Glossary of Terms-- Everything You Wanted to Know About the Eye

Accommodation Eye

Accommodation

The ability of the eye to transition seamlessly from focusing on objects at various distances.

For more information please see: http://www.medicinenet.com/script/main/art.asp?articlekey=10528

Acetate

A type of durable plastic often used in the production of eyeglasses.

For more information please see: http://www.shadesdaddyblog.com/difference-between-standard-plastic-and-acetate/

Automated Lamellar Keratoplasty

A form of refractive surgery, focusing on the superficial layers of the eye, meant to correct vision.

For more information please see: http://www.aoa.org/patients-and-public/caring-for-your-vision/corneal-modifications/refractive-surgery-and-corneal-modification-definitions?sso=y

Amblyopia

Also known as “lazy eye”. Vision disorder that occurs when the brain favors one eye over the other, leading to decreased vision in the weak eye.

For more information please see: https://nei.nih.gov/health/amblyopia (Or link to our article?)

Amsler Grid

Amsler Grid

A graph used as a tool for early detection of macular degeneration. Macular degeneration will cause the grid to appear wavy, blurred, or with missing parts.

For more information please see: http://www.amd.org/the-amsler-grid/

Anterior Chamber

The part of the eye that is in between the cornea and the iris.

For more information please see: http://www.eophtha.com/eophtha/anatomy/anatomyofanteriorchamber.html

Aphakia

An eye disorder in which the eye is missing its lens. This results in long-sightedness and a loss of accommodation.

For more information please see: http://www.eyehealthweb.com/aphakia/#

Aqueous Humor

The fluid between the cornea and lens of the eye. Aqueous humor production and drainage create intraocular pressure.

For more information please see: http://www.eyepedia.co.uk/eyes-vision/eye-anatomy/internal-eye/aqueous-humour/

A-Scan

An ultrasound performed on the eye to diagnose various vision disorders.

For more information please see:http://emedicine.medscape.com/article/1228447-overview

Asthenopia

Also known as eyestrain. This condition can be caused by excessive computer use, reading, or other activities that reduce the frequency of blinking.

For more information please see: http://www.eyehealthweb.com/eye-strain/#

Astigmatism

Astigmatism

Blurred vision as a result of an irregularly shaped cornea.

For more information please see: http://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/astigmatism?sso=y

Background Retinopathy

Damage to the small blood vessels in the eye, often caused by diabetes.

For more information please see: http://www.diabetes.co.uk/diabetes-complications/background-retinopathy.html

Bifocals

Eyeglasses with two lens powers allow the wearer to see both up close and far away clearly.

For more information please see: http://www.allaboutvision.com/lenses/multifocal.htm

Binocular Vision

The brain’s ability to receive the images transmitted by both the left and right eye and combine them into one image.

For more information please see: http://www.city-optometry.com/2015/06/05/binocular-vision-dysfunction-and-treatment/

Blepharitis

Inflammation and irritation of the eyelid.

For more information please see: http://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/blepharitis?sso=y (Or our article about it)

Blind Spot

An area in the vision plane of each eye that lacks vision receptors.

For more information please see: https://www.britannica.com/science/blind-spot

B-Scan

An ultrasound done on the eyes, through closed eyelids, to detect various eye diseases.

For more information please see: http://www.advancedsightcenter.com/Home/PatientEducationLibrary/tabid/8610/ctl/View/mid/13781/Default.aspx?ContentPubID=435

Cataract

Cataract

Clouding of the eye’s lens, resulting in impaired vision. Cataracts are the most common cause of vision loss in people over the age of 40.

For more information please see: http://www.allaboutvision.com/conditions/cataracts.htm

Central Retinal Artery

The artery that transports blood into the eye.

For more information please see: http://www.medicinenet.com/script/main/art.asp?articlekey=10589

Central Retinal Vein

The vein that transports blood out of the eye.

