Correlation between Automated Perimetry and Optical Coherence Tomography in Post Treatment Follow-up of Papilledema due to Idiopathic Intracranial Hypertension

Objective: To assess correlation between functional changes of the optic nerve evaluated with automated perimetry (AP) and morphological changes of retinal nerve fiber layer (RNFL) evaluated with optical coherence tomography (OCT) in post treatment follow-up of papilledema due to idiopathic intracranial hypertension (IIH).  Methods: We prospectively reviewed 40 eyes (20 patients) having recently diagnosed first attack of IIH with papilledema. Frisén grade of papilledema, Perimetric mean deviation (PMD) and spectral domain optical coherence tomography (SD-OCT) measurement of peripapillary retinal nerve fiber layer (RNFL) thickness were recorded at presentation and at 1^st ,3^rd and 6^th months after starting treatment. We excluded patients with papilledema due to causes other than IIH or glaucoma, and patients who were unwilling to give consent. Results: Our study included 20 patients (40 eyes). Age of patients ranged from 13 to 39 years (mean 27.55±8.4 years). Significant improvement of Frisén grade of papilledema was found throughout the study (p < 0.0001). No patients in the study showed worsening of papilledema grade through the follow up period. There was a significant improvement (p < 0.001) of the retinal nerve fiber layer (RNFL) thickness through the follow up in all patients. At presentation, the median papilledema grade was 2 (range 2-3), which dropped gradually through the study to reach a median of 1 (range 0-1) at the last visit. The mean PMD at presentation was -2.05 ±7.25 dB, improved gradually to reach a mean of -0.59 ±4.02 dB at the last visit. RNFL thickness was (176.7±89µ) at presentation, declined significantly (p < 0.001) to 131.16±25.50 then 121.57±14.20µ then 120.3±14.7µ at 1^st, 3^rd and 6^th month respectively. There was a significant correlation between PMD and RNFL thickness at the last visit (p=0.04). There was also a significant correlation (p < 0.013) between Frisén grade of papilledema and RNFL thickness at all visits. We found that the correlation between papilledema grade and RNFL thickness (r=0.590) was stronger than the correlation between papilledema grade and PMD (r=-0.205) as shown by the correlation coefficient (r). We found no correlation between any of patient’s age, laterality of the eye, oral contraceptive pills (OCP) intake or body mass index (BMI) and any of the study findings including best corrected visual acuity (BCVA), Frisén grade of papilledema, PMD or RNFL thickness. Conclusion: Our study showed a significant correlation between RNFL thickness and PMD at the end-of-study visit. Post treatment improvement of RNFL thickness was paralleled by recovery in PMD. As shown by the correlation coefficient (r), we found that the correlation between papilledema grade and RNFL thickness (r=0.590) was stronger than the correlation between papilledema grade and PMD (r=-0.205).