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AIM: To compare the distribution characteristics of axial sagittal front power(ASF), true net power(TNP), total corneal refractive power(TCRP)and the difference in back-front corneal radius ratio(B/F ratio)after cataract surgery.METHODS: A prospective study. A total of 156 patients(156 eyes)with age-related cataract who attend Weifang Eye Hospital for cataract surgery from December 2020 to May 2021 were collected. Pentacam was performed before operation and 3mo after operation to collect ASF, TNP and TCRP on 2, 4 and 6mm diameters rings and areas on the corneal apex and pupil-centered, as well as B/F ratio.RESULTS: 3mo after operation, there was no statistical difference in ASF on the 2mm diameters ring and area centered on the corneal apex compared with preoperative values(all P>0.05), however, the ASF values on the 4 and 6mm diameters rings and areas were significantly different from those before surgery(all P0.05). The postoperative values of TNP and TCRP on the 2, 4 and 6mm diameters rings and areas centered on the corneal apex and centered on the pupil were statistically different before surgery(all P

AIM:To compare the difference, correlation and consistency of corneal biological parameters measured by IOL Master 700 and Pentacam before cataract extraction and intraocular lens implantation in different age groups.METHODS: Cross-sectional study. A total of 87 cataract patients(162 eyes)in Weifang Eye Hospital from February to September 2020 were collected, including 44 males(80 eyes)and 43 females(82 eyes)(age 61.2±9.87 years). The patients were divided into four groups: group A [17 cases(32 eyes), 40-50 years old], group B [25 cases(47 eyes), 51-60 years old], group C [28 cases(53 eyes), 61-70 years old], and group D [17 cases(30 eyes), 71-80 years old]. The preoperative corneal biological parameters of cataract patients were measured by IOL Master 700 and Pentacam, and the flat axis corneal curvature(K1), steep axis corneal curvature(K2), mean corneal curvature(Km), corneal astigmatism, anterior chamber depth(ACD)and central corneal thickness(CCT)were recorded. The difference and correlation of measurement results between two kinds of biometric instruments in different age groups were analyzed. RESULTS: Except for the corneal astigmatism in group C and K1 and corneal astigmatism in group D, there were significant differences between the two instruments(t=2.746, -2.582, 2.637, all P

AIM: To compare the visual quality of cataract patients with high myopia after regional refraction or diffraction refraction multi-focal intraocular lens(MIOL)implantation by using objective optical quality analysis system(OQASⅡ).METHODS: Retrospective study. From January 2019 to January 2020, 38 patients with 44 eyes diagnosed as cataract with high myopia that had underwent femtosecond laser-assisted phacoemulsification combined with intraocular lens implantation in our hospital were selected. Regional refraction MIOL group includes 19 cases 22 eyes, and diffraction refraction MIOL group includes 19 cases 22 eyes. After 3mo follow up, OQASⅡ measured objective visual quality and questionnaire surveys were conducted on the subjective visual quality of the patients. Record the patient's subjective near spectacle independence, visual disturbance symptoms, and satisfaction.RESULTS: After 3mo follow-up, the uncorrected distance visual acuity(UCDVA), uncorrected intermediate visual acuity(UCIVA)and uncorrected near visual acuity(UCNVA)had no difference(P>0.05), and the best corrected distance visual acuity(BCDVA), best corrected intermediate visual acuity(BCIVA)and best corrected near visual acuity(BCNVA)had no difference(P>0.05). The objective scattering index(OSI)values of regional refraction MIOL group and diffraction refraction MIOL group were 1.97±1.10 and 2.07±1.02(P=0.755). The MTF cut off of regional refraction MIOL group and diffraction refraction MIOL group were 31.89±14.61 and 33.17±9.83c/deg, respectively(P=0.734). There was no statistically significant difference in OV100%, OV20%, OV9% between the two groups(all P>0.05).CONCLUSION: Cataract patients with high myopia can obtain better distance, middle and diffraction refraction MIOL implantation, and OQASⅡ can objectively reflect the visual quality after cataract surgery.