For more information please see: http://www.medicinenet.com/script/main/art.asp?articlekey=10594

Central Vision

The eye’s ability to see and focus on objects straight in front of you.

For more information please see: https://driversed.com/resources/terms/central_vision.aspx

Chalazion

A bump inside the eyelid that develops as a result of a stye.

For more information please see: http://www.allaboutvision.com/conditions/chalazion.htm

Choroid

A vascular layer in the eye between the retina and sclera.

For more information please see: http://www.eyepedia.co.uk/eyes-vision/eye-anatomy/internal-eye/choroid/

Color Blindness

An inability to differentiate between different colors.

For more information please see: https://nei.nih.gov/health/color_blindness/facts_about

Cone

Cone

A photoreceptor in the eye that allows the eye to see various colors.

For more information please see: http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html

Conjunctiva

A moist membrane that encompasses the outside of the eye.

For more information please see: http://www.medicinenet.com/script/main/art.asp?articlekey=9893

Conjunctivitis

A common eye disease in which the eye’s conjunctiva becomes inflamed and swollen. It is often referred to as “pink eye” due to the pink color of the inflamed conjunctiva.

For more information please see: http://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/conjunctivitis?sso=y

Convergence

The eyes’ ability to work together and turn inward in order to focus on things, such as the words in a book.

For more information please see: https://nei.nih.gov/news/pressreleases/101308

Cornea

The transparent covering of the front portion of the eye. The cornea allows light into the eye and focuses it, allowing for clear vision.

For more information please see: http://www.healthline.com/human-body-maps/cornea

Cross-eyed

Term referring to Strabismus: a condition in which the eyes are misaligned.

For more information please see: http://www.strabismus.org

Crystalline Lens

A clear lens that refracts light and allows the eye to accommodate.

For more information please see: https://www.aao.org/bcscsnippetdetail.aspx?id=f38d473f-c836-4fe6-8555-20d34ce19816

Cycloplegic Refraction

Cycloplegic Refraction

An eye exam in which drops are used to relax the eye in order to get the most accurate prescription possible.

For more information please see: https://www.verywell.com/cycloplegic-refraction-3421806

Diabetic Retinopathy

Too much sugar in the blood, which can lead to lasting damage to the eyes.

For more information please see: http://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/diabetic-retinopathy?sso=y

Dilated Pupil

The pupils are the black openings in the center of the eyes. They appear larger when dilated. Dilated pupils occur in dark conditions when the eye needs to let more light in.

For more information please see: https://www.healthgrades.com/symptoms/dilated-pupils

Diopter

A unit of measurement indicating how strong your eyeglass or contact lens prescription is.

For more information please see: http://www.vision-training.com/en/Vision%20test/Understand%20presecription.html

Diplopia

Commonly referred to as “double vision”, diplopia is the occurrence of one object being perceived as two.

For more information please see: http://www.merckmanuals.com/professional/eye-disorders/symptoms-of-ophthalmologic-disorders/diplopia

Drusen

Fatty deposits under the eye’s retina. Drusen can also occur as deposits of protein and calcium in the optic nerve.

For more information please see: https://www.aao.org/eye-health/diseases/what-are-drusen

Dry Eye Syndrome

A condition in which the eye does not naturally produce enough tears to lubricate itself.

For more information please see: http://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/dry-eye?sso=y

Ectropion

A condition characterized by the eyelid turning outward away from the eye.

For more information please see: http://www.mayoclinic.org/diseases-conditions/ectropion/home/ovc-20169256

Emmetropia

Emmetropia

Emmetropia is the condition of the eyes when they have no refractive errors and vision is perfect.

For more information please see: https://www.verywell.com/what-is-emmetropia-vision-3421548

Estropia

A condition in which one or both eyes turn inward.

For more information please see: https://www.aapos.org/terms/conditions/48

Excimer Laser

Laser commonly used for eye surgeries.

