Relief of Cystoid Macular Edema-Induced Focal Axonal Compression with Anti-Vascular Endothelial Growth Factor Treatment

Eyyup Karahan; Aliaa Abdelhakim; Ceren Durmaz; Tongalp H Tezel

doi:10.1167/tvst.9.4.18

Relief of Cystoid Macular Edema-Induced Focal Axonal Compression with Anti-Vascular Endothelial Growth Factor Treatment

Transl Vis Sci Technol. 2020 Mar 18;9(4):18. doi: 10.1167/tvst.9.4.18. eCollection 2020 Mar.

Authors

Eyyup Karahan^{1

2}, Aliaa Abdelhakim¹, Ceren Durmaz^{1

3}, Tongalp H Tezel¹

Affiliations

¹ Department of Ophthalmology, Columbia University, Vagelos College of Physicians and Surgeons, New York, NY, USA.
² Department of Ophthalmology, Balikesir University, Balikesir, Turkey.
³ Department of Ophthalmology, Dokuz Eylul University, Izmir, Turkey.

Abstract

Purpose: To evaluate the mechanical compression of retinal nerve fiber layer (RNFL) by intraretinal cysts in macular edema and its relief with anti-vascular endothelial growth factor (anti-VEGF) treatment.

Methods: Optical coherence tomography scans were used to measure RNFL thickness and reflectance at seven preselected points at and around the peak of the edema before and after anti-VEGF treatment in 10 patients (11 eyes) with branch retina vein occlusion (BRVO) and diabetic macular edema (DME). Scans through nonedematous retina and from the fellow eyes were taken as controls. Correlations were sought between the changes in retinal and RNFL thickness, RNFL reflectance, and the size of the intraretinal cysts.

Results: Postinjection RNFL thickness decreased significantly only at peak point of the edema (18.1 ± 2.7 vs. 13.8 ± 1.2 µm; P = 0.038), at its nasal edge (20.1 ± 2.7 vs. 15.5 ± 1.4 µm; P = 0.026), and 500 µm away from its nasal border (35.7 ± 6.0 vs. 20.1 ± 2.7 µm; P = 0.006) suggesting focal stagnation of the axoplasmic flow owing to compression at its peak point. Significant postinjection decreases in RNFL reflectivity were also noted at peak point of the cyst (164.9 ± 10.3 vs. 141.5 ± 12.6 arbitrary units [AU]; P = 0.037), at its nasal edge (166.8 ± 7.8 vs. 135.1 ± 10.2 AU; P = 0.02), and 1500 µm away from temporal edge (160.2 ± 6.2 vs. 141.1 ± 6.4 AU; P = 0.022). Cyst proximity to RNFL (D₅₀ = 50 µm) was the only determinant significantly affecting the magnitude of the RNFL thickness change after anti-VEGF treatment (P = 0.001).

Conclusions: Intraretinal cysts due to BRVO and DME locally compress overlying axons and induce anatomic changes suggestive of axoplasmic stagnation. This compression can be relieved with anti-VEGF treatment.

Translational relevance: Focal compression of RFNL by retinal cysts may indicate a need for early treatment of macular edema to prevent axonal loss, especially in patients with low axonal reserve.

Keywords: anti-VEGF treatment; axonal compression; ganglion cells; image analysis; macular edema; optical coherence tomography.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Axons
Diabetic Retinopathy*
Humans
Macular Edema* / diagnosis
Retinal Ganglion Cells
Tomography, Optical Coherence