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Home » Eye Care Services » Eye Health & Emergencies » Eye Conditions & Glossary

Eye Conditions & Glossary

The following is a list of common eye conditions and a glossary of eye terms.

  • Marcus Gunn pupil or afferent pupillary defect (APD) is a medical sign observed during the swinging-flashlight test whereupon the patient's pupils constrict less (therefore appearing to dilate) when a bright light is swung from the unaffected eye to the affected eye. The affected eye still senses the light and produces pupillary sphincter constriction to some degree, albeit reduced. The most common cause of Marcus Gunn pupil is a lesion of the optic nerve (between the retina and the optic chiasm) or severe retinal disease. It is named after Scottish ophthalmologist Robert Marcus Gunn.
  • Cataracts are a common cause of vision loss after age 55. Learn more about recognizing cataracts symptoms, protecting your eyes and understanding cataract surgery.
  • How does diabetes affect vision? What does diabetes mean for eyesight? Learn more about eye problems resulting from diabetes including diabetic retinopathy, the most common diabetic eye disease and a leading contributor to blindness for adults in America.
  • Are you bothered by red, itchy eyes? You may have allergies.

  • Glaucoma is an eye disease that causes damage to the optic nerve due to a buildup of pressure in the eye. Known as the “sneak thief of vision,” this condition will cause a loss of the peripheral vision.
  • Commonly called “lazy eye,” amblyopia can be treated successfully if detected early enough in childhood.

  • Macular Degeneration is an eye disease that affects the portion of the eye responsible for processing fine detail and providing sharp central vision (called the macula).
  • Anisometropia is the condition in which the two eyes have unequal refractive power; that is, are in different states of myopia (nearsightedness), hyperopia (farsightedness).

  • A lens treatment for your glasses that helps to reduce distracting glare and eye fatigue by reducing the amount of light reflecting off the lens surface and making the lenses appear clearer.  You eyes will also be more visible behind the lenses.
  • Asteroid bodies are a relatively common finding in the vitreous that can occur in one eye and in patients over the age of 60.  This physiological change in the vitreous is also related to a similar condition of the vitreous called synchysis scintillans.
     
  • Often mistakenly called “stigmatism,” this common vision problem can be corrected with eyeglasses, contact lenses or refractive surgery.

  • Bell's palsy is a sudden paralysis of the facial muscles on one side of the face
  • Lenses that use two different distinct powers in each lens, usually for near and distance correction.
  • Red, swollen eyelids and crusty debris at the base of your eyelashes are signs you may have blepharitis.
  • A thorough eye exam is helpful in diagnosing a variety of ocular, as well as systemic cancers.  Such as Breast Cancer, Lung Cancer, Melanoma, Retinoblastoma and more.
  • Cellulitis refers to an inflammation or an infection of cellular or soft tissues around the face and eyes.  
  • A hordeolum or a chalazion is commonly called a stye.  
  • A nevus is a collection of pigmented cells similar to ordinary freckles, or a mole, found on the skin.  A nevus can occur in several areas of the eye.  A nevus on the retina is commonly called a choroidal nevus due to its location at the base of the retina.  
  • AIDS or other diseases that affect your immune system can increase your risk of serious eye problems from cytomegalovirus (CMV) infection.

  • A lack of ability to distinguish certain colors.  Commonly called "color blindness", the most common form of color deficiency is the inability to distinguish shades of red and green.
  • The transparent, multi-layered front part of the eye that covers the pupil and iris.  It provides most of the eye's optical power.
  •  Recurrent corneal erosions are described as repeated disruptions of the outer-most surface of the cornea, the clear window of the eye.  
  • Paragon CRT (Corneal Refractive Therapy) lenses are used for FDA approved overnight corneal reshaping.
  • Dermatitis identifies an inflammatory condition of the skin.  
  • Diplopia, commonly known as double vision, is the simultaneous perception of two images of a single object that may be displaced horizontally, vertically, diagonally (i.e., both vertically and horizontally), or rotationally in relation to each other. 
  • Drusen, often called exudates, are yellowish, round, dome-shaped deposits of cholesterol and triglycerides deep in the retina.  
  • Basal Cell Carcinomas are most common (90% of eyelid tumors).  Other eyelid skin cancers are squamous cell tumors and malignant melanomas which are less likely, but more dangerous.
  • “Floaters” are usually normal and harmless. But if you notice a sudden increase in floaters or floaters accompanied by flashes of light, see your eye doctor immediately.
  • Also called farsightedness, hyperopia is a common vision problem that can cause headaches, eyestrain and trouble reading.