For more information please see: https://www.rp-photonics.com/excimer_lasers.html

Extropia

A condition in which one or both eyes turn outward.

For more information please see: http://www.strabismus.org/exotropia_eye_turns_out.html

Extraocular Muscles

A series of six muscles that attach to the eye and allow it to move.

For more information please see: https://www.aapos.org/terms/conditions/22

Eyelids

Skin that covers the eye in order to protect it from injury, regulate light intake, and regulate tear production.

For more information please see: http://emedicine.medscape.com/article/834932-overview

Farsightedness

Also known as hyperopia, farsightedness is a condition in which the eyes cannot properly focus on objects that are nearby.

For more information please see: http://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/hyperopia?sso=y

Floaters

Spots that appear in one’s field of vision due to bits of vitreous break loose in the eye and “float” around.

For more information please see: http://www.allaboutvision.com/conditions/spotsfloats.htm

Fluorescein Angiography

Fluorescein Angiography

A procedure in which dye is injected into the bloodstream, allowing your eye care professional to photograph the blood vessels in the back of the eye in order to diagnose various conditions.

For more information please see: http://www.healthline.com/health/fluorescein-angiography#Overview1

Fovea

Small indented area on the retina which provides the eye’s sharpest vision due to a concentration of cones in this area.

For more information please see: http://hyperphysics.phy-astr.gsu.edu/hbase/vision/retina.html

Fundus

The inner lining of the eyeball.

For more information please see: http://www.medicinenet.com/script/main/art.asp?articlekey=10602

Glaucoma

An eye condition characterized by damage to the optic nerve, often associated with eye pressure.

For more information please see: https://nei.nih.gov/health/glaucoma/glaucoma_facts

Gonioscopy

An eye exam to view the anterior chamber of the eye and examine the eye’s drainage angle.

For more information please see: http://www.webmd.com/children/gonioscopy#1

Hyperopia

Also known as farsightedness, hyperopia is a condition in which the eyes cannot properly focus on objects that are nearby.

For more information please see: http://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/hyperopia?sso=y

Hyphema

Hyphema

Pooling of blood in the front of the eye between the cornea and iris.

For more information please see: https://www.aao.org/eye-health/diseases/what-is-hyphema

Intraocular Pressure

The pressure inside the eye based upon how much aqueous humor is present in the eye.

For more information please see: http://www.allaboutvision.com/conditions/hypertension.htm

Intraocular Lens

A replacement lens that is surgically implanted into the eye after the natural lens has been removed, often due to cataracts.

For more information please see: http://www.allaboutvision.com/conditions/iols.htm

Iris

The colored portion of the eye which is responsible for regulating the amount of light that enters the eye.

For more information please see: http://www.healthline.com/human-body-maps/iris-eye

Keratoconus

An eye disease resulting in blurred vision due to the cornea adopting a cone-like shape.

For more information please see: http://www.allaboutvision.com/conditions/keratoconus.htm

Keratometry

The measurement of the cornea’s curve.

For more information please see: http://optometrytimes.modernmedicine.com/optometrytimes/content/tags/cataract-surgery/why-keratometry-important?page=full

Lacrimal Gland

A gland that secretes tears into the eye.

For more information please see: http://medical-dictionary.thefreedictionary.com/lacrimal+gland

LASIK

A popular laser refractive eye surgery.

For more information please see: http://www.allaboutvision.com/visionsurgery/

Lazy Eye

Lazy Eye

Also known as amblyopia. It is a vision disorder that occurs when the brain favors one eye over the other, leading to decreased vision in the weak eye.

For more information please see: https://nei.nih.gov/health/amblyopia (Or link to our article?)

Legal Blindness

The degree of visual impairment that limits allowed activity under the law.

For more information please see: http://www.allaboutvision.com/lowvision/legally-blind.htm

Lens

A transparent structure within the eye that refracts light in order to create a clear image.

