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

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.