Effect of Intraocular Pressure Control on Visual Field Progression in the HORIZON Trial

Area of Science:

• Ophthalmology
• Glaucoma Research
• Surgical Innovation

Background:

• Glaucoma management requires monitoring visual field (VF) Mean Deviation (MD) progression.
• Cataract surgery (CS) is a common procedure for visually significant cataracts.
• The HORIZON trial investigated the efficacy of Hydrus Microstent (HMS) implantation during CS.

Purpose of the Study:

• To analyze how intraocular pressure (IOP) characteristics influence the 5-year rate of VF MD progression.
• To compare MD progression between CS with and without HMS implantation.

Main Methods:

• Post-hoc analysis of a randomized clinical trial (HORIZON).
• Included patients with glaucoma and cataract, randomized to CS with or without HMS.
• Utilized a Bayesian hierarchical model to assess MD progression rates and the impact of various IOP metrics (post-operative mean IOP, washed-out IOP, day-1 IOP).

Main Results:

• The CS-HMS group showed a significantly slower MD progression rate (-0.30 dB/year) compared to the CS-only group (-0.55 dB/year), a 44.6% reduction.
• Increased IOP metrics were associated with faster MD progression.
• The difference in MD progression between groups was largely explained by post-operative washed-out IOP (WO-IOP) metrics, not day-1 IOP or mean post-operative IOP (MIOP).

Conclusions:

• The combination of CS and HMS implantation resulted in a significantly slower rate of VF MD progression over 5 years.
• The protective effect of HMS on VF progression is primarily attributed to its influence on post-operative washed-out IOP, rather than immediate post-operative IOP.
• This suggests WO-IOP is a critical factor in the long-term visual field stability in glaucoma patients undergoing combined procedures.