ocular anatomy · hordeolum the point where the upper and lower eyelids meet is called a. ora...

Course #

720Ocular Anatomy

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Darrell Grise, ODLenny Jankowski ,CPOT, coa

3 Layers Fibrous Layer

*Cornea*Sclera

Vascular Layer Vascular Layer*Choroid*Ciliary body*Iris

Nerve Layer*Retina *Macula*Optic nerve

What is the main function of each layer?

oilaqueous

snot

What functions does each layer of the tear perform?

A complex mixture of proteins, mucins, and electrolytes coated by a lipid layer

• Antimicrobial proteins• Growth factors &

suppressors of inflammation

• Soluble mucin helps stabilize tear film

• Electrolytes for proper osmolarity (295-300)– pH slightly alkaline (7.4)

Why is a tear salty tasting?

Left:Transillumination of eyelid showingmeibomian glands

Right:Secretion of

lipid at lid margin

• The lipid layer restricts evaporation to 5-10% of tear flow– Also helps lubricate

Where does a contact lens rest?

What function does the pupil have?

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Lacrimal Apparatus◦ Lacrimal gland - located

under the frontal bone at upper-outer angle of the orbit

◦ Lacrimal canals/ducts (6-12)12)

◦ Conjunctival sac◦ Puncta (um)…drainage ports

(2 ea eye)◦ Canaliculi (us)◦ Lacrimal sac◦ Nasolacrimal duct - drains

into the nose

Sometimes a person cannot produce natural tears that they might need some punctal plugs.

Index of refraction is 1.37 Approximately .5mm in thickness Transparent Organ (no blood vessels / avascular) Primary function is refraction of light rays Refractive power approx + 45.00 D

What is it called when blood vessels grow onto the cornea?

Composed of 5 6 layers ◦ Epithelium…24 hr healing Outermost layer 5 cell layers thick Heals very quickly ea s e y qu c y Does not scar

◦ Bowman's membrane- layer just under the epithelium NOTE: will scar

◦ Stroma – middle tissue that forms 90% of the cornea◦ Dua’s Layer – Newly discovered layer of the cornea ◦ Descemet's membrane- thin elastic layer deep in the

cornea ◦ Endothelium - only one cell layer thick; lines undersurface

of the cornea, where it regulates corneal water content

What cranial nerve is tied to corneal sensations?

A cellophane-like membrane which covers the anterior sclera and continues to the back surfaces of the lids to form a conjunctival sac

Has blood vessels which can burst and cause subconjunctivalhemorrhage

Three parts◦ Bulbar◦ Palpebral◦ Fornix - where bulbar and

palpebral meet

White in color Primary function is

protection Pierced posteriorly by the

tioptic nerve Acts as insertion points

for the six EOMs Junction between the

cornea and sclera is called the Limbus


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Manufactured by ciliary body

Characteristics:◦ Clear◦ Watery consistency (99%

H2O) Functions Functions ◦ Refraction of light◦ Intraocular Pressure

(IOP)◦ Believed to nourish

posterior surface of the cornea and the crystalline lens

Flows from posterior chamber through the pupil into the anterior chamber

How does aqueous flow out of anterior chamber?

Most anterior portion of the vascular layer

Gives the eye its color Gives the eye its color, i.e. blue eyes, brown eyes, etc.

Consists of blood vessels, pigment and muscle tissue

Regulates light Smaller with age

What does the sphincter muscle control?

Functions◦ Refraction of light

approx 12-14 diopters fof power

◦ Accommodation Focus adjustment of the

eye Presbyopia is the loss in

accommodation First noticed around age

40. Due to a loss in flexibility of the lens

Name the three main parts of the lens

3 things happen during accommodation:◦ Pupils constrict◦ Eyes converge◦ Lens gets thicker

The crystalline lens contains a high degree of e c ysta e e s co ta s a g deg ee oprotein◦ Changes in the lens protein causes the lens to lose its

transparency which is a condition termed "cataract"◦ Aphakia is the absence of a lens. It can be removed during

cataractextraction

How much focusing power does the lens have?

Located near the base of the iris and posterior to itposterior to it

Composed of blood vessels and muscle fibers (ciliary muscle)

Cilliary process produces aqueous

Ciliary body is attached to suspensatory ligaments called?

Characteristics:◦ Gel-like fluid that

fills the eye◦ Refraction of light◦ Refraction of light◦ Internal support◦ Give the eye shape

Spots in vision may be floaters in the vitreous Post vitreous detachment

How many chambers are inside the eye?


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Divided into four quadrants like the brain

Fovea at exact center Optic nerve head is located Opt c e e ead s ocated

in nasal half Each quadrant is

responsible for the vision in the opposite field of view

Ora Serrata◦ Land mark attachment

site for choroid and retina

◦ Most anterior portion of retina

◦ Composed of almost all rods

How many layers are in the retina?

Identification of Retinal Layers

ILMILM GCLGCLNFLNFL IPLIPL OPLOPL

Cross-sectional image of live tissue; a virtual biopsy

IS/OSIS/OS RPE/CCRPE/CC ChoroidChoroid

NFL: Nerve Fiber LayerILM: Inner Limiting MembraneGCL: Ganglion Cell Layer

IPL: Inner Plexiform Layer OPL: Outer Plexiform

IS/OS: Junction of inner and outer photoreceptor segments RPE: Retinal Pigment EpitheliumCC: Choriocapillaris

Stratus OCT™

Visual Receptors are Cones and Rods◦ Cones Produce color vision Responsible for detailed vision Used in day vision = “Photopic” = normal and high levels ofUsed in day vision = Photopic = normal and high levels of illumination

◦ Rods…120 million Produce black and white vision Function in dim light = “Scotopic” = low level of illumination

◦ Cones and Rods… 6 million Used under mesopic vision = between scotopic and photopic Both rods and cones are used.

