Informed Consent In Glaucoma Surgery

From Kahook's Essentials Of Glaucoma Therapy
Primary authors
  • Nathan M. Radcliffe, MD

Informed consent is the term used to describe a process of communication between the physician and patient prior to a patient agreeing to undergo a medical intervention. Although a written consent form is typically signed to document this process, the communication itself is the focus of the informed consent process. The American Medical Association lists several important steps in the informed consent process[1] and notes that physicians are ethically and legally obligated to disclose or provide the following:

  1. The medical diagnosis
  2. The procedure’s nature and purpose
  3. The procedure’s risks and benefits
  4. Alternatives to the procedure (and their risks and benefits)
  5. The risks and benefits of no intervention
  6. An opportunity for the patient to ask questions

Additionally, the patient should demonstrate an understanding of the above material, which can be challenging given that not all patients with glaucoma will possess the appropriate health literacy to understand their glaucoma and what might be required to treat it.[2] In one study, only one-half of patients undergoing glaucoma surgery had a moderate understanding of their surgical problem despite over 90% of physicians reporting that they had taken enough time to explain the problem.[3]

Glaucoma surgery represents a unique paradigm in ophthalmology, and the process of informed consent in glaucoma surgery deserves special consideration. Whereas surgeries for cataract, corneal disease, and many retinal problems are usually performed to alleviate existing visual problems, glaucoma surgery is, on many levels, a prophylactic intervention designed to stabilize vision, or more to the point, to decrease the rate of progressive visual loss.[4] Many candidates for glaucoma surgery will be asymptomatic at the time that surgery is being proposed. Rarely will a patient undergo- ing a glaucoma filtration procedure see or feel better after the surgery, and patients will frequently experience a small amount of visual reduction or local ocular symptoms associated with the surgery to stabilize vision in the long run.[5]

Adverse outcomes often occur in glaucoma surgery. It is important that the informed consent process in glaucoma surgery include a frank discussion of the likelihood of complications. The surgeon and patient should consider whether, given a bad outcome, they would be able to look back and both agree that the possibility of the complication had been discussed and given appropriate consideration during the informed consent process. Any glaucoma surgeon performing a significant number of procedures will eventually have a patient who experiences severe vision loss in association with a glaucoma procedure. By carefully considering the risk profile of intervention and discussing all options in detail, both the patient and surgeon will be psychologically prepared for an adverse outcome should one occur.

When discussing the potential benefits of glaucoma filtration surgery, consider the highest-quality and most recent evidence. In the first 3 years of follow-up during the prospective Tube Versus Trabeculectomy Study, the cumulative probability of failure (intraocular pressure [IOP] above 21 mmHg or less than 20% reduction, hypotony, reoperation, or loss of light perception) was 15.1% in the tube group and 30.7% in the trabeculectomy group. Postoperative complications were common in both groups and occurred in 39% of the tube group and 60% of the trabeculectomy group, with roughly one-quarter of each group requiring reoperation for these complications.[6] Cataract worsening requiring cataract extraction is common following trabeculectomy and should be mentioned during the informed consent process.[7] Inflammation (uveitis), infection (early or late endophthalmitis), bleeding (hyphema and choroidal hemorrhage), as well as corneal decompensation and retinal detachment are additional potential complications to include. It is important that the patient understand that reoperation for any of the above complications is possible. Potential surgical augmentations, such as laser suture lysis, stenting suture removal, bleb needling, antifibrosis injection, or goniopuncture, should be mentioned at the time of the initial consent if the surgeon feels there is a reasonable likelihood that these procedures will be required and especially if the implied success rate includes the use of these enhancements.

The patient should be reminded that compliance with prescribed eye drops and postoperative visits is essential for the safety and efficacy of the procedure. Patients can sometimes frame the choice for surgery in terms of surgery instead of eye drops, and it is helpful to remind them that a suc- cessful surgery might include better IOP control on the same medications or similar IOP control with fewer medications. Similarly, patients can be unhappy following glaucoma surgery, even with excellent IOP control without medications in the case of bleb dysthesia. Finally, the possibility of rare, life-threatening systemic side effects should be disclosed, as should the potential for rare and sometimes unforeseeable side effects that have not been discussed.


In glaucoma surgery, it is important to provide a meaningful and extensive discussion of the risks, benefits, and alternatives of a proposed surgical intervention. By asking the patient to explain the diagnosis, proposed treatments, and potential complications in his or her own words, the surgeon will be able to assess the patient’s understanding of the procedure and directly address any misconceptions. The possibility for adverse outcomes is relatively high in glaucoma surgery and should be addressed directly, and the patient should have a clear understanding that the glaucoma surgery is intended to preserve (not restore) vision. By providing the patient with appropriate expectations heading into surgery, the clinician can optimize the likelihood of both the surgeon and patient being pleased with the out- come, even in the most challenging glaucoma cases.


  1. American Medical Association. Patient physician relationship topics: informed consent. AMA Web site. Retrieved from topics/patient-physician-relationship-topics/informed-consent.shtml
  2. Muir KW, Lee PP. Literacy and informed consent: a case for literacy screening in glaucoma research. Arch Ophthalmol. 2009;127(5):698-699.
  3. Kang KD, Abdul Majid AS, Kwag JH, Kim YD, Yim HB. A prospective audit on the validity of written informed consent prior to glaucoma surgery: an Asian perspective. Graefes Arch Clin Exp Ophthalmol. 2010;248(5):687-701.
  4. Folgar FA, de Moraes CG, Prata TS, et al. Glaucoma surgery decreases the rates of localized and global visual field progression. Am J Ophthalmol. 2010;149(2):258-264.
  5. Janz NK, Wren PA, Lichter PR, et al; CIGTS Study Group. The Collaborative Initial Glaucoma Treatment Study: interim quality of life findings after initial medical or surgi- cal treatment of glaucoma. Ophthalmology. 2001;108(11):1954-1965.
  6. Gedde SJ, Schiffman JC, Feuer WJ, Herndon LW, Brandt JD, Budenz DL; Tube Versus Trabeculectomy Study Group. Three-year follow-up of the tube versus trabeculectomy study. Am J Ophthalmol. 2009;148(5):670-684.
  7. Wong TT, Khaw PT, Aung T, et al. The singapore 5-fluorouracil trabeculectomy study: effects on intraocular pressure control and disease progression at 3 years. Ophthalmol- ogy. 2009;116(2):175-184.