Abstract
Purpose :
Vessel density (VD), as assessed by OCT Angiography (OCTA), is thought to be relevant in the prognosis of glaucoma. We intended to verify whether a rapid decrease of intra-ocular pressure (IOP) during the early post-operative period of glaucoma surgery was accompanied by an increase in VD.
Methods :
We present an observational prospective clinical study of patients with increased intra-ocular pressure shortly after glaucoma surgery (from day 0 to week 6), in which we performed an OCTA, before and 15 minutes after normalization of IOP (through laser suture lysis, removal of releasable sutures or goniopuncture). We included patients from April to September 2018, previously submitted to glaucoma surgery, presenting for the routine post-operative consultation with IOP of 21mmHg or higher, who accepted to participate and to sign consent (we had local Ethics Committee approval). Other ophthalmological or systemic pathologies were excluded. We performed an OCTA (Triton, Topcon®) with scans of 4.5 x 4.5mm centered in the optic disc, before consultation and after the manoeuvre to decrease the IOP; fifteen minutes later, IOP was measured and a new OCTA was performed.
Results :
Four patients (3 males, 1 female, 15 to 71 years old) were included in our analysis. We have observed a rapid increase in vascular density, as detected by OCTA, after normalisation of intra-ocular pressure (through goniopuncture after sclerectomy, and suture laser lysis or removal of releasable suture after trabeculectomy) in the early post-operative period (in figure 1, the VD is represented by a colour scale, in which blue and dark colours represent low VD; and yellow, orange and red colours represent high VD; in panel A before, and in panel B after these manoeuvres; in patients 1 to 4).
Conclusions :
In all cases, a rapid decrease in intraocular pressure after each of these manoeuvres was associated with a marked improvement in whole-image optic disc VD. These preliminary results corroborate the dynamic nature of vessel density in glaucomatous eyes. We introduce a new concept: rise-up, in which a rapid decrease in intra-ocular pressure is associated with a rapid increase in the whole-image optic nerve vessel density. To our knowledge, we are the first to identity an immediate substantial increase in the vessel density, in the early glaucoma post-operative period. Further prospective studies with a larger sample are welcomed.
This abstract was presented at the 2019 ARVO Imaging in the Eye Conference, held in Vancouver, Canada, April 26-27, 2019.