aqueous & vitreous

Question 1

what are the 3 layers of the tear film ?

Answer 1

1) mucous layer
2) water layer
3) lipid layer

Question 2

what produces the aqueous humour?

Answer 2

ciliary body

Question 3

what is the role of the aqueous humour?

Answer 3

process of production + drainage of tears

Question 4

what 2 avascular tissue does the aqueous humour support?

Answer 4

cornea + lens

Question 5

What is the difference in composition of aqueous humour & blood plasma:

Answer 5

aqueous has virtually no protein

Question 6

why is the aqueous humour low in proteins?

Answer 6

• as proteins are big molecules and therefore would scatter a lot of light
• we want to create transparent optical system, so we want to get rid of the protein

Question 7

where does the aqueous humour flow through?

Answer 7

aqueous humour flows through the pupil into the anterior chamber where it circulates & eventually drains at the angle formed between the iris & periphery of the cornea

Question 8

function of the aqueous humour

Answer 8

• provides nutrients to cornea, through glucose
• remove the metabolic waste products such as lactic acid produced from these 2 tissues: lens + cornea

Question 9

what generates the IOP?

Answer 9

• The aqueous humour generates the IOP

Question 10

What condition can an abnormal IOP indicate?

Answer 10

glaucoma

Question 11

how much of the total volume of the eye does the vitreous humour account for?

Answer 11

• Fills 80% of the total volume of the eye

Question 12

functions of the vitreous humour

Answer 12

• helps maintain the shape of the eye
• supports retinal attachment
• storage area for retinal metabolites for lens + retina

Question 13

what are the 3 components of the vitreous humour?

Answer 13

1) collagen fibrils (less than the cornea)
2) proteoglycans –> the proteoglycans that it contains are hyaluronic acid
3) water –> makes up most of the vitreous

Question 14

what is the composition of the vitreous humour?

Answer 14

99% water
1% sold - collagen –> HA

Question 15

where are the collagens fibrils distributed in the vitreous?

Answer 15

• collagen fibrils NOT uniformly distributed throughout the vitreous
• collagen fibrils tend to pre-dominant in the periphery of the vitreous

Question 16

what happens to the vitreous to with age?

Answer 16

• the vitreous becomes more watery and less gel-like with age

Question 17

symptoms to look out for in PVD

Answer 17

serious :
- complain if pronounced floater that they have just seen, floater described as circular often in peripheral of vision –> corresponds to the blindspots
- circular floaters may constantly move around with eye movement

Question 18

what serious condition could a PVD result in?

Answer 18

rarely occurs, as the vitreous pulls away it can create a tear in the retina –> leading to a retinal detachment

Question 19

can PVD be asymptotic?

Answer 19

yes