Diabetic Retinopathy

Question 1

How many people have diabetes?

Answer 1

• Approx. 422 million people have diabetes worldwide (WHO)
• Over 4.9 million people have diabetes in UK
• > 5.3 million people in UK population will be diabetic by 2025
  Diabetic retinopathy is leading cause of blindness in working UK population

Question 2

What causes diabetes?

Answer 2

Normal: pancreas creates hormone insulin, food is digested and enters blood stream, insulin moves glucose out of the blood into the cels, glucose broken down and becomes energy

Diabetic: pancreas creates hormone insulin, food is digested and enters blood stream, body UNABLE to break down glucose into energy, cells not reacting to insulin and not enoough insulin to move glucose. Problem starts after digested food - body cannot break down glucose

Question 3

What are the types of Diabetes Mellitus?

Answer 3

• Insulin Dependent (IDDM) – type 1 (~10% - less common)
• Non-Insulin Dependent (NIDDM) – type 2 (more common – related to diet/lifestyle)
• Pre-Diabetes – blood glucose level above normal but not high enough to be diagnosed
• Gestational – ladies in mid to late pregnancy, usually resolves after giving birth
• Can also occur as a secondary condition to medication or surgery – due to underlying conditions

Question 4

Signs of diabetic eye disease in anterior and posterior segments?

Answer 4

• Anterior Segment
  o Dry Eye
  o Diabetic Keratopathy
  o Uveitis
  o Cataract
• Posterior Segment
  o Vitreous Haemorrhages
  o Diabetic Retinopathy (DR)

Question 5

Give examples of anterior segment complications of diabetes?

Answer 5

• Aqueous Deficient Dry eye – most commonly seen in DM
  o May be microvascular changes in lacriminal gland
  o Underlying diabetic neuropathy – reduced lacriminal innveervation
  o Reduced corneal sensitivtity – reduced reflex tearing
• Diabetic neurotrophic keratopathy
• Epithelial fragility
• Delayed epithelial healing
• Superficial punctate keratopathy
• Persistent epithelial defects
• Recurrent corneal erosions
• Neurotrophic corneal ulceration
• Filamentary keratitis
• Descemet‘s folds

Question 6

What is a common factor in diabetes?

Answer 6

corneal involvement – whenever cornea is at risk then could be a precursor to visual impairment in these pxs. Look really thoroughly and under high mag to catch any subtle changed in DM pxs

Question 7

Describe diabetic keratophathy?

Answer 7

• 70% of diabetic patients suffer from corneal complications
• Cornea experiences 4-fold higher glucose level in diabetics
• Examples:
  o 1. Superficial punctate keratitis
  o 2. Recurrent corneal erosion
  o 3. Persistent epithelial defect (corneal)
  o 4. Diabetic neurotrophic keratopathy
• Diabetic keratopathy – cornea which does not have normal wound healing or normal healing mechanism – can lead to recurrent or persistent corneal epithelial defects & unresponsiveness to tx especially if blood glucose level is v high or out of control at that time

Question 8

Describe neurotrophic keratopathy?

Answer 8

• Occurs in up to 64% of diabetic patients
  o Importance of identifying and managing corneal issues in DM pxs
• Involves reduction of corneal nerve density – impaired corneal sensitivity
• May lead to permanent vision loss
• Characterised by structural and functional changes of cornea
  o Impaired corneal sensitivity
  o Epithelial defects (loss of protective function)
  o Impaired healing
  o Corneal ulceration – as lid keeps going over them since they are there for long time
  o Loss of vision
  o Three stages
• Won’t feel epithelial defects on the eye and then will have them for long time as not healing properly – can lead to ulceration and eventually loss of vision
• Stage 1: px may present like this – may not have any sxs due to reduced corneal sensitivity – may tell you eye(s) is redder than normal
  o When assess cornea – reduced TBUT and may/may not see punctate epithelial keratopathy (can see it just near pupil)
  o Want to catch pxs at this stage
• Stage 2: epithelial defect gets significantly worse and starts to break down
  o Peripheral cornea getting hazy and oedematous
  o Difficult to manage from here
  o Eye redder than before
• Stage 3: most advanced stage – stroma involved here – ulceration – whole cornea oedematous
  o Neovasc going on – incredibly hypoxic – never a good sign
  o This stage is complicated – cornea at high risk of perforation
   Open to microorganisms if it perforates – px may end up with condition e.g. endophthalmitis which is even harder to control due to their DM

Question 9

Describe corneal sensitivity in diabetes?

