Application of total keratometry in ten intraocular lens power calculation formulas in highly myopic eyes

Background:The accuracy of using total keratometry(TK)value in recent IOL power calculation formulas in highly myopic eyes remained unknown.Methods:Highly myopic patients who underwent uneventful cataract surgery were prospectively enrolled in this prospective comparative study.At one month postoperatively,standard deviation(SD)of the prediction errors(PEs),mean and median absolute error(MedAE)of 103 highly myopic eyes were back-calculated and compared among ten formulas,including XGboost,RBF 3.0,Kane,Barrett Universal II,Emmetropia Verifying Optical 2.0,Cooke K6,Haigis,SRK/T,and Wang-Koch modifications of Haigis and SRK/T formulas,using either TK or standard keratometry(K)value.Results:In highly myopic eyes,despite good agreement between TK and K(P>0.05),larger differences between the two were associated with smaller central corneal thickness(P<0.05).As to the refractive errors,TK method showed no differences compared to K method.The XGBoost,RBF 3.0 and Kane ranked top three when considering SDs of PEs.Using TK value,the XGboost calculator was comparable with the RBF 3.0 formula(P>0.05),which both presented smaller MedAEs than others(all P<0.05).As for the percentage of eyes within±0.50 D or±0.75 D of PE,the XGBoost TK showed comparable percentages with the RBF 3.0 TK formula(74.76%vs.66.99%,or 90.29%vs.87.38%,P>0.05),and statistically larger percentages than the other eight formulas(P<0.05).Conclusions:Highly myopic eyes with thinner corneas tend to have larger differences between TK and K.The XGboost enhancement calculator and RBF 3.0 formula using TK showed the most promising outcomes in highly myopic eyes.

A Genome‑Wide Association Study for Susceptibility to Axial Length in Highly Myopic Eyes

High myopia has long been highly prevalent worldwide with a largely yet unexplained genetic contribution.To identify novel susceptibility genes for axial length(AL)in highly myopic eyes,a genome-wide association study(GWAS)was performed using the genomic dataset of 350 deep whole-genome sequencing data from highly myopic patients.Top single nucleotide polymorphisms(SNPs)were functionally annotated.Immunofluorescence staining,quantitative polymerase chain reaction,and western blot were performed using neural retina of form-deprived myopic mice.Enrichment analyses were further performed.We identified the four top SNPs and found that ADAM Metallopeptidase With Thrombospondin Type 1 Motif 16(ADAMTS16)and Phosphatidylinositol Glycan Anchor Biosynthesis Class Z(PIGZ)had the potential of clinical signifi-cance.Animal experiments confirmed that PIGZ expression could be observed and showed higher expression level in form-deprived mice,especially in the ganglion cell layer.The messenger RNA(mRNA)levels of both ADAMTS16 and PIGZ were significantly higher in the neural retina of form-deprived eyes(p=0.005 and 0.007 respectively),and both proteins showed significantly upregulated expression in the neural retina of deprived eyes(p=0.004 and 0.042,respectively).Enrichment analysis revealed a significant role of cellular adhesion and signal transduction in AL,and also several AL-related pathways including circadian entrainment and inflammatory mediator regulation of transient receptor potential channels were proposed.In conclusion,the current study identified four novel SNPs associated with AL in highly myopic eyes and confirmed that the expression of ADAMTS16 and PIGZ was significantly upregulated in neural retina of deprived eyes.Enrichment analyses provided novel insight into the etiology of high myopia and opened avenues for future research interest.

Morphological features of anterior segment:factors influencing intraocular pressure after cataract surgery in nanophthalmos

Purpose:To investigate the anterior segment in nanophthalmic eyes and their association with intraocular pressure after cataract surgery.Methods:Thirty-two nanophthalmic eyes(axial length[AL]<18.5 mm)in 18 patients and 35 normal eyes(21.0≤AL≤24.5 mm)in 35 controls who had undergone uneventful cataract surgery were included.Swept-source optical coherence tomography was used to compare the anterior segment structures between the two groups.The associations between the anterior segment characteristics of nanophthalmic eyes and postoperative intraocular pressure(IOP)were also investigated.Results:The IOP-lowering effect of cataract surgery was remarkably insufficient in nanophthalmic eyes.Peripheral anterior synechiae(PAS)were observed in 56%(18/32)of nanophthalmic eyes,and a characteristic boomerangshaped iris was observed in 28%(9/32).The anterior surface of the iris seemed"smoother"in nanophthalmic eyes than in normal eyes.Schlemm's canal(SC)diameter,SC area,trabecular meshwork(TM)thickness,TM width,and TM area were generally smaller in the nanophthalmic eyes.Younger age,higher preoperative IOP,broader PAS,and smaller SC area were main contributors to higher postoperative IOP.AL and SC diameter may also be of great importance in IOP prediction in patients without glaucoma surgery and PAS.Conclusions:The morphological features of the anterior segment in nanophthalmic eyes are significantly different from those of normal eyes.Influencing factors such as age,AL,preoperative IOP,extent of PAS,SC and TM size could all be prognostic for IOP after cataract surgery in nanophthalmic eyes.Trial registration:ClinicalTrails.gov,Trial registration number:NCT02182921,Registered 8 July 2014.

