Relative peripheral refraction and its role in myopia onset in teenage students

AIM:To characterize peripheral refraction and its relationship with myopia development in a selected group of male teenage Chinese students.METHODS:This 2-year prospective cohort study randomly enrolled 85 non-myopic boys(age,14-16 y)from the Experimental Class of Air Force in China.Cycloplegic peripheral refraction was examined at 0°,±10°,and±20°along the horizontal visual field in the right eye at the baseline and 2-year follow-up.RESULTS:The incidence of myopia at the 2-year followup was 15.29%(13/85).The baseline central refraction(CR)and peripheral refraction at±10°were significantly lower in students who developed myopia than in those who did not(P<0.05).Relative peripheral refraction(RPR)did not differ between students with and without myopia(P>0.05).At the 2-year follow-up,the RPR at±10°and 20°nasal was significantly more hyperopic in the myopic group than in the non-myopic group.Multiple linear regression analysis indicated that the change in CR was significantly correlated with the changes in RPR at 20°nasal,10°nasal,and 20°temporal.Multivariate Logistic regression analysis indicated that the baseline CR[odds ratio(OR):0.092,95%confidence interval(CI):0.012-0.688,P=0.020]and the baseline RPR at 10°nasal(OR:0.182,95%CI:0.042-0.799,P=0.024)were significantly correlated with incident myopia(Omnibus test,χ=10.20,P=0.006).CONCLUSION:CR change is significantly correlated with changes in RPR,and students who develop myopia have more relative peripheral hyperopia.More baseline CR and relative peripheral hyperopia at 10°nasal are protective of myopia onset.

Clinical outcomes of transepithelial photorefractive keratectomy versus femtosecond laser assisted keratomileusis for correction of high myopia in South Egyptian population

AIM: To evaluate the safety and efficacy of transepithelial photorefractive keratectomy(t-PRK) with adjuvant mitomycin C(MMC) versus femtosecond laser assisted keratomileusis(Femto-LASIK) in correction of high myopia.METHODS: Prospective randomized comparative study including 156 eyes of 156 patients with high myopia and a spherical equivalent refraction(SER) <-6.00 D. They were divided randomly into two groups: Group A included 72 eyes treated with t-PRK with adjuvant MMC and Group B included 84 eyes treated with Femto-LASIK. Visual acuity, SER, corneal topography, pachymetry and keratometry were assessed for 12 mo postoperatively.RESULTS: The preoperative mean SER was-8.86±1.81 and-9.25±1.70 D in t-PRK MMC group and Femto-LASIK respectively(P=0.99) which improved to-0.65±0.43 D and-0.69±0.50 D at 12 mo follow up. Mean SER remained stable during the 12 mo of follow-up, with no statistically significant difference between the two groups(P=0.64). In t-PRK MMC group, only six eyes needed retreatment after six months of follow up. And two eyes showed haze(one reversible haze grade 2, while the other had dense irreversible haze grade 4).CONCLUSION: t-PRK MMC provides safe and satisfactory visual outcomes and acceptable risk as Femto-LASIK in patients with high myopia.

Relative peripheral refraction in school children with different refractive errors using a novel multispectral refraction topographer

AIM:To compare relative peripheral refraction(RPR)in Chinese school children with different refractive errors using multispectral refraction topography(MRT).METHODS:A total of 713 eyes of primary school children[172 emmetropia(E),429 low myopia(LM),80 moderate myopia(MM),and 32 low hypermetropia(LH)]aged 10 to 13y were analyzed.RPRs were measured using MRT without mydriasis.MRT results showed RPR at 0-15°(RPR 0-15),15°-30°(RPR 15-30),and 30°-45°(RPR 30-45)annular in the inferior(RPR-I),superior(RPR-S),nasal(RPR-N),and temporal(RPR-T)quadrants.Spherical equivalent(SE)was detected and calculated using an autorefractor.RESULTS:There were significant differences of RPR 15-30 between groups MM[0.02(-0.12;0.18)]and LH[-0.13(-0.36;0.12)](P<0.05),MM and E[-0.06(-0.20;0.10)](P<0.05),and LM[-0.02(-0.15;0.15)]and E(P<0.05).There were also significant differences of RPR 30-45 between groups MM[0.45(0.18;0.74)]and E[0.29(-0.09;0.67)](P<0.05),and LM[0.44(0.14;0.76)]and E(P<0.001).RPR values increased from the hyperopic to medium myopic group in each annular.There were significant differences of RPR-S between groups MM[-0.02(-0.60;0.30)]and E[-0.44(-0.89;-0.04)](P<0.001),and LM[-0.28(-0.71;0.12)]and E(P<0.05).There were also significant differences of RPR-T between groups MM[0.37(0.21;0.78)]and LH[0.14(-0.52;0.50)](P<0.05),LM[0.41(0.06;0.84)]and LH(P<0.05),and LM and E[0.29(-0.10;0.68),P<0.05].A Spearman’s correlation analysis showed a negative correlation between RPR and SE in the 15°-30°(P=0.005),30°-45°(P<0.05)annular(P=0.002),superior(P<0.001),and temporal(P=0.001)quadrants.CONCLUSION:Without pupil dilation,values for RPR 15-30,30-45,RPR-S,and T shows significant differences between myopic eyes and emmetropia,and the differences are negatively correlated with SE.

