Peripapillary Intrachoroidal Cavitation

Abstract

Peripapillary intrachoroidal cavitation (PICC) is a yellow-orange lesion, located at the outer border of the myopic conus. First described as a localized detachment of the retinal pigment epithelium, its intrachoroidal location was later revealed, justifying its current name. PICC is related to other myopic complications such as posterior staphyloma, but its pathogenesis is not clear to date. Although it has been considered a benign condition, most eyes with PICC show visual field defects, which leads to diagnostic uncertainty as these deficits resemble those seen in glaucoma. Furthermore, eyes with PICC may develop macular detachment with retinoschisis. Finally, misdiagnosis of PICC as a metastatic choroidal tumor may lead to unnecessary and anxiety-inducing investigations. Advances in optical coherence tomography (OCT) imaging have improved the visualization of ocular structures, contributing to the understanding of PICC. Recently, high optic nerve sheath traction forces during eye movements in highly myopic eyes have been suggested as promoters of PICC, renewing interest around this condition. However, a review of PICC is still lacking. Therefore, we aimed to provide a concise yet comprehensive overview of the current state of the art, focusing on OCT illustrations, pathophysiology and potential future perspectives based on the biomechanics of the optic nerve.

Keywords: biomechanics; border tissue; gamma peripapillary atrophy; myopia; optic nerve sheaths; peripapillary intrachoroidal cavitation; peripapillary staphyloma.

Figure 1

Peripapillary intrachoroidal cavitation (PICC). (A) Fundus picture. PICC is the yellow-orange lesion at the outer border of the myopic conus (black star) (B). Infrared image showing the location of sections (C) to (F). (C–F) PICC is the hyporeflective space behind the plane of Bruch’s membrane (BM). (C) Slice along the line x, below the optic nerve head (ONH). (D–F) Orange arrow = border tissue of the choroid (BT). (D) Section along the arrow y, through the ONH. The BT is continuous between the BM and the sclera (green arrow). (E) Section through the ONH, along the arrow z. The BT is discontinuous between the red and orange arrows. (F) Along the myopic conus (arrow t). The BT shows a discontinuity between the red and orange arrows. (A–F) Red star = PICC. (C–F) Red arrow = BM. The fundus picture was taken using VISUCAM^® non-mydriatic camera (PRO NM Carl Zeiss Meditec, Jena, Germany). The device used for OCT is the Spectral Domain OCT Spectralis^® OCT HRA-OCT, model S3300 (Heidelberg Engineering GmbH, Heidelberg Germany).

Figure 2

OCT-angiography of a peripapillary intrachoroidal cavitation (PICC). (A–C) Yellow star = PICC. (A) Fundus image with a PICC. (B) En-face OCT-A at the level of the superficial radial peripapillary capillary. Reduced vascular density at the area of PICC is observed. (C) En-face OCT-A at the level of choroid. Reduced vascular density is also seen at the area of PICC. The device used is the PLEX Elite^® 9000 SS OCTA (Carl Zeiss Meditec AG, Jena, Germany). A 6 × 6 mm field of view centered on the papilla. The fundus picture was taken using VISUCAM^® non-mydriatic camera (PRO NM Carl Zeiss Meditec, Jena, Germany). The device used for OCT-A is the PLEX Elite^® 9000 SS OCTA (Carl Zeiss Meditec AG, Jena, Germany). A 6 × 6 mm field of view centered on the papilla.

Figure 3

Optical coherence tomography (OCT) and OCT-angiography (OCT-A) in a case of peripapillary intrachoroidal cavitation (PICC). (A) Fundus image with a PICC at the outer border of the conus (red arrow). (B,C) Sections along the green arrow in (A). (B) OCT B-scan disclosing the PICC. Gamma peripapillary atrophy is between the two ends of the Bruch’s membrane (red lines). The retinal layers (dashed yellow arrow) herniate through them. (C) B-scan OCT-A showing the absence of signal inside the choroid. There is a signal (in pink) against Bruch’s membrane, corresponding to the choriocapillaris. Behind the intrachoroidal hyporeflective space, another signal corresponding to the sclera is perceived. The retinal vascular signal is red. (D) Infrared image with the green arrow indicating the location of sections. (E,F) The section is below the optic disc. (F) No signal is seen in the hyporeflective choroidal space between the sclera and the choriocapillaris. A signal is present at the level of choriocapillaris. PICC = yellow star. S = sclera. The fundus picture was taken using VISUCAM^® non-mydriatic camera (PRO NM Carl Zeiss Meditec, Jena, Germany). The device used for OCT and infrared image is the Spectral Domain OCT Spectralis^® HRA-OCT, model S3300 (Heidelberg Engineering GmbH, Heidelberg Germany). The device used for OCT-angiography is the Swept-source OCT Triton DRI Topcon corporation.

