2. KNOW WHAT IS CPNSIDERED NORMAL
MUST KNOW WHICH ABNORMALITIES ARE
CONTACT LENS RELATED AND WHICH ARE
NOT
MUST KNOW WHICH CONDITIONS SHOULD
BE REFERRED OUT TO AN OPTOMETRIST
/OPHTHALMOLOGIST
5. refers to inflammation
Example: blepharitis = inflammation of the eyelids
6. Refers to an abnormal condition
Example: ptosis
7. Refers to a tumor OR to a disorder for which there
is no cure.
Examples: glaucoma
carcinoma
8. Index of Refraction
◦ Tear Film – 1.3375
◦ Cornea – 1.3376
◦ Aqueous and Vitreous Humor – 1.336
◦ Crystalline Lens – 1.42 – 1.43
◦ The “Globe” makes up 5/6 of the eyeball in the
socket.
◦ 1/6 of the anterior surface is made up of the
anterior corneal surface.
9. The Eye is approximately 24 mm long in the normal adult eye.
The circumference is between 69mm and 81 mm
The Cornea makes up 75% of the refracting surface of the
eye.
The average refractive surface of the cornea is about +43.00 D.
The average thickness of the cornea is at the center is .52mm
and at the periphery measure about .71mm
The HVID is approximately 11.5 mm horizontally and 10.5 mm
vertically (12.00 mm /11mm)
The Crystalline lens diameter is about 6.5 mm to 9mm. The
power of the crystalline lens is about +20.00. The lens is 3-4
mm thick.
10. accessory structures are considered part of the
eye, but not part of the eyeball itself.
The accessory structures of the eye:
◦ Eyelids
◦ Eyelashes
◦ Lacrimal apparatus
◦ Conjunctiva
14. Opening formed by the lid margins
Adult: 28 – 30 mm horizontal by 14-15 mm vertical
Lower margin meets lower cornea limbus
Upper margin covers top 1-2 mm of cornea
15. Junction of upper and lower lid margins
Lateral canthus ( temporal)
Medial canthus (nasal)
◦ Caruncle = small yellowish elevation in medial canthus;
contains sweat and sebaceous glands
16.
17. a thickened fold of conjunctiva
Also called the semilunar fold
Is a ‘Vestigial remnant’: it is a homolog of the
nictitating membrane seen on sharks.
18. Vertical fold of skin extending from upper to lower
lid
Seen in infants and disappears
EXCEPT in Asians = forms the characteristic
almond shaped eye
19.
20. Upper and lower holes
An opening through which tears drain
21. Imaginary line dividing the lid margin into inner
and outer halves
Lid margin is about 2 mm thick
Inner margin has openings of the Meibomian
glands
Eyelashes are attached to the front margin half
24. Upper lid extends from the lid margin to the
eyebrow with a crease called the ‘sulcus’,
Separates the orbital portion of the lid from the
tarsal portion
25. Divided into four layers:
◦ 1: Skin
◦ 2: Muscle (orbicularis oculi muscle)
◦ 3: Orbital septum, ocular muscles and tarsal plate
◦ 4: Palpebral conjunctiva
26. very thin
◦ Thinnest found on body
containing no subcutaneous fat
is supported by a tarsal plate.
◦ This tarsal plate is a fibrous layer that gives the lids
shape, strength, and a place for muscles to attach.
27. Is a sphincter muscle
Encircles the palpebral fissure
Responsible for eyelid closure
29. Levator palpebrae superioris muscle: raises the
upper lid
Muscle of Muller:
◦ smooth, involuntary muscle that contributes to lid tone
◦ Lies deep in the orbital septum
◦ Runs vertically
◦ Originates from the levator muscle
◦ Inserts into the tarsal plate
30. Firm connective tissue
Gives the lid shape, support and firmness
About 1mm thick
Extends almost from canthus to canthus
33. Two muscles are
responsible for eyelid
movement.
The orbicularis oculi
closes the eyelids
and is innervated by
cranial nerve 7.