Answer 9

• Up to 55 % of diabetic patients have reduced corneal sensitivity
• Corneal sensitivity is still difficult to measure and quantify
• When assessing px cornea and putting NaFl in – pay attention and see if px says anything about you putting that in – shows corneal sensation if they feel something going in eye
• Important consideration for patients who want to try CLs
  o Not recommended to fit a CL on a DM patient

Question 10

Describe anterior uveitis in diabetes?

Answer 10

• Presenting feature – can be presenting feature in undiagnosed DM
• Disruption in Blood-retina barrier in eye – increases amount of inflammation in eye
• Poor glycaemic control
• Type 1 – younger patients
• Advanced Type 2 (adults) (may also have peripheral Neuropathy etc.)
• Acute
• Anterior
• Signs: limbal injection, photophobia, cells/flare (cells in the image), keratic precipitates, iris synechiae

Question 11

Describe cataract in diabetes?

Answer 11

• More prone to develop cataract earlier than non-DM
• Cortical
• Nuclear
• Snowflake
  o Juvenile onset and DM difficult to control
  o Developed quite young
  o Characteristically due to DM (usually type 1)

Question 12

What proportion of DM pxs have diabetic retinopathy?

Answer 12

~1/3 of DM patients also have Diabetic Retinopathy

Question 13

Main risk factors for diabetic retinopathy?

Answer 13

• Hyperglycaemia – poor blood glucose level control
  o Variation in blood glucose control is also a risk factor
• Hypertension
• Diabetes duration – longer px has been DM, more likely they are to have form of DR
• Ethnicity (African, Hispanic, South Asian)
• Puberty and pregnancy (DM type 1)

Question 14

What are the clinical signs of diabetic retinopathy?

Answer 14

• Microaneurisms
  o Small bulges in smaller finer BVs in retina
  o Seen in centre of this image
• Retinal haemorrhages
  o Flame, dot or blot haemorrhages
   Dot – smaller and rounder
   Blot – larger and uneven
• Hard exudates
  o Caused by lipid leaking from BVs due to damaged blood retina barrier
• Cotton-wool spots
  o Accumulation of axoplasmic debris within bundles of ganglion cell axons
  o Tells you that specific region of retina is ischaemic –
  Not enough oxygen there and general indication
  there is underlying nerve fibre layer damage
• Venous tortuosity and beading
  o Beading - bulges in and out like sausages
• Neovascularisation
  o Can be in retina or into posterior vitreous which can result in tractional retinal detachment
• Tractional retinal detachment
• Macular oedema
  o Can see microaneurysm next to cyst in macula

Question 15

What are the classifications and grading schemes for Diabetic retinopathy?

Answer 15

• Various classification systems are in use
• Examples:
  o ETDRS = Early Treatment Diabetic Retinopathy Study
  o AAO = American Academy of Ophthalmology
  o NSC = National Screening Committee
  o SDRGS = Scottish Diabetic Retinopathy Grading Scheme
• Overview available in
  o The Royal College of Ophthalmologists: Diabetic Retinopathy Guidelines, December 2012
• NB Guidelines can and will change with time, always check local health board recommendations

Question 16

What are you assessing in Scottish Diabetic Retinopathy Grading Scheme?

Answer 16

• When assessing fundus, you are grading 2 things:
  o General and peripheral retina
  o Macula
• And notes any other findings as normally would

Question 17

Scottish DR Grading Scheme -> R0? R1? R2? R3? R4?

