Download Ophthalmic Terminology 101 Lynn E. Konkel, MS, CPOT Heart of

Ophthalmic Terminology 101
Lynn E. Konkel, MS, CPOT
Heart of America Congress – February 2013
I.
Major Parts of the Eye
a. Cornea – the front surface of the eye responsible for most of the light
bending power (refraction) of the eye. This surface is transparent and
highly curved.
b. Sclera – tough, fibrous protective outer coating of the eye. It is white,
opaque and continuous with the cornea.
c. Conjunctiva – a thin, clear, mucous membrane that covers the sclera.
Has three sections, palbepral, bulbar and fornix.
d. Limbus – the junction between the highly curved cornea and flatter sclera.
e. Iris – the colored part of the eye, located behind the cornea. Its main
function is to control the amount of light entering the eye.
f. Pupil – the opening in the center of the iris. The area where light enters
the eye.
g. Crystalline Lens – a pliable (can change shape, therefore power),
transparent structure that bends light (refraction) in the eye and is located
directly behind the pupil/iris. It is the second major refracting surface of the
eye.
h. Suspensory Ligaments – the ligaments that attach the crystalline lens with
the ciliary body.
i.
Anterior Chamber – the space between the back of the cornea and front of
the front of the iris. This space is filled with a watery fluid called aqueous
humor.
j.
Posterior Chamber – the space behind the iris and the front of the lens.
k. Aqueous Humor – the watery fluid that is produced by the ciliary body and
fills the anterior chamber.
l.
Ciliary Body – this structure has two main purposes: 1. provide the muscle
power to alter the shape of the crystalline lens, 2. produce the fluid called
aqueous humor that fills the front part of the eyeball.
m. Ora Serrata – the place in the eye where the retina stops and the ciliary
body begins. The retina actually has a serrated or notched edge.
n. Canal of Schlemm – the canal is located within the limbus area and allows
the aqueous humor to drain from the eye.
o. Choroid – the vascular (blood carrying) layer of the eye. This layer is just
posterior (meaning behind) the retina and anterior to the sclera. The
choroid provides nutrition to the retina.
p. Retina – the nervous layer (contains nerve cells, rods and cones, that
respond to light) of the eye. It covers the majority of the inside surface of
the eye. This thin membrane contains 10 layers.
q. Uveal Tract – the iris, ciliary body and choroid. These are the structures
of the eye that are vascular.
r. Vitreous Chamber – the space behind the lens and ciliary body and in
front of the retina.
s. Vitreous Humor – the jellylike substance that fills the vitreous chamber.
This substance helps the eye maintain its shape.
t. Optic Nerve – the pathway that conducts visual signals from the retina to
the brain.
u. Optic Disc – approx. 2.0 mm depression of the optic nerve which is formed
by the gathering of all the transparent nerve fibers from the light sensitive
retina. The optic disc itself is not light sensitive since it is lacking nerve
cells; therefore there is no vision here.
v. Physiological Cup – a funnel-shaped depression in the central area of the
optic disc. This is the point where blood vessels enter and leave the retina.
w. Artery – a tubular vessel that carries blood from the heart to the various
parts of the body.
x. Vein – a tubular vessel that carries blood from various parts of the body to
the heart.
y. Macula – an ill-defined and somewhat yellow area of the central retina that
is avascular (a=without, vascular = blood vessels). This portion of the
retina is used for central vision and its health is important for good visual
acuity.
z. Fovea Centralis – Means "center pit" and it is the center spot within the
macula; a light shining directly on the retina with produces a bright reflex.
The area of the macula used for the most detailed vision.
II.
Prefixes, Suffixes and Root Words
a. See handouts
III.
Ophthalmic Terms
a. Accommodation – increase in optical power of the crystalline lens. Occurs
when the ciliary body contracts, loosening the zonule fibers allowing the
flexible lens to bulge forward. Maintains proper focus for near vision.
1. Accommodative Triad – convergence, accommodation, miosis
b. Amblyopia – loss or lack of development of central vision in one eye that is
unrelated to any eye health problem and is not correctable with lenses.
c. Ametropia – any refractive disorder of the eyes that is correctable.
d. Aniseikonia – different retinal image sizes.
e. Anisocoria – different pupil sizes
f. Anisometropia – difference in refractive errors between the two eyes.
g. Aphakia – absence of the crystalline lens.