34. Thin, transparent mucous membrane
Lines the inside of the lids
Adheres to the tarsus
Continues over anterior sclera ( then called ‘bulbar
conjunctiva’)
Attaches at the limbus
35. Junction of palpebral and bulbar conjunctiva
Prevents anything from getting ‘lost’ inside the eye
39. Glands of Zeiss - These are sebaceous
glands associated with the eyelashes.
Tarsal glands - (Meibomian glands) -
These glands line the inner margin of the lid
and produce a lipid-rich product that
prevents the lids from sticking together.
Lacrimal caruncle - This is a mound of
tissue in the medial canthus that produces
thick secretions.
40. Sebaceous glands which lie Underneath and within
the tarsal plate
These glands secrete oils and lipids into the tear film
that keeps the tears from evaporating too quickly.
Have secretory ducts that open along the lid margin
behind the gray line
Meibomian glands may become inflamed and swell
into a granulomatous chalazion that needs to be
excised..
41. Have approximately 25 un the upper lid and 20 in
the lower lid
These secretions form the outer layer of the tear
film
42. Modified sweat glands
Secrete lipids which add to the outer tear film
layer
43. Located inside the lids near the cul de sac that is
formed where the palpebral and bulbar
conjunctiva meet
Considered accessory lacrimal glands
Responsible for the aqueous layer of the tear film
44. Located in the conjunctiva as superficial glands
Secrete mucous
Helps stabilize the tear film
45. Lumps, bumps, infections and tumors.
Range from mild and annoying to severe and
malignant.
Know when to refer for medical attention
46. Inflamed Meibomian
oil gland in the lids.
Lid has a bump.
+/- sore
Usually caused by a
clogged Meibomian
gland.
48. Commonly called a
“stye”
Caused by an inflamed
Zeis gland by an
eyelash follicle.
Lid edge is tender,
swollen and red. May
have a white head on
it.
49.
A stye is a pimple-like infection of a sebaceous
gland or eyelash follicle, similar to a pimple, and is
superficial to the tarsal plate.
Styes are painful, while chalazions are not
50. Ectropion : out – turned lower lid. Can result in corneal
dryness.
Entropian : in – turned lid, usually the lower. Lashes
scratch the globe so pt feels like a FB is in the eye.
Dermatochalasis : extra skin on the upper lids. Usually
associated with aging. Can restrict upper visual field.
Ptosis : drooping upper lid
Trichiasis : inward growing lashes.
51. Lagopthalmos = incomplete eyelid closure
Trichiasis = inward turning of the eyelashes.
Causes irritation to the eye by the eyelashes
58. BLEPHARITIS
inflammation of the eyelids.
Lids may appear swollen, red and crusty and may
itch.
Caused by bacteria, virus, or inflammatory
conditions.
Usually cleared with good lid hygiene.
59. One of the most common eyelid problems
inflammation of the eyelid margin.
Patients typically experience itching, burning, mild
foreign-body sensation, tearing and crusting
around the eyes on awakening.
On examination, the eyelid margins are
erythematous (red) , and thickened with crusts
and debris within the lashes Conjunctival injection
or a mild mucus discharge may be present
60. Treatment of
blepharitis consists
initially of warm
compresses, eyelid
scrubs and
application of
antibiotic ointment
65. Most common eye lid cancer.
Accounts for 90% of eyelid cancers
Usually appears on lower lid
Starts as small, firm, painless nodule with a
smooth pearly appearance.
May have a reddish color from dilated capillaries.
Progresses slowly
77. a group of organs concerned with the production
and drainage of tears; it is a protective device that
helps keep the eye moist and free of dust and
other irritating particles.
The lacrimal gland, which secretes tears, lies over
the upper, outer corner of the eye; its excretory
ducts branch downward toward the eyeball
The Lacrimal ApparatusThe Lacrimal Apparatus
78. A constant stream of tears washes down over the
front of the eye and is drained off through two
small openings located in the inner corner of the
eye.
Through these openings the tears pass into the
lacrimal canaliculus, then through the lacrimal sac
into the nasolacrimal duct and finally into the nasal
cavity
The Lacrimal ApparatusThe Lacrimal Apparatus
79. First refractive interface
Smooth out the optical surface
Keep cornea moist
Lubrication
Provide oxygen to corneal epithelium ( via
dissolved O2)
Carry away waste products
Contain white blood cells and lysosomes to help
with inflammation and healing
80. Secreted by the glands
First, Outermost layer = lipid layer
Second layer = aqueous layer
Third, innermost layer = mucoid layer
83. Oils secreted by the Meibomian and Zeiss glands
About 0.1 u thick ( it’s pretty thin!)
