Abstract
Purpose :
Surrogate markers of diabetic macular oedema(DMO), such as exudates within 1 disc diameter of fovea are graded as M1 in England and referred to the hospital eye services. The advent of optical coherence tomography allows an anatomical quantification and diagnosis of DMO. The aim of this study was to determine the accuracy of the surrogate markers for DMO currently used in the English Diabetic Eye Screening Programme.
Methods :
This was a retrospective clinical audit from the Gloucestershire Diabetic Eye Screening Program between October 2014 to March 2016. All patients have undergone fundus and OCT imaging and graded independently by trained graders. Two-dimensional (2D) markers are graded in the following 3 groups;
1. Microaneurysm or haemorrhage within 1 Disc Diameter (DD);
2. Group of exudates ≥½ disc area entirely within the macula or
3. Exudate within 1 DD of the centre of the fovea.
Fluid on OCT were graded as follows: OCT borderline was defined as the presence of intraretinal cystoid spaces, or subretinal fluid, in the ‘macular area’, without any change in the ILM contour.
OCT positive was defined by the addition of a change in ILM contour or a drop in VA to < 6/12 or a central retinal thickness ≥ 300 µm or a large area of intraretinal fluid > 1 disc area the edge of which is within 1 disc diameter of the central fovea. Statistics were performed using SPSS vers 19.0 to determine sensitivity of markers in DMO.
Results :
Data for 931 eyes were included in this study. Of 146 eyes referred for ‘any microaneurysm or haemorrhage within 1DD of the centre of the fovea only if associated with a best VA of < 6/12’ . 90 (61.6%) were OCT negative, 30 (20.5%) were OCT borderline and 26 (17.8%) were OCT positive. Of 763 eyes referred for ‘exudate within 1 disc diameter’, 374 (49.0%) were OCT negative, 307 (40.2%) were OCT borderline and 82 (10.7%) were OCT positive.
Of 38 eyes referred for ‘group of exudates within the macula’ (with no exudate < 1DD), 12 (31.6%) were OCT negative, 20 (52.6%) were OCT borderline and 6 (15.8%) were OCT positive.
Conclusions :
None of the surrogate markers for DMO used in the current protocols are sufficiently sensitive to diagnose DMO. We suggest a second line screening for those who are OCT positive with 2-dimensional markers to reduce the proportion of patients referred directly to HES.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.