Personalising screening of sight-threatening diabetic retinopathy - qualitative evidence to inform effective implementation
Authors: Byrne P. , Thetford C. , Gabbay M. , Clarke P. , Doncaster E. , Harding S. P. ,   for the ISDR Study Group, Harding Simon P. , Broadbent Deborah M. , Byrne Paula , Fisher Anthony C. , Gabbay Mark , García-Fiñana Marta , James Marilyn , Moitt Tracy , Roberts John , Seddon Daniel , Stratton Irene M. , Vora Jiten P. , Williamson Paula , Appelbe Duncan , Alshukri Ayesh , Cheyne Christopher P. , Darssan Darsy , Eleuteri Antonio , Grierson Christopher , Howard Lola , Howlin Susan U. , Lathe James G. , Mobayen-Rahni Mehrdad , Ovens Andy , Sampson Christopher J. , Silvera Kate , Szmyt David , Thetford Clare , Vazquez-Arango Pilar , Wang Amu , Williams Abigail E. , Collins John , Doncaster Emily , Kelly John , Lees Peter , Lees Sandra , Williams Betty , Bunce Catey , Cooper Helen , Kumar Vineeth , Massat Nathalie , Rogers Chris , Rowlands Alison , Smith Gideon , West Julia , Younis Naveed , Criddle Ticiana , Perrett Stephanie , Jones Lisa 
Published: June 2020

Abstract
Background
Internationally, systematic screening for sight-threatening diabetic retinopathy (STDR) usually includes annual recall. Researchers and policy-makers support extending screening intervals, citing evidence from observational studies with low incidence rates. However, there is little research around the acceptability to people with diabetes (PWD) and health care professionals (HCP) about changing eye screening intervals.

Methods
We conducted a qualitative study to explore issues surrounding acceptability and the barriers and enablers for changing from annual screening, using in-depth, semistructured interviews analysed using the constant comparative method. PWD were recruited from general practices and HCP from eye screening networks and related specialties in North West England using purposive sampling. Interviews were conducted prior to the commencement of and during a randomised controlled trial (RCT) comparing fixed annual with variable (6, 12 or 24 month) interval risk-based screening.

Results
Thirty PWD and 21 HCP participants were interviewed prior to and 30 PWD during the parallel RCT. The data suggests that a move to variable screening intervals was generally acceptable in principle, though highlighted significant concerns and challenges to successful implementation. The current annual interval was recognised as unsustainable against a backdrop of increasing diabetes prevalence. There were important caveats attached to acceptability and a need for clear safeguards around: the safety and reliability of calculating screening intervals, capturing all PWD, referral into screening of PWD with diabetic changes regardless of planned interval. For PWD the 6-month interval was perceived positively as medical reassurance, and the 12-month seen as usual treatment. Concerns were expressed by many HCP and PWD that a 2-year interval was too lengthy and was risky for detecting STDR. There were also concerns about a negative effect upon PWD care and increasing non-attendance rates. Amongst PWD, there was considerable conflation and misunderstanding about different eye-related appointments within the health care system.

Conclusions
Implementing variable-interval screening into clinical practice is generally acceptable to PWD and HCP with important caveats, and misconceptions must be addressed. Clear safeguards against increasing non-attendance, loss of diabetes control and alternative referral pathways are required. For risk calculation systems to be safe, reliable monitoring and clear communication is required.