National diabetic Retinopathy Screening Programmes,

Principles, Processes & Protocols

Dr John DoigConsultant Diabetologist

DRS Clinical Lead Forth Valley

Criteria for Screening

• The Condition

• The Test

• The Treatment

• The Screening Programme

Nationally Managed Screening Programmes

Antenatal

• Down’s Syndrome

• Cystic Fibrosis

• HIV

Newborn

• Phenylketonuria

• Hypothyroidism

• Cystic Fibrosis

• Hearing Impairment

• Haemoglobinopathy

Adult

• Breast Cancer

• Cervical Cancer

• Diabetic Retinopathy

• Colorectal

Screening tests should be:-

• Simple to apply.• Cheap• Easy to perform.• Unambiguous to interpret.• Identify those with disease and exclude those

without.

Effectiveness of Screening

• Reliable, sensitive and specific tests.• Effective treatments• Levels of uptake among target

population.• Compliance with treatment and the

extent to which costs associated with screening are minimised so are not to outweigh benefits.

Why screen for Diabetic Eye Disease?• Diabetic eye complications major cause of visual loss.• Most important preventable cause of blindness in Europe.• Accounts for about 90 % of blindness in diabetic patients.

• St. Vincent Declaration 5 year targets 1989– Incidence of blindness due to diabetes should be

reduced by one third or more.

• Duration of diabetes is the most important predictor.

Sight Threatening Retinopathy Treatment• Most amenable to treatment when no visual

symptoms• If visual symptoms present then prognosis poorer

• Potocoagulation will abolish new vessels in 80 % and prevent blindness in >50% after 10 years

• Photocoagulation will salvage vision in 50-60 %

• Vitrectomy may be effective in restoring meaningful vision > 6/36

National Screening Programmes

• Cover a defined population.

• Have a simple set of objectives.

• Develop valid and reliable criteria to measure performance and produce an annual report.

• Relate performance to explicit quality standards.

• Organise quality assurance systems to help professionals and organisations prevent errors and improve performance.

• Communicate clearly and efficiently with all interested individuals and organisations.

• Co-ordinate the management of these activities, clarifying the responsibilities of all individuals and organisations involved.

Principles and Values of Screening Programme

• Screening Programmes should offer adequate information to facilitate informed choice.

• Professionals involved in screening programmes need development and support.

• Screening Programmes aim to maximise benefit, minimise harm, and make the best use of the resources invested.

• Screening Programmes and Clinical Services should work together to provide a seamless experience if treatment is required.

• Programmes are committed to continuous improvement in performance and standards.

• Confidentiality must be maintained at all times, both in relation to the screening process and its results.

Patient Issues

• individuals involved in this screening programme are unlike those involved in most other screening programmes – already undergoing routine medical care for

their condition– patients of both sexes– wide age range– higher prevalence in some ethnic minorities

Patient Issues• mydriasis is an undesirable feature of screening

• Patient preferences for clear, timely information about all aspects of screening– Fear created by delay in results

• Confidence in service– Low false negative rate– Low false positive rate

• Clear procedures for referral if positive

Detection of Diabetic Retinopathy

• Retinopathy is detected in its earliest and most treatable form only by clinical examination of eyes.

• Ideally suited to screening programs• Screening must be comprehensive, of high

sensitivity (>80%) and specificity (>95%). • Should include measurement of visual

acuity. • Clear line of referral.• Various options:

Slit Lamp Examination• Gold Standard

• Requires Midriasis• Ophthalmologists• Training• Expensive• Slow• No permanent

record.• Difficult to QA

Direct Ophthalmoscopy• Easy• Quick• Cheap

• Requires midriasis• Poor sensitivity 40-

70%• No permanent record• Difficult to QA

Performance of screening

Sensitivity Specificity• General Practitioners 41 89• Hospital Physician 67 96 • Diabetologist 70 97• Ophthalmology registrar 75 97

• Digital photography+trained graders 88 95• Combined 5 field + direct 97 95

Digital Retinal Photography• Relatively easy

with training• Sensitive >80%• Quick• Possible without

midriasis• Permanent

record• Easy to QA

Limitations of screening• Technical

– Not all images are gradable– Delay in image to result– Second examinations– False positive / negative results

• System– Communication between Screening team / Ophthalmology– Communication with patients

