Abstract
Purpose :
To investigate the characteristics and pathogenesis of peripapillary intrachoroidal cavitations (PICCs) in high myopia using a cross-sectional study.
Methods :
Four months of clinic high myopic case data were collected. Images from optical coherence tomography (OCT) were assessed. PICCs were defined as a lobular region at the choroidal level on En Face (3D disc) scan and a corresponding triangular thickening of the choroid with the base at the optic disc border on Radial Lines scan. Large parapapillary choroidal vessels were excluded. The parameters on optic nerve head and peripapillary retinal nerve fiber layer were analyzed for the correlation with overt PICC area.
Results :
Out of 85 subjects (169 eyes) with high myopia, a PICC was detected in 14 patients (17 eyes) who had a mean age of 29.7 ± 10.6 years and a mean spherical equivalent refraction of - 13.0 ± 2.6 diopters in the affected eyes. The lesion appeared as a gray or black lobular region at the choroidal level on En Face (3D disc) scan, most often connected with a sunken part of the myopic crescent. A close relationship of PICC and the choroidal vessels was observed. Although no retinal hole appeared to communicate PICC with the vitreous cavity, a rupture of the border tissue and the herniation of adjacent retina were found both on En Face (3D disc) scan and Radial Lines scan. Compared with the age-matched highly myopic control group, the maximal cup depth and the myopic crescent /disc area ratio were significantly greater, the optic disc tilted index was significantly lower in eyes affected by PICC (P = 0.00, 0.00, 0.00, respectively). The mean overt PICC area was 0.82 ± 0.66 mm2. In multi-factor regression analysis, PICC area was only significantly associated with Avg_C which reflected the RNFL thickness difference between the retinal neurosensory layer above the PICC and the nearby crescent (P = 0.03).
Conclusions :
En Face (3D disc) scan not only presented a recognizable shape of PICC, but also provided many details of its topographical features. Combined with Radial Lines scan of OCT, new clues about the formation of PICCs in high myopia were uncovered through qualitative and quantitative analysis. A “traction-balance” hypothesis about the development and prognosis of PICCs was put forward by our group.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.