Glossary

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A

Commonly Treated Conditions


 
Adult Strabismus
Some adults diagnosed with strabismus – misalignment of the eyes – have had the condition since childhood. However, an adult maybe diagnosed with strabismus having no previous eye conditions or family history.
(Read more...)

Treatment available from our:

 
Albinism

(al-buh-nih-zum)
A lack of pigment or color. The eyes may appear reddish or pink because the blood vessels show through the iris, which already lacks in color.
 

Amblyopia
(am-blee-OH-pee-uh)
Sometimes called "lazy eye," is a condition in which the brain cannot make normal use of the visual information coming from one of the eyes. Usually this is the result of a competition between the eyes at the level of the visual areas of the brain.
(Read more...)

Treatment available from our:

Aniridia
During conception phases, the gene mutation caused in creating a baby’s eyes may be undeveloped or function incorrectly. Aniridia means “without iris” and may lead to other severe eye conditions such as amblyopia, cataracts, glaucoma, nystagmus, or strabismus. 
 

Anisocoria
(a-nice'-ah-kor'-e-ah)
Unequal pupil sizes. 
 

Anisometropia
Power differences between each eye causing a lazy eye or a weaker eye and poor eyesight. The refractive error is different in the two eyes; this can sometimes cause amblyopia (Partial or complete loss of vision in one eye).
(Read more...)

Treatment available from our:

Anterior chamber
Fluid-filled space inside the eye between the iris and the innermost corneal surface (endothelium).


Anterior synechia
(see-neke'-e-ah)
Adhesions between the edge of the pupil and the anterior surface of the lens.

 
Anterior uveitis
(u-v-ite' -us)
Inflammatory cells suspended in the aqueous humor.


Aqueous humor
A clear, watery fluid circulating in the chamber of the eye between the cornea and the lens.


Astigmatism
Can be combined with either nearsightedness or farsightedness, and means that the amount of refractive error is different for vertical and horizontal objects.

Treatment available from our:

 

B

Binocular vision
Blending of the separate images seen by each eye into one composite image.

Treatment available from our:

 

C

Cataracts
A cataract is a clouding of the lens in the eye that affects vision and can occur in either or both eyes. The most common symptoms of a cataract are blurry vision, faded colors, glare, poor night vision and/or double vision.
(Read more...)

Treatment available from our:

 
Childhood glaucoma
Typically occurs within the first year of life when the eye’s drainage system is undeveloped. If left untreated, more severe damage to the optic nerve can occur and potentially lead to blindness.

Treatment available from our:

Clinical Trials
The Vision Center conducts ongoing clinical trials.
(Read More...)

Coats' disease
A rare eye disorder involving abnormal development of the blood vessels of the retina, which lines the interior chamber of the eye.
(Read more...)

Treatment available from our:

Coloboma
A gap in part of the structures of the eye. This gap can occur in the iris, the retina, or the optic nerve and can be large or small. The most common form of gap is caused by an imperfect closure of a cleft, present in the womb but usually closed by birth. Coloboma of the eye is an important cause of childhood visual impairment and blindness. (Read more...) 

Treatment available from our:

Coloboma of the iris
Keyhole-shaped pupil. 
 

Computer-assisted orthoptics
Vision therapy or exercise performed on a computer screen. 
  

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

Treatment available from our:

Congenital cataract
A lens that is opaque or not clear at birth.

 
Convergence insufficiency
This muscle condition causes the eyes to conflict and drift outward, resulting in strain or blurring, double vision and/or headaches.
(Read more...)

Treatment available from our:

Cornea
(KOR-nee-uh)
The transparent, or clear, front surface "front window" of the eye that covers the iris, pupil, and anterior chamber, providing a protective shield to outside harmful objects like germs, dust and dirt. It transmits and focuses light into the eye.

Similar to the lens of a camera, the cornea provides two-thirds of the eye's focusing power, acting as the camera's focus lens. Because of this, its five layers must be free of any cloudy or opaque areas to allow proper vision.

