The Red Eye - PS Flashcards
What tissues make up the eyelids?
Skin, meibominan glands and conjunctiva
Where can you see redness in the eye?
Eyelids, conjunctiva, episclera, sclera, third eyelid, cornea, anterior chamber, anterior uvea, posterior uvea, retina, retrobulbar area
How could you get red eyelids?
Hyperaemia, swelling, ulcers, crusts, loss of hair
Dermatitis of various causes
Meibomian glands have a problem such as infection, neoplasia, granuloma
What are the eyelids intimately associated with?
Cornea and tear film
What knock on effects could be seen with red eyelids?
Loss of protective effect
Loss of oily part of tear film
Contact problem with eyelid hairs/masses and the cornea
What secondary pathologies could be seen as a result of eyelid pathology?
Corneal ulceration
Corneal vascularisation
Excessive tear production
What is the conjunctiva?
Mucus membrane lining of the sclera, 3rd eyelid and underside of eyelid that ends at the limbus (where the white meets the cornea)
What makes up the conjunctiva?
Epithelial cells
Mucus cells (goblet cells)
Lymphoid tissue
Blood vessels
What are the characteristics of conjunctival blood vessels?
Dichotomous branching
Very sensitive to surface irritation
How can conjunctival blood vessels cause redness?
Dilation of vessels and separation of endothelial cells leads to hyperaemia and oedema
What is the episclera?
Connective tissue under conjunctiva up to the limbs
Different looking blood vessels
What are the characteristics of episcleral blood vessels?
No dichotomous branching
Larger, meadner
What does the presence of episcleral blood vessels indicate?
Intra-ocular disease such as uveitis and glaucoma
Severe/chronic surface irritation in some cases
What is the sclera?
True white of the eye
Fibrous tunic continuous with the cornea via the limbus
Collagen fibres and fibroblasts
Emisaria are the holes in the sclera for blood vessels and nerves
What is the structure of the third eyelid?
Lots of lymphoid follicles in the bulbar side and palpebral side
T shaped cartilage core holds the third eyelid up against the eye
Contains the lacrimal gland
How can the third eyelid become red?
Hyperaemic
Cartilage curling outwards
Prolapse of lacrimal gland
What name is given to enlarged lymphoid follicles?
Follicular conjunctivitis
What are the four layers of the cornea?
Epithelium
Stroma
Descemets membrane
Endothelium
What are the characteristics of the corneal epithelium?
Physical barrier to tears, micro-organisms, environment
Hydrophobic
Doesn’t have blood vessels in health
Has nerves
What are the characteristics of the stroma?
Hydrophilic
Stays relatively dehydrated through the action of the endothelium (sodium/potassium pumps) and epithelium (passive)