Precision-Guided Suprachoroidal Injection Using Ultrasound Biomicroscopy and Custom-Length Microneedles

Background and Objective: Suprachoroidal (SC) injection enables targeted posterior drug delivery but relies on subjective tactile feedback to confirm depth. This can require multiple passes or cause intravitreal delivery, increasing patient discomfort and complication risk. This study evaluates whether ultrasound biomicroscopy (UBM) can guide custom needle selection based on scleral thickness to improve first-pass SC injection success. Patients and Methods: Ten ex vivo porcine eyes underwent pre-injection UBM to measure scleral thickness. Custom-length needles (0.5–1.5 mm) were selected accordingly. SC injections were performed under UBM guidance, with imaging confirming entry and injectate spread. Results: UBM confirmed successful SC injection in all specimens, with hypoechoic separation between sclera and choroid. Post-injection, scleral thickness increased significantly (1.13 ± 0.13 mm to 2.28 ± 0.19 mm, P < .0001), validating drug delivery. Conclusion: UBM-guided needle selection enables accurate SC injection and may reduce failed attempts. This approach could enhance the efficacy of SC delivery and support broader clinical use across posterior segment diseases.