Treatment available from our:

Cornea transplant
Replacement of a damaged cornea tissue with healthy donated tissue in the eye. Because of this surgical procedure, vision can often times be restored.

Treatment available from our:

 
Corneal disorders
The cornea can easily be damaged by a foreign object, tear, bacteria and/or hereditary diseases. Some disorders affecting the cornea include: allergies, corneal dystrophies, corneal infections, dry eye, Peter’s anomaly, pink eye and more.

Treatment available from our:

Cortical vision impairment
Decreased vision due to poor functioning of the vision centers in the brain rather than due to eye disease.

Treatment available from our:

Cross-eyes
See strabismus
 
 

D

DeMorsier's Syndrome
See Optic Nerve Hypoplasia (ONH)
 

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
(di-AHP-tur)
Unit to designate the refractive power of a lens.
 

Dislocated lens
A lens that is not in its correct position. 
 

Duane's Syndrome
Duane’s syndrome is a rare, eye movement condition that is diagnosed during childhood. In most cases, only one eye is affected and will have limited movement due to the opposing contractions of the eye muscles. Eyes will stray outward or inward, up or down, and in some cases a head tilt or turn will occur to provide binocular vision and compensate for improper turning of the eye.

Treatment available from our:


E

Esotropia
(ee-soh-TROH-pee-uh)
Cross-eyes. Eye misalignment in which the eyes are turned inward relative to one another.

Treatment available from our:

Exotropia
(eks-oh-TROH-pee-uh)
Wall-eyes. Eye misalignment in which the eyes turn outward.

Treatment available from our:

Extraocular muscles
(eks-truh-AHK-yu-lur)
The extraocular muscles – six relatively small muscles – control the movement of the eyes in the socket, allowing them to rotate or turn horizontally and vertically. As such, these muscles play a crucial role in functional, accurate eye movement.

The six extraocular muscles (eye muscles) are:

  • Medial Rectus Muscle (inner eye muscle)
  • Lateral Rectus Muscle (outer eye muscle)
  • Superior Rectus Muscle (upper eye muscle)
  • Inferior Rectus Muscle (lower eye muscle)
  • Superior Oblique Muscle
  • Inferior Oblique Muscle

Treatment available from our:


Eye birth defects
Consists of a full spectrum of congenital diseases that result in anatomic abnormalities of the eye.

Treatment available from our:

Eyelids
Structures covering the front of the eye, which protect it, limit the amount of light entering the pupil, and distribute tear film over the exposed corneal surface.


Eye tumor
A growth or mass that occurs in or next to the eye.
See Retinoblastoma. 


F

Farsightedness
See hyperopia.
 

Floaters
Particles that float in the vitreous and cast shadows on the retina; seen as spots, cobwebs, spiders, etc. Occurs normally with aging or with vitreous detachment, retinal tears, or inflammation.
 

Fourth nerve palsy
Congenital or acquired dysfunction of the fourth cranial nerve affects the superior oblique eye muscle. May cause a head title due to compensate for the eye that is rotated outward. This condition can be corrected with surgery.

Treatment available from our:

Foveal hypoplasia
Foveal hypoplasia is the underdevelopment of the fovea, a small region in the center of the retina used for seeing fine detail.



G

Glaucoma
(glaw-KOH-muh)
Group of diseases characterized by increased intraocular pressure resulting in damage to the optic nerve and retinal nerve fibers. Glaucoma is the second leading disease in America resulting in blindness. While it is not curable, it can be controlled if detected and treated early. Increased intraocular pressure may cause irreversible damage to the eye if not controlled. Early detection and treatment are hampered by a lack of symptoms in the initial stages of the disease and by low levels of public awareness and knowledge that regular, comprehensive eye examinations are necessary.
(Read more...)

Treatment available from our:


H

Hereditary retinal degeneration
Because of all the complex functions the retina performs, the retina relies on a wide variety of genes to carry out its tasks. Should any one of these genes be lost or mutated, it can have a severe impact on vision. (Read more...)

Treatment available from our:

Horner’s Syndrome
Caused by damage or disruption to the sympathetic nerves to the eye. This results in a small pupil on one eye with a slightly droopy eyelid. When it occurs at birth it results in difference in the color of the eyes.