• Human– Errors & false negative

• Grading guidelines• Training• QA• Process for review & managing errors

Retinal Screening Standards (QIS)• Standard 1: Organisation• Standard 2: Call-Recall and

Failsafe• Standard 3: Screening Process• Standard 4: Proficiency Testing• Standard 5: Referral

Standard 1: Organisation• Well-organised strategic planning group

• LDSAG / MCN / Retinal Screening Group

• Local strategy and implementation plan

• Agreed guidelines for effective communication

• Identified individual with delegated responsibility and authority for co-ordinating and monitoring

• Board Screening Coordinator• Clinical Lead• Service Management

Service specification includes:1. audit 2. training3. quality assurance4. information for people with diabetes5. call-recall6. photography7. grading8. reporting9. follow-up10. treatment

• Arrangements to ensure that the specification is monitored and met

Standard 2: Call-Recall & Failsafe• All eligible people have a written prompt to attend for screening at least

once every year– Accurate / validated Up to Date Diabetes Register

• Arrangements are in place for special cases– Long term institutions– Hospital patients

• A minimum of 80% of eligible people with diabetes are screened within 12 months

• Screening uptake is monitored at NHS Board level

• NSD protocol is followed for the management of non-attenders– 3 attempts at communication

• All staff involved in call-recall receive training on IT systems

Standard 2: Call-Recall & Failsafe• Non discriminatory• Clear guidelines for exclusion

• Protocol defining failsafe procedures for follow-up of eligible people with diabetes with referable grades of retinopathy

WHO CAN BE SUSPENDED?

• 1. Has made his or her own informed choice• 2. Under the age of 12 years• 3. Does not have perception of light vision• 4. Terminally ill• 5. Has a physical or mental disability

preventing either screening or treatment• 6. Currently under the care of an

ophthalmologist for management of diabetic retinopathy.

• 7. Temporarily unavailable• 8. Deceased.

Follow up protocol

• After first ophthalmology examination• Return to screening programme and re-

call for screening in 12 months• Return to the screening programme and

re-call for screening in 6 months• Continue under care of Ophthalmology

for Diabetic Retinopathy. Patient suspended 12 months from DRS

Follow up protocol failsafe• If no record of Eye Clinc visit at expiry of

suspension– Contact ophthalmology care provider to

confirm if still under retinopathy surveillance

– If confirmed suspend 12 months– If no longer under surveillance either

• Ref back to ophthalmology + GP or if discharged

• Suspend appropriate interval for later rebooking

Standard 3: Screening Process • Photographs are taken using equipment and techniques in

accordance with national guidelines.

• All staff have full training in retinal screening before working unsupervised

• Staff undertake continuing professional development (CPD)

• A minimum of 80% of people screened are sent the result in writing within 4 weeks

– Training / Use of Midriatics– MHRA for Tropicamide prescribing– PGD’s for other midriatics– Avoidable technical failure– Patient factors

*

Standard 4: Proficiency Testing• All grading staff have successfully completed a recognised training

programme. (C&G)– Scottish Diabetic Retinopathy Grading Scheme 2007 v1.0– Level 1– Level 2– Level 3 (Currently Ophthalmologist)– Slit Lamp Examiner

• Competency of individual graders assessed by ongoing quality assurance. (500 randomly selected patients)

• Clinically important grading errors further investigated and/or additional training of the grader is carried out.

• Screening history review of those developing referable retinopathy and audit is undertaken

• External quality assurance (EQA).

Standard 5: Referral

• All eligible people with referable retinopathy, are referred to an ophthalmologist for assessment and treatment.

• Diabetes care provider should be notified of all people whose eye examination has revealed retinopathy

Meeting & Reporting Targets• Ongoing Audit• National agreed minimum data set

– 100% Eligible patients invited annually– 80% Eligible population screened in 12 months– % Eligible population screened in 2 years– % Re-screen for Tech Failure– Average time for report– 80% receive result within 20 working days– % negative– % observable– % referable– % referable referred to ophthalmologist– Average time to ophthalmologist– % graders with target 500 sets QA– QA error rate (False neg, False pos, Poor Quality image)

• Scottish Diabetes Retinopathy Screening Collaborative

http://www.ndrs.scot.nhs.uk/index.htm