Patients with severe or progressive zonulopathy are at risk for late postoperative subluxation or dislocation of a capsular tension ring-IOL-capsular bag complex, which occurred about 6 years after implantation.
She and her colleagues began observing an increased number of IOLs that became dislocated in the capsular bag. Lab evaluation of 86 initial cases showed that none had a CTR.
"This indirectly suggested the efficacy of the CTR in preventing dislocation," said Dr. Werner, associate director of the Intermountain Ocular Research Center, John A. Moran Eye Center, Salt Lake City. "However, since then we have received different specimens with a CTR at the Berlin Eye Research Institute and the Moran Eye Center."
All specimens were evaluated at the Berlin Eye Research Institute and the Moran Eye Center. The investigators sent questionnaires to the surgeons who provided the specimens to obtain a complete history for each case.
Dr. Werner reported the results from 20 cases (18 patients) from Europe. The patients were a mean of 76.36 ± 8.59 years of age at the time of the explantation; the average time of the explantations was 72.11 ± 32.33 months following implantation. The average time to explantation was only 58 months when the investigators considered only cases with capsulorhexis phimosis, she explained.
"The most important condition associated with dislocation of the CTR-IOL complex was pseudoexfoliation, which was associated with at least eight patients," Dr. Werner said.
The capsular tension rings were made of polymethylmethacrylate. The study patients had different IOL designs, specifically, a three-piece hydrophobic acrylic IOL in 10 cases, a one-piece hydrophobic acrylic IOL in five cases, a three-piece silicone IOL in four cases, and a one-piece hydrophilic acrylic IOL in one case. Ten cases had a Soemmering's ring.
Clinical studies had initially suggested that use of a CTR would prevent capsular contraction and phimosis, Dr. Werner explained.
"However, our study and others have shown that this complication is still a concern even in the presence of a CTR," she said.
"We believe that it is very important to analyze long-term CTR complication data that [are] now becoming available," Dr. Werner concluded. "This will help define the degree of instability that can be stabilized with a CTR alone and the degree that will require further support, such as a modified CTR."
Liliana Werner, MD, PhD
Dr. Werner has no financial interestin the subject matter.