BLOG: Saving vision with MIGS
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Key takeaways:
- A new study used HORIZON data to assess 5-year Hydrus outcomes.
- The rate of visual field progression was higher in those that underwent cataract surgery alone vs. cataract surgery and Hydrus implantation.
The IOP-lowering efficacy of microinvasive glaucoma surgeries has been demonstrated in a number of studies in the ophthalmic literature.
Although IOP lowering is currently the only proven method to decrease risk for glaucomatous irreversible vision loss, it is simply a surrogate and risk factor for functional damage. The end result of glaucomatous damage — permanent visual field loss — is what is paramount in measuring the success of our medical treatments and surgical procedures.
Because of the relative novelty of MIGS procedures and generally slow rate of visual field loss in glaucomatous disease, there have been a paucity of studies investigating their impact in this realm —until recently. Montesano and colleagues recently published on visual field outcomes 5 years after implantation of the Hydrus microstent (Alcon) (Figure). The investigator group used data from the HORIZON trial to perform their study.
The HORIZON trial was a prospective clinical trial that compared IOP outcomes in patients randomly assigned to cataract surgery alone vs. cataract surgery combined with the Hydrus microstent. Consistent with other pivotal MIGS trials, the HORIZON study found that patients randomly assigned to cataract surgery with the Hydrus microstent experienced greater IOP lowering compared with cataract surgery alone after 2 years and without the influence of medications.
In their recent study, Montesano and colleagues analyzed visual field data collected from the HORIZON trial over a 5-year time frame. In the study, automated visual fields were performed in both patient groups 6 and 12 months after randomization and annually thereafter out to 5 years. Importantly, analysis of the visual field data and comparison between the two patient groups were conducted in a masked fashion. The masked graders used pointwise sensitivity data from visual field printouts and excluded data from visual fields with high false-positive rates. Data from 3,701 visual field printouts obtained from 554 patients were used for the analysis. Using a linear mixed effect model, the rate of visual field progression was found to be significantly higher in the patient group that underwent cataract surgery alone vs. the group that underwent cataract surgery combined with implantation of the Hydrus microstent (P = .0138). Survival analysis also indicated a greater proportion of fast visual field progressors in the cataract surgery alone group compared with the group that underwent Hydrus microstent implantation (P = .0170).
Montesano and colleagues should be congratulated for conducting a landmark study showing that combining a MIGS procedure with cataract surgery results in higher likelihood of meaningful visual field preservation. Now, armed with this powerful data, we may move on to patient education of these benefits and incorporation into our surgical decision-making processes.
Reference:
- Montesano G, et al. Am J Ophthalmol. 2023;doi:10.1016/j.ajo.2023.02.008.
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