Retinal venule diameters decreased following 6 months of treatment for high intracranial pressure in Idiopathic Intracranial Hypertension Treatment Trial participants

Abstract

Purpose : Prior studies support an association between increased retinal venule diameter and elevated intracranial pressure (ICP). The purpose of this study was to test the hypothesis that retinal venule diameters decrease in association with long term therapy for high ICP in subjects with idiopathic intracranial hypertension (IIH).

Methods : The Idiopathic Intracranial Hypertension Treatment Trial (IIHTT) photographic reading center used standardized procedures to measure area of optic disc elevation (ODE) and diameters of 4 arterioles and 4 venules 2.7mm from the optic disc center from fundus photos of both eyes of participants in the IIHTT at baseline and after 6 months of randomized treatment with either placebo+diet or acetazolamide+diet. Average absolute and relative change in arteriole (D_a) and venule (D_v) diameters at 6 months compared to baseline were modeled for eyes with measurement of at least 1 vessel at both time points (163 eyes in 82 subjects) using linear generalized estimating equation (GEE) models accounting for within subject correlations, age, gender and treatment group. Pearson correlation between vessel diameter (D_a, D_v) change and absolute ODE change was calculated for study eyes (worst seeing eye at baseline in each subject).

Results : D_v decreased following 6 months of treatment (absolute 17.8 um(95% CI 8.1-27.3), p<0.0005; relative 14.0%(95% CI 6.7-21.3%), p<0.0005, GEE) with a larger change in eyes receiving acetazolamide (4.4 um vs. placebo,p=0.065; 3.4% vs. placebo,p=0.060, GEE). D_v change was associated with absolute ODE change (absolute r=0.50, relative r=0.45, p<0.0005). There was no change in absolute or relative D_a after treatment (p=0.48, 0.75, GEE).

Conclusions : Retinal venule diameter decreased and arteriole diameter did not change in association with treatment for elevated intracranial pressure in IIHTT participants. This association was more pronounced in subjects treated with acetazolamide and suggests a drug effect on ocular and cerebral hemodynamics.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.

 

Association between change in area of optic disc elevation and change in retinal venule diameter in subjects with idiopathic intracranial hypertension after 6 months of treatment with either acetazolamide+diet or placebo+diet. Each marker represents one eye.