All scanners are equal, but some scanners are more equal than others Zeiss Stratus – 4.5% Topcon OCT1000 – 6.5% Heidelberg Spectralis – 8.7% Zeiss Cirrus – 11.8%

Relationship to patient features Older age – 68yrs cf 60 Caucasian – 8.4% cf 3-4% Type 2 diabetes – 8.7% cf 3.9% Poorer vision – 5x more likely – If VA ≤ 6/9 BUT NOT – Sex, glitazone, amblyopia

Relationship to Lesions R Eye %L Eye % No lesions Ma/dot only Blot no Exudate Exudate Other1.1

Can we do any better? Three Grading Strategies Examined – Manual grading Presence/ absence of features SDRGS 2007 – Computer-assisted manual annotation All individual lesions ≤ 2DDr – Fully automated annotation grading Three versions – Automated image analysis – +VA – +VA + Age+ Type DM + Sex

Manual Grading (features)

Scotland – 59.5% sensitivity – 79.0% specificity England – 72.6% sensitivity – 66.8% specificity England plus – 73.3% sensitivity – 70.9% specificity

Computer Assisted, Manual Annotation, Grading Best for sensitivity & specificity Time-consuming procedure Unlikely to be considered for routine screening practice

In Years To Come

Marvin the Manically Depressed Autograder "I think you ought to know…. I'm feeling very depressed......nobody likes me"

DRS in Scotland 2012

What will it cost? Cost per screen £33.13 Cost per OCT screen £31.96 Total cost for ?oedema£65.09 Cost of attending ophthalmology £90.00 (Cost of Slit lamp within DRS £27.29)

TABLE 30 Screening and referral cost per true case of macular oedema detected for 3,170 patients; Adjusted for expected frequency of different patient categories and based on Scottish screening and referral costs * Reference strategy; a figures in table based on assumption that fully automated grading can be implemented at zero net increase in grading costs;++ Represents a cost saving per case missed relative to the reference strategy; d strategy more costly and less effective than an alternative strategy (dominated)

What does it mean? At present we spend £13,750,000 a year – 250,000 £55 – Screening + 1 st visit to ophthalmology – £2,337,500 on ? M2 If we do nothing, other than introduce OCT into the screening pathway we save money

Should we grade differently? Current Scottish Criteria + OCT is the most cost effective of all strategies

What if we do nothing? 20 year “M2” Markov Model Only 5.6% of M2 at risk of visual loss Repetitive nature of screening – 12% of non-referred MO modelled to progress at 12 months cf 5% of referred (laser Rx) More sensitive strategies – More OCTs, more referrals Bilateral incidence 12% – QALY determined by VA in better seeing eye Additional cost per QALY going to strategy 16 – £882,307 at 5 years – £353,927 at 20 years – (£20-30,00 UK threshold for “cost-effectiveness)

What should we do? Cost-effectiveness acceptability curves for the alternative strategies based on a 20 year time horizon and using quality adjusted life years as the measure of effect

How should we manage M2s? Is this the answer? Photos graded as M2 Check VA Do an OCT if VA 6/12 or worse? Otherwise rescreen in 6 months?

Thank You

Modelled visual acuity changes for “CSMO”