Abstract
Abstract: :
Purpose: To determine the extent to which the elevation of the optic nerve head that occurs in patients with pseudotumor cerebri is associated with swelling of the retinal nerve fiber layer. Methods and Materials: Heidleberg Retinal Tomography (HRT) was used to measure surface topography (neuroretinal rim and peripapillary surface height) while retinal nerve fiber layer thickness was measured with Optical Coherence Tomography (OCT – Stratus 3.0, Humphrey–Zeiss). Each test was done once on 24 eyes of 12 females with a medical history of pseudotumor cerebri and clinically evident optic disc swelling. Surface height was determined at two locations, 1100 and 1500 microns from the optic disc center in each of four quadrants (inferior, superior, nasal and temporal). Retinal nerve fiber layer thickness measurements were obtained with concentric circle scans at corresponding neuroretinal rim and peripapillary locations. The correlations between surface topography (surface elevation) and retinal nerve fiber layer thickness were determined. Results: All 24 eyes could be imaged with HRT while 23 eyes could be imaged with OCT. A statistically significant correlation between surface height and nerve fiber layer thickness was observed for neuroretinal rim regions (r = 0.286, p < 0.005). For regions in the peripapillary retina a weaker, but still significant, association (r = 0.212, p < 0.05) was found. Conclusion: The elevation in surface height that occurs during optic disc swelling in patients with pseudotumor cerebri, is associated with an increase in nerve fiber layer thickness. However, this association is relatively weak, accounting for less than 10% of the variance in the observed relationship. Factors other then swelling within the retinal nerve fiber layer must play a major role in the elevation the optic nerve head in pseudotumor cerebri.
Keywords: optic disc • imaging/image analysis: clinical • neuro–ophthalmology: optic nerve