Retinal Changes Induced by Epiretinal Tangential Forces

Abstract

Two kinds of forces are active in vitreoretinal traction diseases: tangential and anterior-posterior forces. However, tangential forces are less characterized and classified in literature compared to the anterior-posterior ones. Tangential epiretinal forces are mainly due to anomalous posterior vitreous detachment (PVD), vitreoschisis, vitreopapillary adhesion (VPA), and epiretinal membranes (ERMs). Anomalous PVD plays a key role in the formation of the tangential vectorial forces on the retinal surface as consequence of gel liquefaction (synchysis) without sufficient and fast vitreous dehiscence at the vitreoretinal interface. The anomalous and persistent adherence of the posterior hyaloid to the retina can lead to vitreomacular/vitreopapillary adhesion or to a formation of avascular fibrocellular tissue (ERM) resulting from the proliferation and transdifferentiation of hyalocytes resident in the cortical vitreous remnants after vitreoschisis. The right interpretation of the forces involved in the epiretinal tangential tractions helps in a better definition of diagnosis, progression, prognosis, and surgical outcomes of vitreomacular interfaces.

Figure 1

OCT images of normal eye. (a)–(d) En face OCT images at different segmentation thicknesses. (e)-(f) Angio-OCT images of, respectively, superficial and deep retinal plexus. (g) Premacular bursa appears on OCT as boat-shaped lacunae in the macular region.

Figure 2

OCT images of myopic eye. Myopic foveoschisis associated with tangential traction due to ERM and vitreoschisis.

Figure 3

OCT images of diabetic eye. (a)–(d) En face OCT images at different segmentation thicknesses. (e) Increased retinal thickness map. (f)-(g) Vitreoschisis associated with vitreopapillary adhesion. The tangential traction induces wrinkling of ILM and intraretinal cysts.

Figure 4

VPA associated with vitreomacular adhesion in diabetic retinopathy. Clear evidence of posterior precortical vitreous pocket at enhanced HD line scan.

Figure 5

(a)-(b) VPA with pseudomacular hole (PMH).

Figure 6

(a) The multicolor fundus photograph shows an iERM (a) with presence of “retinal vessel printings” (b) at fundus autofluorescence induced by tractional forces. The hyperautofluorescent lines (arrows) indicate the original location of the retinal vessels. (c) OCT scan of the same patient shows the cystoid macular edema induced by tractional forces.

Figure 7

(a)-(b) iERM on en face OCT images at different segmentation thicknesses; at 315 microns offset from ILM the traction disappears (b); (c)-(d) angio-OCT images of retinal superficial plexus (c) and retinal deep plexus (d).