Purpose: Evaluation of ocular haemodynamics in patients with acute non-arteritic anterior ischaemic optic neuropathy (NAION) by colour Doppler imaging and fluorescein angiography and correlation of blood flow parameters to visual field loss and visual acuity.
Methods: Blood flow velocities (peak systolic velocity (PSV), end-diastolic velocity (EDV)) of the ophthalmic artery (OA), central retinal artery (CRA) and nasal and temporal posterior ciliary arteries (PCAs) were measured via colour Doppler imaging. Resistive index (RI) of all vessels was calculated (PSV-EDV/PSV). Retinal arteriovenous passage times (AVP) were evaluated using fluorescein angiography (scanning laser ophthalmoscope) and digital image analysis. The visual field global index mean deviation (MD, 30-2 programme, Humphrey Field Analyzer) and visual acuity (logMar) was used for analysis of functional impairment after NAION.
Results: Twenty patients (age: 64.62 ± 11.63 years) with acute NAION were included. Mean duration of symptoms was 7.6 ± 6.9 days. Mean defect was 15.4 ± 8.9 dB, AVP was determined with 1.66 ± 0.37 s. EDV of the CRA was significantly correlated to visual field MD (r = 0.52, p = 0.017) and AVP (r = - 0.49, p = 0.025). The RI of the OA was significantly correlated to visual acuity (r = 0.493, p < 0.037). No significant correlations were recorded for the PCAs. A significant correlation was found between AVP and the EDV of the CRA (r = - 0.49, p = 0.025).
Conclusion: Decreased EDV in the CRA and increased RI in the OA seem to be linked to the functional damage in NAION. An improvement of the retrobulbar circulation might be beneficial in the treatment of NAION.
Keywords: CDI; Fluorescein angiography; NAION; Ocular blood flow; Retrobulbar haemodynamics.