Helps stabilize the tear film and prevents
evaporation of aqueous layer
Lipid layerLipid layer
84. Majority of tear film
Watery
About 7.0u thick
Responsible for keeping the exposed anterior
portion of the eyeball moist
Secreted by the lacrimal gland and the accessory
glands of Krause and Wolfring
Aqueous LayerAqueous Layer
85. Produced by the goblet cells
Makes the cornea wettable by providing a surface
over which the tears will spread easily
Attached to the microvilli ( microscopic finger-like
projections from the surface of the cornea) and
anchors the tear film to the corneal epithelium
Helps Stabilizes the tear film
About 0.5u thick
Mucin LayerMucin Layer
86. Spreads the tears out over the cornea and eye
The tear meniscus = a wedge of tears form along
the top and bottom lid margins as they are
secreted.
Must assess the tear meniscus is adequate before
contact lens fitting
Stain with flourescien
87. Normal blink rate of about every five seconds
This insures tears do not dry out between blinks
( healthy TBUT is 10 sec and over)
BlinkingBlinking
88. As lids come together during a blink – a negative
pressure is created that sucks the tears into the
puncta.
Puncta = drainage holes
Canniculi = drainage pipes that lead to the
lacrimal sac
Lacrimal sac = located in the medial portion of the
inferior orbit; downward extension forms the
nasolacrimal duct
nasolacrimal duct = tears empty into the nasal
passages
Tear drainageTear drainage
89.
90.
91. Problems can occur at the tear production level
(lacrimal gland), the tear drainage level (tear sac)
or tear components (lubrication problems).
Dry eye most common.
92. For blockages: probe is passed through the
punctum into the drainage canal.
For dry eyes: plugs (collagen or silicone) are put
into the puncta to block tear drainage.
94. To measure the stability of the tear film –
specifically the mucin and/or lipid layers
Instill fluorescein
Diffuse illumination
Cobalt blue filter
Normal is 10 seconds
<10 seconds indicates unstable tear film
98. To evaluate the integrity of the lacrimal secretion
system – specifically the aqueous layer
Measures total secretion in 5 minutes
Total secretion = basal secretion + reflex secretion
Expected a minimum of 10 mm in 5 minutes
Topical anesthetic is used
99.
100. To determine the patency of the lacrimal system
from the punctum to inferior meatus of the
nosesese.
101. Done only one eye at a time
Instill fluorescein
Wait 2 minutes
Insert cotton tip applicator into nose approximately
4-5cm
If there is fluorescein on the cotton tip the test is
positive indicating the lacrimal system in not
obstructed
The test is negative when there is not fluorescein
on the cotton tip
110. Skull cavity that houses each eyeball, the extrinsic
muscles and protective fat
Quadrilateral pyramid shape
Opening roughly 40 mm in height, width and depth
The orbitThe orbit
111. The orbital cavity bone formation: 6The orbital cavity bone formation: 6
bonesbones
112.
113.
114. Also called the optic canal
Hole in the orbit
In the sphenoid bone
Optic nerve, ophthalmic artery and sympatric
nerves pass through it
Optic foramenOptic foramen
115. Lateral to the optic foramen
Several cranial nerves pass through
Five of the six extrinsic muscles originate here at
the ‘ Annulus of Zinn’.
Superior orbital fissureSuperior orbital fissure
116. Fascia = sheets of connective tissue that separate
parts of the body
Periorbital fascia = ‘periosterum’ = cover the the
orbital bones to separate it from the eyeball.
Orbital FasciaeOrbital Fasciae
117. Separates the orbital fat from the eyelids
Orbital SeptumOrbital Septum
118. Forms the sheath within which the eyeball moves
Extends from the limbus to the optic nerve
Separates the globe from the orbital fat
Inferior portion thickens to form the ‘ligament of
Lockwood’ which supports the eyeball like a sling
Bulbar fascia = ‘Tenon’sBulbar fascia = ‘Tenon’s
Capsule’Capsule’
119. Fascia that surrounds the eye muscles
Muscular FaciaMuscular Facia
121. The muscles attaches to the outside of the eyeball
Control turning of eye
6 muscles: 4 recti and 2 oblique
Extratrinsic = ExtraocularExtratrinsic = Extraocular
musclesmuscles
122.
