Filter-enhanced intraoperative visualization of subtle posterior capsule rupture: visualization optimization approach with digital quantitative contrast analysis

Subtle posterior capsule rupture (PCR) during phacoemulsification may be difficult to recognize under conventional white coaxial illumination, particularly without vitreous prolapse. This report describes a standardized ImageJ-based workflow for objectively comparing PCR visualization under white illumination, green-filter (red-free) illumination, and retroillumination. Representative surgical frames were converted to 8-bit grayscale, and a fixed elliptical region of interest (5091 pixels) was applied to the tear edge, adjacent intact capsule, and uniform background. Contrast-to-noise ratio increased from 7.38 (white) to 10.26 (green filter) and 11.29 (retroillumination), demonstrating progressive enhancement of tear-to-intact capsule separation. Early enhanced visualization enabled controlled surgical completion without enlarging the defect or anterior vitrectomy and in-the-bag intraocular lens (IOL) implantation. Postoperative day 1 examination demonstrated a stable oval PCR, a deep anterior chamber, and a well-centered IOL. This proof-of-concept technical report introduces a standardized quantitative framework for objectively evaluating microscope illumination strategies for intraoperative visualization of subtle PCR and provides a basis for future validation in larger clinical series.