Retinal and Choroidal Folds in Papilledema

Abstract

Purpose: To determine the frequency, patterns, associations, and biomechanical implications of retinal and choroidal folds in papilledema due to idiopathic intracranial hypertension (IIH).

Methods: Retinal and choroidal folds were studied in patients enrolled in the IIH Treatment Trial using fundus photography (n = 165 study eyes) and spectral-domain optical coherence tomography (SD-OCT; n = 125). We examined the association between folds and peripapillary shape, retinal nerve fiber layer (RNFL) thickness, disc volume, Frisén grade, acuity, perimetric mean deviation, intraocular pressure, intracranial pressure, and refractive error.

Results: We identified three types of folds in IIH patients with papilledema: peripapillary wrinkles (PPW), retinal folds (RF), and choroidal folds (CF). Frequency, with photos, was 26%, 19%, and 1%, respectively; SD-OCT frequency was 46%, 47%, and 10%. At least one type of fold was present in 41% of patients with photos and 73% with SD-OCT. Spectral-domain OCT was more sensitive. Structural parameters related to the severity of papilledema were associated with PPW and RF, whereas anterior deformation of the peripapillary RPE/basement membrane layer was associated with CF and RF. Folds were not associated with vision loss at baseline.

Conclusions: Folds in papilledema are biomechanical signs of stress/strain on the optic nerve head and load-bearing structures induced by intracranial hypertension. Folds are best imaged with SD-OCT. The patterns of retinal and choroidal folds are the products of a complex interplay between the degree of papilledema and anterior deformation of the load-bearing structures (sclera and possibly the lamina cribrosa), both modulated by structural geometry and material properties of the optic nerve head. (ClinicalTrials.gov number, NCT01003639.).

Figure 1

Fundus photographs with examples of peripapillary wrinkles, retinal folds, and choroidal folds in patients with idiopathic intracranial hypertension: (a) temporal concentric peripapillary wrinkles. (b) Inferotemporal spiral peripapillary wrinkles extending toward the macula as retinal folds. (c) Superotemporal spiral peripapillary wrinkles extending toward the macula. (d) Radial retinal folds. (e) Horizontal retinal folds in the papillomacular bundle. (f) Horizontal-oblique choroidal folds with RPE striations.

Figure 2

En face SD-OCT images at the vitreoretinal interface demonstrating peripapillary wrinkles and retinal folds in patients with idiopathic intracranial hypertension: (a) temporal concentric peripapillary wrinkles. (b) Temporal spiral peripapillary wrinkles. (c) Inferotemporal peripapillary spiral wrinkles extending into the macula as retinal folds. (d) Radial retinal folds extending into the macula. (e) Horizontal retinal folds in the papillomacular bundle involving the fovea.

Figure 3

Axial raster images of the folds that occur in patients with idiopathic intracranial hypertension. (a) Optic nerve head with peripapillary wrinkles temporally confined to the nerve fiber layer at the retinopapillary inflection (black arrowhead). Inset magnifies that same area showing closely spaced, hairpin undulations (white arrowhead). (b) Peripapillary wrinkles on both the temporal (double arrowheads) and nasal side (single arrowhead) of the optic nerve head. (c) Nasal and temporal peripapillary intraretinal folds sparing the choroid and retinal surface (black arrows). Opposing surfaces of the folds are in contact forming a crease. Note that the spatial wavelength of the intraretinal folds is substantially wider than PPW. (d) Vertical (sagittal) raster taken through the papillomacular bundle demonstrating retinal folds (between black arrows) confined to the surface layers sparing outer retina and choroid. (e) Vertical raster exhibiting retinal folds associated with fine disharmonic choroidal undulations. (f) Vertical raster through the papillomacular bundle showing coarse widely spaced choroidal folds harmonically associated with surface retinal folds. (g) Fine choroidal folds that involve the retinal pigment epithelial layer and outer retina but spare the surface of the retina. (h) Axial raster showing multiple types of disharmonic folds in a single eye with peripapillary wrinkles, retinal folds and choroidal folds.

Figure 4

Multiple modalities showing OS of a patient with choroidal-retinal folds. (a) fundus photo demonstrating horizontal oblique chorioretinal folds with retinal pigment epithelial (RPE) striations. (b) En face montage at the level of the vitreoretinal interface (VRI) showing horizontal-oblique folds nasal, temporal and superior to the disc extending into the fovea. This pattern suggests a combination of tensile and compressive strain directed superiorly from the nerve head. (c) Axial raster image showing choroidal folds. (d) Cross-sectional vertical raster through the midsection of the papillomacular bundle illustrating broad full thickness harmonic chorioretinal undulations (e) En face montage at the level of the RPE demonstrating choroidal folds that are more widely spaced than surface layer folds in (b). (f) Three-dimensional thickness map with corresponding 3D renditions at the level of the VRI (g) and the RPE (h). Arrow in (f) shows a blood vessel and in (g) demonstrates horizontal line artifact due to subtle z axis movements of the globe or head.

Figure 5

Relative frequency of folds among 125 study eyes comparing fundus photos to SD-OCT.

Figure 6

Biomechanical effects of intracranial hypertension on the optic nerve head (a) results in two principal sources of strain: (a1) anterior deformation (black arrows) of load bearing structures (lamina cribrosa and peripapillary sclera) and (a2) expansive soft tissue swelling of the optic nerve head. The interplay between the severity of papilledema (a2) and shape deformation (a1) modulated by individual factors related to the structural anatomy and material properties determines the pattern and distribution of the folds. (b) Peripapillary wrinkles may be consequent to several types of stress including intrapapillary expansive compression and circumferential hoop (tensile) stress at its base. (c) Horizontal folds are consequent to a tensile strain nasally that generates secondary orthogonal compression in the papillomacular bundle. Axisymmetric compression (not shown) at the scleral flange or symmetrical expansion of the nerve head might explain the radial retinal folds.