自然光暴露对PRK法单眼远视离焦幼年恒河猴角膜组织的影响

目的:探讨自然光暴露对单眼远视离焦幼年恒河猴正常和准分子激光角膜切削术(PRK)损伤后角膜组织潜在的光损伤作用。方法:选取12只2月龄恒河猴,行右眼PRK,矫正度数为-4.0D,制作单眼远视离焦近视动物模型。幼猴体质量和性别均衡配对后分为两组:人工照明组(AL组,n=6)和自然光组(NL组,n=6)。两组幼猴饲养于同一人工照明条件室内饲养环境,NL组幼猴每天9∶00~11∶00和15∶00~17∶00于室外随单笼接受自然光照射。PRK术后裂隙灯检查比较两组PRK眼角膜愈合及haze形成情况;PRK术后50d,每组各取4只幼猴双眼泪液,采用蛋白质芯片法检测泪液11种细胞因子含量。PRK术后180d取角膜组织,分别行病理组织学检查组织结构变化;免疫组织化学法检测TGF-β1和α-SMA表达;TUNEL法检测细胞凋亡以及采用羟胺法和硫代巴比妥酸法分别测定角膜上皮细胞SOD和MDA含量。结果:PRK术后NL组PRK眼出现一过性haze,术后40d两组haze分级评估有差异(P=0.015)。PRK术后50d,两组PRK眼泪液EGF和TGF-β1含量均有差异(P=0.045、0.038),两组间对侧眼均无差异(P>0.05);且AL组、NL组组内泪液TGF-β1水平有差异(P=0.003、0.036)。术后180d,两组双眼角膜组织形态学一致;角膜组织内各层偶见细胞凋亡染色,且无明显TGF-β1和α-SMA表达;两组PRK眼和对侧眼角膜上皮细胞SOD活力和MDA含量均无差异(P>0.05)。结论:自然光照射量可加剧幼猴PRK术后角膜组织修复反应,但远期未对角膜组织造成不可逆病理组织学改变,对正常的幼猴角膜组织无明显光损伤作用。

Accuracy of eight intraocular lens power calculation formulas for segmented multifocal intraocular lens

AIM:To evaluate the accuracy of eight different intraocular lens(IOL)power calculation formulas for a segmented multifocal IOL.METHODS:A total of 53 eyes of 41 adult cataract patients who underwent phacoemulsification and implantation with the SBL-3 segmented multifocal IOL between January 1,2017 and January 31,2019 were included in this retrospective study.Preoperative biometry measurements were obtained using an IOL Master.Manifest refraction was performed at least 4 wk postoperatively.Accuracy of the eight formulas[Barrett Universal II,Emmetropia Verifying Optical(EVO),Haigis,Hill-RBF 2.0,Hoffer Q,Holladay 1,Kane,and SRK/T]was analyzed.RESULTS:Using current lens constants,all formulas exhibited errors of slight myopic shift in refractive prediction.The Barrett Universal II formula had a significantly lower median absolute error(MedAE)than did Holladay 1(P=0.02),Kane(P=0.001)and Hill-RBF 2.0(P<0.001)formulas.The Haigis formula had a lower MedAE value than did the Hill-RBF 2.0 formula(P=0.005).Differences in MedAE values among SRK/T,EVO and Hoffer Q formulas were not significant.After optimizing lens constants,the MedAE values of all formulas were reduced;significant changes were noted for EVO(P=0.022),Haigis(P=0.048);Hill-RBF 2.0(P=0.014),Holladay 1(P=0.045)and Kane(P=0.022)formulas.All formulas performed equally well after optimization of lens constants(P=0.203).CONCLUSION:All eight formulas tend to result in a myopic shift when using current lens constants.Optimized lens constants improve the accuracy of these formulas among adult Chinese patients.

Vitreoretinal surgeons'experience and time interval from pars-plana vitrectomy to cataract extraction

AIM:To identify the association of the vitreoretinal surgeons'experience with the time interval between parsplana vitrectomy(PPV)and cataract extraction(CE).METHODS:Eyes with prior PPV and following CE were included in this retrospective cohort study.The years of practice and the annual case volume were used to describe the surgeons'experience.Multivariable linear regression analysis was used to investigate the relationship between surgeons'experience and the time interval adjusted for the patients age,gender,intraocular tamponade,and case complexity.RESULTS:Of 132430 eyes,1445 eyes were included in this study.In multivariable linear regression analysis,cases performed by surgeons with>20 practice years had longer time intervals compared with surgeons with<10 practice years after adjusted for other variables(β=0.329,95%CI:0.113 to 0.549,P=0.003).No difference in time interval was detected for comparing the lowest with the highest volume groups(β=0.089,95%CI:-0.164 to 0.343,P=0.343).The surgeons'practice years were not directly with the volume.For complicated surgery,the higherpractice-year surgeons had longer time interval than lowerpractice-year surgeons.CONCLUSION:The time intervals from PPV to CE is longer in higher-practice-year surgeons.The surgeons'practice years may have a greater effect on the time interval than annual case volume in high-complexity cases.Matching the complexity of vitreoretinal diseases with the surgeons'practice year should be considered.

Comparison of early changes in ocular surface markers and tear inflammatory mediators after femtosecond lenticule extraction and FS-LASIK

AIM:To compare the short-term impacts of femtosecond lenticule extraction(FLEx)and femtosecond laser-assisted laser in situ keratomileusis(FS-LASIK)on ocular surface measures and tear inflammatory mediators.METHODS:This prospective comparative nonrandomized clinical study comprised 75 eyes(75 patients).Totally 20 male and 15 female patients(age 21.62±3.25 y)with 35 eyes underwent FLEx,and 26 male and 14 female patients(age 20.18±3.59 y)with 40 eyes underwent FS-LASIK.Central corneal sensitivity,noninvasive tear breakup time,corneal fluorescein staining,Schirmer I test,tear meniscus height,and ocular surface disease index were evaluated in all patients.Tear concentrations of nerve growth factor(NGF),interleukin-1α(IL-1α),transforming growth factor-β1(TGF-β1),tumor necrosis factor-α(TNF-α),interferon-γ(IFN-γ),and matrix metalloproteinase-9(MMP-9)were assessed by multiplex antibody microarray.All measurements were performed preoperatively,and 1 d,1 wk,and 1 mo postoperatively.RESULTS:Patients who underwent FLEx exhibited a more moderate reduction in central corneal sensation and less corneal fluorescein staining than those in the FS-LASIK group 1 wk after the procedure(P<0.01).NGF was significantly higher 1 d and 1 wk after surgery in the FS-LASIK group than in the FLEx group(P<0.01).By contrast,compared to those in the FLEx group,higher postoperative values and slower recovery of tear TGF-β1,IL-1α,and TNF-αconcentrations were observed in the FS-LASIK group(P<0.01).Tear concentrations of NGF,TGF-β1,TNF-α,and IL-1αwere correlated with ocular surface changes after FLEx or FS-LASIK surgery.CONCLUSION:There is less early ocular surface disruption and a reduced inflammatory response after FLEx than after FS-LASIK.NGF,TGF-β1,TNF-α,and IL-1αmay contribute to the process of ocular surface recovery.