123. Adduction =medial ( inward) toward the nose from
straight ahead , primary position
Abduction = lateral or outward movement
Elevation = upward movement
Depression = downward movement
Intorsion = rotation of eye downward and inward
Extorsion = rotation of eye downward and outward
Terms of Movement – oneTerms of Movement – one
eyeeye
124. Four
Originate at the annulus of Zinn, at the back of the
globe
Insert into the sclera several mm behind the
limbus
Recti MusclesRecti Muscles
125. Medial rectus: principle adductor
Lateral rectus: abduction
Superior rectus: elevates the eye and also
intorsion
Inferior rectus: depresses and extorts the eye
Recti MusclesRecti Muscles
126. Superior oblique muscle: intorsion
◦ Operates like a pulley system as it goes through a sling
like cartilage called the ‘trochlea’.
◦ Originates at the back of the orbit
◦ Goes through the trochlea
◦ Turns back and extends laterally inot the superior lateral
sclera on the back half of the globe
Oblique MusclesOblique Muscles
127. Inferior Oblique muscle : extorsion
◦ Only muscle that does not originate at the apex of the
orbit
◦ Originates near the nasolacrimal duct, near the maxilla
Oblique MusclesOblique Muscles
128. Work as a group
Not independently
When one muscle is working another is relaxed
though partially contributing to the movement
Ocular MotilityOcular Motility
129. Dextroversion – both eyes move to the right
Levoversion – both eyes move to the left
Supraversion - both eyes move up
Infraversion - both eyes move down
Convergence - both eyes move inward to the nose
Divergence - both eyes move outward, toward the
temples
Terms of Movement – twoTerms of Movement – two
eyeseyes
130. Each eye sees an image
Theses images fall on slightly different ( disparate)
retinal points
Fusion of images in the brain
Creates single image
Different viewing angles for each eye contribute to
stereopsis = 3D vision
Binocular visionBinocular vision
131. Need two eyes for stereopsis
Can be monocular and still have depth perception
◦ Monocular clues =
shadows and highlights
Known object size hint
Linear perspective
Motion parallax ( head movements side to side cause the
sensation that distant objects to move more than closer ones
)
Binocular visionBinocular vision
132. Diplopia = double vision= images formed on non-
corresponding points on retina
Suppression = brain blocks out an image so that it
is not perceived to be there.
Ocular motility problemsOcular motility problems
133. A tendency for one eye or the other to deviate but,
when both eyes are open, the eyes are usually in
alignment and images fused.
If one eye gets covered, it will deviate.
HeterophoriaHeterophoria
135. Also known as ‘Strabismus’
When one eye is turned all the time
Heterotropia types:
◦ Esotropia = inward deviation
◦ Exotropia = outward deviation
◦ Hypertropia = upward deviation
◦ Hypotropia = downward deviation
HeterotropiaHeterotropia
136. NonParalytic strabismus = caused by something
other than muscle weakness ( i.e. abnormal AC/A
ratio indicating inappropriate convergence for the
amount of accommodation demanded by a near
object)
Paralytic strabismus = caused by paralysis of an
extraocular muscle
◦ Correct with prism glasses or surgery
Strabismus typesStrabismus types
137. Permanent reduction in VA that cannot be
corrected.
Caused by deprivation of vision or abnormal
binocular interaction in early childhood
Can be caused by:
◦ Anisometropia
◦ strabismus
◦ Occlusion from ptosis
◦ Occlusion from cataracts
AmblyopiaAmblyopia
139. Three main layers:
1. the sclera
2. the uvea
3. the retina
They enclose the aqueous humor, vitreous humor
and the crystalline lens
Walls of the eyeballWalls of the eyeball
143. mucus membrane that covers the front of the
eyeball.
the “white part” of a patient’s eyes
semi-transparent conjunctiva to the white sclera of
the eyeball underneath.
