In patients with primary open-angle glaucoma (POAG), researchers recently found that retinal nerve fiber layer (RNFL) thinning was spatially consistent and progressive at the location of parapapillary choroidal microvasculature dropout. They noted that it was accompanied by subsequent disc hemorrhage and continued to progress even after the hemorrhage.
The team evaluated parapapillary microvasculature in 50 eyes with POAG and disc hemorrhage at three intervals: one year before, at the time of and one year after the detection of the hemorrhage. Then, they compared progressive changes in RNFL thickness in groups of eyes with and without vascular changes. They defined dropout as an area in the parapapillary deep layer of focal sectoral loss with no visible microvascular network.
The investigators reported a cumulative prevalence of dropout of 76% (38 eyes) at one year after the detection of DH. They noted that all instances of dropout were detected in the same sectoral locations as the hemorrhage. In affected eyes, they discovered that global RNFL thickness and sectoral RNFL thickness at the location of the hemorrhage were significantly reduced, both from one year before to the time of the hemorrhage detection and from hemorrhage detection to one year later.
In eyes without vascular dropout, however, the reductions in global and sectoral RNFL thickness were significant only from the time of hemorrhage detection to one year later.
Kim CY, Lee EJ, Kim JA, et al. Progressive retinal nerve fibre layer thinning and choroidal microvascular dropout at the location of disc haemorrhage in glaucoma. Br J Ophthalmol. July 1, 2020. [Epub ahead of print].