'S' means stop! Critical examination of capsular tension ring movements with Miyake-Apple video analysis

To examine capsular tension ring (CTR) implantation to establish whether there are predictable movements of the CTR during deployment, indicating complicated vs uneventful implantation.

Intermountain Ocular Research Center, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah.

Experimental study.

Nine cadaver eyes were prepared using standard Miyake-Apple protocol with digital video recording. A 4 o'clock-hour zonular dialysis was created, followed by a capsulorhexis and hydrodissection. In 4 eyes, a suture-guided CTR (SGCTR) injector and 8-0 nylon suture through the leading eyelet served as a visible tracer for the CTR. In 5 eyes, a standard CTR was used. The movements of the CTR during implantation were observed.

In all eyes, SGCTR and CTR movements were predictable during implantation. All CTRs displayed cardinal movements within the injector, initially adjacent to the side of the inner diameter of the CTR. As the CTR made contact with lens or capsule, it shifted first to the center and then to the opposite side of the injector lumen. The appearance of an S-curve in the surgeon's view coincided with an obstruction of the leading eyelet and stress on the zonular fibers, as viewed with Miyake-Apple analysis.

Traumatic CTR implantation might be avoided by understanding the characteristics of uneventful insertion vs an insertion complicated by entrapment or entanglement of the CTR. By recognizing the abnormal movements of the CTR associated with an obstruction, a surgeon might avoid iatrogenic complications.