Optic nerve head (optic disc)◦ No receptors -

physiological blind spotspot

◦ Point of exit of optic nerve

◦ Appears yellow compared to the orange choroid


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What disease of the eye primarily focuses on the cup and disc?

The Extra-ocular Muscles (EOM) Organized into an

umbrella-like bundle among the orbital fat, orbital blood vessels and nervesnerves

Six muscles associated with eye movements Superior rectus (S.R.) Inferior rectus (I.R.) Medial rectus (M.R.) Lateral rectus (L.R.) Superior oblique (S.O.) Inferior oblique (I.O.)

How many cranial nerves control these 6 muscles?

What is the name of the point where the muscles come together?

Openings of the orbit◦ Purpose of openings Transmit arteries and/or veins to and from the orbit Transmit nerves to and from the orbit

◦ Types of openings Fissures (crevices/cracks) Foramina (holes) Foramina (holes)

◦ Major openings Optic foramen - II cranial nerve - Optic Nerve Supraorbital fissure - IV cranial nerve - Trochlear Nerve

The transition zone between the sclera and the cornea is called?

1. Frontal bone…forehead

2. Ethmoid bone…weakest

3 Palatine bone smallest3. Palatine bone…smallest

4. Zygomatic bone…strongest

5. Lacrimal bone6. Maxillary bone

7 Layers of the eyelids 1. Skin-thinnest layer 2. Subcutaneous

connective tissue3 Striated Muscle3. Striated Muscle4. Sub-muscular connective

tissue 5. Tarsal plate or fibrous

layer6. Smooth muscle7. Conjunctiva

(Bulbar/Palpebral)

How are Hordoleum and Chalazions treated?


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Eyebrows◦ Thickened ridge of skin with

short hairs◦ Diverts perspiration

Eyelashes◦ Also protects◦ Sebaceous glands at base of

each lash are called Glands of Zeis which produce a lubricating fluid Fluid can harden and clog

the gland, producing a stye or painless chalazion. If painful and infected it is called an external hordeolum

The point where the upper and lower eyelids meet is called

a. ora serratab. canthusc. jointd. sphinx

The blockage of the meibomian gland is called the ___________ when it causes pain, and the _________ when it does not cause pain.

The eyelid will protect your eyes from…a. blinkingb. dust particlesc. stray tearsd. a burning punctum

What main muscles raises the eyelid? What main muscles raises the eyelid?

Name the six layers of the cornea in order

The drain port for tears is called?a. canal of Schlemmb. punctumc. lacrimal glandd. zonnule of Zinn

In what layer of the eye will chronic diseases normally In what layer of the eye will chronic diseases normally manifest?

What structure prevents a contact from going behind the globe of the eye?

What is the most anterior part of the retina.

What is the total power of the Cornea, the crystalline lens assembly, and the overall eye?

What is the most posterior layer of the retina?


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What are the layers of a tear film?

Where is tear mucin produced?

Why is the tear film important in contact lens wear?

Th i i hi h i l ? The optic nerve is which cranial nerve?

What function does the Canal of Schlemm have?

Opia means what?

What is the difference between a tropia and a phoria?

Avascular means what?

How many extra-ocular muscles are oblique?

What does the root word “papill” mean?

Identify the name for the 3 parts of the conjunctiva

In what layer of the eye will the retina be found?

What is the strongest bone of the bony orbit?

What muscle of the lid would be involved in ptosis?

_________ exist when the foveal lines of sight of the two eyes do not point at the same object.◦ A. binocularity◦ B. strabismus◦ C. conjunctivitis◦ D. FB sensation

Of the following all are anomalies of the binocular system except:except:◦ A. strabismus◦ B. Amblyopia◦ C. anomalous correspondence◦ D. conjunctivitis

When the power of the crystalline lens correspond with axial length of the eye, so that parallel light rays are appropriately refracted to focus on the retina is called?◦ A. emmetropia◦ B. ammetropia◦ C. hyperopia◦ D. myopia

An opacity of the crystalline lens is known as?◦ A. photophobia ◦ B. cataract◦ C. edema◦ D. aphakia

Glaucoma screening test that used puff of air onto the eye surface:◦ A. NCT◦ B. snellen◦ C. amsler grid◦ D. accommodation


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Which test uses Pseudo Isochromatic Plates?◦ A. IOP◦ B. color test◦ C. cover/uncover◦ D. snellen

This checks the power of the eye:◦ A. NCT◦ B. taking case history◦ C. Autorefractor◦ D. taking blood pressure

Which test is used to check six cardinal position of gaze for motility?◦ A. Muscle H◦ B. APD◦ C. Amsler Grid◦ D. Tropia

Examination of the eye is performed by using a slit y p y glamp or another name for slit lamp is:◦ A. non-contact tonometer◦ B. biomicroscope ◦ C. pupilometer◦ D. lensometer

What is a good tear BUT(break up time)?

What device checks the peripheral vision?

Wh d i h di b What device measures the distance between the pupils?

What device measures corneal thickness?


ocular anatomy · hordeolum the point where the upper and lower eyelids meet is called a. ora...

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