Answer 17

• R0 = No retinopathy
• R1 = Mild (1 or more microaneurysms, haemorrhages, hard exudates but less than R2) – recall 12/12
• R2 = Moderate (≥4 haemorrhages in one half/hemifield of retina -> horizontal -> superior vs inferior) – observable, recall 6/12
• R3 = Severe (≥4 haemorrhages in both halves/hemifields of retina AND/OR venous beading AND/OR IRMA) – referable
• R4 = Proliferative (active new BVs AND/OR vitreous haemorrhage)

Question 18

When to refer based off DR Grading Scheme?

Answer 18

R0 – R2 = Observe (Check with GP that diabetes and other risk factors controlled, Review annually, Refer if suspect clinically significant macular oedema)
R3 – R4 = Refer to ophthalmologist

• If see diabetic and do see changes make sure they have screening appointment or are in screening service – ask px to go to GP or write to GP

Question 19

R3 management?

Answer 19

• No new BVs yet but on their way
• Management:
  o Refer to ophthalmologist who will monitor closely – not emergency same day  check w/ GP all factors are well controlled
  o Not usually treated with laser unless:
   Other eye has poor sight
   Clinically significant macular oedema
• Check with GP that DM and risk factors are well controlled

Question 20

R4 management?

Answer 20

• New BVs
• Management:
  o Refer to ophthalmologist URGENTLY
  o Urgent unless have advanced changes of retinal detachment or huge retinal bleed –> EMERGENCY

Question 21

Scottish DM Grading Scheme?

Answer 21

• M0 = No maculopathy <2DD of centre of fovea
• M1 = Early (exudates >1 & <2 Disc Diameter (DD) from fovea) – observable 6/12
• M2= Advanced (haemorrhages AND/OR exudates <1DD from fovea)

Question 22

When to refer based off DM grading scheme?

Answer 22

M0 – M1 = Observe (Check with GP that diabetes and other risk factors controlled, Review annually, Refer if suspect clinically significant macular oedema)
M2 = Refer to ophthalmologist (unless VA is >6/7.5)

• If see diabetic and do see changes make sure they have screening appointment or are in screening service – ask px to go to GP or write to GP

Question 23

Management in community of DR & DM?

Answer 23

• Ensure diabetic pxs attend annual retinopathy screening (photos)
• Check fundus in diabetes with dilation – if confident in grading system
• Do not refer R1, R2 or M1
• REFER R3, R4 or M2
• Be aware of undiagnosed diabetes – not everyone with DM knows they have it

Question 24

Who is in the shared care team for patients with diabetes?

Answer 24

• Community optom
• GP
• Diabetic Retinal Screening optom
• Ophthalmologist – if clinically necessary

Question 25

What is the community optoms role in diabetic pxs?

Answer 25

• Screening and early detection of diabetic eye problems
• Monitoring and patient advice
• Treatment of anterior segment disease (within capabilities)
• Referral for further investigation and/or treatment

Question 26

What should be asked by optom in H&S on first presentation of DM px?

Answer 26

• Vision:
  o Px may tell you that their vision fluctuates throughout the day – may be worse when they are hungry or after exercise.
• General Health:
  o Px may tell you they are being investigated for diabetes  pre-diabetic
   “Are you being investigated for any health conditions?”
  o They may be diet controlled (no meds)
• Family History:
  o Who (immediate family) had DM? TYPE? Age of Onset? Any effect on this family members eyes?

Question 27

What should be asked by optom in H&S GH when monitoring DM px?

Answer 27

• General Health:
• If Px is already diagnosed, you need to ask:
  o Type
  o Duration
  o Medications or lifestyle advice
  o Stability with meds/lifestyle
  o Who monitors it?
   Some pxs monitor themselves with at home monitor – some see GP regularly for monitoring
  o When was the last check-up with GP?
   Annual check-up with GP even if px monitors themselves at home
  o Are they attending DRS?
   Important as will impact management and recall
   If yes – when was it? Were they advised of any changes in the back of their eye?
• Px usually sent a letter containing results of DRS
   If no – any reason why not? Consider putting them on annual recall and monitoring them within your practice
• Access issue? Anxious about going?

Question 28

Why is refraction important in DM px?