AIM:To research the visual function of femtosecond laser assisted phacoemulsification in patients with cataract with high myopia. METHODS:Ninety seven patients(97 eyes)of cataract with high myopia underwent standard femtosecond laser assisted phacoemulsification and intraocular lens implantation. The best correct visual acuity(BCVA), accommodative function(negative/positive accommodation, accommodative acuity), convergence function(near point of convergence, convergence scope), accommodative convergence/accommodation(AC/A), visual stereoacuity, were observed preoperatively and postoperatively. RESULTS: BCVA: Compared with preoperative date, the postoperative BCVA were improved significantly(P<0.05). There were no significant difference between the 1d, 1wk, 1mo, 3mo, 6mo, 12mo postoperative CVA(P>0.05). Accommodative function: There were no significant difference between preoperative and postoperative negative accommodation(P>0.05). Positive accommodation: Compared with preoperative date, the 1d, 1wk, 1mo postoperative positive accommodation were no significantly different(P>0.05), but the 3mo, 6mo, 12mo postoperative positive accommodation were significantly different(P<0.05). Convergence function: Near point of convergence: Compared with preoperative date, the 1d,1wk postoperative near point of convergence were significantly different(P<0.05), the 6mo, 12mo were no significantly different(P>0.05). Significant difference was observed among other near point of convergence(P<0.05). Convergence scope: Compared with preoperative date, the 1d, 1wk, 1mo postoperative convergence scope were no significantly different(P>0.05), the 3mo, 6mo, 12mo were significantly different(P<0.05). AC/A: Compared with preoperative date, the 1d, 1wk postoperative date decreased significantly(P<0.05). There was no significantly difference between the 6mo and 1a postoperative date(P>0.05). Significant difference was observed among other AC/A(P<0.05). Visual stereoacuity: Compared with preoperative date, the 1d, 1wk, 1mo postoperative visual steroacuity were no significantly different(P>0.05), the 3mo, 6mo, 1a were significantly different(P<0.05). CONCLUSION: The BCVA of patients of cataract with high myopia which underwent standard femtosecond laser assisted phacoemulsification and intraocular lens implantation improved obviously and early, but the visual function improved slowly.

AIM: To Evaluate the effects of different capsulotomy diameters during phacoemulsification on corneal and blood aqueous barrier. METHODS: Totally 78 cases(100 eyes)with cataract were treated by femtosecond laser assisted phacoemulsification. The patients were randomly divided into two groups. There were 36 cases(50 eyes)in experimental group, in which the capsulotomy diameter was 4.7mm, and 42 cases(50 eyes)in the control group, in which the capsulotomy diameter was 6.0mm. Phacoemulsification power and time were recorded for each procedure. Follow-up exams were performed on 1d, 1wk and 2mo after surgery. Preoperative and postoperative best corrected visual acuity, central corneal thickness, aqueous flare, corneal endothelial cell count were assessed for the two groups. RESULTS: No significant difference was found on preoperative best corrected visual acuity(BCVA), hardness of the lens nucleus, centrel corneal thickness(CCT)and the effective phaco time and the average phaco power of the two groups(P>0.05). There was also no statistically significant difference on BCVA between the two groups after surgery(P>0.05). The change of central corneal thickness and the aqueous flare cells in the experimental group were less than those in the control group at 1d and 1wk postoperatively(PP>0.05). The rate of lost corneal endothelial cell was significantly lower in the experimental group than the control group at 2mo postoperatively(P>0.05). CONCLUSION: The phacoemulsification with small capsulotomy diameters decreases the injury to the corneal and blood aqueous barrier. The patients recovered more quickly.

Cataract with high myopia is research priority associated with the large amount of high myopia patients. The unaided visual acuity and the best-corrected visual acuity are partial for the visual acuity of the patients with cataract. The mechanism and clinical significance of modern visual function measurements associated with cataract and high myopia, including accommodation and convergence, stereoscopic vision, contrast sensitivity, have been introduced. These measurements could be of great value in early diagnosis of cataract, assessment of surgical indication, customized intraocular lens(IOL)selection and evaluation of visual performance after IOL implantation. They could also be helpful to the analysis of postoperative impaired visual function and its management. Having an adequate understanding of the contents and significance of visual function was helpful to the improvement of cataract surgery techniques and postoperative visual acuity.

Cycle impact experiments of limestone rock specimens are carried out with a large-sized (ϕ75 mm) split Hopkinson pressure bar (SHPB) experiment system, the dynamic stress-strain relationships of limestone rock in the impact process are plotted. The energy distribution during the impact process is quantitatively studied, with energy dissipation revealed. At the same time, with the ultrasonic measuring technology, the damage values of limestone rock during the impact are presented. Finally, the relationgship between damage and the stress wave, damage and the energy loss were revealed: the former couple is exponentially related, which can be self-consistent in cyclic impact experiments; the later couple shows a simple linear relationship. [ABSTRACT FROM AUTHOR]