Peripapillary microperimetry and optical coherence tomography angiography in patients with optic disc edema

Purpose To compare the utility of peripapillary microperimetry and optical coherence tomography angiography (OCTA) in the differential diagnosis of patients with optic disc edema, including papilledema, optic neuritis, and anterior ischemic optic neuropathy (AION), all in the acute phase, and to correlate the structural and functional findings in these conditions. Patients and methods This cross–sectional comparative case series study included 55 eyes with optic disc edema. The groups were divided into four groups including: papilledema, optic neuritis, AION and pseudo-papilledema. OCTA was done to evaluate the vascular density (VD) of the optic disc in the acute phase of disc edema. Peripapillary microperimetry was done to evaluate peripapillary retinal sensitivity. The different groups were compared with analysis of all data. The correlation between various parameters of OCTA and peripapillary microperimetry was evaluated. Results There was a significant increase in retinal nerve fiber layer between Papilledema, Optic neuritis, and AION, compared with Pseudo papilledema in the superior, nasal, and temporal quadrants (superior quadrant P value 0.001, 0.001, and 0.001, respectively), (nasal quadrant P value 0.001, 0.012, and 0.007, respectively), (temporal quadrant P -value 0.001, 0.034, and 0.036, respectively). All parameters measured by OCTA showed an overall statistically significant difference between the different groups ( P <0.001), while pair-wise comparison showed that AION had statistically the least VD when compared with the 3 other groups. Optic neuritis also has less vascularity inside the disc, when compared with papilledema and pseudopapilledema ( P =0.028. 0.021, respectively). Peripapillary and superior hemi-field VD was also affected when comparing the papilledema versus the pseudopapilledema group ( P <0.001. P =0.025, respectively). Conclusion OCTA and retinal nerve fiber layer can help differentiate between different etiologies in cases of acute optic disc swelling. AION is the mostly affected compared with all other groups. Superior hemifield and peripapillary VD are most sensitive in differentiating the papilledema from pseudopapilledema. OCTA is a useful tool in early cases of papilledema to differentiate it from pseudo-papilledema that poses a diagnostic dilemma together with other diagnostic tests. Microperimetry is a sensitive tool for the diagnosis and follow up of patients especially with poor visual acuities.