Incidence and progression of ptosis after glaucoma surgery during one year of follow-up

PURPOSE: This study evaluated the incidence and progression of ptosis during the first year after glaucoma surgery. METHOD: This prospective study included patients who underwent initial glaucoma surgery between October 2023 and December 2024. Procedures included microhook ab interno trabeculotomy (µTLO), Preserflo MicroShunt (PMS), trabeculectomy, and Ahmed glaucoma valve (AGV). Margin reflex distance 1 (MRD-1) and MRD-2 were measured preoperatively and at 1, 3, 6, 9 and 12 months using standardised photographs. Ptosis was defined as a decrease in MRD-1 of ≥ 1 mm from baseline. Logistic regression was used to identify factors associated with ptosis. Eyes with absolute MRD-1 ≤ 1 mm were also evaluated at each time point. RESULT: A total of 167 patients were included: 28 underwent µTLO, 102 PMS, 28 trabeculectomy and 8 AGV implantation. Mean (SD) MRD-1 decreased from 2.5 (1.2) mm preoperatively to 2.1 (1.3) mm at one year. Ptosis occurred in 54 eyes (32.3%). MRD-1 decreased significantly from 1 month through 1 year, whereas MRD-2 showed only a transient decrease at 1 month. No significant MRD-1 reduction occurred after µTLO, whereas significant decreases were observed after filtration surgery. AGV implantation and higher preoperative MRD-1 were associated with ptosis. Eyes with MRD-1 ≤ 1 mm increased over time in the PMS and AGV groups but not after µTLO or trabeculectomy. CONCLUSION: Ptosis occurred in about one-third of eyes after glaucoma surgery and progressed up to one year. Filtration surgery was associated with a higher risk of postoperative ptosis.