Purpose To evaluate the efficacy and safety of phacoemulsification combined with glaucoma surgeries based on new criteria of axial length (AL) in nanophthalmos patients with secondary angle closure glaucoma (NSACG). Methods This retrospective study analyzed medical records of NSACG patients, categorized into two groups based on AL. Group 1 (AL: 17-20 mm) underwent phacoemulsification with intraocular lens implantation, viscogonioplasty, and anterior pars plana vitrectomy (PVP), combined with trabeculectomy (Trab) or endoscopic photocoagulation (ECP). Group 2 (AL < 17 mm) underwent PVP combined with trabeculectomy and sclerectomy (PVPTS). Results A total of 22 patients (31 eyes) with NSACG were enrolled with a mean follow-up of 50.2 +/- 26.2 months. Patients with axial length < 17 mm (Group 2) exhibited significantly worse visual acuity (P < 0.05) and required more IOP-lowering medications (P = 0.007) than those with axial length >= 17 mm (Group 1). Postoperatively, both groups demonstrated statistically significant reductions in IOP and the number of IOP-lowering medications (All P < 0.05). IOP reduction >= 20% was achieved in 92.3% (Group 1) and 94.4% (Group 2), with IOP < 21 mmHg in 69.2% and 77.8%, respectively. No postoperative malignant glaucoma occurred in either group. Conclusions PVP combined with Trab or ECP and PVPTS are effective and safe surgical interventions for patients with NSACG. Surgeries applied using the new criteria of AL have the potential to achieve better IOP control outcomes with lower complication rates. Key messages What was known before Nanophthalmos with secondary angle closure glaucoma (NSACG) is challenging to manage surgically due to unique anatomical features and high risk of complications. Short axial length (AL) is a risk factor for postoperative complications in nanophthalmos. What that study addsPhacoemulsification with viscogonioplasty and anterior pars plana vitrectomy (PVP) combined with trabeculectomy or endoscopic cyclophotocoagulation is effective and safe for NSACG patients with AL >= 17 mm and < 20 mm.PVP combined with trabeculectomy and sclerectomy (PVPTS) is effective and safe for NSACG patients with AL < 17 mm.The new AL criteria can be considered an effective surgical intervention strategy in treating patients with NSACG.