Abstract
Purpose :
The NHS Diabetic Eye Screening (DES) programme in the UK recommends any patient with M1 diabetic maculopathy to be referred to secondary care. DES definition of M1 maculopathy includes any exudates within one disc diameter (1DD) of the fovea or an area of exudates that is greater than or equal to half the disc area, all within the macula area.
DES uses flash fundus photography (FP) as the reference standard for maculopathy grading. We compared Multicolor (MC) versus non-stereoscopic FP at identifying M1 maculopathy. We used spectral domain OCT to identify retinal thickening.
Methods :
In this cross-sectional study R1M1 patients who were referred from DES had FP, MC and SD-OCT scan covering at least 1DD of the central macula with B-scans spaced 240µm. The maculopathy was graded based on exudate criteria as described by DES on both MC and FP in a blind fashion and macular oedema and thickness was ascertained on SD-OCT by two independent graders. We defined macular thickening as central subfield thickness of ≥320µm for males and ≥310 µm for females or thickening of ≥360µm in any of the ETDRS grid inner sectors on Heidelberg Spectralis® SD-OCT. Disagreements were resolved by a third grader.
Results :
The study included 185 patients (367 eyes). There was excellent and very good agreement between graders on grading maculopathy based on FP (κ = 0.91*) and MC (κ = 0.82*) respectively. There was a good agreement between FP and MC on grading maculopathy (κ = 0.76*). When compared to the FP reference standard, the MC had sensitivity of 87% (81% - 93%)**, specificity of 90% (87% - 94%)**, positive predictive value of 80% (73% - 88%)** and negative predictive value of 94% (91% - 97%)** in detecting M1 maculopathy.
SD-OCT identified 84 eyes with macular thickening, 47 of which were graded as M0 by FP. 5 eyes with exudates and severe macular oedema requiring urgent intervention were also missed on FP but not on MC. MC, when complemented by SD-OCT, didn’t miss any clinically significant macular oedema.
*= p-value <0.0001
**= 95% confidence interval
Conclusions :
MC integrates synergistically in a single platform with SD-OCT to provide effective monitoring of M1 diabetic maculopathy. The need of FP is eliminated by MC/SD-OCT in dedicated R1M1 virtual clinics not requiring parallel diabetic retinopathy grading.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.