Optical Coherence Tomography Angiography Analysis of the Foveal Avascular Zone and Macular Vessel Density After Anti-VEGF Therapy in Eyes With Diabetic Macular Edema and Retinal Vein Occlusion

Abstract Purpose:To evaluate dimensions of Foveal Avascular Zone (FAZ) at level of superficial and deep capillary plexuses (SCP/DCP), in patients with different grades of non proliferative diabetic retinopathy without Diabetic Macular Edema (DME) using Optical Coherence Tomography Angiography (OCTA).Patients and Methods: 80 type II diabetes mellitus patients and 20 healthy control subjects were included in this cross sectional study ,aged from 40-60 years with DM type 2 of more than five years ,ecxluding proliferative diabetic retinopathy and DME.Patients were subdivided into four groups according to ETDRS Classification (without retinopathy,mild ,moderate and sever retinopathy) .All subjects undewent: measurement of glycosylated hemoglobin level ,standard Structural Optical coherence tomography for the macula and optic nerve head with OCTA for evaluation of FAZ in both SCP and DCP networks of all eyes using (Heidelberg engineering, OCT spectralis, Germany) (SD-OCT). Results: Mean total macular thickness in control group (322.89 ± 16.31 μm) vs (316.57 ± 20.21 μm) in patients` group.Average RNFL thickness(158.61 ± 12.99 μm )in control group vs(156.07 ± 22.58) μm in patients` group.Mean FAZ in SCP in control group ( 0.32 ± 0.12) mm2 versus( 0.44 ± 0.17) mm2 in patients` group, while FAZ IN DCP (0.23) mm2 ± 0.12 in controls versus ( 0.34 ± 0.16) mm2 in patients.There was a statistically significant wider FAZ in DR patients (P-value 0.003).Conclusion: Enlargement of FAZ in SCP and DCP in patients with moderate to severe NPDR without DME was detected using OCTA, proceeded by neurodegenerative changes with reduction in thickness of ORL and GCC layer. This can be used to monitor the progression of the disease and to evaluate the response to treatment.

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Optical Coherence Tomography Angiography of the Foveal Avascular Zone in Retinal Vein Occlusion

Ophthalmologica ◽

10.1159/000445482 ◽

2016 ◽

Vol 235 (4) ◽

pp. 195-202 ◽

Cited By ~ 29

Author(s):

Juliana Wons ◽

Maximilian Pfau ◽

Magdalena A. Wirth ◽

Florentina J. Freiberg ◽

Matthias D. Becker ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Retinal Vein Occlusion ◽

Optical Coherence Tomography Angiography ◽

Plexiform Layer ◽

Foveal Avascular Zone ◽

Inner Plexiform Layer ◽

Optical Coherence ◽

Vein Occlusion ◽

Avascular Zone ◽

Fellow Eyes

Purpose: The aim of the study was to visualize and to quantify pathological foveal avascular zone (FAZ) alterations through optical coherence tomography angiography (OCT-A) in eyes with retinal vein occlusion (RVO) in comparison to the unaffected fellow eyes. Procedures: OCT-A was conducted with the Avanti® RTVue 100 XR system (Optovue Inc., Fremont, Calif., USA). The borders of the superficial vascular layer (SVL) were defined as 3 μm below the internal limiting membrane and 15 μm below the inner plexiform layer, and for the deep vascular layer (DVL) as 15 and 70 μm below the inner plexiform layer, respectively. The length of the horizontal, vertical and maximum FAZ was manually measured for the SVL and DVL in each eye. Additionally, the angle between the maximum FAZ diameter and the papillomacular plane was measured. Results: OCT-A depicted defects within the perifoveal vasculature in eyes with branch retinal vein occlusion (BRVO; n = 11) and central retinal vein occlusion (CRVO; n = 8). These resulted in an enlargement of the maximum FAZ diameter in eyes with RVO (n = 19) in comparison to the healthy fellow eyes (n = 19; 921 ± 213 vs. 724 ± 145 µm; p = 0.008). Furthermore, a significant correlation was found between best-corrected visual acuity (BCVA) and the maximum FAZ diameter in the DVL (Spearman's ρ = -0.423, p < 0.01). Lastly, in the eyes with RVO, the angle between the papillomacular plane and the maximum FAZ diameter was only in 21.05% (SVL) and 15.79% (DVL) of the cases at 0 ± 15 or 90 ± 15°, respectively. In healthy eyes, these angles (which putatively represent a regular FAZ configuration) were more prevalent (SVL 68.42 vs. 21.05%, p = 0.003; DVL 73.68 vs. 15.79%, p < 0.001). Conclusion: OCT-A shows morphological alterations of the FAZ in eyes with CRVO and BRVO. The correlation of the maximum FAZ diameter with BCVA suggests that these alterations are functionally relevant.

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