Five-year results of refractive outcomes and visionrelated quality of life after SMILE for the correction of high myopia

AIM:To evaluate the long-term visual,refractive outcomes and vision-related quality of life after small incision lenticule extraction(SMILE)for the correction of high myopia.METHODS:Thirty patients(60 eyes)with high myopia who underwent SMILE more than 5y were selected as the SMILE group.Another 30 high myopia patients(60 eyes)who had worn corrective spectacles for more than 5y were selected as the control group.In SMILE group,the postoperative follow-up time were 3,6 mo,1 and 5y.Uncorrected distance visual acuity(UDVA),corrected distance visual acuity(CDVA),spherical equivalent(SE),and ocular axial length(AL)were analyzed.The Chinese version of the National Eye Institute Visual Function Questionnaire-25(CHI-NEI-VFQ-25)was used to evaluate the vision-related quality of life in the SMILE group and the control group.RESULTS:In SMILE group,the mean preoperative SE was-7.29±0.87 D(range-6.00 to-9.125 D).At 5-year follow up,the efficacy index and safety index of SMILE were 1.09±0.18 and 1.19±0.12,respectively.Five years postoperatively,44 eyes(73%)obtained a visual acuity of 20/20 or better.There were no eyes with CDVA loss of one or more Snellen lines.Forty-nine eyes(82%)and 57 eyes(95%)were within±0.50 and±1.00 D of attempted correction at 5-year follow-up,respectively.Forty-eight eyes(80%)had astigmatism<0.50 D at 5-year followup.The postoperative mean SE values at 3,6 mo,1,and 5y were 0.11±0.44,0.07±0.45,-0.02±0.41,and-0.15±0.46 D,respectively.No significant change was observed in the ocular AL from before operation to 5y postoperatively(26.08±0.96 mm vs 26.01±0.94 mm,P=0.068).Compared to the control group,the SMILE group showed a significantly higher total score on the CHI-NEI-VFQ-25(90.14 vs 81.43,P<0.001).CONCLUSION:In the present study,in a long-term follow-up we demonstrate that correcting high myopia with SMILE is safe,effective,and predictable.Vision-related quality of life after SMILE is better in the SMILE group than in the control group who wore corrective spectacles.

Effectivity and safety of trifocal intraocular lenses and capsular tension rings implantation for cataract patients with axial high myopia

●AIM:To assess effectivity and safety of trifocal intraocular lenses(IOLs)and capsular tension rings in treating cataract patients with axial high myopia.●METHODS:A prospective nonrandomized controlled clinical trial was conducted.Totally 98 eyes(74 patients)who underwent femtosecond laser-assisted cataract surgery(FLACS)with trifocal IOLs were enrolled in the study and followed up for 2y after surgery:46 eyes(33 patients)with capsular tension ring implantation in the long axial lengths(AL)group(26<AL<29 mm)and 52 eyes(41 patients)in the normal AL group(22<AL<24.5 mm).Postoperative outcomes about effectivity and safety,including the subjective and objective visual quality,and postoperative complications were assessed.●RESULTS:Uncorrected distance visual acuity at 5 m and uncorrected intermediate visual acuity at 60 and 80 cm in the long AL group were significantly worse than those in the normal AL group at 3mo postoperatively(P<0.05).The differences in reading speed,spectacle independence and potential visual complaints between the two groups were not statistically significant(P>0.05).The dysfunctional lens index and total modulation transfer function(MTF)average height were similar between the two groups.The postoperative internal coma aberrations in the axial high myopia eyes were significantly higher than that in the normal AL group(P<0.05).The total satisfaction score in the long AL group(91.32±2.76)was slightly higher than that in the normal AL group(90.36±3.47),but there was no difference(P=0.136).A statistically negative correlation was found between corrected distance visual acuity(CDVA)and dysfunctional lens index(r=-0.382,P=0.009),and between CDVA and the total MTF average height(r=-0.374,P=0.01).But there was no significant correlation between CDVA and total satisfaction score(r=0.059,P=0.696).Postoperative complications mainly presented as posterior capsular opacity(PCO),retinal detachment and cystoid macular edema.There was no difference in the incidence of fundus disease(6.5%vs 3.8%,P=0.663)or PCO(17.4%vs 7.7%,P=0.217)between the two groups at two years.●CONCLUSION:The utilization of trifocal IOL and capsular tension ring implantation is beneficial for cataract patients with axial high myopia undergoing FLACS.This approach not only ensures excellent subjective feelings and objective visual quality,but also does not increase the incidence of postoperative complications.

