Background <p>To evaluate the feasibility, anatomical outcomes, visual results, and safety profile of a modified scleral buckling (SB) technique utilizing 27-gauge direct endoillumination under a heads-up three-dimensional (3D) visualization system for primary rhegmatogenous retinal detachment (RRD).</p> Methods <p>This retrospective case series included consecutive patients with primary RRD who underwent modified SB surgery at a tertiary referral center. Retinal breaks were identified using a 27-gauge endoillumination probe through a valved trocar under a heads-up 3D visualization system with a non-contact wide-angle viewing lens. Anatomical success after a single surgery was the primary outcome. Secondary outcomes included final best-corrected visual acuity (BCVA) and surgical complications.</p> Results <p>Twenty-seven eyes of 27 patients were included, with a mean age of 34.6 ± 12.1 years. Fifteen eyes (56%) were macula-off at presentation. Single-surgery anatomical success was achieved in all cases during a mean follow-up of 9.4 ± 5.9 months. Mean BCVA improved significantly from 0.57 ± 0.55 logMAR preoperatively to 0.21 ± 0.30 logMAR postoperatively (<i>p</i> &lt; 0.001). Twelve eyes (44.4%) achieved a final visual acuity of 20/20. No major intraoperative or postoperative complications, including endophthalmitis, iatrogenic retinal breaks, cataract formation, or vitreous prolapse, were observed.</p> Conclusions <p>This modified SB technique using 27-gauge direct endoillumination and heads-up 3D visualization appears to be a feasible and safe approach for selected cases of primary RRD, demonstrating encouraging anatomical and functional outcomes. However, given the retrospective design, small sample size, and absence of a control group, further prospective comparative studies are warranted to validate these findings.</p>