Abstract
Purpose :
Tight junctions between RPE and endothelial cells are the two main structural elements of the blood-retina barrier (BRB). A third constituent of the BRB is located between the preliminary optic nerve and adjacent retinal and choroidal tissue. It consists of differentiated glial cells connected by tight junctions and was previously denominated as the intermediary tissue of Kuhnt (ITK). So far, descriptions of retinal pathologies associated to disturbance of the ITK are missing. It is the aim of this project to present imaging aspects of cases with retinopathies presumably caused by defects of the ITK.
Methods :
Patients were identified within the last ten years with sub- and/or intraretinal fluid accumulation which could not be explained by diseases of the retina, RPE or choroid. Eyes were analysed by SD-OCT and, except few cases, fluoresceine angiography. Retinal/subretinal fluid accumulation was assigned to a defect of the IKT if fluid was anatomically related or extending through the IKT or fluoresceine angiography indicated fluid penetration through this barrier.
Results :
40 eyes of 29 patients (13 female, 16 male, mean age: 70.8+/-12.5, median: 75.8 years) were identified with peripapillary fluid accumulation meeting the above mentioned criteria. In many cases the fovea was involved. Fluid accumulation was present either in the subretinal space, Henle fibre layer, outer nuclear layer, inner nuclear layer, ganglion cells layer, or a combination of these. Fluid accumulation presented in many cases a bilaminar distribution and resembled typical findings in optic disc pit maculopathy. 3 of 29 patients presented an optic disc pit and in these fluid disappeared after ppV and removal of peripapillary vitreous traction. Peripapillary or papillary vitreous traction was a frequent finding in this series. It was remarkable that many optic nerve heads presented deep central, non-glaucomatous excavations. Several cases were found with neovascularization penetrating the ITK.
Conclusions :
A series of cases was identified with intra- and/or subretinal fluid accumulation probably caused by defects of the ITK. Papillary anomalies, peripapillary or marginal vitreous traction at the optic disc, and papilloretinal neovascularization seem to be important causal factors for breakdown of the retinopapillary barrier. Many of the observed cases share structural aspects of optic disc pit maculopathy.
This is a 2021 Imaging in the Eye Conference abstract.