The conjunctiva starts at the edge of the cornea
(this location is called the limbus). It then flows
back behind the eye, loops forward, and forms the
inside surface of the eyelids
144. The continuity of this conjunctiva is important, as it
keeps objects like eyelashes and your contact
lens from sliding back behind your eyeball.
The conjunctiva is also lax enough to allow your
eyes to freely move. When people get
conjunctivitis, or “pink eye,” this is the tissue layer
affected.
Is in direct environmental contact so subject to
irritations
145. a thickened fold of conjunctiva
Also called the semilunar fold
Is a ‘Vestigial remnant’: it is a homolog of the
nictitating membrane seen on sharks.
146. Abnormal secretions = watery or mucous
discharge
Discomfort
Burning
Itching
Redness/ injection of conjunctival blood vessels
Chemosis = swelling
◦ Chemosis causes : irritants like smoke, smog, allergies,
wind, drugs, crying or eye rubbing
Common symptoms of conjunctivalCommon symptoms of conjunctival
diseasedisease
147. Bleeding just beneath
the conjunctival
surface.
Painless and benign
but causes alarm.
Caused by a ruptured
conjunctival blood
vessel
154. Inflammation of the conjuctiva
Can be viral, allergic, bacterial or chemical
155. Conjunctivas = ‘pink eye’ = inflammation of the
conjunctiva
Several types: allergic, bacterial, chemical, GPC
and viral.
All cause a red eye symptom.
156. Associated with CL
wear
Caused by coated or
poorly fitted cl
Enlarged pappillae on
the tarsal conjunctiva
158. Makes up the anterior 1/6 of the eye’s outer shell.
Average radius of curvature of the front corneal
surface is 7.7 mm
Average radius of curvature of the back corneal
surface is 6.8 m
Average center thickness is 0.5 mm
Average edge thickness is about 1.0 mm
CorneaCornea
159. Though it is shaped like a minus lens ( center
thinner) , it acts like a strong plus lens.
This is because the front surface is in contact with
air and the back is in contact with aqueous humor.
The index of refraction changes here from 1.0 (air)
to 1.34 (tears).
The aqueous has almost the same index of
refraction as the cornea.
Then, There is more refractive power at the front
surface than the back
CorneaCornea
160. Is the most refractive lens of the optical system
Has about +43 D of power
Represents about 70% of eye’s total refractive
power
◦ Front surface +48.8 D
◦ Back surface -5.8 D
CorneaCornea
164. Outermost layer of the cornea and is 5-6 layers
thick, comprises 10% of total corneal thickness
Cells generated at basement level and then move
towards the surface where they eventually die and
slough off.
This migration takes about two weeks
As they move to the surface, they get flatter
The EpitheliumThe Epithelium
165. The flattened surface cells are able to shift and
cover up epithelial damage
This is necessary since the front epithelium is the
first line of defense against injury and infection
The epitheliumThe epithelium
166. If damaged will regenerate without scar tissue
There are three cell layers:
◦ Squamous (Flat)
◦ Wing Cell (Middle layer)
◦ Basal Cell Layer (Inner most layer)
EpitheliumEpithelium
169. Thin elastic acelluar membrane of stromal
collagen
Very thin
if damaged will scar
This membrane cannot be separated from
the stroma – it is like a condensed
anterior portion of the stroma
Bowman’s MembraneBowman’s Membrane
170. Assist the epithelium in adhering to
Bowman’s membrane.
This membrane is secreted by the Basal
cell layer of the epithelium
Separation of the Basement membrane
from the epithelium can lead to “Recurrent
corneal erosion”
Basement Membrane of theBasement Membrane of the
epitheliumepithelium
171. Is the middle layer of the cornea and
makes up about 90% of total corneal
thickness
Made up of collagen fibers and has a
precise arrangement called “Lamellae” to
maintain corneal transparency
Fibers are at right angles to each other –
allows for corneal transparency
If damaged, the stroma will leave a scar.