1. Pseudophakia – the natural lens has been removed and replaced with
a lens implant.
h. Arcus senilus – benign, gray, hazy ring around the limbus, typically
associated with aging.
i.
Blepharitis – inflammation of the eyelids
j.
Blepharoplasty – plastic surgery of the eyelids.
k. Cataract – any opacity of the lens.
l.
Cells & flare – accumulation of white blood cells and protein (cells) in the
normally clear aqueous humor. Clinical sign of eye pathology (iris/ciliary
body).
m. Chalazion – A slowly developing lump that forms due to blockage and
swelling of the meibomian oil gland in the eyelid.
n. Conjuctivitis – inflammation of the conjunctiva
1. Bacterial, viral, allergic
o. Chemosis – swelling of the conjunctivia, associated with allergic
conjunctivitis.
p. Cyclopledia – paralysis of the ciliary muscle results in loss of
accommodation.
1. Cycloplegic – class of drugs that causes the above paralysis.
q. Diplopia – double vision.
r. Dominant eye – eye that is used for sighting, aligning things.
s. Epiphora – tears falling over eyelids.
t. Fixation – moving eyes to align the object on the fovea.
u. Fusion – the brain’s blending of two similar objects into one.
1. Three degrees
v. Glaucoma - A group of disorders leading to progressive damage to the
optic nerve, and is characterized by loss of nerve tissue resulting in loss of
vision (AOA).
1. Primary open angle – the aqueous should drain however there is an
accumulation of fluid that causes increased pressure in the eye
causing optic nerve damage. Most common form of the disease.
2. Angle closure – drainage of aqueous is impeded causing pressure to
suddenly rise.
3. Normal tension – the aqueous should drain and the intraocular
pressure of the eye is normal yet there is optic nerve and visual field
damage consistent with glaucoma.
4. Secondary – caused by trauma, iritis, and other conditions.
w. Heterotropia (strabismus) – a condition in which both eyes do not look at
the same place at the same time.
1. Types – esotropia eye turned in; exotropia eye turned out; hypertropia
eye turned up; hyoptropia eye turned down
2. Accommodative esotropia
x. Heterophoria – when using both eyes they are straight and fixated on the
object however put the eye at rest (cover an eye) and the eye moves to a
different direction.
1. Types – esophoria eye at rest turns in; exophoria eye at rest turns out;
hyperphoria eye at rest turns up; hypophoria eye at rests turns down.
y. Hippus – usually normal rhythmic dilation and constriction of the pupils.
z. Hordeolum – infection of the oil glands of Zeis located in the eyelash
follicle.
aa. Iritis – inflammation of the iris.
bb. Keratitis – inflammation of the cornea.
cc. Keratoconus – hereditary degenerative disease of the cornea
characterized by central thinning and bulging forward of the cornea.
dd. Keratoplasty – surgical replacement of the cornea; corneal transplant.
ee. Leukocoria – white pupil.
ff. Macular degeneration – a disease that causes changes in the macula
resulting in poor central vision. Dry (most common) versus wet.
gg. Miosis – constriction of the pupil.
1. Miotic – class of drugs that works in the iris and the ciliary muscle to
constrict the pupil.
hh. Mydrasis – dilation of the pupil.
1. Mydriatic – class of drugs that work in the iris to dilate the pupil.
ii. Neovascalization – abnormal formation of new blood vessels, can be
found on the limbus, iris, and retina.
jj. Nystagmus - the eyes make repetitive, uncontrolled movements, often
resulting in reduced vision.
kk. Papiledema – inflammation of the optic disc.
ll. Photopic vision – eyesight in daylight condition.
mm. Scotopic vision – eyesight in nighttime condition.
nn. Ptosis – upper eyelid droop
oo. Retinal detachment – a tearing or separation of the retina, the light
sensitive lining at the back of the eye, from the underlying tissue.
pp. Scleritis – inflammation of the sclera.
qq. Scotoma – an area of reduced vision within the normal peripheral vision.
rr. Subconjunctival hemorrhage – a small amount of blood leaks and forms a
hemorrhage under the conjunctiva between the sclera and conjunctiva.
ss. Subluxation – partial or complete dislocation of the lens from it’s normal
position.
tt. Suppression – subconscious ignoring of the central vision of one eye.
