The Diabetic Retinopathy Repair Project - Prevalence And Prognostic Significance Of Ischaemia In Diabetic Macula Disease

Abstract

 

Purpose:

 

To investigate the relationship between Fundus Fluorescein Angiography (FFA) and Optical Coherence Tomography (OCT) derived measurements of retinal vascular morphology and visual acuity in Diabetic Macular Ischaemia (DMI).

 

Methods:

 

Data were retrospectively collected over a period of 6 months. FFAs were analysed by 3 independent graders using the Early Treatment Diabetic Retinopathy Study (EDTRS) protocol for DMI. The Foveal Avascular Zone (FAZ), capillary non-perfusion areas, and OCT images were quantified using custom software.

 

Results:

 

1298 unique patient attendances were identified. 1534 eyes from 767 Type 2 diabetic patients included in the analysis. 45.4% of eyes had no DMI, 16.5% questionable, 16.4% mild, 7.9% moderate, and 3.7% severe ischaemia. Mean FAZ area (mm2) ranged from 0.21 in no DMI to 0.63 in severe DMI. Visual acuity (VA) was reduced in all grades of DMI compared to those with no DMI (p<0.003). VA reduction was correlated FAZ size in the moderate (r=0.47 p=0.006) and severe DMI (r=0.30 p=0.02) subgroups, and in cases with concurrent temporal ischaemia (r=0.59 p=0.0003) and maculopapillar ischaemia (r=0.52 p=0.002). The ratio of inner:outer retinal volume in ETDRS areas 1-9 was negatively correlated to FAZ size (r=-0.29, p= 0.04). A negative correlation was also observed with inner retinal (r=-0.31 p=0.03) but not outer retinal intensity (r=0.09 p=0.51).

 

Conclusions:

 

The extent and location of diabetic macular ischaemia is associated with a reduction of visual acuity and disruption of Inner retinal architecture. The prognostic significance of macular ischaemia is not well understood. Its characterization is an important first step to determine the time point in which patients may be amenable to future regenerative therapies.  

 

 

Keywords: diabetic retinopathy • imaging/image analysis: clinical • clinical (human) or epidemiologic studies: prevalence/incidence