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. 2019 Mar 28;2019(3):CD012743. doi: 10.1002/14651858.CD012743.pub2

Samuelson 2011.

Methods Study design: parallel‐group RCT
Unit of randomization: participants (1 eye per participant)
Number randomized: 240 participants; 117 eyes of 116 participants in the 1 iStent in combination with phacoemulsification group and 123 eyes of 123 participants in phacoemulsification alone group
Unit of analysis: participants (1 eye per participant)
Number analyzed: 240 participants (intention‐to‐treat); 117 eyes of 116 participants in the 1 iStent in combination with phacoemulsification group and 123 eyes of 123 participants in phacoemulsification alone group
Exclusions and losses to follow‐up: 22 eyes/participants; 15 eyes of 15 participants were excluded (6 in the 1 iStent in combination with phacoemulsification group and 9 in the phacoemulsification group) at 12 months, and 7 eyes of 7 participants were lost to follow‐up (5 in the 1 iStent in combination with phacoemulsification group and 2 in phacoemulsification alone group) at 12 months
Handling of missing data: intention‐to‐treat; last observation carried forward analysis
Participants Country: US (29 sites)
Age (mean ± SD): 74.0 ± 8.0 years (range: 53–88 years) in combined surgery group; 73.0 ± 9.0 years (range: 48–88 years) in cataract surgery alone group
Gender: 46 men and 71 women in the 1 iStent in combination with phacoemulsification group; 52 men and 71 women in the phacoemulsification group
Medicated IOP (mean ± SD): 18.7 ± 3.3 mmHg in the 1 iStent in combination with phacoemulsification group; 18.0 ± 3.0 mmHg in the phacoemulsification alone group
Inclusion criteria:

  1. mild‐to‐moderate OAG confirmed by gonioscopy, with definitive characteristic visual field or nerve pathology

  2. IOP ≤ 24 mmHg while taking 1–3 ocular hypotensive medications, with a stable medication regimen for ≥ 2 months

  3. after a washout of ocular hypotensive medication, IOP ≥ 22 mmHg and ≤ 36 mmHg "during normal office hours"

  4. presented with the need for cataract surgery, defined as clinically significant cataract with BCVA of 20/40 or worse in the presence of glare

  5. C:D ratio ≤ 0.8


Exclusion criteria:

  1. severe glaucomatous field defects

  2. severely uncontrolled IOP

  3. angle‐closure glaucoma

  4. neovascular, uveitic, or angle recession glaucoma

  5. previous glaucoma surgery other than iridectomy

  6. previous refractive procedures

  7. known corticosteroid responders

  8. ocular disease that would affect safety

  9. people with monocular vision

  10. fellow eye BCVA worse than 20/200


Diagnoses in participants: OAG, PEXG, and PG; and in need of cataract surgery
Interventions Intervention 1: 1 iStent in combination with phacoemulsification
Intervention 2: phacoemulsification alone
Length of follow‐up: 2 years
Outcomes Primary outcome: proportion of participants with IOP ≤ 21 mmHg without ocular hypotensive medication at 12 and 24 months
Secondary outcomes: proportion of participants with ≥ 20% reduction in IOP from baseline without medication; mean reduction in IOP; mean number of ocular hypotensive medications at 12 months; mean decrease in medications from screening; and mean IOP at 12 and 24 months
Safety outcomes: loss of BCVA of ≥ 1 line ≥ 3 months postoperative; secondary surgical intervention; infection; elevated IOP requiring treatment with oral or intravenous medication or surgical intervention; stent obstruction; corneal thickness; cataract surgery; mean deviation in visual field; frequently reported postoperative ocular complications (≥ 3%); and other complications at 12 and 24 months
Notes Type of study: published
Enrollment start year: 2005
Funding source: Glaukos Corporation, Laguna Hills, CA, USA provided funding/support
Disclosures of interest: investigators reported receiving financial support from or consulting for Alcon, Allergan, AMO, AqueSys, Glaukos, iScience, Ivantis, Lumenis, Pfizer, QLT, and Santen; all trial investigators were consultants to Glaukos for the conduct of this study; 4 trial investigators are equity owners of Glaukos
Publication language: English
Trial registration: NCT00323284
Risk of bias
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Low risk Investigators noted that a "[c]omputer‐generated randomization was performed (PROC PLAN, PC‐SAS, SAS Inc., Cary NC)."
Allocation concealment (selection bias) Unclear risk Allocation concealment not reported.
Blinding of outcome assessment (detection bias) 
 Number of IOP‐lowering drops High risk Quote: "The study was, by design, open‐label, given that there was no way to mask the treatment to the surgeon during the surgical intervention, or to the observer at the time of gonioscopy."
Blinding of outcome assessment (detection bias) 
 IOP measurement High risk Quote: "The study was, by design, open‐label, given that there was no way to mask the treatment to the surgeon during the surgical intervention, or to the observer at the time of gonioscopy."
Incomplete outcome data (attrition bias) 
 All outcomes Low risk Investigators excluded 22/240 (9%) participants from the 12‐month analysis, among whom 11/117 were in the 1 iStent in combination with phacoemulsification and 11/123 were in cataract surgery alone group.
Selective reporting (reporting bias) Low risk Outcomes described in the results matched those specified in methods and in the ClinicalTrials.gov record.