Answer 28

• Biggest indication that there is a blood sugar level vascular condition: Fluctuating visual acuity throughout refraction
• You should consider DM (or vascular condition) as part of your differential diagnosis whilst refracting if this is the case, especially if there are other risk factors

Question 29

Describe anterior and posterior eye health assessment in DM pxs?

Answer 29

Anterior:
* Quantitative and qualitative evaluation of tear film
* Measurement of corneal sensitivity
* Treat any dry eye and monitor corneal defects
* Look for inflammation in the anterior chamber
* Look for any structural changes in the lens
* Refer if persistent visual impairment (or risk of)

Posterior:
* Fundoscopy Assessment
* Consider dilation (irrespective of px age) if:
o Small pupils (<2mm)
o >1 year since Px attended DRS
o Poor blood glucose level control (get idea of this through H+S and Refraction)
o First eye exam since diagnosis (yet to attend DRS)
* Assessment can be aided with fundus photography
o The best way to detect retinopathy early—when still treatable and before vision is irreversibly lost
o Can detect subtle changes overtime
 Useful to look back on pxs with DR previous pics

MUST record R number and M number to grade both retina and macula on record

Question 30

Which further tests should be done by optom in DM pxs?

Answer 30

• Take digital retinal photograph
  o Grading in this photo based on Scottish DRS Grading:
   Mild tortuosity in inferior arcades and superiorly too
   Finer BVs looking tortuosity
   IRMA
   Blot haemorrages and dot haemorrhages
   Image superior and inferior hemifield
   Microanneurysms
   R3 – refer to ophthalmologist
   Macula:
• Exudates within 1 disc diameter of fovea
• Refer this too
• Hugh chance of maculopathy
• OCT Scan:
  o Fibrous tissue or new vessels can attact self to posterior vitreous  over time can lead to tractional retinal detachement
• Optomap
• VF function
  o 10-2 – central foveal sensitivity
  o Amsler – if distortion then straight away know there is something macular going on

Question 30

What is the optom’s management of DM pxs?

Answer 30

• Monitor:
  o Every 2 years if Px is under a DRS scheme and seen annually
  o Annually, if Px does not under a DRS scheme and seen annually
   You would then be responsible for screening them annually
• (This can vary depending on health board)
• Letter to GP:
  o To reassess blood glucose level and/or medication if clinically indicated
   If refraction fluctuating or found new background retinopathy
• Referral:
  o GP – If first presentation at eye exam, for assessment and diagnosis
  o Ophthalmology - If clinically indicated

Question 31

Describe the GP’s job in DM pxs - investigation/diagnosis/management?

Answer 31

Investigation and (Confirmation of) Diagnosis:
* May go to GP due to sxs or referred in by optom
* Assessment of Blood Glucose Level
o Blood Test
o Urine Test
* Once diagnosed, Px name goes on diabetes list
* All diabetic patients are invited to attend annual retinal screening

Management:
* Management of underlying IDDM or NIDDM
o Can give advice of improving diet
o Put on meds
 Insulin – type 1
 Metformin – type 2
* Monitor Px frequently to check general health
o Glycated haemoglobin (HbA1c) blood test (IDDM)
o Generally pxs self-monitor and if issue then they go to GP
* Referral to community optometry for eye test – especially if new diagnosis
* Referral into local diabetic retinal screening (DRS) scheme

Question 32

Describe diabetic retinal screening (DRS) and what the optom does?

Answer 32

NHS Diabetic Retinal Screening Service:
* Nation-wide service
* All diabetic patients over 12 years of age will be invited annually
* Screening based primarily on digital fundus images
* Non-mydriatic fundus photo (technicians, nurses)
* Dilation if required (approx. 25% of patients)
* All images will be graded by an Optometrist
Optom’s Role at Diabetic Retinal Screening Service:
* Medical Retina Specialisation (from CoO)
* Advanced grading of digital fundus images
* Run slit-lamp clinics
* Clinical decision-making/referrals to ophthalmology

Question 33

Describe diabetic retinal screening (DRS) - management, health board screenings and DRS referral criteria?

