Ophthalmic Terminology and Abbreviations

Abduction

The movement of the eye towards the temple

Abrasion (corneal)

Loss of the epithelial layer of the cornea. To be differentiated from a laceration of the cornea which extends deeper than Bowman’s layer.

Accommodation

The ability, the mechanism or the process of the eye to attain maximum sharpness of the retinal image at a variety of distances by adjusting the dioptric power of the crystalline lens through contraction or relaxation.

Add

Refers to the strength of a bifocal addition to a spectacle lens. It is the amount of plus power which must be added to the distance prescription to assist the eye’s accommodation at a given distance, usually intermediate or near. An Add can also be placed in a contact lens.

Adduction

Movement of the eye toward the nose

Albinism

Congenital absence of pigment in the skin, hair, retina, and iris. Often associated with reduced visual acuity and light sensitivity.

Allen cards

Cards with pictures that are used for testing vision in preschool children or illiterate patients.

Amaurosis

Partial or total blindness from any cause; blindness occurring without noticeable change in the eye, such as from cortical cause, hysteria, intoxication, vascular, etc.

Amaurosis fugax

Transient visual loss

Amblyopia

Decrease vision in one or both eyes due to abnormal development of vision in infancy or childhood

Ametropia

Any refractive error of the eye that can be corrected by spectacles or other visual aids

Aniridia

A rare congenital disorder in which there is a variable degree of hypoplasia or the absence of iris tissue associated with multiple other ocular changes, some present from birth and some arising progressively over time

Anisocoria

Refers to the condition in which the pupils of the eyes are not equal in diameter

Anisometropia

A refractive error which exhibits a notable difference in prescription from eye to eye. This condition often leads to visual discomfort at near due to prismatic effect or dissimilar image sizes between the two retinas

Anterior Basement Membrane Dystrophy (ABMD+EBMD)

Known as Map-Dot-Fingerprint Corneal Dystrophy, Cogan’s Microcystic Dystrophy, Epithelial Basement Dystrophy. It is an inherited disorder of the cornea that may present with symptoms such as recurrent corneal erosions and/or blurred vision.

Anterior Chamber

The space inside the eye just behind the cornea and in front of the iris. It is filled with aqueous humor.

Anti-VEGF

Anti-vascular endothelial growth factor.

Aphakia

The state of the eye when the crystalline lens has been removed and an intraocular lens implant was not utilized. these patients usually have a high-plus refractive error.

Applanation

The flattening of a convex surface; applanation tonometry flattens the cornea for measurement of intraocular pressure.

Aqueous Humor

The clear, watery fluid that fills the anterior and posterior chambers of the front part of the inner eye; important for the nutrition and metabolism of the cornea and crystalline lens.

Aqueous shunt

A device used to reduce the intraocular pressure (IOP) in glaucoma by draining the fluid (aqueous humor) from inside the eye to a small blister or bleb behind the eyelid. The tube portion enters the front of the eye, or anterior chamber, while the “plate” portion of the implant sits on the surface of the eyeball underneath the conjunctiva and is covered by the eyelid. The fluid that collects is then absorbed by the eye’s own veins and transported out of the eye cavity.

Astigmatism

A refractive error in which light rays entering the eye fail to come to a single focal point; caused by different degrees of refraction in various meridians of the cornea and/or lens, most often at right angles to each other.

Corneal astigmatism

Astigmatism that is the result of the cornea not being spherical. It is determined by the K reading of the cornea.

Residual Astigmatism

The difference between the corneal astigmatism and the total astigmatism of the eye. The total astigmatism of the eye is the astigmatism present in the refraction. Thus the total astigmatism is composed of the corneal astigmatism and the residual astigmatism. The residual astigmatism is due to the tilt or other abnormality of the crystalline lens or other factors within the eye. It is also referred to as lenticular astigmatism.

Irregular Astigmatism

Astigmatism where the two principal meridians of the eye are not at right angles to each other.

