AIM: To introduce and evaluate the clinical efficacy of a new technique, the use of viscoelastic substances (VS) to close leaking sclerotomy in 23G microincision vitrectomy, and to observe its effect on the visual acuity and intraocular pressure (IOP) of patients. METHODS: Patients who underwent 23G vitrectomy in Ningbo Eye Hospital before the use of VS technique (June 2019 to September 2020) and after the use of VS technique (October 2020 to December 2021) were selected as the subjects of this study. The above cases underwent operation by the same surgeon and were retrospectively analyzed. VS technique was used as the alternative to suturing, in which a small amount of VS was injected at the leaking sclerotomy and then gently massaged to confirm leaking sclerotomy closure. RESULTS: A total of 174 eyes were covered in the study, including 84 eyes in the control group (before the use of VS technique) and 90 eyes in the VS technique group. The number of eyes that needed to be sutured decreased considerably from 42.9% in the control group to 3.3% in the VS technique group, and the proportion of subconjunctival hemorrhage at 1-2d after surgery decreased remarkably from 35.7% in the control group to 2.2% in the VS technique group. No substantial differences in the incidence of mean IOP and low IOP were found between 1-2 and 3-20d after surgery in the VS technique group. No major complications associated with VS technique were identified during the study. CONCLUSION: In 23G microincision vitrectomy, VS technique is a safe, simple, and effective method to close leaking sclerotomy.