Retinal nerve fiber layer thickness analysis in cases of papilledema using optical coherence tomography – A case control study.

BACKGROUND: Papilledema is defined as an optic disk swelling that is secondary to elevated intracranial pressure. Early diagnosis of papilledema can help in early intervention thus preventing visual loss and even death. Optical coherence tomography (OCT) is a non-invasive imaging technique which can detect and quantify diffuse thickening of the retinal nerve fiber layer (RNFL) in eyes with optic disk edema.

AIMS: To assess the difference in the RNFL thickness in patients with papilledema from controls using OCT and to correlate the RNFL thickness with the degree of papilledema.

SETTING AND DESIGN: A case control study was conducted from August 2011 to July 2013 in a tertiary care medical college of south India.

METHODS AND MATERIALS: All adult patients diagnosed or suspected to have papilledema were included in the study. Disk photographs were graded according to modified Frisen criteria. Fast RNFL protocol on time-domain OCT was used. Cases and controls were compared.

STATISTICAL ANALYSIS: RNFL thickness was compared using an independent samples t-test. Correlation between RNFL thickness and modified Frisen scale of papilledema was done using Spearman correlation. GraphPad InStat 3 version was used.

RESULTS: A total of 100 cases and 126 controls were studied. Statistically significant thickening of retinal nerve fiber layer (RNFL) was seen in all quadrants in patients with papilledema as compared to controls. A positive correlation was found between Frisen grading of papilledema RNFL thickness measurements.

CONCLUSIONS: RNFL thickening was mainly in the inferior and superior peripapillary region and was greater in higher grades of papilledema. A strong positive correlation was found between RNFL thickness and the Frisen scale for grading of papilledema. OCT can be included as a routine non-invasive quantitative tool for detection of early papilledema.