Regular Astigmatism

Condition in which light rays come to two focal image lines 90 degrees apart.

Compound Regular

The two focal lines of light rays are either in front of the retina, compound myopic astigmatism, or behind the retina, compound hyperopic astigmatism.

Mixed Regular

The light rays come to two focal lines-one in front of the retina and one behind the retina.

Simple Regular

The light rays come to two focal lines-one on the retina and the other either in front of the retina (simple myopic astigmatism) or behind the retina (simple hyperopic astigmatism).

With-the-Rule Astigmatism (WTR)

Most common type of astigmatism. The flattest meridian is in the horizontal plane and the steepest meridian is in the vertical plane; may be corrected with a horizontal minus cylinder or vertical plus cylinder.

Against-the-Rule Astigmatism (ATR)

The flattest meridian is in the vertical plane and the steepest meridian is in the horizontal plane; may be corrected with a vertical minus cylinder or horizontal plus cylinder.

Autoclave

A machine that uses high pressure and steam to sterilize instruments.

Base (of a prism)

Thickest edge of a prism, opposite the apex.

Binocular

Pertaining to the use of both eyes

Biometry (ocular)

The statistical analysis of biological observations. In ophthalmology, the term refers to a measurement of the distance between various ocular structures using A-scan and B-scan ultrasound instrumentation.

Birdshot Choroidopathy

A rare form of posterior uveitis which mainly affects the retina and choroid.

Blepharitis

Any inflammation of the eyelid, commonly the margins.

Blepharoplasty

Excision of excess skin and orbital fat in an eyelid for functional reasons (when causing a visual field deficit) or for cosmetic reasons.

Blepharospasm

Spasm of the orbicularis oculi muscle resulting in excessive twitching.

Botulinum Toxin Type A

Neurotoxin injected into muscles for temporary paralysis

Bullous Keratopathy

Edema of the corneal stroma and epithelium which results in formation of Bullae on the corneal surface. It may occur in Fuch’s endothelial dystrophy, advanced glaucoma and iridocyclitis. It is a result of damaged endothelial cells.

Canaliculus

Inferior and superior tubes that carry tears from the punctum to the lacrimal sac.

Cataract

Refers to the partial or complete loss of transparency of the crystalline lens of the eye or its capsule, or both. There are a multitude of causes, all with the result of a loss of visual acuity. Opaqueness in the center of the lens (affecting the line of sight) is most serious, peripheral opacities are less so.

Cell & Flare

Observed upon ocular examination of the anterior chamber with the slit lamp biomicroscope, after surgery of examination for uveitis or iritis; “cell” refers to individual inflammatory cells while “flare” is the foggy appearance given by protein that has leaked from inflamed blood vessels.

Computer Vision Syndrome

Eye discomfort and vision problems that result from prolonged use of digital screens including tablets, computers, and cell phone use.

Central Serous Chorioretinopathy

Also known as chorioretinopathy, commonly referred to as CSCR, is a condition in which fluid accumulates under the retina, causing a serous (fluid-filled) detachment and vision loss. Men develop this condition more commonly than women, and some physicians believe it could be caused by stress.

Chalazion

An inflammatory mass that is noninfectious, usually painless, in the eye lid. A blockage of the meibomian gland secretions results in the extravasation of material from the gland that causes a granuloma to form. It is to be differentiated from a stye or hordeolum which is usually a painful inflammation/infection of the follicles and the glands of Zeis and Mol that are present on the eyelid margin.

Cone

Refers to the retinal receptor cell that provides sharp visual acuity and color discrimination; located mainly in the fovea.

Conjunctiva

The mucous membrane that lines the back of the eyelids and the front part of the eyeball to the limbus.

Conjunctival Chalasis or Conjunctivochalasis

A condition in which the conjunctiva loses its normal elasticity and no longer adheres well to the underlying sclera. This leads to redundancy of the conjunctiva which bunches up along the lower lid margin and disturbs the tear meniscus which may aggravate or mimic dry eye syndrome.

