1. JI LOPEZ, CAMILLE JI LORENZO, ADRIAN
ANATOMY OF THE EYES
JI LOPEZ, CAMILLE
JI LORENZO, ADRIAN

2. Elevation of the superior (upper) eyelid
MUSCLES OF THE EYES
Muscle
Innervation
Primary function
Levator palpebrae superioris
Oculomotor nerve
Elevation of the superior (upper) eyelid
Superior rectus
Elevation
Inferior rectus
Depression
Lateral rectus
Abducens nerve
Abduction
Medial rectus
Adduction
Superior oblique
Trochlear nerve
Intorsion
Inferior oblique
Extorsion

3. THE EYES
The outer layer (sclera or white, and cornea) is fibrous  and protective.
The middle layer (choroid, ciliary body and the iris) is vascular.
The innermost layer (the retina) is nervous or sensory.

4. SCLERA “white of the eye”
It is the fibrous, protective, outer layer of the eye containing collagen and elastic fiber
In children: thinner & translucent -> bluish tinge
In the elderly, fatty deposits on the sclera can make it appear slightly yellow.
In young age, the sclera is thinner and more translucent, allowing the underlying tissue to show through and giving it a bluish tinge.
As we grow older, fatty deposits on tthe sclera tends to make it appear more yellow.
The sclera forms the posterior five-sixths of the connective tissue coat of the globe. It is continuous with the dura mater and the cornea, and maintains the shape of the globe, offering resistance to internal and external forces, and provides an attachment for the extraocular muscle insertions.

5. SCLERA
The thickness of the sclera varies from 1mm at the posterior pole to 0.3 mm just behind the rectus muscle insertions
The collagen of the sclera is continuous with the cornea. Four layers of the sclera are:
episclera
stroma
lamina fusca
endothelium
The sclera is opaque due to the irregularity of the collagen fibers, as opposed to the near-uniform thickness and parallel arrangement of the corneal collagen. Moreover, the cornea bears moremucopolysaccharide (a carbohydrate that has among its repeating units a nitrogenous sugar, hexosamine) to embed the fibrils.

6. CORNEA Avascular, transparent
front part of the eye that covers the iris, pupil, and anterior chamber.
Together with the lens, the cornea refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power
The cornea has unmyelinated nerve endings sensitive to touch, temperature and chemicals; a touch of the cornea causes an involuntary reflex to close the eyelid. Because transparency is of prime importance the cornea does not have blood vessels; it receives nutrients via diffusion from the tear fluid at the outside and the aqueous humour at the inside and also from neurotrophins supplied by nerve fibres that innervate it. In humans, the cornea has a diameter of about 11.5 mm and a thickness of 0.5–0.6 mm in the center and 0.6–0.8 mm at the periphery. Transparency, avascularity, the presence of immature resident immune cells, and immunologic privilege makes the cornea a very special tissue. The cornea has no blood supply; it gets oxygen directly through the air. Oxygen first dissolves in the tears and then diffuses throughout the cornea to keep it healthy.[4]
It borders with the sclera by the corneal limbus.
The most abundant soluble protein in mammalian cornea is albumin.[5
Slit lamp image of the cornea, iris and lens

7. Layers of the Cornea 1. Anterior Corneal epithelium 2. Bowman's layer
- non-keratinized stratified squamous epithelium
2. Bowman's layer 
-  a tough layer that protects the corneal stroma, consisting of a similar irregularly arranged collagen fibers
3. Corneal stroma (Substancia Propia)
- thick, transparent middle layer, consisting of regularly arranged collagen fibers along with sparsely distributed interconnected keratocytes, which are the cells for general repair and maintenance

8. Layers of the Cornea 4. Descemet's membrane
- thin acellular layer that serves as the modified basement membrane of the corneal endothelium, from which the cells are derived
5. Corneal endothelium
- a simple squamous or low cuboidal monolayer.
- responsible for regulating fluid and solute transport between the aqueous and corneal stromal compartments.