Why carry out this study?

The success of many current glaucoma surgeries (including trabeculectomy) are dependent on the preoperative conjunctival status, which is adversely affected by exposure to topical glaucoma medications.

Most eyes undergoing glaucoma surgery have had long-term exposure to topical glaucoma medications, but the effect of this exposure has not yet been accurately quantified.

Our aim was to quantify the threshold exposure to preoperative topical glaucoma medications that is associated with increasingly poor postoperative outcome, to help predict high-risk cases.

What was learned from the study?

The use of the Glaucoma Medication Intensity Index (GMII) allows a more accurate assessment of preoperative exposure to topical glaucoma medications.

A preoperative GMII ≥ 80 was associated lwith lower trabeculotomy success in terms of postoperative survival time, intraocular pressure, reduction in medications, and subsequent requirement for needling procedures.

Use of the preoperative GMII to predict high-risk trabeculectomy cases can allow the surgeon to plan accordingly and optimize the patient’s postoperative outcome.