Silvia Bopp Bremen, Germany

Introduction:

Implantation of a capsular tension rings (CTR) in eyes with radial capsular tears and posterior capsular defects are wrong indications in view of the risk that posterior luxation of the CTR can occur. Vitreoretinal surgery for removal of the large, rigid intravitreal foreign body is recommended, if additional complications are present.

Case report:

A 72-year old male patient presented with postoperative visual deterioration (0.8 to 0.3) and cystoid macular edema 9 months after cataract surgery elsewhere. There was no previous medical data available. Slit lamp examination showed a large posterior capsule defect and a slightly decentered IOL. In addition, a bend PMMA-structure was found behind the IOL in the anterior vitreous cavity. The foreign body was entangled by vitreous fibres and moved in accor-dance with ocular motility. Together with slit lamp findings, a broken PMMA-haptic was suspected. Removal was indicated because of visible vitreous traction and chronic cystoid macular edema unresponsive to medical treatment. During vitrectomy, we unexpectedly found a posterior dislocated capsular tension ring (CTR). The ring was cut into two pieces and excised carefully via the sclerotomies. Postoperatively, cystoid macular edema resolved and vision improved to 0.6. Videoclips will show the surgical procedure.

Discussion:

Rationales for the implantation of CTRs are difficult anatomic situations in cataractous eyes, such as a zonular weakness, zonular defects and zonulolysis in order to allow IOL-implantation into the capsular bag and preserve long-term IOL centration. This goal is achieved, if the capsular bag shape is largely preserved despite of difficult lens surgery. For two reasons implantation of CTRs in the presence of posterior capsular defects or radial tears is contraindicated: firstly, the capsule’s contour cannot be maintained in this situation and secondly, there is a significant risk to loose the CTR into the vitreous cavity and create even more severe problems. Alternatively, IOL-implantation with scleral suturing or an AC-IOL should be considered in this situation.

Conclusions:

The benefits of CTRs are out of discussion, following indications and contraindications. Removal of a posterior dislocated CTR is reported only once in the literature. If extraction of the CTR is considered, risk and benefit must be considered seriously, as a dislocated CTR can remain asymptomatic. If extraction is indicated, careful vitreoretinal techniques should be applied similar to the management of dislocated IOLs.