Objective  To observe the efficacy and safety of pars plana vitrectomy (PPV) combined with subretinal injection of dexamethasone in treating refractory diabetic macular edema (DME). Methods A prospective case study. From January 2024 to March 2024, 9 cases with 10 eyes of refractory DME diagnosed at Tianjin Eye Hospital were included in the study. All eyes had a central macular thickness (CMT) of greater than 275 μm despite receiving intravitreal injection of anti-vascular endothelial growth factor (VEGF) drug at least 5 times. All eyes underwent 25G PPV combined with internal limiting membrane (ILM) peeling and subretinal injection of dexamethasone sodium phosphate. Best-corrected visual acuity (BCVA), microperimetry, and optical coherence tomography examinations were performed on all eyes before and 1 and 3 months after surgery. BCVA was assessed using an international standard visual acuity chart and converted to logarithm of the minimum angle of resolution (logMAR) for statistical analysis. Paired t-tests were used to compare changes in BCVA, mean macular sensitivity (MS), and CMT before and after surgery. The intraoperative and postoperative complications were recorded. Results Among the 9 cases with 10 eyes, there were 4 males with 5 eyes and 5 females with 5 eyes. Age ranged from 43 to 79 (65.3±10.8) years. Preoperative and postoperative logMAR BCVA at 1 and 3 months were 0.84±0.25, 0.72±0.31, and 0.63±0.22, respectively. MS was (16.48±5.03), (16.6±6.31), and (18.0±5.33) dB, respectively. CMT was (437.5±90.4), (306.9±87.4), and (288.7±87.3) μm, respectively. Compared with data before surgery, BCVA: the difference was not statistically significant at 1 month (t=2.025, P=0.074), but was statistically significant at 3 months (t=5.161, P=0.001), MS: the differences at 1 and 3 months were not statistically significant (t=－0.078, －1.022, P=0.940, 0.334), CMT: the differences were of statistical significance at both 1 and 3 months (t=2.892, 3.175, P=0.018, 0.011), and the difference between 1 and 3 months post-surgery was also statistically significant (t=2.427, P=0.038). No complications such as macular hole, vitreous hemorrhage, or retinal detachment occurred during or after surgery in any eyes. No cases of increased intraocular pressure or cataracts were reported during the follow-up period. Conclusion PPV combined with ILM peeling and subretinal injection of dexamethasone can effectively reduce CMT in refractory DME eyes and improve visual acuity, with good safety.

Citation： Zhang Hui, Wang Ying, Han Quanhong. Clinical observation of pars plana vitrectomy combined with subretinal injection of dexamethasone for the treatment of refractory diabetic macular edema. Chinese Journal of Ocular Fundus Diseases, 2025, 41(1): 21-24. doi: 10.3760/cma.j.cn511434-20240715-00262 Copy

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