Rhegmatogenous Detachment

Question 1

Why does a rheg detachment occur?

Answer 1

Because of the formation of a break in the retinal tissue which leads to an influx of vitreous fluid under the retina in the subretinal space

Question 2

Where is the subretinal space?

Answer 2

It separates the retina from the RPE

Question 3

What is needed for a rheg to occur?

Answer 3

A tear or a break

Question 4

What causes the break in a rheg?

Answer 4

The tension between the detaching vit and the ILM which causes the retina to tear

Question 5

What is the percentage of px with PVD’s that get a rheg detachment?

Answer 5

7-13% of acute and symptomatics

Question 6

What increases the risk of developing a rheg?

Answer 6

A PVD with complications such as PVD with vit haemorrhage

Question 7

What is the main concern with PVD’s?

Answer 7

The chance of a break or a tear

Question 8

What shape does retinal tear demonstrate?

Answer 8

Horseshoe or U shape

Question 9

What indicates detachment has taken place?

Answer 9

Cloudy white borders

Question 10

What is the treatment of a retinal break?

Answer 10

Prophylactic treatment with laser or cryotherapy which protects against detachment. The aim is to freeze or burn the retinal tissue around the break in which the scarring leads to sealing the retina in place reducing the progression of a detachment which is a poorer prognosis than just a break

Question 11

What happens to the influx of fluid during a rheg?

Answer 11

It accumulates in the subretinal space which increases the seperation between the vit and retina

Question 12

What is the incidence of rheg detachments? (%)

Answer 12

6.3-11.3/100000

Question 13

Briefly describe the risk factors of rheg detachment

Answer 13

Fellow eye affected, family history, PVD, age, myopia, trauma,

Question 14

Explain why PVD is a risk factor for rheg

Answer 14

Having acute and symptomatic PVD with a sudden onset is more likely to lead to a detachment. The tension between the post vit and ILM can be sufficient enough to cause a tear or break and the greater the tension, the higher the risk.
Tears are more likely to develop across strong attachments and with PVD’s that have been complicated with haemorrhages because if the tension is high enough to cause a haemorrhage then it’s high enough to cause a break. PVD’s which are incomplete due to strong attachments increase the risk. Incomplete focuses tension on a specific area which increases the force and increases the chance of a break

Question 15

Explain why age is a risk factor for rheg

Answer 15

Rheg requires an influx of fluid to separate the retina and the more advanced liquidation then the greater the risk of enough fluid to cause a detachment. Age increases the risk of rheg by increasing the fluid and age also leads to an increase risk of PVD

Question 16

What is the incidence in getting rheg in 25-44, over 60 and 75-84?

Answer 16

6.8/100000 for 25-44
20x for over 60
69.5 75-85

Question 17

Explain why myopia increases the risk of rheg?

Answer 17

It accelerates vit degeneration and makes the vitreous more liquid faster. Myopia also has axial elongation which leads to a thinner retina and a thinner retina is more likely to tear. The risk depends on the amount of myopia. Low myopia:4x high myopia: 10x
-1mm of elongation= increased risk of rheg by 1.3x

Question 18

How much of the population do myopia account for in rheg detachments?

Answer 18

50%

Question 19

Explain why and how trauma increases the risk of rheg

Answer 19

Blunt blows to the head can cause an increase of ocular holes and tears. 6-19% of rheg have holes or tears.
Cataract surgery increases the risk of rheg due to an increase risk of PVD during cat surgery

Question 20

Has the risk of cataract surgery and rheg decreased or increased?

Answer 20

It’s decreased due to intra capsular cat extraction with the pharmacoemulsification and the risk has reduced to 0.68-0.9% and rheg may develop several years after surgery

Question 21

Explain the sx of rheg

Answer 21

PVD sx-f/f and sudden shower of small dot like floaters showing RPE cells have escaped. Flashing lights are reported in the temporal field. A curtain veil or shadow shows detachment has already occurred and the location can show where it’s detached and it’s the opposite quadrant

Question 22

Explain what happens with VA in rheg?

Answer 22

Unless rheg is advanced and has compromised the macula va will be unaffected. If a vitreous haemorrhage is close to the visual axis this may reduce vision

Question 23

Explain what will happen with the pupils in a rheg

Answer 23

+RAPD, and when there’s a sufficient detachment the afferent signal eye to brain are reduced. Normal reactions with less advanced rheg

Question 24

What will happen to the iop in rheg px’s?

Answer 24

The iop will be reduced

Question 25

Explain what happens to the visual fields in a px with rheg?

Answer 25

Peripheral field defects indicate detachment.

Question 26

What's the issue with normal standard fields when you suspect rheg detachments? And how do we overcome this?

Answer 26

Standard perimeters only assess central 30 deg so the px can still show full fields. We overcome this by assessing fields via the confrontation method which may reveal defects

Question 27

Explain what happens to the anterior vitreous and how is it caused?

Answer 27

Small dark brown cells will appear known as tobacco dust. This is caused by release of RPE cells into the vitreous and they could only have escaped via a break in the retina and even if the break isn't seen, it indicates a break is somewhere

Question 28

What is the referral for finding tobacco dust?

Answer 28

If you cannot find a break or tear but see tobacco dust, you need to emergency refer them because a break could be too peripheral so are normally without gold standard.

Question 29

How would you assess for a break?

Answer 29

It requires indirect volk or opthal with dilation

Question 30

Where are most retinal breaks associated with rheg found?

Answer 30

Superior temporal followed by superior nasal and inferior temporal by 15% of breaks

Question 31

What is the most common type of break?

Answer 31

U or horseshoe shape

Question 32

Describe an operculated tear

Answer 32

It's a ripped round segment that's completely separated from the retina leaving a hole and maybe seen in the vitreous

Question 33

Breaks are initially flat, what then occurs?

Answer 33

Oedema develops because of vitreous fluid going through the break into subretinal space. As the fluid increases, the break transforms into a detachment

Question 34

What appearance does oedema give to the retina?

Answer 34

Milky white appearance and loss of smooth uniform flatness blurring the vessels

Question 35

What is it called when the detachment advances into the central retina and macula?

Answer 35

Macula off means the macula is affected

Question 36

What is the referral if you see vitreous haemorrhages, tobacco dust or retinal break and holes

Answer 36

Emergency referral and telephone to explain their findings

Question 37

What happens if the px is asymptomatic or have holes that are longstanding?

Answer 37

They don't qualify for treatment because they're unlikely to progress and if they have no other signs linking them to detachment then referral isn't needed

Question 38

What is the gold standard for viewing in the periphery and how does it work?

Answer 38

Goldman 3 mirror and this works by placing the lens in contact with the cornea and the mirrors allow the optom to overcome the curvature and view peripheral retina. You can also indent the sclera to bring the peripheral retina around the ora into focus