At some point, we have all observed a glaucoma attending who talks a progressing patient out of surgery. These attendings typically emphasize infection, the snuff syndrome, and choroidal hemorrhages, while downplaying the opportunity to avoid total blindness with surgery. One can’t help but think that these surgeons would rather patients go blind of their own disease than lose vision at a surgeon’s hands. This is the philosophy of those who prefer to make errors of omission. And while no one wants to see a patient lose vision from either cause, we know that glaucoma surgery prevents more blindness than it causes.
We may also have encountered an aggressive glaucoma surgeon who adheres religiously to the AGIS study findings that one needs a pressure under 14 to be stable in glaucoma1 and operates on everyone above that target. While I certainly can follow this physician’s reasoning, this surgeon is at risk of making an error of commission.
Generally speaking, all human beings (doctors comfortably included) overestimate small risks and underestimate large risks. For example, some withhold prostaglandin analogs (PGAs) out of an imaginary fear that they cause cystoid macular edema (CME), but generally think little about the high probability of dry eye or lack of efficacy from noncompliance when prescribing drop therapy.
(I believe the question of PGAs causing CME has been put to rest. A study of roughly 40,000 patients found no signals that PGAs were causing acute CME. In fact, the data showed patients on a PGA had a lower risk of CME compared to other topical anti-glaucoma agents.2 However, I digress…)
There have been tremendous innovations in drug delivery and other interventional therapies over the past decade in glaucoma. Most of them are underutilized, in part due to risk estimation errors. A surgeon who has performed 100 successful MIGS procedures, but stops performing them because of a hyphema (which resolves), is probably overestimating the level of risk associated with a transient complication and underestimating the meaningful benefit of additional IOP reduction from MIGS. On the other hand, a surgeon who doesn’t want to use PGA-based drop therapy due to fears of CME is overestimating an imaginary risk while ignoring the more significant risk of visual loss due to noncompliance.
Glaucoma is a relentless, progressive, irreversible, and blinding disease that is best addressed with early and appropriately aggressive intervention. Let’s be careful not to underestimate that risk. GP
References
1. The Advanced Glaucoma Intervention Study (AGIS): 7. The relationship between control of intraocular pressure and visual field deterioration.The AGIS Investigators. Am J Ophthalmol. 2000;130(4):429-440. doi:10.1016/s0002-9394(00)00538-9
2. Zhou Y, Bicket AK, Marwah S, Stein JD, Kishor KS; SOURCE Consortium. Incidence of acute cystoid macular edema after starting a prostaglandin analog compared with other classes of glaucoma medications. Ophthalmol Glaucoma. 2025;8(1):4-11. doi:10.1016/j.ogla.2024.07.010
