High myopia is a leading cause of blindness worldwide. Myopia progression may lead to pathological changes of lens and affect the outcome of lens surgery, but the underlying mechanism remains unclear. Here, we find an increased lens size in highly myopic eyes associated with up-regulation of β/γ-crystallin expressions. Similar findings are replicated in two independent mouse models of high myopia. Mechanistic studies show that the transcription factor MAF plays an essential role in up-regulating β/γ-crystallins in high myopia, by direct activation of the crystallin gene promoters and by activation of TGF-β1-Smad signaling. Our results establish lens morphological and molecular changes as a characteristic feature of high myopia, and point to the dysregulation of the MAF-TGF-β1-crystallin axis as an underlying mechanism, providing an insight for therapeutic interventions.

Background To evaluate the distribution of lens thickness (LT) and its associations with other ocular biometric factors among cataract patients in Shanghai. Methods Twenty-four thousand thirteen eyes from 24,013 cataract patients were retrospectively included. Ocular biometric factors including LT, central corneal thickness (CCT), anterior chamber depth (ACD), white-to-white (WTW) distance, anterior corneal curvature, and axial length (AL) were obtained using the IOLMaster700. The associations between LT and general or ocular factors were assessed. Results The mean age was 62.5 ± 13.6 years and 56.1% were female. The mean LT was 4.51 ± 0.46 mm. The LT was greater in older patients (P < 0.001). LT was positively correlated with CCT, while negatively correlated with ACD, WTW, and anterior corneal curvature (P < 0.001). Multivariate analysis revealed that increased LT was associated with older age, male gender, thicker CCT, shallower ACD, larger WTW, and flatter anterior corneal curvature (P < 0.001). LT changed with a variable behavior according to AL. In short eyes LT increased as AL increased, then decreased with longer AL in normal eyes and moderate myopic eyes, but increased again as AL increased in highly myopic eyes. Thickest LT was found in the 20.01–22 mm AL group. The correlation between LT and other biometric factors remained significant when stratified by ALs. Conclusions In a large Chinese cataractous population, we found that the thicker lens may be associated with older age, male gender, thicker CCT, shallower ACD, larger WTW, and flatter anterior corneal curvature. As AL increased, the change of LT was nonlinear, with the thickest lens seen in the 20–22 mm AL group.

PurposeTo investigate the incidence of the early transient intraocular pressure (IOP) spike after cataract surgery in eyes with highly myopic cataract (HMC) and associated risk factors.MethodsConsecutive patients treated with phacoemulsification were recruited. IOP was measured before and 1 day, 3 days, 1 week and 3 months after surgery. Axial length (AL) and anterior chamber depth (ACD) were recorded, and optic disc tilt, rotation and beta-zone peripapillary atrophy (β-PPA) were measured from fundus photographs taken 1 week after surgery. Backward stepwise multiple linear regression was used to investigate the risk factors for early transient IOP spike in the HMC group.ResultsFinally, 94 eyes of 94 HMC patients and 67 eyes of 67 age-related cataract (ARC) controls were included in analysis. The incidence of early IOP spike was 10% in the ARC group and 28% in the HMC group (OR=3.277, p<0.05) at 1 day after surgery. In the HMC group with IOP spikes, more males were seen and affected eyes showed longer AL, shallower ACD, greater optic disc tilt, and larger β-PPA than those without (all p<0.05). Multivariate analysis showed that sex, AL, ACD, and area of β-PPA were significantly associated with an early transient IOP spike in HMC eyes (all p<0.05).ConclusionsHighly myopic eyes are more susceptible to early transient IOP spike after cataract surgery, and male sex, longer AL, shallower ACD, and greater β-PPA are associated risk factors.Clinical trial registration numberNCT02182921.