Usually associated with an eye that is turned or diplopia.
uu. Synechia – the adhering of the iris with another structure (commonly the
lens)
vv. Uveitis – inflammation of the uveal tract.
ww. Vitreous detachment (posterior vitreous detachment) – separation of the
vitreous gel from the retina.
IV.
Refractive Terms
a. Myopia – light within the eye focuses prior to the retina, distant vision is
blurred.
i. Axial – eyeball too long
ii. Refractive - cornea/lens too strong; too much curvature
iii. Correct with concave (minus) lenses, spreads the light rays out prior to
getting to the eye moving the focal point toward the retina.
b. Hyperopia – light entering the eye focuses theoretically after the retina,
near vision is blurred.
i. Axial – eyeball to short
ii. Refractive = cornea/lens not strong enough, not enough curvature
iii. Correct with convex (plus) lenses, bends the light rays prior to getting
to the eye in order to move up the focal point.
c. Astigmatism – the eye is not spherical causing the light to focus in two
places.
i. Corneal – measured with a keratometer, obtain the area of greatest
and least curvature
1. Regular versus irregular
2. With the rule – the steepest curvature is vertical
a. 44.25 @ 180; 45.50 @ 90
3. Against the rule – the steepest curvature is horizontal
a. 46.00 @ 20; 44.00 @ 110
4. Oblique – the steepest and weakest curves are between 30 & 60;
120 & 150
ii. Ocular – looking at the refraction determines the type of ocular
astigmatism
1. Simple – one point of focus is directly on the retina and the other is
either before or after the retina.
a. Simple myopic – Plano -1.00 x 90
b. Simple hyperopic – Plano +1.00 x 90 (+1.00 -1.00 x 180)
2. Compound – both focal points are either in front of the retina
(myopic) or behind the retina (hyperopic).
a. Myopic – -2.00 -1.00 x 175 (powers on lens are -2.00/-3.00)
b. Hyperopic – +1.25 -0.50 x 20 (powers on lens are +1.25/+0.75)
3. Mixed – one focal point is before the retina and the other is behind
a. +0.50 -2.00 x 35 (powers on lens are +0.50/-1.50)
iii. Presbyopia
V.
Optical Terms
a. Refraction – bending of light.
i. Lens – bends light to form an image
ii. Test – using the phoropter to find the lenses that neutralize a person’s
refractive error.
b. Prism – a lens that deviates light but does not focus light. Has an apex
and a base.
c. Diopter – a unit of measure for optical lenses. A one diopter lens will
focus light at one meter.
d. Lens types
i. Sphrerical – lens that has one focal length.
1. Concave – a series of prisms stacked apex to apex, causing parallel
light to diverge.
2. Convex – a series of prisms stacked base to base, causing parallel
light to converge.
ii. Cylindrical – a lens with a flat area (no power) and 90 degrees from the
flat area is the place of strongest curve. Example – plano -2.00 x 90
iii. Spherocylindrical – a lens that combines a sphere with a cylinder lens.
This lens has two focal points.
iv. Axis – the area of no cylinder power. Used for lens orientation in front
of the eye for patients with astigmatism.
v. Aspherical – a lens that is without a spherical surface, often used in
high refractive errors, helps to minimize distortion.
e. Base curve – starting curve of a lens, usually the front surface curve on a
lens measured using a lens clock.
f. Index of refraction – the ratio of the speed of light in air to the speed of
light in a material. The higher the ratio the more the material bends light
the thinner the lens will become.
g. Optical Center – the point on a lens where the bases (plus lens) or apexes
(minus lens) meet.
h. Distance between optical centers – measurement in millimeters between
the two optical centers in a pair of glasses
Resources:
Dictionary of Eye Terminology 6th edition, Cassin, Rubin (2011), Triad
Clinical Anatomy of the Visual System 2nd edition, Remington, Butterworth-Heinemann