Keratocytes and Wandering cells assist
the stroma in repair
Stroma (Substantia Propria)Stroma (Substantia Propria)
172. Elastic, basement membrane secreted by
the endothelium
Will reform if damaged
Blends into the trabecular meshwork of
the cornea
Can rupture and edges will curl up under
slit lamp observation
Descemet’s MembraneDescemet’s Membrane
173. Is the innermost layer of the cornea
Is a single layer of cells for maintaining
the integrity of the cornea from within
Cells are “hexagonal” in shape
Looks like an “endothelial mosaic”
Highly specialized layer and cells do not
regenerate when damaged
EndotheliumEndothelium
174. Polymegethism – Variation in cell size
Polymorphism – Variation in cell shape
Endothelial Guttata – deposits on the
endothelium indicating endothelial
dysfunction
Endothelium DisordersEndothelium Disorders
175.
176. Constant regeneration of new epithelium cells
Intricate pattern of lamellar fibers in the stroma
Both the epithelium and stroma are a little
dehydrated
◦ Constant absorption of nutrients from fluids like tears and
aqueous
◦ Excess fluid taken out by osmosis and evaporation
◦ DETURGESCENCE = process where liquid is removed
from stroma by the endothelium
What keeps the corneaWhat keeps the cornea
clear?clear?
177. Cornea needs energy
Dependent on oxygen diffused through the tears
( for anterior cornea) and from the aqueous ( for
posterior cornea)
HYPOXIA = lack of oxygen
If corneal hypoxia occurs = cornea has no energy
to dehydrate = swelling ( edema) occurs = causes
loss of transparency = cloudy cornea
Corneal metabolismCorneal metabolism
178. Branches of the ophthalmic division of cranial
nerve V, the trigeminal nerve
Nerves concentrated in anterior stroma and send
branches to epithelium
Responsible for the intense pain felt in a corneal
abrasion
Corneal nervesCorneal nerves
179. Transition from clear cornea to opaque sclera
Translucent with ill defined borders
About 1mm width
Contains blood vessels that supply peripheral
cornea with nutrients.
LimbusLimbus
183. CORNEAL DYSTROPHY = breakdown of certain
corneal layers. Results in corneal clouding c
decreased VA.
Cause: inherited
184. Extensive corneal
swelling
Caused by
dysfunctional
endothelial cells
BULLAE = pockets of
fluid in the epithelium.
Can cause pain if
they break
Bullous keratopathyBullous keratopathy
185. Swelling or fluid
retention of tissue
Corneal edemaCorneal edema
186. Endothelial dystrophy
Endothelial cells die
due to decemet’s
membrane
malfunction
Corneal GuttataCorneal Guttata
187. Groups of white blood
cells in the corneal
tissue
InfiltratesInfiltrates
194. New blood vessels in
the cornea
Neovascularization of theNeovascularization of the
corneacornea
195. Recurring loss of
epithelial tissue after
corneal injury
Recurrent corneal erosionsRecurrent corneal erosions
196. Loss of corneal tissue
as a result of trauma,
burns, infection or
inflammation
UlcerUlcer
197. An abrasion is a scratch on the the corneal
surface. If only the epithelium is involved then
healing occurs within 24 – 48 hours. If deeper
layers are involved it takes longer.
Must be treated with antibiotics immediately to
prevent infection.
Symptoms include foreign body sensation, light
sensitivity and tearing.
198. Corneal Scars occur when an abrasion goes
deeper than the outer epithelial layer. If a scar is
central it can disturb vision.
Corneal ulcers can occur when an abrasion
becomes infected. Scarring can result from a
resolved ulcer if deep corneal tissue is involved.
199. Corneal Transplants = most commonly
transplanted tissue in the US. About 40,000 cases
a year. Diseased cornea is replaced with a donor
cornea and sewn into place.
Refractive surgery= LASIK, Radial Keratotomy.
200. Irrigate immediately for at least 15 minutes.
Use tap water if no saline is available.
Alkaline materials (cement, bleach) are more
serious than acidic because an of greater
penetration and possible deep tissue damage.
Acidic materials often result in surface burns
alone.
201. Aim away from the cornea if possible.
Have pt rest their head on something, if possible.
Hold lids away to insure stream lands in eye.
Strong, steady stream into the eye.
Hold towels under the eye. Cover check and chin
to catch fluid.