Fabrication of UV-Curing Linalool-Polysiloxane Hybrid Films with High Refractive Index and Transparency

In this article,a series of high refractive indices(1.50-1.53)thiol phenyl polysiloxane(TPS)were synthesized via hydrolytic sol-gel reaction.The Fourier transform infrared spectra(FT-IR)and nuclear magnetic resonance spectra(NMR)results showed that TPS conformed to the predicted structures.Natural terpene linalool was exploited as photocrosslinker to fabricate UV-curing linalool-polysiloxane hybrid films(LPH)with TPS via photoinitiated thiol-ene reaction.LPH rapidly cured under UV irradiation at the intensity of 80 mW/cm^(2) in 30 s,exhibiting good UV-curing properties.The optical transmittance of LPH in the wavelength of 300-800 nm was over 90%,exhibiting good optical transparency.The water contact angle and water vapor permeability results showed that the introduction of phenyl groups enhance the hydrophobicity and water vapor barrier properties of LPH.The results indicated the potential of LPHs in the applications of optical functional coatings.

Early changes in corneal densitometry after FS-LASIK combined with accelerated corneal cross-linking for correction of high myopia

AIM:To observe the effects of femtosecond laserassisted excimer laser in situ keratomileusis combined with accelerated corneal cross-linking(FS-LASIK Xtra)on corneal densitometry after correcting for high myopia.METHODS:In this prospectively study,130 patients underwent FS-LASIK or FS-LASIK Xtra for high myopia.Their right eyes were selected for inclusion in the study,of which 65 cases of 65 eyes in the FS-LASIK group,65 patients with 65 eyes in the FS-LASIK Xtra group.Patients were evaluated for corneal densitometry at 1,3,and 6mo postoperatively using Pentacam Scheimpflug imaging.RESULTS:Preoperative differences in corneal densitometry between the FS-LASIK and FS-LASIK Xtra groups in different ranges were not statistically significant(P>0.05).Layer-by-layer analysis revealed statistically significant differences in the anterior(120μm),central,and total layer corneal densitometry between the FS-LASIK and FS-LASIK Xtra groups at 1 and 3mo postoperatively(all P<0.05),the FS-LASIK Xtra group is higher than that of the FS-LASIK group.Analysis of different diameter ranges showed statistically significant differences between the FS-LASIK group and the FS-LASIK Xtra group at 1mo postoperatively in the ranges of 0–2,2–6,and 6–10 mm(both P<0.05);At 3mo postoperatively,the FS-LASIK Xtra group is higher than that of the FS-LASIK group in the ranges of 0–2 and 2–6 mm(P<0.05).At 6mo postoperatively,there were no statistically significant differences in corneal densitometry between the FS-LASIK group and the FS-LASIK Xtra group in different diameter ranges(all P>0.05).CONCLUSION:There is an increase in internal corneal densitometry during the early postoperative period after FS-LASIK Xtra for correction of high myopia.However,the densitometry values decreased to the level of conventional FS-LASIK at 6mo after surgery,with the most significant changes observed in the superficial central zone.

Single-step transepithelial photorefractive keratectomy in high myopia：qualitative and quantitative visual functions

AIM：To investigate quantitative and qualitative optical outcomes of single-step transepithelial photorefractive keratectomy（Trans PRK）in high myopia.METHODS：In a prospective interventional case-series,30 eyes with high myopia（-6.00 to-8.75 D）with（up to-3.00 D）or without astigmatism were enrolled from Bina Eye Hospital,Tehran,Iran. One-step Trans PRK was performed with aberration-free aspherical optimized profile and SCHWIND AMARIS 500 laser. One-year follow-up results for refraction,visual acuities,vector analysis,ocular wavefront（OWF）and corneal wave-front（CWF）higher order aberrations（HOA）,contrast sensitivity（CS）,and postoperative haze were assessed.RESULTS：After the surgery,both photopic and mesopic CSs significantly improved（both P〈0.001）. We detected significant induction of OWF coma and trefoil（P〈0.001 for both）HOAs; CWF coma（P=0.002）,spherical（P〈0.001）,and tetrafoil（P=0.003）HOAs in 6 mm analysis diameter; and CWF trefoil（P=0.04）HOA in 4 mm analysis diameter. The range of mean induction observed for various HOAs was0.005-0.11 μm. The 86.7% of eyes reached an uncorrected distance visual acuity of 20/20 or better; 96.7% of eyes were within ±0.5 D of targeted spherical refraction. In vector analysis,mean correction index value was 1.03 and mean index of success was 0.22. By 12mo after the operation,no eye lost any number of corrected distancevisual acuity lines. We detected no corneal haze greater than 1~＋ throughout the follow-up.CONCLUSION：Our findings show promising effects of single-step Trans PRK on quality of vision in high myopic eyes. It also improves refraction and visual acuity.

