Introduction to Ocular Anatomy & Histology

Visual System

Takes information from the environment in the form of light to analyze and interpret it

Purpose of the Visual System

So an organism can "see"

What do eyes convert the light rays to?

Neural Signals

What houses and protects the eye?

Bony, Fatty, and Connective Tissue

What covers and protects the eye?

Eyelids

Where are the glands that produce tears located?

Within the eyelids

What directs the movement of both eyes for binocular vision?

Muscles

In which ways can the eye be viewed?

1. Anterior

2. Posterior

3. Superficial

4. Deep

Superficial can be referred to as...

External

Deep can be referred to as...

Internal

External (Superficial)

Oriented towards the surface or towards the exterior of the eye

Internal (Deep)

Oriented towards the center of the eye or interior of the eye

How many Tunics are within the Eye?

3

List the 3 Tunics:

1. Fibrous Tunic

2. Uveal/Vascular Tunic

3. Nervous Tunic

What is the outermost tunic?

Fibrous Tonic

What does the Fibrous Tunic consist of?

1. Cornea

2. Limbus

3. Sclera

What is the middle tunic?

Uveal/Vascular Tunic

What does the Uveal/Vascular Tunic consist of?

1. Choroid

2. Ciliary Body

3. Iris

What is the inner tunic?

Nervous Tunic

What does the Nervous Tunic consist of?

1. Sensory Retina

2. Retinal Pigmented Epithelium

List the components of the eye that are within the Anterior Portion (8)

1. Cornea

2. Limbus

3. Anterior Sclera

4. Anterior Chamber (Aqueous humor)

5. Iris

6. Lens (Suspensory Ligament)

7. Ciliary Body

8. Posterior Chamber (Aqueous humor)

List the components of the eye that are within the Posterior Portion

1. Sclera

2. Choroid

3. Retina

4. Vitreous Humor

5. Fovea

6. Optic Nerve

What are the 3 Chambers of the Eye?

1. Anterior Chamber

2. Posterior Chamber

3. Vitreous Chamber

What is the largest chamber within the eye?

Vitreous Chamber

Which chamber(s) are filled with aqueous?

Anterior and Posterior Chamber

Why is it important to have the chambers filled with aqueous? (2)

Provides the Avascular Tissue nutrition and removes waste

Main function of Vitreous Chamber

Maintains eye shape

Where is the Anterior Chamber?

Behind the cornea and is in-front of the lens

Where is the Posterior Chamber?

Behind the Iris and adjacent to the Lens

Eyelids Function (4)

1. Protects eye from foreign bodies and dust

2. Blinks as a reflex

3. Helps to spread tears

4. Limits light entering the eye

What are the thinnest layer of skin found throughout the entire body?

Eyelids

Functions of Nasolacrimal System (2)

1. Produce tears via the Lacrimal Gland

2. Drain tears via the Drainage System

What produces tears?

Lacrimal Gland

Where do tears drain into?

Nasal Cavity

Cornea

Clear "cap" directly in front of the colored part of our eyes

Functions of Cornea (3)

1. Transparency

2. Refractive Power

3. Protection

Conjuctiva

Thin, transparent layer of cells

-Covers the Sclera and Inner Eyelid

Describe the type of cells found within Conjuctiva:

Thin mucoid translucent layer of cells

Functions of Conjuctiva (3)

1. Protect the Sclera from Organisms

2. Produce part of the tear film

3. Provide nutrition and lubrication to the Cornea

What is the white part of the eye called?

Sclera

Describe the Sclera layer of the eye:

Opaque, fibrous, tough, and protective outer layer of the eye

-Continuous with the Cornea and with the sheath covering the Optic Nerve

Functions of the Sclera (3)

1. Provides protection

2. Maintains shape of eye

3. Eye muscles attach to Sclera

Limbus

Transition zone between Cornea & Sclera

Where does the fluid of the eye drain?

Canal of Schlemm found within the Limbus of the Eye

Iris

Colored portion of the eye

Functions of the Iris (2)

1. Controls the size and shape of the Pupil (Thus, it controls the illumination to the Retina)

2. Gives eyes color

Can the Ciliary Body be seen just by looking at someone?

Cannot be seen!! Patient must be imaged

Functions of the Ciliary Body (2)

1. Produces aqueous or fluid of Anterior & Posterior Chamber

2. Ring of muscle that changes shape of lens to maintain focus

Functions of the Lens

Focuses light rays onto the Retina

Choroid

Vascular layer of the eye lying between Retina and Sclera

Functions of the Choroid

1. Nourishes the outer layers of the Retina

2. Prevents reflection of light

Retina

Converts light into a stimulus that is transmitted to the brain to be interpreted as an image

What type of tissue does the Retina consist of?

Nervous Tissue

Functions of the Retina

1. Receives light

2. Converts light to visual energy

3. Transmits light

Which cells are light sensitive?

Rods and Cones

Fovea

Area of Retina where light is focused for clear vision

Functions of the Fovea

Gives us clear vision & color vision

Where is the Blind Spot within the eye?

Where the Optic Nerve leaves the eye

Function of the Optic Nerve

Transmits nerve impulses from the Retina ultimately to Visual Cortex