Study Weighs Glaucoma Implant Against MIGS Procedure

Phacoemulsification, destruction of the opaque lens by ultrasound, ophthalmic eye surgery. eye lens replacement, intraocular lens installation, surgical cataract treatment in Russia in Ulan-Ude.
Cataract extraction combined with excisional goniotomy or MIGS devices led to reductions in intraocular pressure and medication burden in glaucoma.

This article is part of Ophthalmology Advisor’s conference coverage from the 2021 meeting of American Society of Cataract and Refractive Surgery (ASCRS), held in Las Vegas from July 23 to 27, 2021. The team at Ophthalmology Advisor will be reporting on a variety of research presented by the cataract and refractive surgery experts at ASCRS. Check back for more from the ASCRS 2021 Meeting.


Cataract surgery can provide an opportunity for ophthalmologists to stave off glaucoma progression in patients who have mild to moderate glaucoma. Treating disease early while removing cataracts can kill two birds with one stone. But there’s more than one way to kill that second bird. One potential option is to conduct excisional goniotomy, an implant-free procedure that removes the inner wall of Schlemm’s canal.1 Another option includes the use of a drainage device that allows for aqueous drainage through the canal, ultimately reducing intraocular pressure (IOP).2 Both approaches can be categorized as a minimally invasive cataract surgery (MIGS) and can potentially delay the use of topical glaucoma drops. 

In a poster presented at the American Society of Cataract and Refractive Surgery (ASCRS) meeting in Las Vegas, from July 23 to 27, 2021, researchers compared the medication burden and mean IOPs of patients who underwent excisional goniotomy with those who were implanted with 1 of 2 types of implants. 

The researchers evaluated 55 eyes of 51 patients with mild to moderate primary open-angle glaucoma who were implanted with iStent® (Glaukos), iStent Inject® (Glaukos), or who received treatment with the implant-free excisional goniotomy procedure using a Kahook Dual Blade® (KDB, New World Medical). The retrospective study included data from patient records for at least 12 months and up to 5 years. 

At baseline, mean preoperative IOP was 19.15±5.29 mm Hg, and patients used a mean of 1.67 medications. For the 35 eyes that were implanted with the iStent, patients’ mean IOP decreased by 3.70±4.50 mm Hg (P <.001) and mean number of medications decreased by 1.06±0.32 (P <.001).  

Another 7 eyes were implanted with the iStent Inject. At 12 months, these patients had a mean IOP decrease of 6.64±2.38 mm Hg (P <.001) and reduced medications by a mean of 1.25±0.96 (P <.001).

The patients who received treatment with KDB (13 eyes) had a mean IOP decrease of 3.59±3.84 mm Hg (P =.082) at 12 months, and their mean number of medications decreased by 0.57±0.60 (P =.061).

The research demonstrates that patients who underwent cataract surgery and received glaucoma implants, both iStent and iStent Inject, experienced statistically significant reductions in IOP and were able to decrease the amount of glaucoma medications they used at 12 months. Patients who underwent cataract surgery and excisional goniotomy using a KDB did not show statistically significant reductions in either IOP or medication burden. 

The researchers speculate that the findings regarding KDB “may be due to inherent technique variability.” 

Disclosure: Some study authors declared affiliations with the biotech, pharmaceutical, and/or device companies. Please see the original references for a full list of disclosures.  

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1. Berdahl JP, Gallardo MJ, ElMallah MK, et al. Six-month outcomes of goniotomy performed with the Kahook dual blade as a stand-alone glaucoma procedure. Adv Ther. 2018;35:2093–2102. doi:10.1007/s12325-018-0803-0  

2. Raju L, Chen S, Goyal H. An evaluation of three minimally invasive glaucoma surgeries (MIGS) combined with phacoemulsification for treatment of open-angle glaucoma. Presented at: 2021 ASCRS Annual Meeting; July 23-27, 2021; Las Vegas, NV. Poster 72886.