Improving the Value of
Screening For Macular
Oedema using
Surrogate Photographic
Markers
Dr John Olson
NHS Grampian
Improving The Economic Value Of Photographic Screening
For Optical Coherence Tomography Detectable Macular
Oedema –
A Prospective Multicentre, United Kingdom Study
• Olson J, Sharp P , Goatman K, Prescott G, Scotland G, Fleming
A, Philip S, Santiago C, Borooah S, Broadbent D, Chong V,
Dodson P, Harding S, Leese G, Styles C, Swa K, Wharton H
• Health Technol Assess, Vol 17,, May- June 2013, In Press
A Success Story?
• Systematic screening
programme for
diabetic retinopathy
Missing the target?
• The health-economic case is
based on the detection of
people with, or at risk of
– proliferative diabetic
retinopathy
– before they develop
complications
• Vitreous haemorrhage
• Traction retinal detachment
• But 90% of referrals are for ?
diabetic macular oedema
Why?
• Retinal photographs are not discriminatory for
proliferative retinopathy or its precursors
• Other things may be present
– e.g. diabetic “maculopathy”
– We have to manage these findings
How did we get there?
• Retinopathy grades
based on ETDRS
• Maculopathy grades
basedon
…(GOBSAT)
Different management
New Vessels
Oedema
Definitive treatment
Indefinite treatment
Management independent Management depended
of visual acuity
on visual acuity
2 D red structure
3 D transparent elevation
Few false +ves
Many false +ves


What did ISMO question?
• Can we do it better?
• What will it cost?
• What will it mean?
The Answers In Short- Can Grading
Schemes do it better ?
• Computer says
nah
The Answers In Short- Can OCT do it
better ?
• Yes
• Increases the specificity
of referrals
• With no loss of
sensitivity
The AnswersWhat will it cost?
• Less
• If you use OCT
• Whatever grading
strategy you use
• Saves you money
The AnswersWhat will it mean?
Study Highlights
Study centres
Aberdeen
Birmingham
Aberdeen
Dundee
Dundee
Glasgow
Edinburgh
Edinburgh
Glasgow
Liverpool
Oxford
Liverpool
Birmingham
Oxford
© 2008 Google-Imagery © 2008 TerraMetrics
Every day practice
Aberdeen
Dundee
Glasgow
Edinburgh
Liverpool
Birmingham
Oxford
3450 Subjects
• Photographic signs of diabetic retinopathy
– exudates ≤ 2DDr
– blot haemorrhages ≤ 1DDr
– dot haemorrhages/microaneurysms ≤ 1DDr
• Each subject had photography and optical
coherence tomography on both eyes, where
possible.
Patient Characteristics
•
•
•
•
Median age 60
60.7% male
85.4% Caucasian
77.4% type 2 diabetes
370 Excluded (10.5%)
•
•
•
•
•
6 years older
Female
Asian/ Black
Zeiss Stratus
Topcon OCT 1000
Lesion Distribution
Expected %
Recruited %
Ma/dot only
69.8
40.3
Blot no exudate
8.6
8.4
Exudate
21.6
20.4
No Ma/dot/blot/
exudate ≤ 1DDr
28.1
Definition of Macular Oedema
• Central ETDRS region
thickness > 250µm
• OR any of 5 inner
regions > 300µm
• AND visible intraretinal
cyst/ area of subretinal
fluid
Prevalence of oedema
• 7.7% of study
population
• Prevalence differed
greatly by centre
– 3.7% to 12.2%
• Prevalence differed
greatly by scanner
– 4.5% to 11.8%
Relationship to Centre
•
•
•
•
•
•
•
Aberdeen
Birmingham
Dundee
Edinburgh
Liverpool
Dunfermline
Oxford
12.0%
3.7%
12.2%
6.4%
2.9%
4.4%
7.7%