Conjunctivitis

Inflammation of the conjunctiva

Bacterial conjunctivitis

Usually infects both eyes and produces a heavy discharge of pus and mucus. It is treated with antibiotic eye drops.

Viral conjunctivitis

It is a highly contagious acute conjunctival infection often caused by adenovirus. Symptoms include irritation, photophobia, and watery discharge.

Convergence

The directional property of a bundle of light rays turned or bent toward a real image point; to be distinguished from the divergence property of a bundle of rays emanating from a point source. Also, the turning inward of the eyes in order to intersect each line of sight at a near finite point.

Convergence insufficiency

A common binocular vision disorder characterized by the inability of the eyes to maintain convergence (turning inwards) during near vision tasks; instead they have a tendency to drift outwards. It is characterized by signs of eye strain, blurry vision and double vision.

Cornea

The transparent anterior portion of an eye serving as the first and largest refracting medium (approximately 2/3 of the eye’s power)

Corneal Ectasia

A noninflammatory condition that results in corneal thinning with distortion of the shape of the cornea. Conditions such as keratoconus, keratoglobus, pellucid marginal degeneration, post refractive surgical procedures, and wound ectasia after penetrating keratoplasty.

Corneal Ulcer

Loss of tissue (corneal epithelium and stroma) from the cornea. It is an inflammatory process with progressive erosion and necrosis often, but not always, associated with a pathological agent such as bacteria, fungal or viral infections. In addition, cornea exposure, drying or sequelae from autoimmune diseases can be associated with corneal ulcers.

Corneal Pannus

A fibrovascular ingrowth into the cornea from the limbus. It is often caused by inflammation from a variety of causes such as contact lens wear (over wear syndrome or poorly fitted lens) and inflammation of the lids and conjunctiva.

Cryotherapy

A method that uses localized freezing temperatures (often applied via a probe) to treat certain conditions. The application of the freezing temperature causes necrosis and ischemia to the applied tissue and induces an inflammatory reaction. A few of the more common ophthalmic uses are the following: to treat retinal tears, advanced end stage glaucoma, abnormal lashes, and malignancies of the eyelids and conjunctiva.

Crosslinking

A minimally invasive FDA approved outpatient procedure, also known as corneal collagen crosslinking which uses riboflavin and UV-A light to strengthen the cornea. It a useful treatment option n treating keratoconus and ecstatic conditions following corneal refractive surgery.

Cul-de-sac

The ocular fornix

Cycloplegia

Paralysis of the ciliary muscle and loss of the power of accommodation, often accompanied by dilation of the pupil. It may be pathological or induced with drops.

Dacryocystitis

Inflammation of the lacrimal sac.

Dacryocystorhinostomy (DCR)

A surgical procedure that creates a new tear drainage for the tears to flow into the nose when there is blockage in the nasolacrimal outflow system.

Deep Anterior Lamellar Keratoplasty (DALK)

A partial thickness corneal transplant that involves transplantation of the corneal stroma leaving Descemet’s membrane and endothelium in place in a setting of normally functioning endothelium.

Dermatochalasis

Blepharochalasis; dropping eye lid tissue caused by redundancy of skin in eyelids, caused by atrophy of the elastic tissue

Descemet Membrane Endothelia Keratoplasty (DMEK)

A partial corneal transplant similar to DSEK. Descemet membrane and endothelium is removed from the patient and is replaced with donor corneal endothelium and Descemet membrane without additional stroma.

Descemet’s Folds

Redundancy of Descemet’s membrane due to increased corneal thickness.

Descemet’s Stripping Endothelial Keratoplasty (DSEK)

A partial thickness corneal transplant procedure that replaces the diseased endothelium with a thin donor graft of posterior corneal stroma, Decrement’s membrane, and endothelium. The surgical procedure is performed through a small incision, which is self-sealing or requires only 1 or 2 sutures. An air bubble in the anterior chamber helps to unfold the graft and hold the graft in position.