For more information please see: http://www.healthline.com/human-body-maps/lens

Low Vision

A loss of vision that makes completing normal tasks difficult.

For more information please see: https://www.aao.org/eye-health/diseases/low-vision

Macula

The center of the retina, where vision is processed the most clearly.

For more information please see: http://www.brightfocus.org/macular/infographic/normal-macula

Myopia

A refractive error, also known as nearsightedness, that makes distant objects appear out of focus.

For more information please see: http://www.allaboutvision.com/conditions/myopia.htm

Nearsightedness

Also known as Myopia, nearsightedness is a refractive error that makes distance objects appear out of focus.

For more information please see: http://www.allaboutvision.com/conditions/myopia.htm

Nystagmus

A vision condition in which the eyes make repetitive involuntary movements which result in reduced vision.

For more information please see: http://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/nystagmus?sso=y

Ophthalmologist

A medical doctor who specializes in vision and eye care.

For more information please see: https://www.aapos.org/terms/conditions/132

Ophthalmoscope

Ophthalmoscope

A medical device used to examine the eye.

For more information please see: http://www.healthline.com/health/ophthalmoscopy#Procedure4

Optic disc

The beginning of the optic nerve. The optic disk lacks rods and cones, which as a result, creates a blind spot in each eye.

For more information please see: http://www.dictionary.com/browse/optic-disk

Optician

Technicians who fit patients with glasses and contact lenses.

For more information please see: https://www.aapos.org/terms/conditions/132

Optic nerve

The nerve in the back of the eye that transmits electrical impulses to the brain, allowing the brain to receive visual information.

For more information please see: http://www.healthline.com/human-body-maps/optic-nerve

Optometrist

A healthcare professional licensed to practice optometry, which includes eye exams, prescribing glasses and contact lenses and diagnosing and treating eye disease.

For more information please see: https://www.aapos.org/terms/conditions/132

Orthoptics

The discipline in healthcare that focuses on the diagnoses and treatment of eye disorders, particularly eye movement disorders.

For more information please see: https://www.orthoptics.org.au/about-orthoptics/what-is-orthoptics/

Patching

In patients with amblyopia, patching is covering the strong eye with an eye patch for periods of time in order to improve vision in the weaker eye.

For more information please see: https://www.aapos.org/terms/conditions/86

Perimetry

The measurement of the visual field.

For more information please see: http://www.perimetry.org/Perimetr.htm

Peripheral Vision

Vision outside of the center of one’s gaze, often called “side vision”.

For more information please see: http://www.eyehealthweb.com/peripheral-vision/

Phacoemulsification

Phacoemulsification

The most common type of cataract surgery.

For more information please see: http://www.webmd.com/eye-health/cataracts/extracapsular-surgery-for-cataracts

Photophobia

Sensitivity to light, which can range from a minor irritation to extreme intolerance and can occur as a symptom of several eye conditions.

For more information please see: http://www.allaboutvision.com/conditions/lightsensitive.htm

Pinguecula

Raised, yellow bumps on the sclera or white part of the eye.

For more information please see: http://www.allaboutvision.com/conditions/pinguecula.htm

Pink eye

Pink eye is more formally known as conjunctivitis. It is a common eye disease in which the eye’s conjunctiva becomes inflamed and swollen.

For more information please see: http://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/conjunctivitis?sso=y

Presbyopia

The inability to focus on objects that are near to you. Presbyopia is related to aging and the eye’s lens becoming thicker and less flexible with age.

For more information please see: http://www.allaboutvision.com/conditions/presbyopia.htm

Photorefractive Keratectomy

Photorefractive Keratectomy

A common type of refractive surgery to correct refractive errors in the eye.

For more information please see: http://www.allaboutvision.com/visionsurgery/prk.htm

Progressive Lens

Eyeglasses meant to correct presbyopia. Progressive lenses are often referred to as “no line bifocals”.

