Donut-Shaped Intrastromal Keratoplasty (Dsik) As An Alternative To Dalk In Moderate To Advanced Keratoconus

To present the Donut-Shaped Intrastromal Keratoplasty (DSIK) technique associated with intrastromal corneal ring segment implantation as an alternative to Deep Anterior Lamellar Keratoplasty (DALK) in selected cases of moderate to advanced keratoconus.

Setting : Private Clinic, Belo Horizonte, Brazil

A 26-year-old female patient, spectacle-dependent due to high myopia and intolerant to contact lenses, sought evaluation because of decreased visual acuity and refractive discomfort. Corrected distance visual acuity was 20/80 (OD: -10.00 -4.50 ×105) and 20/60 (OS: -7.00 -2.50 ×90). Corneal tomography revealed bilateral keratoconus. Slit-lamp biomicroscopy showed clear corneas without central striae or opacities.
Intervention: A combined surgical approach with DSIK and intrastromal corneal ring segment implantation was performed. The DSIK technique consists of implanting a 360-degree ring-shaped stromal graft to promote corneal regularization and biomechanical reinforcement. The procedure may be performed as a standalone, combined, or sequential approach with ring implantation, according to individualized surgical planning.
Results: Significant improvement in corneal regularity and visual acuity was observed, with reduction of spherical equivalent and irregular astigmatism. The cornea remained clear postoperatively, with no relevant intraoperative or postoperative complications.

DSIK, particularly when associated with intrastromal corneal ring implantation, represents a promising alternative to DALK in patients with moderate to advanced keratoconus and clear corneas, enabling meaningful visual rehabilitation through a less invasive and tissue-preserving approach.