Editors Selection IGR 21-4

Surgical Treatment: Phaco and IOP in Eyes Previously Implanted with Drainage Devices

Robert Feldman

Comment by Robert Feldman on:

91083 The Effect of Phacoemulsification on Intraocular Pressure in Eyes with Preexisting Glaucoma Drainage Implants, Wong SH; Radell JE; Dangda S et al., Ophthalmology. Glaucoma, 2020; 0:

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In this study, Wang et al. retrospectively reviewed patients who underwent phacoemulsification in eyes with preexisting glaucoma drainage implants (GDI). They present results of 51 eyes of 45 patients to evaluate the effect on IOP control. This is important because many patients who are phakic and undergo GDI will develop cataracts requiring extraction during the first 5 years.1 The authors were unable to demonstrate any effect on IOP of cataract extraction in this setting and although underpowered were unable to detect a difference between various implant types.

These results are different than cataract surgery in previously unoperated eyes where IOP is expected to decrease about 3 mmHg and different than lens extraction after trabeculectomy which in most reports results in an increased failure rate.2,3

The results suggest that the mechanism of failure of a GDI may be different than a trabeculectomy and that postoperative inflammation does not lead to decreased permeability of the implant capsule. In any case the results confirm that phacoemulsification may be safely performed in eyes with a pre-existing GDI without risking loss of control of the glaucoma.

Phacoemulsification may be safely performed in eyes with a pre-existing GDI


  1. Gedde SJ, Herndon LJ, Brandt JD, et al. Postoperative Complications in the Tube Versus Trabeculectomy (TVT) Study During Five Years of Follow-up. Am J Ophthalmol. 2012;153(5):804-814.
  2. Mathew RG, Parvizi S, Murdoch IE. Success of trabeculectomy surgery in relation to cataract surgery: 5-year outcomes. Brit J Ophthalmol. 2019;103(10):1395-1400.
  3. Husain R, Liang S, Foster PJ, et al. Cataract surgery after trabeculectomy: the effect on trabeculectomy function. Arch Ophthalmol. 2012;130(2):165-170.

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