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Weiye Li, Majda Hadziahmetovic, Jason Lange; The region-dependent neovascularization and macular layer-specific edema and ischemia in proliferative diabetic retinopathy. Invest. Ophthalmol. Vis. Sci. 2017;58(8):81.
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© ARVO (1962-2015); The Authors (2016-present)
Diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR) are two major vision threatening complications of diabetic patients. However, the region-dependent relationship between non-perfusion (NP) and neovascularization (NV), and the correlation between macular layer-specific edema and ischemia have not been completely clarified in PDR.
This cohort study includes 27 consecutive treatment naïve PDR patients at the Drexel Eye Physicians from October 2015 to September 2016. Ultra-wide field fluorescein-angiography, SD-OCT and OCT angiography (OCTA) were used for imaging studies. The relationship between far-peripheral (fp), mid-peripheral (mp) and central retinal (cr) zones were analyzed by calculating indexes of NP (NPI) and NV (NVI). The macular layers were analyzed by using central subfield thickness (CSFT), ganglion cell layer thickness (GCLT), and inner nuclear layer thickness (INLT).
The orders of mean NPI (fp>mp>cr) and NVI (mp>cr>fp) were demonstrated by zones. Using linear regression analysis, the greater fpNPI was associated with a higher mpNVI (p<0.01). Across the cohort, no association was found between fp NPI with CSFT, however, fpNPI was significantly correlated with a decrease in GCLT in the para-foveal region (p<0.05). In subgroup analysis, when NVD was present, crNPI was significantly correlated with crNVI (p < 0.05). Further subgroup analysis also revealed that when CSFT (20 eyes) was larger than 300 µm, OCTA showed overt compromise of deep retinal capillary plexus.
The retinal mpNV depends on the severity of NP at neighboring fp. Similarly crNV, when NVD is present, depends on the NP at cr. Therefore, both NVE and NVD formation in PDR are region-dependent. CSFT, an indicator of DME, does not correlate with NPI in any retinal zones, thus indicating that the underlying mechanisms of DME involve multiple factors rather than NP alone. For example, the retinal NP correlating with the decrease in GCLT suggests macular edema and macular ischemia co-exist in PDR. This relationship is further corroborated by OCTA findings. Therefore, new algorithms for PDR management may be proposed as we further elucidate the pathophysiology of DME.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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