Treatment available from our:

Hydrocephalus
An abnormal accumulation of cerebrospinal fluid (CSF) within cavities called ventricles inside the brain. (The word "hydrocephalus" comes from the Greek: "hydro" means water, "cephalus" means head).
(Read more...)

Treatment available from our:

 
Hyperopia
(hi-pur-OH-pee-uh) or farsightedness, (also known as hypermetropia) is when the eyes are not naturally focused anywhere, not even for far distance. The child has to make special focusing efforts even to see far away, and extra focusing efforts on top of that to see up close.

Treatment available from our:


Hypertropia
Eye misalignment in which the eyes turn upward.

Treatment available from our:

Hyphema
(hi-phe'-ma)
Blood or a blood clot(s) in the aqueous humor obscuring the color of the iris following injury or trauma.


Hypopituitarism
The underactivity of the pituitary gland, resulting in inadequate hormone production. The development of the pituitary gland, found at the base of the brain, can be affected by optic nerve hypoplasia (ONH). The pituitary gland is the body’s master control gland; it makes and directs important hormones required for growth, energy control and sexual development.
(Read more...)

Treatment available from our:

Hypopyon
(hi-pope'-e-an)
A white layer of inflammatory cells that have settled out of the aqueous humor onto the surface of the iris and obscures the inferior portion of the iris.


Hypotropia
Eye misalignment in which the eyes turn downward.

Treatment available from our:

Intracranial pressure
Increased pressure within the head, that is often monitored after head trauma or injury. 
 

Intracranial Pressure Monitor
Currently the only way to measure cranial pressure is a spinal tap or surgery to measure the pressure. Spinal taps are done thousands times a year to measure intracranial pressure in people with head trauma, headaches or inflammatory disease. High pressure is treated with medications or surgery to prevent complications such as vision loss, headaches, nausea or even a stroke.

Being able to effectively measure intracranial pressure without an x-ray or spinal tap would save money and discomfort. Eye Technology Institute physicians have invented a device that calculates pressure intracranial pressure by scanning the optic nerve in back of the eye with optical coherence tomography. This involves modification of a device that is commonly available in ophthalmology offices. We are currently testing its accuracy.

 
Intraocular Lens
This plastic polymer lens is surgically implanted to replace the focusing power of the natural lens of the eye following cataract extraction. The Intraocular Lens (IOL) comprises two types of lenses; non-foldable (made of a hard plastic material) and foldable (made of silicone or acrylic).

  • Diagnosis: The most common diagnosis in children leading to recommendation for an intraocular lens is cataracts, where there is a need to replace the eye’s focusing power.
  • Treatment: A surgical procedure to insert the intraocular lens inside the eye. It can be done under local anesthesia in adults and general anesthesia in children and can take up to 30 minutes.

Treatment available from our:

Iris
The circular, colored curtain of the eye, which opens and closes to regulate the amount of light entering the eye.
 

Iris neovascularization
Abnormal vessels growing in the iris. 
  

Iritis
(i-rite-us)
Inflammation of the iris, the structure of the eye that gives the color and forms the pupil. Iritis can be caused by trauma to the eye, rheumatologic or infectious causes.

 

L

Laser
High energy light source that uses light emitted by the natural vibrations of atoms (of a gas or solid material) to cut, burn or dissolve tissues for various clinical purposes.
 

LASIK
(LAY-sik)
Type of refractive surgery in which the cornea is reshaped to change its optical power. A disc of cornea is raised as a flap, then an excimer laser is used to reshape the intrastromal bed, producing surgical flattening of the cornea. Used for correcting myopia, hyperopia, and astigmatism.

Treatment available from our:

Lazy eye
See amblyopia. 
 

Legal blindness
Best-corrected visual acuity of 20/200 or less, or reduction in visual field to 20¡ or less, in the better seeing eye. 
 

Lens
A transparent structure behind the iris that changes shape to focus light rays onto the retina in the back of the eye.

