Glaucoma Filtering Surgery Confers Higher Risk of Postoperative Ptosis than MIGS

Compared to patients who undergo MIGS procedures, those who receive glaucoma filtering surgeries (i.e., PreserFlo MicroShunt, trabeculectomy, Ahmed glaucoma valve) face a higher risk of developing ptosis that may continue worsening over the first postoperative year, study finds. A higher preoperative margin reflex distance 2 also presented as a predictive factor. Photo: Paul Ajamian, OD. Click image to enlarge. Several studies have identified ptosis as a potential complication of glaucoma surgery, but few have followed its long-term course. Researchers recently sought to track how eyelid position changes over the first year after surgery and identify factors—including specific procedure types—linked to ptosis. They found that ptosis occurred in nearly one-third of patients and, in many cases, continued to worsen beyond six months postoperatively.To conduct this prospective study, researchers followed 167 patients who underwent initial glaucoma surgery at a single hospital in Japan over 14 months. Procedures included microhook ab interno trabeculotomy (µTLO; n=28), PreserFlo MicroShunt (n=102), trabeculectomy (n=28) and Ahmed glaucoma valve implantation (n=8). Mean age was 68.9 years, and 52.7% of patients were men. Primary open-angle glaucoma accounted for 62.3% of cases and exfoliation glaucoma for 16.8%. The team measured margin reflex distance 1 (MRD-1) and MRD-2 from standardized slit-lamp photographs before surgery and at one, three, six, nine and 12 months postoperatively. Ptosis was defined as a drop in MRD-1 of at least 1mm from baseline. At one year, mean MRD-1 declined to 2.1mm (from 2.5mm at baseline), while mean MRD-2 remained essentially unchanged at 5.8mm (vs. 5.9mm at baseline). Overall, 54 eyes (32.3%) met the study definition of ptosis at one year. MRD-1 decreased significantly from one month through one year after surgery, whereas MRD-2 showed only a transient decrease at one month. This pattern, the researchers say, suggests “that early postoperative narrowing of the palpebral fissure is influenced by both the upper and lower eyelids, whereas subsequent progression is primarily attributable to changes in the upper eyelid.”Ptosis incidence also varied by surgery type; no significant MRD-1 reduction occurred after µTLO—a MIGS procedure—while significant MRD-1 declines were seen after all three filtration surgeries (PreserFlo MicroShunt, trabeculectomy and Ahmed glaucoma valve). On regression analysis, the Ahmed valve was strongly associated with ptosis, with an odds ratio of 12.0.Higher preoperative MRD-1 (odds ratio: 1.38) was also identified as a risk factor. None of the other factors analyzed in this study showed predictive value (age, sex, glaucoma type, combined cataract surgery, surgeon and reoperation).“During filtration surgery, the superior conjunctiva is exposed by infraduction using corneal traction sutures, a manoeuvre specific to glaucoma surgery that may impose mechanical stress on the eyelid,” the researchers wrote in their paper. While this may help explain why ptosis occurs more frequently after filtration surgery than after MIGS, mechanical stress is unlikely to account for progression lasting up to a year after surgery, the authors posited. “Notably,” they wrote, “PreserFlo MicroShunt, which generally requires a shorter operative time than trabeculectomy, was associated with a higher tendency towards ptosis,” which may imply that, “in addition to intraoperative factors, the presence of an implant may contribute to postoperative ptosis following filtration surgery.”A notable limitation of this study is its inclusion of only Japanese patients. The authors suggest these findings be further explored in more ethnically diverse cohorts, given that “MRD-1 values are known to vary by ethnicity, being higher in Caucasian populations and lower in Asian populations.”In conclusion, the authors wrote that these results “highlight the importance of long-term monitoring of eyelid position after glaucoma surgery and may inform surgical decision-making and timing of ptosis management.”Click here for the journal source. Okuzumi N, Mori S, Katakami K, et al. Incidence and progression of ptosis after glaucoma surgery during one year of follow-up. Graefes Arch Clin Exp Ophthalmol. June 25, 2026. [Epub ahead of print]. This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.