The Red Eye Flashcards
Where can you see redness of the eye?
- Eyelids
- Conjunctiva/episclera/sclera
- Cornea
- Anterior chamber
- Anterior uvea
- Posterior uvea/retina
- Retrobulbar area
How might we get red eyelids?
Loss of protective effect
Loss of oily part of the tear film from meibomian glands
Contact problems: eyelid hairs or masses
What causes hyperaemia?
Irritation of the white of the eyes
What causes vascularisation?
Corneal irritation
What are the characteristics of conjunctival blood vessels?
Dichotomous branching
Dilation of the vessels and separation of endothelial cells
- Hyperemia
- Oedema
What are the characteristics of episcleral vessels?
No dichotomous branching
Larger
Meander
What do episcleral vessels indicate?
Intraocular disease mostly (uveitis and glaucoma)
Sever or chronic surface irritations in some cases.
What are the 4 layers of the cornea in order?
- Epithelium
- Storma
- Descemet’s membrane
- Endothelium
What are the char of the corneal epithelium?
It is hydrophobic, does not have blood vessels when healthy and has nerves
What are the characteristics of the stroma?
It is hydrophilic and stays relatively dehydrated due tot the actions of the epithelium (acting as a passive barrier) and the endothelium (which actively pumps fluid back into the anterior chamber). This allows the stroma to stay transparent.
What occurs when the stroma is overhydrated?
Corneal oedema
What a re the characteristics of the decement’s memebrane?
A thin collagen layer acting as a basement membrane for the endothelium.
What are the causes of corneal odema and give the pathophysiology…
1) Uveitis/Glaucoma
2) Lens luxation
3) Primary degeneration
All of the above lead to endothelial failure and allow for the over hydration of the stroma and thus corneal oedema
What us the iridocorneal angle?
An angle formed by the iris and cornea to allow for drainage of the aqueous humour from the eye by pumping fluid into the episcleral vessels.
Describe the route of aqueous humour…
Ciliary body -> Posterior chamber -> Pupil -> Anterior chamber -> ICA/uvea/sclera -> out
What intraocular pressure is considered glaucoma?
> 22mmHg
What intraocular pressure is considered uveitis?
< 12mmHg
What disease cause loss of epithelium in the cornea?
Corneal ulcer
What disease result in damage to the corneal endothelium?
Glaucoma
Uveitis
Lens luxation
Primary endothelial degeneration
What disease result in vascularisation and thus leakage of the cornea?
Any irritating problem of the cornea (e.g. KCS, eyelid problems, LPI), ulcers and uveitis
What is the anterior chamber filled with?
Aqueous humour
What does the aqueous humour do?
It establishes intraocular pressure.
Name the two primary disease affecting the anterior chamber
Uveitis and glaucoma
How does glaucoma cause an increase in intraocular pressure?
ICA closure/clogging increasing IOP
How does uveitis increase intraocular pressure?
It increases the uveosclearal outflow and thus decrease IOP.
What are the parts of the anterior uvea?
Iris and ciliary body
What are the parts to the posterior uvea?
Choroid
What are the common denominators of the uvea?
It is a mesh of blood vessels that usually contains a lot of pigment
What is miosis?
Iris spams with resulting pain (the opposite of mydriasis)
What are the causes of uveitis?
Miosis
Endothelial cell separation resulting in leakage of blood components
Adhesion of iris to the anterior lens (Posterior synchiae)
Development of preiridal fibrovascular memebranes (PIFMS)
What are PIFMs?
Preiridal fibrovascular membranes. These grow over the iris and in pale irses are visible as rubeosis iridis. It may lead to bleeding in the eye (hyphema) and close/blockage of the ICA - Secondary glaucoma.
What is panuveitis?
Inflammation of both the anterior and posterior uvea
What is in the orbit in addition to the eye?
Extraocular muscles Optic nerve Sympathetic and parasympathetic innervation Blood vessels Lacrimal gland Zygomatic salivary gland Connective tissues Nearby anatomical areas (sinuses etc).
What can retrobulbar area problems lead to?
Altered position of the eye within the orbit
Altered relationship with the eyelids
Possible increase pressure around the eye
Swelling/infection of tissues around it including conjunctiva
Vision loss
Pupillary problems
Restriction of ocular movement