 
 
M

Macula
Small central area of the retina surrounding the fovea; area of acute central vision.

Treatment available from our:


Morning glory syndrome
A birth defect of the hole in the back of the eye through which the optic nerve exits on its pathway to the brain. This results in a funnel-shaped optic nerve head with the retina dragged into it causing the retinal vessels to radiate out from its center like spokes. Reflection from within the eye may give the appearance of a white pupil. MGS nearly always affects only one eye. Vision in the affected eye may be severely impaired or may worsen. There is an increased risk of retinal detachment.
(Read more...)

Treatment available from our:

Myopia
(mi-OH-pee-uh) 
Nearsightedness, is when the eyes are naturally focused up close, and adding special focusing efforts only bring the focus closer, so vision is always blurry for distant objects.

Treatment available from our:

 

N

Nasolacrimal duct obstruction (NLD)
A fairly common condition in which the tear drainage from the eye into the nose – the nasolacrimal duct – is closed off. When a blockage occurs in the NLD, tears build up on the surface of the eye, preventing bacteria or debris from clearing. This may cause infections or discharge.
(Read more...)

Treatment available from our:

 
Nearsightedness
See myopia.

Nystagmus
Commonly described as rapid to-and-fro involuntary movements of the eye, which may reduce vision in one or both eyes. Nystagmus may improve over time. 
 

O

Ocular disorders
Disorders that are found in the eye.


Ocular misalignment
Often referred to as strabismus, misaligned eyes can turn in or out, up or down. Strabismus can cause amblyopia (lazy eye) also in which vision is suppressed in one eye.
 

Ophthalmologist
(ahf-thal-MAH-loh-jist)
Physician (MD) specializing in diagnosis and treatment of refractive, medical and surgical problems related to eye diseases and disorders.

 
Optic nerve
The nerve that connects the eye to the brain and carries the impulses formed by the retina to the visual cortex. The optic nerve in the brain is about one-and-a-half inches in length, and contains approximately 1.2 million nerve fibers.

Treatment available from our:


Optic nerve birth defects
An outcome of undeveloped nerves from the eye to the brain, the optic nerve consists of connections that may not have fully developed during gestation.

Treatment available from our:


Optic nerve hypoplasia (ONH)
A disease of the hypothalamus in the base of the brain. ONH is the under-development or absence of the optic nerve combined with possible brain and endocrine abnormalities. It is also known as Septo-Optic Dysplasia or DeMorsier's Syndrome. Now at epidemic proportions, ONH is the single leading cause of blindness and visual impairment in young children.  
(Read more...)

Treatment available from our:

Optic neuritis
Optic neuritis is the inflammation of the optic nerve. As this nerve transmits visual information to the brain, optic neuritis may cause temporary vision loss. 
 

Optometrist
(ahp-TAHM-uh-trist)
Doctor of optometry (OD) specializing in vision problems, treating vision conditions with spectacles, contact lenses, low vision aids and vision therapy, and prescribing medications for certain eye diseases.
 

Orthoptics
Discipline dealing with the diagnosis and treatment of defective eye coordination, binocular vision, and functional amblyopia by non-medical and non-surgical methods, e.g., glasses, prisms, exercises.

 

P

Papilledema
Swelling of the front of the optic nerve, usually in both eyes, caused by elevated intracranial pressure. Without the relief of the pressure in the brain, permanent vision loss may develop.
 

Papillitis
Papillitis is optic neuritis affecting the front of the optic nerve. It has similar appearance as papilledema, except that this condition usually affects one eye causing acute temporary vision loss.


Patching
Covering an amblyopic patient's preferred eye, to improve vision in the other eye. 
 

Peripheral vision
Side vision; vision elicited by stimuli falling on retinal areas distant from the macula.


Peters Anomaly
In this rare congenital disorder, the cornea may be scarred, and cataracts and glaucoma can develop. Congenital clouding of the cornea, secondary to its maldevelopment, requires early transplantation for a child to see. This disease often involves physical delays in the child.
(Read more...)

Treatment available from our:

Posterior Uveitis
(u-v-ite'-us)
An inflammation of the uvea, which may include areas of the eye such as the iris, ciliary body, and choroids.

