Longitudinal Measurement of Hemodynamic Changes within the Posterior Optic Nerve Head in Rodent Nonarteritic Anterior Ischemic Optic Neuropathy

ObjectiveTo assess the in vivo dynamic blood flow features of posterior optic nerve head (ONH) in rat model of nonarteritic anterior ischemic optic neuropathy (rNAION). MethodsrNAION was established with Rose Bengal and argon green laser in Sprague-Dawley rats. Fundus photography and fundus fluorescein angiography (FFA) were performed to assess the dynamic changes of optic disc in morphology in 90 days and in blood perfusion in 3 hours after the induction of disease. Histological examinations were performed to evaluate the success of modeling. Thedynamic blood flow kinetics of posterior ONH in rNAION were measured by Laser Doppler Flowmetry (LDF) on the day 3, 7, 14, 21, and 40 after the disease induction. One-way ANOVA, Student'st-test and Bonferroni adjustment were used for multiple comparisons of kinetic measurements of blood flow. ResultsOptic disc edema and subsequent resolution associated with the development of optic disc pallor were observed in rNAION. FFA showed that the optic disc was hypofluorescence in the early phase and hyperfluorescence in the late phase. Histological studies suggested edema and loosened tissues of ONH, loss of retinal ganglion cells (RGCs), optic nerve substance and gliosis. Compared to the naive rats, the blood flow kinetics of posterior ONH in rNAION significant reduced at each time point after modeling (F=175.06,P<0.0001). The reductions were specifically remarkable in 14 days after the disease induction (AllP<0.01). Conclusions Continuous blood perfusion reduction was found in rNAION, with significant alteration in 14 days after disease induction. Our results provided important information for understanding the hemodynamic changes in rNAION.

Clinical characteristics of progressive nonarteritic anterior ischemic optic neuropathy

AIM:To study whether patients with progressive nonarteritic anterior ischemic optic neuropathy(NAION)present earlier than patients with stable NAION and to describe their clinical characteristics and visual outcome.METHODS:This was a retrospective chart review.All patients with NAION seen during the acute stage from January 2012 to December 2018 were reviewed.Patients were included if they had documented disc edema and follow up of at least 3 mo.Patients with progressive NAION were identified if they worsened in 2 out of 3 parameters:visual acuity≥3 Snellen lines;Color vision≥4 Ishihara plates;the visual field defect involved a new quadrant.The clinical characteristics,time from symptom onset to presentation,systemic risk factors and visual outcome were compared to patients with stable NAION.RESULTS:Totally 122 NAION cases met the inclusion criteria.Mean age was 58.1 y(range 22-74),70%were men.Twenty cases(16.4%)had progressive NAION.Patients with progressive NAION did not differ from stable NAION in their demographics,systemic risk factors or in their initial visual deficit.At last follow up,median visual acuity was 1.0 log MAR(IQR 0.64-1.55)in patients with progressive NAION,vs 0.18(IQR 0.1-0.63)in stable NAION(P<0.001).Median color vision testing was 0 plates correct(IQR 0-2.5%)vs 92%plates correct(IQR 50%-100%)in the stable NAION group(P<0.001).Patients with progressive NAION differed in the time from symptom onset to presentation(median 2 d vs 5 d,P=0.011).CONCLUSION:We find no identifiable risk factors associated with progressive NAION.Progressors arrive earlier for ophthalmological evaluation.

Change of retinal nerve fiber layer thickness in patients with nonarteritic inflammatory anterior ischemic optic neuropathy

In this study, 16 patients （19 eyes） with nonarteritic anterior ischemic optic neuropathy in the acute stage （within 4 weeks） and resolving stage （after 12 weeks） were diagnosed by a series of complete ophthalmic examinations, including fundus examination, optical coherence tomography and fluorescein fundus angiography, and visual field defects were measured with standard automated perimetry. The contralateral uninvolved eyes were used as controls. The retinal nerve fiber layer thickness was determined by optical coherence tomography which showed that the mean retinal nerve fiber layer thickness and the retinal nerve fiber layer thickness from temporal, superior, nasal and inferior quadrants were significantly higher for all measurements in the acute stage than the corresponding normal values. In comparison, the retinal nerve fiber layer thickness from each optic disc quadrant was found to be significantly lower when measured at the resolving stages, than in the control group. Statistical analysis on the correlation between optic disc nerve fiber layer thickness and visual defects demonstrated a positive correlation in the acute stage and a negative correlation in the resolving stage. Our experimental findings indicate that optical coherence tomography is a useful diagnostic method for nonarteritic anterior ischemic optic neuropathy and can be used to evaluate the effect of treatment.