For more information please see: http://www.allaboutvision.com/lenses/progressives.htm

Proliferative Retinopathy

An advanced form of diabetic retinopathy in which blood vessels grow in the retina and in the vitreous fluid of the eye, blurring vision.

For more information please see: http://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/diabetic-retinopathy?sso=y

Pterygium

Often referred to as “surfer’s eye”, this eye condition results in a pink growth on the surface of the eye and is likely due to excessive dryness of the eye and exposure to ultraviolet rays.

For more information please see: http://www.webmd.com/eye-health/pterygium-surfers-eye#1

Ptosis

Ptosis is a drooping of the eye’s upper eyelid. It can be present at birth or occur later in life and in extreme cases can affect vision.

For more information please see: https://www.aao.org/eye-health/diseases/what-is-ptosis

Pupil

The pupil is the black circle in the center of the eye which allows light to pass into the lens.

For more information please see: http://www.webmd.com/eye-health/picture-of-the-eyes#1

Radial Keratotomy

A surgery to correct nearsightedness by making small incisions in the cornea to flatten it and improve vision.

For more information please see: http://www.webmd.com/eye-health/radial-keratotomy-rk-for-nearsightedness

Refraction

The bending of light within the eye that allows the eye to focus and see clearly.

For more information please see: https://www.verywell.com/refraction-in-your-eye-or-vision-exam-3421821

Refractive Error

Refractive Error

A refractive error occurs when the eye is unable to properly focus due to light errors in the bending of light in the eye. The most common refractive errors are myopia, hyperopia, presbyopia, and astigmatism.

For more information please see: https://nei.nih.gov/health/errors/errors

Retina

A thin layer of tissue near the back of the eye that receives light and transmits messages to the brain.

For more information please see: http://www.healthline.com/human-body-maps/retina

Retinal Detachment

A condition in which the retina becomes disconnected from the back of the eye where it is usually fixed. If not treated immediately, retinal detachment can lead to permanent vision loss.

For more information please see: https://nei.nih.gov/health/retinaldetach/retinaldetach

Retinoscopy

A form of eye test to determine the eye’s refractive error by shining a light into the eye and applying various lenses.

For more information please see: https://www.aapos.org/terms/conditions/95

Rod

Light sensitive cells in the eye that allow us to see in dim lighting.

For more information please see: https://www.ncbi.nlm.nih.gov/pubmedhealth/PMHT0024258/

Scheme’s Canal

The canal in the eye through which the aqueous humor drains.

For more information please see: https://www.merriam-webster.com/medical/canal%20of%20Schlemm

Sclera

The white tissue of the eyeball.

For more information please see: http://www.healthline.com/human-body-maps/sclera

Secondary Cataract

“Secondary cataract” refers to posterior capsular opacification, a condition that can sometimes occur after cataract surgery. This is a clouding of the piece of the lens that is left intact during cataract surgery. This clouding can be corrected with a brief and simple procedure.

For more information please see: http://www.allaboutvision.com/conditions/faq-cataract-secondary.htm

Slit Lamp

An eye exam that uses a low power microscope and light to expose structures in the front of the eye.

For more information please see: https://medlineplus.gov/ency/article/003880.htm

Snellen Chart

Snellen Chart

A letter chart in which there are eleven rows of capital letters, getting progressively smaller with each row. This chart is a common tool in eye examinations.

For more information please see: http://www.allaboutvision.com/eye-test/

Strabismus

Often referred to as “cross-eyed”, strabismus is a condition in which the eyes are misaligned.

For more information please see: http://www.strabismus.org

Stye

A bump on the eyelid as a result of a blocked gland.

For more information please see: http://www.medicinenet.com/sty_stye/article.htm

Tonometry

A test of the eye’s internal pressure by applying external pressure to the eye and measuring resistance.

For more information please see: http://www.webmd.com/eye-health/tonometry#1

Trabecular Meshwork

A spongy tissue through which aqueous humor drains from the eye.