Decentration and tilt of plate-haptic multifocal intraocular lenses in myopic eyes

Background:To investigate the decentration and tilt of plate-haptic multifocal intraocular lenses(MfIOLs)in myopic eyes.Methods:Myopic(axial length[AXL]>24.5 mm)and non-myopic(21.0 mm<AXL≤24.5 mm)cataract eyes were enrolled in this prospective study and randomly assigned to receive implantation of Zeiss AT LISA tri 839MP lenses(Group A)or Tecnis ZMB00 lenses(Group B).In total,122 eyes of 122 patients were available for analysis.Decentration and tilt of MfIOLs,high-order aberrations(HOAs),and modulation transfer functions(MTFs)were evaluated using the OPD-Scan III aberrometer 3 months postoperatively.Subjective symptoms were assessed with a Quality of Vision questionnaire.Results:Near and distance visual acuities,tilt and horizontal decentration did not differ between the two groups,postoperatively.However,myopic eyes of Group B showed greater vertical decentration than those of Group A(−0.17±0.14 mm vs.-0.03±0.09 mm,respectively),particularly when the MfIOLs were placed horizontally or obliquely.Overall decentration of myopic eyes was greater in Group B than in Group A(0.41±0.15 mm vs.0.16±0.10 mm,respectively).In Group B,AXL was negatively correlated with vertical decentration and positively correlated with overall decentration.No such correlations were found in Group A.Intraocular total HOAs,coma,trefoil and spherical aberrations were lower in Group A than in Group B for a 6.0 mm pupil among myopic eyes.Generally,Group A had better MTFs and fewer subjective symptoms than Group B among myopic eyes.Conclusions:Plate-haptic design of MfIOLs may be a suggested option for myopic cataract eyes due to the less inferior decentration and better visual quality postoperatively.

重视悄然来临的“屈光手术后时代”

中国作为近视大国,其屈光手术从最早的放射状角膜切开手术到今天的全飞秒激光小切口角膜基质透镜取出术和有晶状体眼后房型人工晶状体植入术,已经历了20~30年的高速发展时期,这在很大程度上解决了许多近视患者的脱镜问题。然而,随着时间的流逝,早期接受屈光手术的患者们逐渐开始出现白内障,这也意味着“屈光手术后时代”的悄然来临。在该时代背景下,中国的白内障手术医师需要做充分准备以应对:角膜屈光手术后人工晶状体度数计算准确性有待提高,有晶状体眼后房型人工晶状体的取出,及最大程度满足这些患者的脱镜意愿等方面的挑战。

Lens thickness and associated ocular biometric factors among cataract patients in Shanghai

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 20.01-22mm 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 20-22mm AL group.

Measurement of crystalline lens tilt in high myopic eyes before cataract surgery using swept-source optical coherence tomography

Background:To measure the crystalline lens tilt in eyes with various degrees of myopia before cataract surgery using swept-source optical coherence tomography(SS-OCT).Methods:We used SS-OCT(IOLMaster 700)to scan 131 emmetropic eyes(axial length<24.5 mm),25 mild/moderate myopic eyes(axial length 24.5–26 mm),and 123 high myopic eyes(52,29,and 42 eyes with axial lengths of 26–28,28–30,and>30 mm,respectively)as part of the routine preoperative examination before cataract surgery.SS-OCT involved B-scans along six meridians.The data were analyzed to assess the magnitude and orientation of the lens tilt and their correlation with other optical biometric parameters.Result:The mean tilt was 3.36±0.98°in emmetropic eyes,3.07±1.04°in mild/medium myopic eyes,and 2.35±1.01°in high myopic eyes.Tilt correlated significantly and inversely with axial length(Pearson’s r=−0.427,P<0.001).The crystalline lens tilt predominantly faced the upper outer quadrant relative to the visual axis,symmetrically in both eyes,with mean angles of 24.32°and 147.36°in the right and left eyes,respectively.The variability in the lens tilt direction increased with increasing axial length(χ^(2) test,P<0.001).Conclusion:The magnitude of crystalline lens tilt decreased with increasing axial length.The direction of tilt was predominantly towards the upper outer quadrant in both eyes.The variability in the tilt orientation increased with increasing axial length.Trial registration:NIH(clinicaltrial.gov),NCT03062085.Registered 23 February 2017.

