Abstract and Introduction
Abstract
Purpose To compare the degree of tilt and decentration of an intraocular lens (IOL), refractive status, and prediction error between eyes that underwent trans-scleral suturing of the IOL within the capsular bag (in-the-bag scleral suturing) and eyes that underwent scleral suturing outside of the bag (out-of-the-bag scleral suturing) because of severe zonular dehiscence.
Patients and methods Thirty eyes that underwent in-the-bag scleral suturing of an IOL and 38 eyes that underwent out-of-the-bag scleral suturing were recruited sequentially. The tilt and decentration of the IOL, anterior chamber depth, manifest refractive spherical equivalent (MRSE), prediction error, and incidence of complications were examined.
Results The mean tilt angle and the decentration length of the IOL of the in-the-bag suturing group were significantly less than those of the out-of-the-bag suturing group (P=0.0003 in tilt and P=0.0391 in decentration), although the anterior chamber depth was similar. The mean MRSE and prediction error of the in-the-bag suturing group were less than those of the out-of-the-bag suturing group (P=0.0006 in MRSE and P=0.0034 in error). The incidence of vitreous loss was less in the in-the-bag suturing group than in the out-of-the-bag suturing group (20% vs63.2%, P=0.0009).
Conclusions The tilt and decentration of the IOL after in-the-bag scleral suturing are significantly less than those after out-of-the-bag scleral suturing, which may lead to less MRSE and less prediction error. As the incidence of vitreous loss is less after in-the-bag scleral suturing, in-the-bag suturing is advantageous for eyes of younger patients and of less complicated cases.
Introduction
When performing cataract surgery for eyes with severe zonular dehiscence or lens subluxation, surgeons need to employ a surgical technique to fixate an intraocular lens (IOL) without adequate capsular support; these techniques include implantation of an open-loop anterior chamber IOL (AC-IOL); scleral suture fixation of a posterior chamber IOL (PC-IOL); iris suture fixation of a PC-IOL; and scleral fixation of a modified capsular tension ring with the IOL. However, after implantation of an AC-IOL, corneal endothelial damage or glaucoma escalation remain a concern in spite of refinement in design. In addition, after suturing of a PC-IOL to the sclera or iris, postoperative tilt and decentration due to inadequate haptic position is of particular concern. Previous studies have shown that marked tilt or decentration after scleral fixation occurs in approximately in 8–23% of cases. Our quantitative study has shown that the decentration or tilt of the IOL after scleral suturing is significantly greater than that after either in-the-bag or out-of-the-bag implantation of the IOL, which lead to a myopic shift. Furthermore, only one case report described by Kohnen et al showed quantitatively that the degree of decentration and tilt was relatively small after scleral fixation of the modified capsular tension ring.
Conventionally, intracapsular cataract extraction is performed for eyes with severe zonular dehiscence or lens subluxation. However, advances in surgical devices have increased our ability to preserve the capsular bag after cataract extraction—even in eyes with zonular dehiscence or lens subluxation. By using capsule stabilization devices, such as a flexible iris retractor, capsule expander, or capsular tension ring, phacoemulsification can be accomplished without worsening of zonular dehiscence. When the capsular bag is preserved, a PC-IOL can be sutured to the sclera or the iris within the bag, which we have called 'in-the-bag suturing of the IOL.' The surgical technique of in-the-bag scleral suturing is more difficult than that of scleral suturing outside of the lens capsule, termed 'out-of-the-bag suturing', and in-the-bag suturing is not applicable for more serious cases. However, in-the-bag scleral suturing is assumed to be advantageous in terms of less IOL displacement, less prediction error, and less vitreous loss.
The objective of this study was to examine the degree of IOL tilt and decentration, anterior chamber depth, refractive states, prediction error, and the incidence of operative complications in eyes that underwent in-the-bag scleral suturing of the IOL. In this study, eyes that underwent out-of-the-bag scleral suturing of the IOL served as controls.