Diabetic Retinopathy

A leading cause of blindness due to damage to the retina from diabetes. The retinopathy consists of retinal hemorrhages, microaneurysms, retinal ischemia (cotton wool spots), and hard exudates from vessel leakage. As the disease progresses one can develop macular edema with reduced vision, proliferation of new fragile vessels, vitreous hemorrhage, fibrovascular proliferation and retinal detachment.

Diopters

A measurement of the focusing power of the lens.

Diplopia

Refers to double vision.

Disc

Refers to the optic disc or optic nerve head which is the exit site of retinal nerve fibers from the eye.

Disinfection

The use of a chemical procedure that eliminates most recognized pathogenic microorganisms. There are three levels of disinfection recognized:
- High-level: Kills all organisms except high levels of bacterial spores, and is effected with a chemical germicide cleared for marketing as a sterilant by the Food and Drug Administration.
- Intermediate-level: Kills bacteria (including mycobacteria) and most viruses with a chemical.
- Low-level: Kills some viruses and bacteria with a chemical germicide registered as a hospital disinfectant by the EPA.

Drusen

Typically small, white hyaline deposits lying beneath the retinal pigment epithelium in the macula and often associated with Age Related Macular Degeneration.

Dislocated Intra Ocular Lens

Occurs when the lens moves out of place (subluxed).

Dunctions

Monocularly, any movement of the eye through use of the extraocular muscles (abduction, adduction).

Dysphotopsia

• Negative: Appears as a shadow or dark crescent on the side

• Positive: Described as an arc of light under certain lighting conditions.

Ectropion

The turning outward of the eyelid.

Emmetropia

The state where an eye requires no visual correction. In emmetropia, an infinitely distant object is imaged sharply on the retina without inducing an accommodative response.

Endophthalmitis

An inflammatory condition of the aqueous and/or vitreous humor, usually caused by infection. Noninfectious endophthalmitis may result from various causes such as retained lens material after an operation or from toxic agents.

Entropion

The turning inward of the margin of the eyelid.

Enucleation

Removal of the entire eye from its socket.

Epiphora

An overflow of tears onto the cheek, may be the result of a lacrimal duct obstruction.

Epiretinal membrane

Also known as cellophane maculopathy or macular pucker that can develop on the surface of the macula area.

Esophoria

The tendency for the eyes to turn inward when fixation is broken.

Esotropia

Constant inward turning of the eye.

Evaporative Dry Eye

Most common form of dry eye syndrome in which there is an abnormality of the quality of the tears usually a result of abnormal meibomian gland secretions.

Evisceration

Surgical removal of the inner contents of the eye with the sclera left intact.

Excision of Chalazion

Removal of obstructed meibomian gland in the eyelid.

Exophoria

Tendency for the eyes to turn outward when fixation is broken.

Exophthalmos

An abnormal protrusion of the eyeball from the orbit.

Exotropia

Constant outward turning of the eye.

Eyelid Lesion Removal

Removal of small growths (papillomas, verrucae, xanthelasma) from the eyelid.

Femtosecond Laser

A laser which emits ultra-short duration pulses of energy to minimize damage of surrounding tissues used during cataract and refractive surgery.

Filamentary Keratitis

A chronic corneal condition characterized by multiple filaments attached to areas of compromised corneal epithelium. Filamentary keratitis is often present in severe dry eye syndrome.

Filtering Procedure

A channel is created from the anterior chamber to the external surface of the eye under conjunctiva, allowing aqueous fluid to seep into a filtering bleb from which it is slowly absorbed and helps to control intraocular pressure.

Fissure

A cleft or groove within a tissue.

Fluorescein Angiography (FA)

Photographic technique used to examine retinal and choroidal circulation following intravenous injection of fluorescein dye.