Morphological features of anterior segment:factors influencing intraocular pressure after cataract surgery in nanophthalmos

Purpose:To investigate the anterior segment in nanophthalmic eyes and their association with intraocular pressure after cataract surgery.Methods:Thirty-two nanophthalmic eyes(axial length[AL]<18.5 mm)in 18 patients and 35 normal eyes(21≤AL≤24.5 mm)in 35 controls who had undergone uneventful cataract surgery were included.Swept-source optical coherence tomography was used to compare the anterior segment structures between the two groups.The associations between the anterior segment characteristics of nanophthalmic eyes and postoperative intraocular pressure(IOP)were also investigated.Results:The IOP-lowering effect of cataract surgery was remarkably insufficient in nanophthalmic eyes.Peripheral anterior synechiae(PAS)were observed in 56%(18/32)of nanophthalmic eyes,and a characteristic boomerangshaped iris was observed in 28%(9/32).The anterior surface of the iris seemed“smoother”in nanophthalmic eyes than in normal eyes.Schlemm’s canal(SC)diameter,SC area,trabecular meshwork(TM)thickness,TM width,and TM area were generally smaller in the nanophthalmic eyes.Younger age,higher preoperative IOP,broader PAS,and smaller SC area were main contributors to higher postoperative IOP.AL and SC diameter may also be of great importance in IOP prediction in patients without glaucoma surgery and PAS.Conclusions:The morphological features of the anterior segment in nanophthalmic eyes are significantly different from those of normal eyes.Influencing factors such as age,AL,preoperative IOP,extent of PAS,SC and TM size could all be prognostic for IOP after cataract surgery in nanophthalmic eyes.

Measurement of crystalline lens tilt in high myopic eyes before cataract surgery using swept-source optical coherence tomography

Background:To measure the crystalline lens tilt in eyes with various degrees of myopia before cataract surgery using swept-source optical coherence tomography(SS-OCT).Methods:We used SS-OCT(lOLMaster 700)to scan 131 emmetropic eyes(axial length<24.5 mm);25 mild/moderate myopic eyes(axial length 24.5-26 mm),and 123 high myopic eyes(52,29,and 42 eyes with axial lengths of 26-28,28-BO,and>30 mm,respectively)as part of the routine preoperative examination before cataract surgery.SS-OCT involved B-scans along six meridians.The data were analyzed to assess the magnitude and orientation of the lens tilt and their correlation with other optical biometric parameters.Result:The mean tilt was 3.36±0.98。in emmetropic eyes,3.07±1.04° in mild/medium myopic eyes,and 2.35±1.01° in high myopic eyes.Tilt correlated significantly and inversely with axial length(Pearson,sr=-0.427,P<0.001).The crystalline lens tilt predominantly faced the upper outer quadrant relative to the visual axis,symmetrically in both eyes,with mean angles of 24.32°and 147.36°in the right and left eyes,respectively.The variability in the lens tilt direction increased with increasing axial length(x2 test,P<0.001).Conclusion:The magnitude of crystalline lens tilt decreased with increasing axial length.The direction of tilt was predominantly towards the upper outer quadrant in both eyes.The variability in the tilt orientation increased with increasing axial length.Trial registration:NIH(clinicaltrial.gov),NCT03062085.Registered 23 February 2017.

Inhibitory effect of lanosterol on cataractous lens of cynomolgus monkeys using a subconjunctival drug release system Keke

Background:To evaluate the effect of lanosterol on cataractous lens of cynomolgus monkeys using a subconjunctival drug release system.Methods:Nine elder cynomolgus monkeys were used,consisting of three monkeys without cataract as controls,three monkeys with naturally occurring cortical cataract,and three monkeys with nuclear cataract as intervention groups.Nanoparticulated thermogel with lanosterol and fluorescein was administered by subconjunctival injection in the monkeys with cataract.Fluorescence changes of injected thermogel and cataract progression were observed.Lanosterol concentration in aqueous humor,solubility changes in lens proteins,and oxidative stress levels were analyzed in the lenses of the control and intervention groups.Results:Injected thermogel showed decreased fluorescence during follow up.Lanosterol concentration in aqueous humor increased in the first 2 weeks and then gradually decreased,which was in accordance with the changes in cortical lens clarity.However,lenses with nuclear opacification showed little change.In the cortical region of lenses with cortical cataract,solubility ofα-crystallin was significantly increased after administration of lanosterol,as well as the reduction of oxidative stress.Conclusions:We demonstrated the effect of lanosterol on cataract progression based on in vivo models of primates.Lanosterol showed a short-term and reliable reversal effect on reducing cataract severity in cortical cataract in the early stages,possibly due to the increase in the solubility of lens proteins and changes in the oxidative stress status.Lanosterol administration using subconjunctival drug release system could be a promising nonsurgical approach for future clinical studies of cataract prevention and treatment.