Pt may have to swallow liquid too (naso –
lacrimal ). Tell pt this is normal.
202. To evaluate the integrity of the corneal surface
and conjunctival epithelium
Dyes
◦ Sodium Fluorescein
◦ Rose Bengal
◦ Lissamine Green
215. Contains the vascular system that nourishes
theeye.
Consists of :
CHOROID
CILIARY BODY
IRIS
Uveal tractUveal tract
216. Extends from the optic nerve to the ciliary body
Very dark layer due to high amount of pigment
Contains many arteries and veins
Ciliary arteries:
◦ Short posterior ciliary arteries ( supply the choroid)
◦ Long posterior ciliary arteries ( supply the iris)
◦ Anterior ciliary arteries ( supply ciiary body and sclera)
CHOROIDCHOROID
217. Must differentiate to know cause and location of
inflammation. Both appear red …
The conjunctival blood vessels are more
numerous towards the fornices and less towards
the limbus
The anterior ciliary blood vessels are more
numerous towards the limbus.
Also, anterior ciliary blood vessels appear a
deeper, purple red color
Anterior ciliary blood vessels vs.Anterior ciliary blood vessels vs.
conjunctival blood vesselsconjunctival blood vessels
218. Is an extension of the choroid
Encircles the globe behind the iris
Consists of :
◦ Ciliary muscle ( which attaches to the lens via the
zonules)
◦ Ciliary processes that secrete aqueous humor into the
eye
Ciliary BodyCiliary Body
220. Extension of uveal tract. Ciliary body changes to
the iris.
Circular aperture called the pupil
Pupil adjusts amount of light entering the eye.
Color of iris depends on amount of pigment
present: heavily pigmented = brown, lightly
pigmented = blue
IrisIris
221. DILATOR PUPILLAE = dilates the pupil
SPHINCTER PUPILLAE = constricts the pupil
As one muscle works, the other relaxes
Iris muscles (2)Iris muscles (2)
222. Normally round
Regular in shape
Equal in size
Actually nasally decentered in the iris
MYDRIASIS = dilation in low illumination and
excited emotional states
MIOSIS = constriction
PupilPupil
223. UVEITIS = inflammation of the uvea
◦ Symptoms:
◦ Blurry, cloudy vision
◦ Can’t accommodate
◦ Light sensitivity (photophobia)
◦ Pain or Dull ache over brow bone
◦ Red eye with peri limbal injection
◦ Irregular pupil shape
◦ Cells and flare in anterior chamber
◦ Abnormal pupillary response
◦ Keratic precipitates : cells adhering to the posterior
cornea
Uveal tract disordersUveal tract disorders
240. The anterior chamber lies inside the eye between
the iris and the cornea. It is filled with aqueous
fluid. The aqueous flows from behind the pupil into
the drainage angle created by the iris and cornea.
241. Aqueous is secreted by the ciliary body
Drains into the angle formed by cornea and iris
Drainage Pathway:
Angle –( to the ) - trabecular meshwork ––( to the )
- canal of schlemm ––( to the ) ciliary veins –
carry away aqueous with the blood
Anterior Chamber Aqueous pathAnterior Chamber Aqueous path
243. Smallest chamber
Located behind the iris but in front of the vitreous
In the middle is the lens
Outer border is the ciliary processes of the ciliary
body
Filled with aqueous humor
Posterior ChamberPosterior Chamber
244. Posterior most in eyeball
Largest chamber
Extends from posterior lens to optic nerve
Walls lined with retina
Filled with vitreous humor : collagen filberts
suspended in a viscous gel
PVD – posterior vitreous detachment: vitreous
shrinkage that can cause retinal detachments
Vitreous chamberVitreous chamber
245. Blood in the anterior
chamber .
Usually caused by
trauma.
246. Inflammatory cells in
the anterior chamber.
( white blood cells or
pus)
Caused by infection
247. Inadequate space at
the drainage angle.
Causes outflow
problems and inc
IOP.
Can be a cause of
glaucoma
248.
249. Glaucoma is a condition which causes irreversible
damage to the optic nerve.
Can cause irreversible blindness if untreated.
There are several types of glaucoma.
The most common is “open angle glaucoma”.
