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AIM:To investigate the effect of small incision lenticule extraction(SMILE)on the treatment of myopia patients, and the impact on corneal biomechanics.METHODS:Retrospective study. A total of 120 myopic patients(240 eyes)who were scheduled to undergo corneal refractive surgery in Anyang Eye Hospital from January 2020 to December 2021 were selected. The patients were divided into SMILE group(64 patients, 128 eyes)and transepithelial photorefractive keratectomy(TransPRK)group(56 patients, 112 eyes)according to the surgical treatment method. The two groups were compared in terms of uncorrected visual acuity, corneal biomechanics, corneal endothelial cell count, posterior corneal surface height and corneal surface regularity index at 1, 7 d, 1, 3, 6 mo and 1 a after surgery, and surgical complications.RESULTS:The uncorrected visual acuity of the SMILE group at 1, 7 d and 1 mo after surgery was better than that of the TransPRK group(all P0.05). Compared with preoperative values, corneal-compensated intraocular pressure, Goldmann-correlated intraocular pressure, corneal resistance factor, and corneal hysteresis in both groups showed a first decreasing and then increasing trend after surgery. The corneal-compensated intraocular pressure, Goldmann-correlated intraocular pressure, corneal resistance factor, and corneal hysteresis in the SMILE group at 1, 7 d and 1 mo after surgery were higher than those in the TransPRK group(all P0.05). There were no significant changes of corneal endothelial cell count and corneal posterior surface height in the two groups after surgery(all P>0.05). Furthermore, corneal surface regularity index of the two groups showed a first increasing and then decreasing trend after surgery, with no statistically significant difference between the groups(P>0.05), and there was no statistically significant difference in the incidence of postoperative complications between the groups(P>0.05).CONCLUSION:Compared with TransPRK, SMILE has less influence on corneal biomechanics, and better visual recovery in the early stage. There is no difference in long-term visual acuity between the two surgeries, and both have good safety and effectiveness.

This study investigated the effect of Sm additions on the microstructure, thermal conductivity, and mechanical properties of Mg-Zn-Zr alloy. The results indicate that the addition of Sm led to the formation of a rare-earth phase at the grain boundaries, and the grain size was significantly refined in the extruded state. The thermal conductivity of Mg alloy increased with the increase in Sm content because of the formation of a rare-earth phase that helps to dissolve the Zn atoms in the α-Mg matrix. Moreover, the as-extruded Mg alloy exhibited a higher thermal conductivity (up to124 W (m K)−1) than its as-cast counterparts. The Sm-containing as-extruded Mg alloy showed excellent yield strength of up to 254 MPa, and also a good plastic deformation ability. [ABSTRACT FROM AUTHOR]

Traces of non-magnetic atoms at the grain boundaries can effectively increase the coercivity of sintered Nd-Fe-B magnets. These atoms also have chance to occupy crystallographic Fe sites in Nd [ABSTRACT FROM AUTHOR]