Figure 4

Structural choroidal findings in peripapillary intrachoroidal cavitation (PICC). (A) Fundus picture showing the yellow-orange aspect of PICC at the outer border of the myopic conus (yellow star). (B) Section along the green arrow in the corresponding infrared image. Intrachoroidal schisis (blue dots) are within the PICC cavity. (C) Section along the green arrow in the corresponding infrared image, through the full-thickness defect. This defect enables communication between the PICC and vitreous cavity. Nerve fibers (yellow arrow) herniate into the PICC cavity. (D) Fundus picture of the eye presented on OCT section. (E) The PICC is not apparent. (E) Section along the green arrow in the corresponding infrared image. The yellow arrow shows the bending of the temporal vessel in the PICC. ON = optic nerve. Red star = PICC. The fundus pictures were taken using VISUCAM^® non-mydriatic camera (PRO NM Carl Zeiss Meditec, Jena, Germany). The device used for OCT is the Spectral Domain OCT Spectralis^® HRA-OCT, model S3300 (Heidelberg Engineering GmbH, Heidelberg Germany).

Figure 5

Discontinuity of the border tissue of choroid in a peripapillary intrachoroidal cavitation (PICC). (A) PICC presents as the hyporeflectivity behind the plane of Bruch’s membrane (red arrow). The border tissue of the choroid (yellow arrow) is the hyperreflective line between the Bruch’s membrane (red arrow) and the border of the scleral canal (dashed blue arrow). In the opposite side, it is between the red and blue arrows. In both cases, it is intact. (B,C) The border tissue of the choroid has a discontinuity (dashed yellow arrows) on the side with gamma peripapillary atrophy. (A–C) Red star = PICC. The device used is the Spectral Domain OCT Spectralis^® HRA-OCT, model S3300 (Heidelberg Engineering GmbH, Heidelberg Germany).

Figure 6

Illustration of a peripapillary intrachoroidal cavitations (PICC) presenting a retinoschisis. The section is along the green arrow in the infrared image. The PICC (yellow star) coexists with a huge retinoschisis (R). Nerve fiber layers herniate into the PICC cavity. The green lines indicate the ends of the Bruch’s membrane, allowing a communication between the PICC and the vitreous cavity. The appearance of a connection (double red arrow) between the PICC cavity and the retinoschisis would promote retinal detachment. The device used is the Spectral Domain OCT Spectralis^® HRA-OCT, model S3300 (Heidelberg Engineering GmbH, Heidelberg Germany).

Figure 7

Traction of the dura mater in the pathogenesis of peripapillary intrachoroidal cavitation (PICC). (A) Fundus picture showing the yellow-orange aspect of PICC at the outer border of the myopic conus (green star). (B–F) Serial OCT sections towards the optic nerve head showing changes in the posterior curvature of the choroid and landmarks of PICC. (B) Wedge-shaped deformation of the posterior choroidal wall with the detachment of the supra-choroid. The dotted red and yellow lines outline the steepening of the scleral flange in front of the subarachnoid space. (B–F) The scleral flange is bowed backwards due to the traction of the dura mater. (A–F) Red star = PICC. (B–F) Yellow star = subarachnoid space. d = dura mater. (C–F) Blue line = scleral flange. Yellow dot = optic nerve. (D–F) LC = lamina cribrosa. The fundus picture was taken using VISUCAM^® non-mydriatic camera (PRO NM Carl Zeiss Meditec, Jena, Germany). The device used is the Spectral Domain OCT Spectralis^® HRA-OCT, model S3300 (Heidelberg Engineering GmbH, Heidelberg, Germany).

Figure 8

Landmarks of the peripapillary intrachoroidal cavitation (PICC). LC = lamina cribrosa. SF = scleral flange, the sclera between the dura and the pia mater. D = dura mater. PICC (red star) is in front of the subarachnoid space (yellow star). It is a suprachoroidal detachment. It is suggested to be promoted by a direct traction force (blue arrow) of the dura mater during eye movements. A tangential component of this traction force squeezes the choroid at the end of the posterior outpouching (red arrowheads). The device used is the Spectral Domain OCT Spectralis^® HRA-OCT, model S3300 (Heidelberg Engineering GmbH, Heidelberg Germany).