The Red Eye

Question 1

Where can you see redness of the eye?

Answer 1

• Eyelids
• Conjunctiva/episclera/sclera
• Cornea
• Anterior chamber
• Anterior uvea
• Posterior uvea/retina
• Retrobulbar area

Question 2

How might we get red eyelids?

Answer 2

Loss of protective effect
Loss of oily part of the tear film from meibomian glands
Contact problems: eyelid hairs or masses

Question 3

What causes hyperaemia?

Answer 3

Irritation of the white of the eyes

Question 4

What causes vascularisation?

Answer 4

Corneal irritation

Question 5

What are the characteristics of conjunctival blood vessels?

Answer 5

Dichotomous branching
Dilation of the vessels and separation of endothelial cells
- Hyperemia
- Oedema

Question 6

What are the characteristics of episcleral vessels?

Answer 6

No dichotomous branching
Larger
Meander

Question 7

What do episcleral vessels indicate?

Answer 7

Intraocular disease mostly (uveitis and glaucoma)

Sever or chronic surface irritations in some cases.

Question 8

What are the 4 layers of the cornea in order?

Answer 8

1. Epithelium
2. Storma
3. Descemet’s membrane
4. Endothelium

Question 9

What are the char of the corneal epithelium?

Answer 9

It is hydrophobic, does not have blood vessels when healthy and has nerves

Question 10

What are the characteristics of the stroma?

Answer 10

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.

Question 11

What occurs when the stroma is overhydrated?

Answer 11

Corneal oedema

Question 12

What a re the characteristics of the decement’s memebrane?

Answer 12

A thin collagen layer acting as a basement membrane for the endothelium.

Question 13

What are the causes of corneal odema and give the pathophysiology…

Answer 13

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

Question 14

What us the iridocorneal angle?

Answer 14

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.

Question 15

Describe the route of aqueous humour…

Answer 15

Ciliary body -> Posterior chamber -> Pupil -> Anterior chamber -> ICA/uvea/sclera -> out

Question 16

What intraocular pressure is considered glaucoma?

Answer 16

> 22mmHg

Question 17

What intraocular pressure is considered uveitis?

Answer 17

< 12mmHg

Question 18

What disease cause loss of epithelium in the cornea?

Answer 18

Corneal ulcer

Question 19

What disease result in damage to the corneal endothelium?

Answer 19

Glaucoma
Uveitis
Lens luxation
Primary endothelial degeneration

Question 20

What disease result in vascularisation and thus leakage of the cornea?

Answer 20

Any irritating problem of the cornea (e.g. KCS, eyelid problems, LPI), ulcers and uveitis

Question 21

What is the anterior chamber filled with?

Answer 21

Aqueous humour

Question 22

What does the aqueous humour do?

Answer 22

It establishes intraocular pressure.

Question 23

Name the two primary disease affecting the anterior chamber

Answer 23

Uveitis and glaucoma

Question 24

How does glaucoma cause an increase in intraocular pressure?

Answer 24

ICA closure/clogging increasing IOP

Question 25

How does uveitis increase intraocular pressure?

Answer 25

It increases the uveosclearal outflow and thus decrease IOP.

Question 26

What are the parts of the anterior uvea?

Answer 26

Iris and ciliary body

Question 27

What are the parts to the posterior uvea?

Answer 27

Choroid

Question 28

What are the common denominators of the uvea?

Answer 28

It is a mesh of blood vessels that usually contains a lot of pigment

Question 29

What is miosis?

Answer 29

Iris spams with resulting pain (the opposite of mydriasis)

Question 30

What are the causes of uveitis?

Answer 30

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)

Question 31

What are PIFMs?

Answer 31

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.

Question 32

What is panuveitis?

Answer 32

Inflammation of both the anterior and posterior uvea

Question 33

What is in the orbit in addition to the eye?

Answer 33

``` Extraocular muscles Optic nerve Sympathetic and parasympathetic innervation Blood vessels Lacrimal gland Zygomatic salivary gland Connective tissues Nearby anatomical areas (sinuses etc). ```

Question 34

What can retrobulbar area problems lead to?

Answer 34

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