Direct Costs of Second Aqueous Shunt Implant Versus Transscleral Cyclophotocoagulation (The Assists Trial)

Jack X. Ma, Alice Z. Chuang, Robert M. Feldman, Steve L. Mansberger, Angelo P. Tanna, Lauren S. Blieden, Daniel Shoham, Nicholas P. Bell, Ronald L. Gross, Louis R. Pasquale, David S. Greenfield, Jeffrey M. Liebmann, Robert N. Weinreb

Research output: Contribution to journalArticlepeer-review


Précis: The cost of cyclophotocoagulation is less than the cost of a second glaucoma drainage device. Purpose: To compare the total direct costs of implantation of a second glaucoma drainage device (SGDD) with transscleral cyclophotocoagulation (CPC) for patients with inadequately controlled intraocular pressure (IOP) reduction, despite the presence of a preexisting glaucoma drainage device in the ASSISTS clinical trial. Methods: We compared the total direct cost per patient, including the initial study procedure, medications, additional procedures, and clinic visits during the study period. The relative costs for each procedure during the 90-day global period and the entire study period were compared. The cost of the procedure, including facility fees and anesthesia costs, were determined using the 2021 Medicare fee schedule. Average wholesale prices for self-administered medications were obtained from The Wilcoxon rank sum test was used to compare costs between procedures. Results: Forty-two eyes of 42 participants were randomized to SGDD (n=22) or CPC (n=20). One CPC eye was lost to follow-up after initial treatment and was excluded. The mean (±SD, median) duration of follow-up was 17.1 (±12.8, 11.7) months and 20.3 (±11.4, 15.1) months for SGDD and CPC, respectively (P=0.42, 2 sample t test). The mean total direct costs (±SD, median) per patient during the study period were $8790 (±$3421, $6805 for the SGDD group) and $4090 (±$1424, $3566) for the CPC group (P<0.001). Similarly, the global period cost was higher in the SGDD group than in the CPC group [$6173 (±$830, $5861) vs. $2569 (±$652, $2628); P<0.001]. The monthly cost after the 90-day global period was $215 (±$314, $100) for SGDD and $103 (±$74, $86) for CPC (P=0.31). The cost of IOP-lowering medications was not significantly different between groups during the global period (P=0.19) or after the global period (P=0.23). Conclusion: The total direct cost in the SGDD group was more than double that in the CPC group, driven largely by the cost of the study procedure. The costs of IOP-lowering medications were not significantly different between groups. When considering treatment options for patients with a failed primary GDD, clinicians should be aware of differences in costs between these treatment strategies.

Original languageEnglish
Pages (from-to)145-150
Number of pages6
JournalJournal of Glaucoma
Issue number3
StatePublished - 1 Mar 2023
Externally publishedYes


  • aqueous shunt
  • costs
  • cyclophotocoagulation
  • drainage device
  • glaucoma
  • tube shunt


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