Retinopathy

Question 1

What is retinopathy?

Answer 1

disease of the retina that causes impairment or loss of vision

Question 2

what are the types of retinopathy?

Answer 2

diabetes
hypertension
radiation
retinal vascular disease
trauma

Question 3

what are the most common affect of diabetic retinopathy?

Answer 3

• affecting the small vessels (microangiopathy)
  
  • precapillary arterioles
  • capillaries
  • postcapillary venules

Question 4

what vessels are affected in diabetic retinopathy?

Answer 4

• precapillary arterioles
  
  • capillaries
  • postcapillary venules

Question 5

what is the pathology of microangiopathy (affecting the small vessels)?

Answer 5

1. thickening/multilayering of basement membranes
2. degeneration of endothelial cells and pericytes
3. subsequent capillary non-perfusion and tissue ischemia

Question 6

what are the clinical features of diabetic retinopathy?

Answer 6

1. Microaneurysms - Weakening of vessel wall causing bulging of walls
2. Haemorrhage
   
   • Damage to vessel walls => (bleed into layers of retina)
   • Dot haemorrhage – rupture of capillaries in outer plexiform layer
   • Blot haemorrhage – larger than dot haemorrhages, bleeding from
     capillaries – tracks between photoreceptors + RPE
   • Flame haemorrhages – rupture of small arteriole => leakage into nerve
     fibre layer
3. Hard exudates
   
   • Endothelial damage => plasma leakage into outer plexiform layer – “”
4. Cotton wool spots
   
   • Swollen ends of interrupted axons in nerve fibre layer due to micro-
     infarction
5. Venous beading
   
   • Beaded appearance to veins, reflects retinal ischaemia

Question 7

what are the features of advanced diabetic retinopathy?

Answer 7

1. Intraretinal microvascular abnormalities (IRMA)
   
   • Vascular abnormalities in venous side of capillary bed (do not leak) causing a precursors of neovascularisation
2. Neovascularisation
   
   • New vessels grow from venous side of capillary bed in area of non-perfusion (new vessels leak)
   • Due to vasoproliferative factors released by ischaemic retina => proliferation of endothelial cells at edge of ischaemic area
   • New vessels grow near disc “NVE”, elsewhere in retina “NVE”, in the anterior chamber angle “NVA” and in the iris “NVI”/rubosis iridis
   • Vessels can bleed into vitreous, cause retinal detachment, and glaucoma

Question 8

when are diabetic retinopathy reviews undergone? and when?

Answer 8

annually

for diabetic patients

Question 9

what do diabetic retinopathy reviews assess?

Answer 9

photographs of the retina then classified into severity levels

Question 10

describe diabetic maculopathy?

Answer 10

leaking of macula, often with exudates, often surrounding a microaneurysms known as DIABETIC MACULAR OEDEMA

Question 11

What is diabetic macular oedema?

Answer 11

leaking of macula often surrounding a micro aneurysm

Question 12

what can be seen from a diabetic retinopathy review?

Answer 12

1. cotton wool spots
2. microaneurysms, oedema and exudates
3. neovascularisation

Question 13

what can be seen from proliferative diabetic retinopathy in a retinal scan?

Answer 13

abnormal vessels - haemorrage in the retina

Question 14

how is diabetic retinopathy managed?

Answer 14

systemic control
- glycaemic control
- BP control
- cholesterol control
- support renal function
- smoking cessation
- weight control
- exercice

Question 15

how are diabetic retinopathy monitored?

Answer 15

1. yearly screening for mild NPDR
2. hospital service screening for pre-proliferative/moderate-severe NPDR
3. laser for proliferative
4. macular laser for maculopathy

Question 16

what is panretinal photocoagulation (PRP)?

Answer 16

green laser absorbed by the RPE pigment

laser is converted into thermal energy causing outer retinal cell death and coagulative necrosis
= reducing neovascularisation stimulus - VEGF

Question 17

what are the risks of PRP?

Answer 17

1. pain
2. loss of peripheral field e.g. when driving
3. accidental foveal burns = decreased viewing
4. retinal detachment
5. haemorrhage

Question 18

what is macular laser?

Answer 18

similar to PRP

used for gentle burns to macula and treat macular oedema

Question 19

what is intravitreal anti-VEGF?

Answer 19

for diabetic macular oedema

Question 20

name licensed intravitreal anti-VEGF?

Answer 20

aflibercept
ranibizumab

Question 21

what is aflibercept prescribing based upon?

Answer 21

central retinal thickness >400micrometres

Question 22

how is central retinal thickness determined?

Answer 22

optical coherence topography

Question 23

describe optical coherence topography

Answer 23

uses infrared light to capture an image of layers of retina to measure central retinal thickness

Question 24

what is ranibizumab prescribing based upon?

Answer 24

visual impairments due to diabetic macular oedema
with a central retinal thickness >400 micrometres

Question 25

what is the mechanism of action of intravitreal corticosteroid?

Answer 25

suppress inflammation causing a reduce in oedema
with anti-VEGF properties

Question 26

name the risks of intravitreal corticosteroid?

Answer 26

1. infection
2. haemorrhage
3. retinal detachment
4. increasing intraocular pressure
5. cataract

Question 27

name an examples of intravitreal corticosteroids?

Answer 27

1. dexamethasone intravitreal

Question 28

what is retinal vein occlusion?

Answer 28

blockage of the venules

Question 29

describe the treatment of retinal vein occlusion

Answer 29

1. treat underlying hypertension conditions
2. PRP
3. control IOP
4. intravitreal therapy
   
   • corticosteroid
   • anti-VEGF

Question 30

describe clinical features seen of retinal vein occlusion

Answer 30

1. ischemia of the retina /widespread ischemia
2. multiple haemorrhages
3. oedema
4. wool spots

Question 31

describe the treatment of retinal artery occlusion

Answer 31

1. treat underlying hypertension conditions
2. treat underlying vasculitis/arteritis
3. lower IOP