Clinical Outcomes and Complications After INTACS Implantation in Keratoconus: A Systematic Review

Background/Objectives: Keratoconus is a progressive corneal ectatic disorder leading to irregular astigmatism and visual impairment. INTACS intracorneal ring segments are used to improve corneal shape and visual function; however, postoperative complications may occur. A comprehensive and evidence-based evaluation of visual outcomes and complications after INTACS implantation is therefore warranted. Methods: PubMed, Scopus, and Google Scholar were searched for English-language articles published between January 2015 and December 2025 using the terms INTACS, intracorneal ring segments, keratoconus, and complications, following a systematic literature search conducted in accordance with PRISMA 2020 guidelines. Only studies reporting INTACS-specific outcomes were included. Studies evaluating other intracorneal ring systems were excluded unless INTACS data could be separately extracted. Results: Seventeen studies comprising 544 eyes were included. INTACS implantation was associated with consistent improvements in visual acuity and corneal parameters. However, clinically relevant device-related complications, including segment migration, extrusion, and the need for secondary procedures such as repositioning or explantation, remain an important limitation. These findings indicate that although INTACS is an effective corneal regularization strategy, long-term safety depends on careful patient selection, precise surgical technique, and close postoperative surveillance. Conclusions: INTACS implantation is an effective option for visual rehabilitation in patients with keratoconus; however, its long-term safety is limited by the risk of device-related complications. Careful patient selection, appropriate surgical technique, and structured postoperative follow-up are essential to optimize outcomes and minimize adverse events.