Anatomic evaluation of the Morcher capsular tension ring by ultrasound biomicroscopy

Effect of capsular tension ring on optical and multifunctional lens position outcomes: a systematic review and a meta-analysis

AIM

To evaluate the effect of capsular tension rings with multifunctional lens position and optical outcomes.

METHODS

We defined multifunctional lens as more than improving vision, but also to restore visual quality. PubMed, EMBASE, Cochrane Library and Scopus were searched for English-language articles published up to November 11, 2020. Randomized controlled trials and comparative prospective clinical trials were selected. Data extraction was completed by independent pairs of reviewers. The risk of bias was evaluated using the Cochrane Collaboration's risk-of-bias tool for RCTs and select items from the Newcastle-Ottawa Scale for comparative prospective clinical trials.

RESULTS

A total of 5 randomized controlled trials and 6 prospective comparative clinical trials were included. One thousand nine hundred and ninety-nine eyes of implantation intraocular lens were evaluated. Capsular tension ring was helpful in un-corrected distance visual acuity (SMD: 0.54, 95% CI = 0.15 to 0.94, p = 0.829) in 1st month. Contrary to 1st month, no show positive effect in 3rd month un-corrected distance visual acuity (SMD: - 0.30, 95% CI = - 0.70 to - 0.10, p = 0.311), corrected distance visual acuity (SMD: 0.02, 95% CI = - 0.78 to 0.81, p < 0.001), sphere (SMD: 0.44, 95% CI = - 0.43 to 1.31, p < 0.001), cylinder (SMD: - 0.12, 95% CI = - 0.36 to 0.13, p = 0.262), and spherical equivalent (SMD: 0.41, 95% CI = 0.13 to 0.69, p = 0.084). Our study also revealed low correlation between capsular tension ring and postoperative optical outcome with un-corrected distance visual acuity (SMD: 0.43, 95% CI = - 0.69 to 1.56, p = 0.001), corrected distance visual acuity (SMD: - 0.11, 95%CI = - 0.43 to 0.20, p = 0.56), sphere (SMD: - 0.26, 95%CI = - 1.18 to 0.66, p = 0.005), cylinder (SMD: 0.10, 95% CI = - 0.39 to 0.59, p = 0.075), spherical equivalent (SMD: 0.22, 95%CI = - 0.10 to 0.54, p = 0.849) in 6th month. The position of intraocular lens co-implantation with capsular tension ring has no significant difference in 1st week with lens decentration (SMD: - 0.34, 95% CI = - 1.19 to 0.51, p = 0.038) and tilt (SMD: - 1.00, 95% CI = - 2.19 to 0.19, p = 0.007), but capsular tension ring is helpful to prevent lens tilt in 1st month (SMD: - 0.67, 95%CI = - 1.08 to 0.27, p = 0.323). In 3rd month, there was no significant difference between two groups in lens rotation (SMD: - 0.51, 95%CI = - 1.71 to 0.69, p < 0.001).

CONCLUSION

The correlation is low between capsular tension ring and postoperative optical outcomes and lens position, based on small numbers of studies in a short range of follow-up.

Effect of the capsular tension ring on refractive outcome after phacoemulsification

Purpose: To evaluate how capsular tension rings (CTR) affect refractive outcomes following cataract extraction by phacoemulsification complicated by zonular instability.

Study design: Retrospective.

Methods: In a retrospective case-control study, the 29 eyes of 29 patients with CTRs were compared with the 29 eyes of patients without zonular instability following routine phacoemulsification, with mean arithmetic refractive prediction error (ArRPE) and mean absolute refractive prediction error (AbRPE) as primary outcome measures.

Results: A comparison of eyes with and without CTRs according to the SRK/ T formula revealed no statistically significant difference in ArRPE (0.52 vs. 0.45 D, p = 0.570) or AbRPE (0.52 vs. 0.55 D, p = 0.799). Postoperative hypermetropic shift occurred in most cases in both groups, although the mean difference between eyes with CTR (22/ 29) and without CTR (25/ 29) was not statistically significant (p = 0.315).

Conclusion: Implanting CTRs did not consistently affect refractive outcomes versus routine phacoemulsification. Results suggest that intraocular lens power can be calculated as usual when CTRs are used.

Abbreviations: CTR = capsular tension ring, ArRPE = arithmetic refractive prediction errors, AbRPE = absolute refractive prediction errors, IOL = intraocular lens, WTW = white-to-white, ACD = anterior chamber depths, AL = axial lengths, RPE = refractive prediction error

All about capsular tension rings

PURPOSE OF REVIEW

To discuss capsular tension devices and recent evidence regarding their use.

RECENT FINDINGS

The capsular tension ring, modified capsular tension ring, and capsular tension segment are well established tools for use during phacoemulsification when zonular instability is present. Recent research has provided additional evidence of their benefits in decreasing intraoperative and postoperative complications.

SUMMARY

Endocapsular support devices allow for cataract surgery success in the setting of zonular instability.

Modified capsular tension ring for cortical removal after implantation

We describe a modification of the original 14C Morcher capsular tension ring. The new ring, the Henderson capsule tension ring (HCTR, Morcher), is an open C-shaped loop made of poly(methyl methacrylate). It has 8 equally spaced indentations of 0.15 mm to improve the ease of removing nuclear and cortical material while maintaining equal expansion of the capsular bag. The HCTR is currently under review by the U.S. Food and Drug Administration.

Adjunct devices for managing challenging cases in cataract surgery: pupil expansion and stabilization of the capsular bag

PURPOSE OF REVIEW

Patients anticipate favorable surgical outcomes when having cataract surgery. The modern-day cataract surgeon should employ all necessary means to achieve this result. A working knowledge of adjunct devices for pupil expansion and capsular-bag stabilization can significantly improve surgical outcomes.

RECENT FINDINGS

Adjunct devices for pupil expansion include the Beehler pupil dilator, nylon iris hooks, and pupillary rings, including the Perfect Pupil, the Graether 2000, and the Morcher pupil dilator. Capsular-bag stabilization can be accomplished with capsular tension rings, capsular tension segments or iris hooks. The recent literature on these devices is reviewed.

SUMMARY

Impaired visualization through a small pupil and poor tissue stabilization increases the chance of tissue damage, retained nuclear material, and vitreous loss. Fortunately, inadequate mydriasis and instability of the capsular bag can be managed safely with the use of adjunct tools. Preoperative planning, familiarity with available tools, and accessibility of these devices in the operative setting is necessary.