 
Preferential looking test
Infants and toddlers are not able to identify figures for vision testing. However, when certain striped figures are presented, the child’s eyes and head movements are monitored to see if they prefer looking at the figure. Visual acuity is estimated based on the finest stripes that an infant prefers.

This device measures visual acuity in pre-verbal toddlers and infants by tracking eye movements and recording how quickly the children respond to a novel target on a TV screen. The device does not require any attachments; children can sit in a family member’s lap while being tested. We are currently in Phase 2 clinical studies to determine the device’s accuracy for very young children.


Presbyopia
Occurs in adults, not children, is when the aging eye loses its ability to make special focusing efforts, resulting in the need for reading glasses to see up close.

 
Pseudostrabismus
In pseudostrabismus, a child’s eyes appear to be crossed but are not true crossed eyes. The undeveloped facial features on the baby or child’s face often reveal the presence of pseudostrabismus.
(Read more...)

Treatment available from our:

Pseudotumor cerebri
Meaning "false brain tumor," it is raised intracranial pressure of unknown cause. It is better described as idiopathic intracranical hypertension (IIH). If not controlled, IIH may lead to progressive, permanent, vision loss. 
 

Pupil
The dark aperture or opening in the center of the iris which gets bigger or smaller, depending on the light coming in.



R

Raman spectroscopy
This innovative technology measures blood glucose levels without the necessity of a needle stick, which could be useful for people with diabetes and other conditions. The concentration of specific molecules in the aqueous humor or watery fluid of the eye provides an accurate reflection of their concentrations in the blood or in the brain.

The new technology uses infrared light, which is comfortable for the patient and doesn’t damage the eye. It is based on Raman Spectroscopy, which elicits a molecular “signature.” The technique may also allow non-invasive monitoring of how children metabolize chemotherapy or antibiotics or how they respond to insulin treatment. It also can detect alcohol levels.

The Eye Technology Institute currently is in Phase I clinical trials for the measurement device to demonstrate that it is safe and effective in humans.

Treatment available from our:

Red Reflex Testing
Red reflex testing is an essential component of the neonatal, infant, and child physical examination. This statement, which is a revision of the previous policy statement published in 2002, describes the rationale for testing, the technique used to perform this examination, and the indications for referral to an ophthalmologist experienced in the examination of children.
 

Refraction
Test to determine an eye's refractive error and the best corrective lenses to be prescribed. Series of lenses in graded powers are presented to determine which provide sharpest, clearest vision.

Treatment available from our:

Refractive disorders
Refers to common conditions such as astigmatism, farsightedness (hyperopia), nearsightedness (myopia) and presbyopia. Refractive surgery, glasses, contact lenses are typically used in treating refractive disorders.

Treatment available from our:


Refractive error
Refractive error, also referred to as refraction, or your child's eye prescription, is a measure of how sharply your child's eyes are naturally focused for far away when he or she is not making special focusing efforts. When there is no refractive error, the eyes are naturally focused for far distance, and special focusing efforts are only used to change the eyes' focus to closer objects. A large refractive error can cause blurry vision and may need glasses correction.

Treatment available from our:

Refractive surgery
Using sophisticated surgical techniques and state-of-the-art equipment, surgeons at the Cornea Institute reshape the corneal surface and remove the refractive error in the eye. Most refractive eye surgeries are performed on an outpatient basis, with most procedures lasting less than one hour in duration. The eye is usually numbed with eye drops prior to surgery. Recovery times vary depending on the surgery, but can last anywhere from a couple of days to a few months.

Treatment available from our:

Retina
(RET-ih-nuh)
The retina, the inner layer and light sensing structure of the eye, contains a million rods and 7 million cones, which handle vision in low light and color, respectively.

Treatment available from our:

Retina disorders
A retina disorder causes messages from the retina to the brain is interrupted. There are various types of retina disorders that may lead to visual deficits or even blindness.

