Eye and Vision Flashcards
What are the 3 layers of the eye?
1) Outer Layer: Sclera and Cornea
2) Middle Layer: Uvea
3) Inner Layer: Retina
What is the role of the outer layer?
1) Barrier to infection: Tough layers made up of collagen
2) Light transmission: Transparent (Responsible for 2/3 refractive power of eye)
What is the 5 layer structure of the outer eye?
1) Epithelium
2) Bowman’s Layer
3) Stroma
4) Descemet’s Layer
5) Endothelium
What are the features of middle layer?
1) Iris: Coloured part with dilator and sphincter pupillae muscles (Pupillary reflexes)
2) Ciliary Body
3) Choroid: Blood supply to outer 1/3
What does the Ciliary Body produce and how?
Glandular Epithelium produces aqueous humour (Smooth ciliary muscle controls accomodation)
What does the Inner Layer contain and main role?
1) Retina
2) Specialised organ of phototransduction
What are the main features of the Retina?
1) Macula Lutea (Spot for visual acuity)
2) Fovea Centralis
3) Cones
4) Rods
What cells are found in the Retina?
1) Bipolar cells
2) Retinal ganglion cells
3) Mullers glial cells
4) Amacrine and horizontal cells
(Retinal Photoreceptors)
What happens in the Anterior Segment of the eye?
1) Aqueous Humour
2) Nutrition to lens and cornea
3) Maintain intraocular pressure
What is the role of the lens? (3)
1) Biconvex
2) Responsible for 1/3 refractive power
3) Accomodation
What is found in the posterior segment? (4)
1) Vitreous Humour
2) Avascular Viscoelastic Gel
3) Hyaluronic Acid (GAG)
4) Collagen
What is contained in the Adnexae?
1) Lids (Protection)
2) Conjunctiva (Mucous Membrane and Protective (Goblet and Lymphoid))
3) Tear Film: 3 layers for protection and nutrition for cornea
Retina Blood supply?
1) Inner: Central Retinal Artery and drained by retinal veins
2) Outer: Choroid artery (outer 1/3)
Does the eye have lymphatic drainage?
Conjuctiva and lids to submandibular and pre-auricular nodes