  • Organic foreign bodies could create a fungal infection.  Metalic foreign bodies, depending on the speed at which they hit the eye, could potentially injure the retina or at least develop a rust ring.  
  • A tiny spot in the center of the retina that contains only cone cells. This area is responsible for our sharpness of vision.
  •    Fuch's Dystrophy, or the observation of guttata, is a progressive loss of the back layer of cells (endothelial layer) that keep the window of the eye, the cornea, clear.  As these cells are lost, the cornea will swell resulting in foggy or blurred vision.  If the swelling becomes severe, blisters may form on the cornea resulting in pain and variable vision.
  • A dense lens material that results in thinner, lightweight lenses than standard plastic.  Index refers to index of refraction which is the speed that light travels through the lens.  Higher Index lenses are available from 1.56 to 1.74 (the higher the number, the thinner the lens).  They benefit people with stronger prescription eyeglasses.
  • Histoplasmosis is a fungal infection of the retina.  
  • Also called farsightedness, hyperopia is a common vision problem that can cause headaches, eyestrain and trouble reading.
  • The pigmented (colored) membrane that lies between the cornea and the crystalline lens that shape to focus light rays onto the retina.
  •  The iris, the colored part of the eye, is muscle tissue with a thin layer of pigment laying on the surface.  The function of the iris muscle is to decrease the pupil size in bright light and increase the pupil size in darkness.  Iritis is an inflammation of this iris muscle.  
  • This eye disease causes the cornea to grow thinner and bulge forward in an irregular cone-shape. Treatment options range from gas permeable contact lenses to a cornea transplant.

  •  LASIK is the most commonly performed refractive surgery proceedure. LASIK is short for "laser-assisted in situ keratomileusis."


  • Lattice degeneration describes focal areas of thinned retina.  
  • The eye's natural lens located directly behind the iris.  It has the ability to change shape to focus light rays onto the retina.
  • The part of the retina responsible for the sharp, central vision needed to read or drive.
  • Slight irritation of the eye caused by a foreign body on the eye's surface such as sand, dirt or eyelashes.  Wash your hands, then flush the eye with lukewarm water for up to 15 minutes.  If the irritation remains and discomfort continues, call our office immediately.
  • Multi-focal lenses let you focus on two or more distances through the same lens (usually distance, intermediate, and near).  Also know as Bi-focals, Tri-focals, or Progressives.
  • Also called nearsightedness, myopia is a very common vision problem, affecting up to one-third of the U.S. population.

  • Commonly called "night blindness," this is a condition that presents as impaired vision in dim light or darkness.
  • A condition of involuntary eye movement, either congenital or acquired.
  • You’ve heard of high blood pressure, but what about high eye pressure?

  • A migraine headache is usually a throbbing headache often accompanied by nausea, extreme sensitivity to light, sounds, tingling sensations, and on occasion, a visual disturbance called an aura. The visual aura is most often not associated with a headache, however an aura can precede the classic migraine headache.

  • A bundle of nerve fibers that carries messages from the eyes to the brain.
  • Optic neuritis is inflammation of the optic nerve.  
  • Optomap Retinal Imaging provides a 200 degree retinal image with a quarter of a second flash.  A dilated-view without dilation drops.
  • Refers to lenses that automatically change from clear to dark in the presence of ultraviolet (UV) radiation.  Some of the most common photochromic lenses are Transitions® lenses.
  • If you have light sensitive eyes, you might be experiencing photophobia.

  • Pingueculae and pterygia are funny-looking words for growths on the surface of your eye.

  • This acute and contagious form of conjunctivitis is particularly common among preschoolers and school-age children.
    For more information and pictures about "Pink Eye" click HERE.

  • This is a lens material often used for minor prescriptions.  Very few lenses are made from glass today, since glass is heavier, thicker, and can shatter.  Also referred to as standard index or by the brand name CR-39.
  • Polarized lenses diminishes glare from reflections off of horizontal surfaces.
  • Multi-focal lenses with no visible lines where the lens gradually changes from distance to near.  Also called PALs (Progressive Addition Lenses).
  • Ptosis is a drooping eyelid. Surgery is usually required to correct this problem.

  • The opening in the center of the iris that changes size to control how much light is entering the eye.
  • An instrument used to measure the distance between pupils. This measurement is used to position the eyeglass prescription correctly in front of each eye.
  • Test to determine an eye's refractive error and the best corrective lenses to be prescribed.
  • Part of the rear two-thirds of the eye that converts images from the eye's optical system into impulses that are transferred by the optic nerve to the brain.  Consists of layers that include rods and cones.
  • A detached retina is a medical emergency. Learn the warning signs of a retinal detachment and what you can do to avoid permanent vision loss.

  • These inherited disorders, commonly abbreviated as RP, cause progressive peripheral vision loss, night blindness and central vision loss.

  • Retinoschisis is a condition where the retina splits apart in a small area.  
  • These are cells inside the eye used by the retina to process light.  Rods are used for low light levels (night vision), cones are used for sharp visual acuity and color perception.
  • The white part of the eye - composed of fibrous tissue that protects the inner workings of the eye.
  • Herpes zoster, or shingles, is an infection of the nervous system with a strain of the herpes virus.  
  • Types of lenses that correct one vision problem, like near or far-sightedness.
  • Sometimes called "crossed eyes" in young children, this condition is the lack of coordination between the eyes, such as one or both eyes turning in, out, up or down.
  • Commonly referred to as "UV Rays", these are light waves that consist of both UVA and UVB rays from the sun.  Without proper protection, chronic exposure to UV rays can lead to various eye conditions and damage.
  • This common problem is simply an infected lid gland. Learn how to prevent and treat styes.

  • This inflammatory eye disease can cause permanent vision loss if not promptly treated.
  • Assessment of the eye's ability to distinguish object details and shape - numerically experessed as 20/20, 20/70, etc.

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