface of the eye. Firm rubbing of the eyes can also cause an abrasion.
corneal ulcer: an erosion or open sore in the outer layers of the cornea caused by infection, abrasion, foreign bodies, severe allergy, severe dryness of the eye, various types of inflammatory disorders, stress, and an impaired immune system. Symptoms include eye pain, redness, blurred vision, light sensitivity, increased tearing, or a white patch on the cornea.


diabetic retinopathy: leading cause of blindness among individuals of working age; caused by complications associated with diabetes in which blood vessels of the retina become damaged and leak causing retinal swelling and the formation of deposits (non-proliferative or background retinopathy). The condition becomes more serious when new, weaker vessels form on the surface of the retina that can bleed into the vitreous causing severe visual impairment (proliferative retinopathy).
diopter: unit of measurement that describes the refractive (light-bending) power of a lens and is used in prescriptions. A negative value indicates a correction for nearsightedness (myopia), while a positive value indicates a correction for farsightedness (hyperopia).


farsightedness: see hyperopia.
floaters: small clumps of cells or gel in the vitreous that appear as specks or clouds moving within the field of vision. These clumps or strands are caused by a thickening or shrinking of the vitreous gel within the eye which then pulls away from the back surface of the eye (posterior vitreous detachment).


glaucoma: a disease in which the optic nerve becomes damaged. This is most often caused by an elevated pressure inside the eye (intraocular pressure) due to the build up of a liquid substance called the aqueous humor. This condition is the leading cause of blindness among African-Americans.


high index: a term used to describe a type of spectacle lens that has a higher index of refraction than standard glass or plastic lenses. Because theses lenses are more dense than standard glass or plastic, light rays pass more quickly through the lens to the eye and do so with less material (i.e. thinner, lighter lenses).
hyperopia: farsightedness; vision of nearby objects is impaired, while distance objects remain in relative focus. Light is focused on a point that lies behind the retina.


iris: the muscular diaphragm that controls the size of the pupil. The iris itself is NOT responsible for eye color, but rather allows the pigmentation of the choroid (a layer beneath the sclera or white portion of the eye) to be visible.


keratoconus: a progressive thinning of the cornea which results in a cone-shaped bulge that causes blurry or distorted vision. This condition may result from heredity, injury, or certain eye or other diseases. Usually the cornea heals and regains stability without causing severe visual impairment, but in few instances the cornea will gradually deteriorate and require a corneal transplant.


LASIK: Laser-Assisted In Situ Keratomileusis; a type of refractive surgery in which a thin layer of corneal tissue is removed via laser to correct certain degrees of myopia.
lens: transparent structure within the eye that focuses light rays upon the retina.


macula: small area of the retina that contains specialized light-sensitive cells that provide detail and allow for performance of fine tasks and reading.
multifocal: term that describes a type of lens (spectacle or contact lens) that has more than one focal area such as bifocal, trifocal, or progressive (“no-line bifocal”) lenses.
myopia: nearsightedness; close objects are in relative focus while distant objects are blurred. Light is focused on a point that lies in front of the retina.


nearsightedness: see myopia.


ocular hypertension: a condition of elevated pressure within the eye (intraocular pressure) that may lead to glaucoma.
ophthalmologist: a doctor of medicine (M.D.) or doctor of osteopathy (D.O.) who specializes in both the medical treatment and surgical care of the eyes and the visual system. Ophthalmologists must complete four or more years of medical school, one year of internship, and three or more years of specialized training and experience.
optician: state licensed professionals who interpret and fill a prescription from an optometrist or ophthalmologist for corrective eyewear. An optician is trained in the selection and fitting of eyeglasses and contacts (with special license). Qualifications for licensure include successful completion of a 2 year college program in optical science or a 2 year apprenticeship under a licensed optician or optometrist, followed by a state license examination. Opticians must also attend continuing education classes each year to maintain their license.
optometrist: doctors of optometry (O.D.) who specialize in the examination of the eyes and the visual system as well as the diagnosis and treatment of certain ocular diseases, injuries, and other health problems. An optometrist can prescribe many ophthalmic medications, but cannot perform surgery. They may, however, participate in pre-operative and post-operative care relating to eye surgery. Optometrists must complete four years of post-graduate optometry school.