Treatment available from our:

Retinal detachment
Separation of the retina from the underlying pigment epithelium. Disrupts visual cell structure and thus markedly disturbs vision. Almost always caused by a retinal tear; often requires immediate surgical repair.
(Read more...)

Treatment available from our:

Retinal diseases
Anomalies of the retina that may at some point, lead to a visual impairment if not caught early in life. The most common type of retinal disease in children is Retinopathy of Prematurity (ROP). 

Treatment available from our:

Retinitis pigmentosa
Usually inherited condition characterized by progressive degeneration of the retina, resulting in night blindness and decreased peripheral vision.

Treatment available from our:

Retinoblastoma
(reh-tin-oh-blast-oma) (Rb)
A malignant cancer of early childhood that arises from immature retinal cells in one or both eyes.
(Read more...)

Treatment available from our:

Retinopathy of prematurity (ROP)
The second leading cause of blindness in infants. It results from premature birth, which interrupts the normal development of blood vessels in the retina, the light sensitive part of the eye essential for vision. Abnormal blood vessels can begin to grow the wrong direction and lead to lifelong blindness.

Treatment available from our:

Retinoscope (RET-in-oh-skohp)
Device for measuring an eye's refractive error with no response required from the patient. Light is projected into the eye, and the movements of the light reflection from the eye are neutralized (eliminated) with lenses.


Rod
Light-sensitive, specialized retinal receptor cell that works at low light levels (night vision). A normal retina contains 150 million rods.

Treatment available from our:

S 

Septo-Optic Dysplasia
Optic Nerve Hypoplasia (ONH) is the under-development or absence of the optic nerve combined with possible brain and endocrine abnormalities. It is also known as Septo-Optic Dysplasia or DeMorsier's Syndrome. 
(Read more...)
 

Sixth nerve palsy
Dysfunction of the sixth cranial nerve affects the lateral rectus muscle and does not allow the eye to turn outward. Typically common in one eye, the disorder can in some cases affect both. Surgery or injection of Botox may help or correct the problem.

Treatment available from our:

Spasmus nutans
Spasmus nutans is a fine nystagmus (rapid eye movements), head tilting and nodding. This condition may start as early as four months to one year old, but usually resolves by age three years.  
 

Strabismus
(struh-BIZ-mus)
Misalignment of the eyes, which makes it impossible for the brain to use the information from the two eyes together normally. 
(Read more...)

Treatment available from our:

Superior oblique palsy
See fourth nerve palsy.

 

T

Third nerve palsy
Congenital or acquired dysfunction of the third cranial nerve and the brain results in difficulty moving the eye up, down, or toward the nose. It also causes drooping of the eyelid and may cause a dilated pupil.

Treatment available from our:

Traumatic cataract
Injury to the lens causing the lens to become opaque.
 

 
U

Uveitis
Inflammation of the pigmented layer of tissue within the eye from a variety of causes. If not treated, uveitis can lead to blindness, glaucoma, or light sensitivity. 


V 

Vitreous (VlT-ree-us) body
A transparent jelly-like substance, which provides a cushioned support for the rest of the eye and a clear unobstructed path for light to travel to the retina. The vitreous humor, the clear gel in the vitreous body, makes up about 80% of the eye's total volume. 
 

Vitreous detachment
Separation of vitreous gel from retinal surface. Usually innocuous, but can cause retinal tears, which may lead to retinal detachment. Frequently occurs with aging as the vitreous liquifies, or in some disease states, e.g. diabetes and high myopia.

Treatment available from our:

Vitreous hemorrhage
Blood in the vitreous caused by bleeding from the iris, retinal vessels, underlying choroids and many other causes that may initiate bleeding in the eye.  
 

Vitreous traction
The vitreous is the clear gel in the eye and when we are born is adherent to the surface of the retina. As we get older (typically after the age of 20), the vitreous can separate from the retina. As it separates, it can "tickle" the retina and cause it to think that it is seeing lights (similar to what happens when you hit your funny bone). Once the vitreous separates cleanly, the flashes stop. In those cases where the vitreous is very adherent, it can't release and instead tears the retina at that spot, creating a hole that can lead to a retinal detachment.