Answer 33

Management:
* Any images that may require referral will be graded at least by two graders (2 optometrists)
* Referral from DRS directly to ophthalmology outpatient clinic
* Screening result letter will be sent to patient and GP
* If image quality at screening appointment inadequate: patient to be booked for appointment at slit-lamp clinic
o May be due to lens opacities or corneal issues or if px’s alignment was not good for various reasons
NHS Diabetic Retinal Screening Service:
* Format of screening can vary based on health board:
o Glasgow: Patients attend hospital-based screening clinics, also mobile clinics (van-based)
o Lothian: Patients attend hospital or GP practice-based screening clinic, or are seen annually by their community optometrist
o Ayrshire: Patients are see locally by an accredited (medical retina) community optometrist
* Advantages of DRS: quality assurance and get outcome reports for px
DRS Referral Criteria:
* Can be considered appropriate for community optometry
* Retinopathy and maculopathy are graded separately
* Refer to Ophthalmology only if graded as:
o R3 (advanced background retinopathy)
o R4 (proliferative retinopathy)
o M2 (severe maculopathy)

Question 34

Describe ophthalmologist management of Diabetic retinopathy - pan-retinal photocoagulation (PRP)?

Answer 34

• Gold standard treatment
• Usually visible laser light
• Use CL to focus on the retina – promotes more oxygen to the region to prevent new BVs
• Goal is to minimise the amount of scarring a laser scar will leave
• Can result in choroidal infusions, macular oedema, VF defects, night vision defects (as effecting peripheral vision), exudative retinal detachments
  Laser treatment used to be the main treatment for retinopathy, although increasingly anti-VEGF injections are taking over
  Due to DR, px ends up with areas in retina of ischaemic hypoxia. Ischaemic – blood not getting there. Hypoxia – lack of oxygen. Due to this, results in increase production of Vascular Endothelial Growth Factor (VEGF) (causes neovasc and/or oedema in retina).
  Healthy retina on L, DM retina on R
  Bottom to top: choroid, RPE, photoreceptor layer, outer nuclear layer, outer plexiform layer, inner nuclear layer, inner plexiform layer, ganglion cell layer, nerve fibre layer.
  Outer retina: layers outer plexiform layer to RPE
  Inner nuclear layer to NFL = inner retina (closer to light)
  Most of DR goes on in inner retina – pan-retinal photocoagulation  laser targets outer retina as photoreceptors use up a lot of oxygen supply which comes into retina. Meaning they coagulate/stop the outer retina using up as much oxygen so they can preserve or enhance the oxygen for the inner retina where all the DR is  as a result they remove the ischaemic hypoxia.
  Due to the scarring and other side-effects, pxs are choosing to go for anti-VEGF injections instead of PRP  keep eye on research to see which becomes gold standard.

Question 35

Describe ophthalmologist management of Diabetic retinopathy - anti-Vascular Endothelial Growth Factor txs?

Answer 35

• VEGF – protein which promotes growth of new BVs and also makes BVs weak and leak more
  o Plays big role in proliferative retinopathy
• Anti-VEGF agents can arrest, or even reverse, proliferative retinopathy and macular oedema
• E.g., intravitreal (injection) ranibizumab (LUCENTIS®)
• Less destructive than laser

Question 36

Describe ophthalmologist management of Diabetic retinopathy - intravitreal corticosteroids?

Answer 36

• Intraocular (intravitreal) corticosteroids widely used to treat macular oedema
• Modest improvement of VA possible – unlikely to go back to 100%
• Long-acting steroid implants may be used

Question 37

Describe ophthalmologist management of Diabetic retinopathy - vitrectomy?

Answer 37

• May be useful in advanced diabetic retinopathy
• Example: vitreous haemorrhage
  o Or vitreoretinal traction
  o New BVs – grow from retina into vitreous and can pull on vitreous more – can result in tractional retinal detachment or retinal tear
   May get more floaters
• May develop in proliferative DR, when new fragile vessels burst
• Surgical removal of vitreous