Called the “sneaky thief of sight” since it first
affects peripheral vision which often goes
unnoticed. By the time it affects central vision it is
advanced.
251. The fluid in the anterior chamber (called aqueous) is
constantly being formed and drained. This creates a
pressure inside the eye called the intra-ocular
pressure (IOP).
The IOP is independent of a person’s blood pressure.
If the aqueous is not being drained well the aqueous
will build up and cause the IOP to increase.
The high pressure is transmitted to the back of the eye
and damages the weakest spot – the optic nerve.
252. Family history of GL
Age (over 40)
High myopia
African ancestry
Trauma
Medications
253. There is no ‘cure’
It can usually be controlled by medical treatment
Eye drops are the first line of treatment to try to
lower the IOP.
Most cases are controlled with eye drops only.
Some cases will also need laser treatment or
surgery to open drainage pathways.
255. Uncommon but important to recognize
Drainage gets totally blocked and IOP builds up
rapidly. Will cause irreversible damage to the optic
nerve if IOP is not decreased in a matter of hours.
Profound symptoms: severe pain, red eye, halos
around lights and hazy vision.
Send to emergency room immediately for
medications and/or iridotomy.
256.
257. Usually, it is triggered by situations in which the
pupil dilates and the iris blocks the drainage
angle.
Can be from a routine dilation in an eye care
setting.
259. Light sensitive layer
Photoreceptors ( light sensitive nerves)
Optic nerve = convergence of photoreceptors to
form a nerve bundle
Direct brain extension
RetinaRetina
260. Rods = responsible for scotopic vision ( in low
light) . Poor visual acuity. Responsible for
peripheral vision
Cones = color vision, and sharp, clear central
vision. Operate in bright illumination.
Retinal photoreceptorsRetinal photoreceptors
261. Ora serrata = scalloped anterior edge of the
retina. Edges to ciliary body
Macula lutea = ‘yellow spot’.
◦ About 4.5 mm in diameter
◦ Located temporal to the optic nerve
◦ Is at the visual axis endpoint
◦ Slightly yellow appearance with a dark pigment layer
behind it
◦ CENTER IS THE ‘FOVEA CENTRALIS’
Retinal regionsRetinal regions
262. 1.5 MM DEPRESSION THAT CONTAINS ONLY
CONES
GIVES SHARPEST IMAGES
BEST VISION POSSIBLE
VISUAL AXIS SHOULD CONNECT THE OBJECT
BEING VIEWED WITH THE FOVEA
‘FOVEA CENTRALIS’
263. Area between the macula area and ora serrata
Changes from cones to mostly rods
Peripheral retinaPeripheral retina
264. Interior portion of the posterior globe
Visualized with an ophthalmoscope or BIO
Fovea, macula, retinal arteries and veins and the
optic disc seen
The FundusThe Fundus
265. marks the exit of the optic nerve to the brain;
located about 3mm nasally from the macula
No photoreceptors here
Called the ‘blind spot
Brain fills it in so we are not usually aware of it
OPTIC DISCOPTIC DISC
266. Diabetic retinopathy= hemorrhaging from diabetes
Macular degeneration = loss of central vision;
usually age related
Retinal detachment
Retinitis pigmentosa = hereditary loss of rods.
Retinal diseasesRetinal diseases
267. The Theory of Trichomacy
◦ The retina has three different types of cones with
different photopigments: blue, red and yellow.
◦ Each responds to the light of that color’s wavelength
spectrum
◦ The mixture of these cones in our retinas give the variety
of colors perceived
Color VisionColor Vision
268. Anomalous trichromats
◦ Have all the photopigmented cone types
◦ Perceive all colors but are less sensitive to one color
DiChromats
◦ Two different photopigmented cones
◦ See less color variety
Monochromats =
◦ very rare
◦ only have one type of photopigmented cones
◦ See black, white and gray
Color vision deficienciesColor vision deficiencies
269. More prominent in males
Tinted contact lenses help improve color
discrimination for some
Color vision deficiencyColor vision deficiency
271. Located behind the pupil and iris
Biconvex shape
About 10 mm diameter
Lens grows throughout life in layers
Completely enveloped by outer layer ‘ lens
capsule’.
LensLens