photochromic lenses: spectacle lenses that undergo a chemical reaction when exposed to the ultraviolet (UV) wavelengths in sunlight. The reaction causes molecules within the lens to absorb light which causes them to darken.
pinguecula: a common, non-cancerous growth of the clear, thin tissue (conjunctiva). The growth is raised slightly from the surface of the white part of the eye (sclera). A pingueculum is a small, yellowish bump on the conjunctiva near the cornea. It can appear on either side of the cornea, but occurs more often on the nose (nasal) side.
presbyopia: condition that arises when the lens in the eye becomes less flexible, making it difficult to bring close objects into focus and requiring special correction via bifocal or multifocal lenses or contacts. Often becoming noticeable by the age of 40-45, presbyopia is not a disease, but simply a natural part of the aging process.
prescription analysis: Once your eye examination is complete and all the necessary tests have been done, the optometrist will give you a copy of your prescription. This contains the precise measurements of the type of prescription lenses that you will need in order to have the clearest, most comfortable vision.
pupil: the adjustable opening at the center of the iris that allows variable amounts of light into the eye. The pupil will expand or dilate in response to low light conditions in an attempt to bring more light into the eye and will reduce in size when intense light is present.


refractive surgery: a surgical procedure that corrects problems with visual acuity with the objective of reducing or eliminating the need for prescription glasses or contact lenses.
retina: a thin layer of light sensitive nerve tissue lining the interior of the eye that translates light waves into nerve impulses that are sent to the brain.
retinal detachment: occurs when the retina separates from the rear wall of the eye. Vision loss occurs at these detached areas.
retinitis pigments: a genetically inherited condition in which rod cells degenerate causing impaired vision in low light conditions and may eventually lead to diminished peripheral perception.
RGP: Rigid Gas Permeable; a type of contact lens that is made of a permeable plastic that is custom made to the shape of the cornea and allows for oxygen to pass through the lens to the eye.
rods: light-sensitive cells located in the peripheral (side) areas of the retina. They are responsible for detecting movement, shape, light and dark. The visual picture provided by rods is in black and white.
RK: Radial Keratotomy; a surgical procedure in which several incisions are made in the cornea in a radial or spoke-like pattern in order to flatten the cornea and correct for myopia.


sclera: the outer layer of the eye that forms the visible white area of the eye and extends from the cornea in the front of the eye to the back of the eye where it meets and surrounds the optic nerve.
strabismus: “crossed eyes”; a condition in which the one or both of the eyes are misaligned caused by poor muscular control. The condition often occurs in children before 21 months of age but may develop as late as age 6. Treatments include corrective eyewear, visual therapy, or surgery.
sty: an inflammation of the eyelid near the eyelash caused by a blockage of a gland in the eyelid due to bacterial infection.


toric lenses: a lens used to correct astigmatism by providing two different optical powers at 90-degree angles to each other.
trifocal: a lens designed with three different focal areas. Often the top segment provides distance correction, a center segment corrects for intermediate distances, and the lower portion corrects for near objects and reading.


ultraviolet (UV): light rays that compose part of the invisible portion of the electromagnetic spectrum. Excess exposure to UV radiation can be harmful to eyes and skin resulting in sunburn, skin cancer, cataracts, etc.
UVA: a component of ultraviolet radiation that can pass through window glass and penetrate the layers of the skin. This light is most intense during early morning and afternoon hours and is responsible for tanning of the skin and wrinkles. Greater than 90% of UV radiation is composed of UVA.
UVB: a component of ultraviolet radiation that is most intense during midday. Unlike UVA, it cannot penetrate window glass, but is associated with sunburn.


visual acuity test: The visual acuity test is used to determine the smallest letters you can read on a standardized chart (Snellen chart) or a card held 20 feet away. Special charts are used when testing at distances shorter than 20 feet. The visual acuity test is a routine part of an eye examination or general physical examination, particularly if there is a change in vision or a problem with vision. In children, the test is performed to screen for vision problems. Vision problems in young children can often be corrected or improved. Undetected or untreated problems may lead to permanent vision damage.