Optic nerve head microvascular characteristics in patients with unilateral pseudoexfoliation syndrome: an optical coherence tomography angiography study.

Purpose: To compare vascular microcirculation changes of the optic nerve head (ONH) and to evaluate the peripapillary retinal nerve fiber layer (RNFL) in the patients with unilateral pseudoexfoliation syndrome (PEXS), other eyes of these patients without PEXS and healthy control eyes using optical coherence tomography angiography (OCTA) and spectral domain optical coherence tomography (SD-OCT).

Methods:  This cross-sectional study enrolled 29 pseudoexfoliative (PEX) and 29 fellow eyes of patients with unilateral PEXS, and 28 healthy eyes as controls. According to inclusion criteria the study group with asymmetric PEXS were normotensive and no glaucoma diagnosis. The vascularity of optic disc was evaluated with OCTA and peripapillary retinal nerve fiber layer with SD-OCT. ONH 4.5 × 4.5 mm OCTA gave us perfusion density (PD) and flow index (FI). Differences between the groups according to continuous variables were determined by independent samples t test. A p value less than 0.05 was considered as significant.

Results: Twenty-nine patients with the mean age of 66.21 ± 7.55 (49-79) years was compared with 28 individuals in control group with mean age of 66.79 ± 4.43 (60-75) years. There was no difference regarding the age (p = 0.725). Female and male distribution in two groups were same (p = 0.219). Intraocular pressure (IOP) in PEXS group was measured as 16.17 ± 4.58 (10-21) mmHg, however IOP in the fellow eye was measured as 14.79 ± 3.35 (11-19) mmHg (p = 0.064) and control group was measured as 12.53 ± 1.66 (10-17) mmHg (p = 0.000). In the group with PEXS, the superior FI was found to be lower 0.39 ± 0.06 (0.26-0.45) (p = 0.008) than control group 0.42 ± 0.21 (0.36-0.45), and temporal FI in PEXS eyes was measured 0.42 ± 0.06 (0.32-0.52), which was significantly lower than control group (p = 0.022). Nasal FI was the parameter which was found significantly different from the PEXS free fellow eyes. The nasal FI value of eyes with PEX was 0.40 ± 0.05 (0.30-0.46), while the same value in PEX free fellow eyes was 0.42 ± 0.04 (0.33-0.47) (p = 0.029).

Conclusions: ONH evaluation with OCTA especially in the nasal segment is important for early diagnosis. OCTA can be a new method in follow-up and early diagnosis of patients with asymmetric PEXS to control ONH microcirculation and to evaluate early glaucomatose changes in both eyes.