Influence of IOL Weight on Long-Term IOL Stability in Highly Myopic Eyes

Effects of capsulorhexis size and position on post-surgical IOL alignment

In cataract surgery, post-surgical stability of the intraocular lens plays a major role. This study aims to explore how the size and decentration of the capsulorhexis affect intraocular lens decentration and tilt by using numerical methods. Finite element models included zonules, ciliary body, capsular bag, and an IOL with two open-loop haptics were built. Capsulorhexes were modeled with a 4.5- and 5.5-mm diameter. The capsulorhexis was shifted 0.5-1 mm in two in-plane directions normal to the optical axis. Three IOLs with different powers (5 D, 29 D, and 34 D) were compared. The results were also compared with currently published numerical and clinical studies. With different capsulorhexes sizes and locations, the decentration varied from 0.43 to 8.3 μm, and the tilt varied 0.02° - 0.09°. The 34 D lens had the largest tilt and decentration when capsulorhexis changed sizes or decentered. The simulation showed that capsulorhexis size and decentration have only a minor effect on IOL decentration or tilt that will in most cases not be noticeable to the patient.

Analysis of intraocular lens tilt and decentration after cataract surgery in eyes with high myopia using the anterior segment optical coherence tomography

This retrospective study investigated the degree of intraocular lens (IOL) tilt and decentration after cataract surgery in eyes with varying degrees of myopia using the anterior segment optical coherence tomography (AS-OCT). Eyes of 76 patients were analyzed and divided into three groups: mild myopia (emmetropia to - 1.5 diopter [D], Group 1), moderate myopia (- 1.5 D to - 6.0 D, Group 2), and high myopia (over - 6.0 D, Group 3). Postoperative IOL decentration, tilt, and lens diameter were evaluated using swept-source AS-OCT under mesopic conditions without dilation eyedrop. Postoperative parameters revealed no difference in IOL tilt, but IOL decentration was significantly different among the groups, and the degree of decentration was greater in Group 3 (P = 0.007). Univariable regression analysis indicated that age, sex, preoperative uncorrected distant visual acuity, corrected distant visual acuity, intraocular pressure, spherical equivalent, preoperative anterior chamber depth and lens thickness had no influence on postoperative IOL decentration, but axial length (AL) was significantly related to IOL decentration (P = 0.001). This association was confirmed using multivariable regression analysis, establishing a significant correlation between AL and IOL decentration (P = 0.001) on AS-OCT, showing an increase in IOL decentration associated with increasing AL.

Effectiveness of prophylactic capsular tension ring implantation during cataract surgery in highly myopic eyes

PURPOSE

To assess the effectiveness of prophylactic capsular tension ring (CTR) implantation during cataract surgery in highly myopic eyes.

SETTING

Eye and Ear, Nose, and Throat Hospital of Fudan University, Shanghai, China.

DESIGN

Prospective cohort study.

METHODS

Consecutive highly myopic patients treated with cataract surgery were recruited and randomized to undergo CTR implantation or not. The outcomes compared between the 2 groups included axial lens position (ALP), intraocular lens (IOL) decentration and tilt, area of anterior capsule opening, severity of anterior capsular opacification (ACO), and posterior capsular opacification (PCO) at 1 year postoperatively.

RESULTS

A total of 55 highly myopic eyes with CTRs implanted and 55 without were included in the analysis. At 1 year postoperatively, no significant differences were detected between the CTR and non-CTR groups for the mean ALP, IOL decentration, or tilt (all P > .05). However, the CTR group had a significantly larger area of anterior capsule opening (23.62 ± 3.30 mm2 vs 21.85 ± 2.30 mm2, P = .003), and less severe ACO (P = .033) and PCO (PCO-3 mm: 0.06 ± 0.13 vs 0.13 ± 0.20, P = .038; PCO-C: 0.15 ± 0.18 vs 0.25 ± 0.26, P = .026) than the non-CTR group. The corrected distance visual acuity, prediction error, and higher-order aberrations did not differ between the 2 groups (all P > .05).

CONCLUSIONS

In highly myopic eyes, although prophylactic CTR implantation can reduce the severity of capsular contraction and opacification, it does not significantly affect postoperative IOL stability or visual outcomes.

Complications of high myopia: An update from clinical manifestations to underlying mechanisms

Background

High myopia is one of the major causes of visual impairment and has an ever-increasing prevalence, especially in East Asia. It is characterized by excessive axial elongation, leading to various blinding complications that extend beyond mere refractive errors and persist immovably after refractive surgery, presenting substantial public health challenge.

Main text

High myopia-related complications include lens pathologies, atrophic and tractional maculopathy, choroidal neovascularization, peripheral retinal degenerations and retinal detachment, and glaucoma and heightened susceptibility to intraocular pressure (IOP) elevation. Pathological lens changes characteristic of high myopia include early cataractogenesis, overgrowth of lens, weakened zonules, and postoperative capsular contraction syndrome, possibly driven by inflammatory pathogenesis, etc. Dome-shaped macula and cilioretinal arteries are two newly identified protective factors for central vision of highly myopic patients. These patients also face risks of open-angle glaucoma and IOP spike following intraocular surgery. Morphologic alternations of optic nerve in high myopia can complicate early glaucoma detection, necessitating comprehensive examinations and close follow-up. Anatomically, thinner trabecular meshwork increases this risk; conversely lamina cribrosa defects may offer a fluid outlet, potentially mitigating the pressure. Notably, anxiety has emerged as the first recognized extra-ocular complication in high myopia, with an underlying inflammatory pathogenesis that connects visual stimulus, blood and brain.

Conclusions

High myopia induces multiple ocular and potential mental health complications, underscoring the need to develop more effective strategies to improve both physical and emotional well-being of these patients, among which anti-inflammation might possibly represent a promising new target.

Actual lens positions of three intraocular lenses in highly myopic eyes: an ultrasound biomicroscopy-based study

AIM

To evaluate the actual lens positions (ALPs) of three intraocular lenses (IOLs) in highly myopic eyes and to identify relevant factors using ultrasound biomicroscopy (UBM).

METHODS

Ninety-three highly myopic eyes (93 patients) that underwent uneventful cataract surgery were included: 36 eyes were implanted with Zeiss 409MP IOLs, 27 with Rayner 920H IOLs and 30 with HumanOptics MCX11 IOLs. The prediction error (PE), ALP determined by UBM and the factors associated with ALP at 3 months after surgery were evaluated.

RESULTS

The eyes in the MCX11 IOL group had a more hyperopic PE (0.67±0.45 diopters (D)) and greater ALP (4.86±0.39 mm) than those in the 409MP and 920H IOL groups at 3 months after surgery (PE: -0.25±0.54 and -0.16±0.65 D, respectively; ALP: 4.34±0.26 and 4.14±0.32 mm, respectively). The MCX11 IOLs showed more backward bending deformation after surgery than 409MP and 920H IOLs. The radius of curvature of the IOL was negatively correlated with ALP (r=-0.532, p=0.002) in the MCX11 IOL group, but not in the other two groups. Multivariate analysis showed that MCX11 IOLs were more prone to bending in highly myopic eyes with a smaller anterior capsular opening (β=0.236, p=0.023) and lower implanted power (β=0.542, p=0.001).

CONCLUSION

In highly myopic eyes, IOLs with good capsular support show less backward bending, which result in a more stable lens position and refractive status postoperatively. Severe capsular contraction and low implanted power are risk factors for bending of certain IOLs.