Effect Of Intraocular Pressure Control On Visual Field Progression In The Horizon Trial
Published 2026 - 44th Congress of the ESCRS
Reference: FP28.07 | Type: Free paper | DOI: 10.82333/2txa-gn26
Authors: Dr Giovanni Montesano* 1 , Dr Giovanni Ometto 2 , A/Prof. Iqbal Ike K Ahmed 3 , Gus Gazzard 4
1NIHR Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology,London,United Kingdom; Optometry and Visual Sciences,City St George’s, University of London,London,United Kingdom, 2Optometry and Visual Sciences,City St George’s, University of London,London,United Kingdom;NIHR Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology,London,United Kingdom, 3John A. Moran Eye Center, University of Utah,Salt Lake City, Utah,United States;Department of Ophthalmology and Vision Sciences,University of Toronto, Toronto,Toronto,Canada, 4NIHR Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology,London,United Kingdom
Purpose
To analyze the effect of intraocular pressure (IOP) characteristics on the 5-year rate of visual field (VF) Mean Deviation (MD) progression in the HORIZON trial.
Setting
Post-hoc analysis of data from a randomized clinical trial, recruiting patients with glaucoma and visually significant cataract randomized to cataract surgery (CS) with or without the implant of the Hydrus Microstent (HMS).
Methods
One eye of each participant with at least 3 reliable VFs (false positive errors < 15%) over at least 1 year was included. We used a published Bayesian hierarchical model, designed to minimize the effect of perimetric noise and learning. We compared the mean rate of MD progression between the two arms and measured the effect of post-operative mean IOP (MIOP), peak washed-out and mean washed-out IOP (WO-PIOP and WO-MIOP) and day-1 IOP. These IOP metrics were mean-centered and standardized (divided by their standard deviation, SD), to allow a direct comparison of their effect.
Results
Data from 517 eyes (352 in the CS-HMS arm) were analyzed. The MD rate was -0.55 [-0.72,-0.39] dB/year (Mean [95%-Credible Intervals]) for CS only and -0.30 [-0.38, -0.22] for CS-HMS (44.6 [18.0,64.2]% reduction, p=0.004). Increase in all IOP metrics was significantly associated with a faster MD rate. MIOP, WO-MIOP and WO-PIOP had similar effects. Day-1 IOP had a much smaller effect. The difference in rate between the two arms remained significant after adjusting for MIOP (p=0.002), but was largely eliminated after adjusting for WO-MIOP and WO-PIOP (p=0.455). The MD rate in the CS arm remained significantly faster than CS-HMS (p=0.001) after removing eyes with a day-1 IOP spike (IOP>40 mmHg or 10 mmHg above the WO baseline IOP).
Conclusions
The MD rate was significantly slower in the CS-HMS arm in the HORIZON trial, compared to CS alone. This difference was not explained by day-1 IOP spikes or MIOP, but was largely accounted for by WO-IOP metrics.