IOP reduction and glaucoma drop usage improved after receiving phacoemulsification with iStent insertion.
IOP reduction and glaucoma drop usage improved after receiving phacoemulsification with iStent insertion. Photo: Joseph W. Sowka, OD. Click image to enlarge.

There have been many recent advancements in glaucoma care and management to try to ease the burden of eye drops. One such positive development is the iStent (Glaukos), a popular minimally invasive glaucoma device on the market.

Able to be inserted either at the time of phacoemulsification or as a stand-alone procedure, this study looked at the device’s intraocular pressure (IOP)-reducing ability when inserted at the time of cataract surgery. The systematic review compared the effects between patients who received phaco alone with ocular hypertension or open-angle glaucoma. Endpoints included reduced IOP and the mean reduction in number of glaucoma drops.

A total of 1,453 eyes were included from 10 studies. Of those, 853 received combined treatment of phaco with the iStent, and 600 underwent just conventional cataract surgery. Reduction of IOP was greater in the combined surgery group with an average drop of 4.7±2mm Hg. Phacoemulsification alone resulted in an IOP reduction of 2.8±1.9mm Hg on average.

Similarly, use of postoperative eye drops was also reduced more in the combined group. These patients experienced an average decrease in topical drops of 1.2±0.3 vs. phacoemulsification alone, which saw a decrease of 0.6±0.6 drops.

Based on these results, the study authors noted that the “iStent has a synergistic effect with phacoemulsification.” This echoes the results of two prior meta-analyses, adding to this study’s validity.

A 22% IOP reduction was observed in the combined surgery group, while phacoemulsification alone resulted in a 14% IOP decrease. The authors added that in their subgroup analysis excluding the iStent inject, IOP reduction was less following combined surgery. However, the change in glaucoma eye drops remained the same.

The authors concluded, “Although the results were statistically significant with iStent showing a good safety profile and offering the benefit of decreasing the dependence on glaucoma eye drops, the clinical implications are still debatable. Further studies are still needed to assess the long-term IOP-lowering effect of iStent, the protective effect on the optic nerve and how long it may delay the need for future, more invasive glaucoma surgeries.”

Kahale F, Chanbour W, El Zein L, et al. Phacoemulsification with and without iStent: a systematic review and meta-analysis of comparative studies. Ophthalmic Res. May 26, 2023. [Epub ahead of print].