Preliminary results of a new intrastromal corneal ring segment as a tissue saving procedure in photorefractive keratectomy to correct moderate to high myopia

AIM:To evaluate the clinical results after implantation of a new intrastromal corneal ring segment(ICRS)associated with photorefractive keratectomy(PRK)to correct high myopia(HM)patients with thin corneas.METHODS:We evaluated 42 eyes of 23 HM patients that had ICRS implantation followed by PRK.The mean age of patients was 29.1±7.12 y(range 18 to 40 years old).Uncorrected visual acuity(UCVA),best corrected visual acuity(BCVA),keratometry,spherical equivalent,pachymetry,and aberrometry were compared using ANOVA with repeated measurements evaluated preoperatively and at last follow-up visit after the procedures.The refractive predictability and simulated/real corneal ablation were also assessed.RESULTS:The mean follow-up time after PRK was 6.8±1.6 mo.The mean preoperative UCVA improved from 20/800 preoperative to 20/100 after ICRS and 20/35 after PRK.The mean preoperative BCVA was 20/25(range from 20/30 to 20/20)and remained unchanged after ICRS implantation.Following the PRK the mean BCVA was 20/25(range from 20/30 to 20/20).The mean spherical equivalent decreased from-7.25±1.12(range-5.00 to-9.00)preoperatively to-3.32±1.0(range-2.00 to-5.00)postoperatively(P<0.001)after ICRS implantation and decreased from-2.44±1.51 preoperatively to 0.32±0.45(range-0.625 to 0.875)postoperatively(P<0.001)after PRK.The change in BCVA and topographic astigmatism was statistically significant(P<0.0001).CONCLUSION:ICRS in HM associated with PRK can be a tissue saving procedure and an alternative surgical option for correction of moderate to high myopia.

Factors affecting single-step transepithelial photorefractive keratectomy outcome in the treatment of mild,moderate,and high myopia:a cohort study

AIM:To investigate the effect of preoperative factors on visual acuity,higher-order aberrations(HOAs),and index of success for spherical change(S.IOS)after transepithelial photorefractive keratectomy(t-PRK)for treating different grades of myopia.METHODS:This was a retrospective one-armed cohort study where patients with high,moderate,or mild myopia treated with single-step t-PRK using Amaris 500 Hz excimer laser were evaluated for visual acuity,refractive status,corneal topography,HOAs,S.IOS,and mean efficiency and safety index before and 6 mo after surgery.RESULTS:A total of 154 eyes of 77 patients with mild(n=59),moderate(n=83),and high(n=12)myopia were reviewed.The efficiency and safety indices for vision recovery by single-step t-PRK were 98%and 100%,respectively.The achieved spherical equivalent(SE)was within 1 diopter(D)in 151(98%)eyes.The median of the S.IOS was 1.18[interquartile range(IQR)1.0,1.4].The change in S.IOS was significantly correlated with age(P=0.007),6.5 mm ablation zone(Mann-Whitney U test,P<0.01),and mild and moderate grade of myopia(Kruskal–Wallis test,P<0.001).Trefoil aberration,spherical aberration,and aberration coefficient types of HOA increased significantly(Wilcoxon test,P<0.001)6 mo post-surgery.There was a significant correlation between spherical aberration and aberration coefficient HOAs by myopia grades(P<0.05).CONCLUSION:Single-step t-PRK has promising short-term outcomes for refractive corrections and vision improvement to treat all three grades of myopia.

Clinical Effect Analysis of Posterior Chamber Intraocular Lens Implantation for Correcting High Myopia and Astigmatism

Objective:To explore the corrective effect of posterior chamber intraocular lens implantation with phakic eyes in the treatment of high myopia and astigmatism.Methods:From May 2023,the hospital began to collect the case data of diagnosis and treatment of high myopia and astigmatism.By May 2024,310 cases were included,all of which were treated with posterior chamber intraocular lens implantation.The visual acuity,astigmatism and axial position of the intraocular lens were observed before and after treatment.Results:At different time points after the operation,the patient’s vision was significantly improved compared with that before the operation(P<0.05),and the vision level was equal to or greater than the best-corrected vision before the operation.At different time points after the operation,the average rotation of the intraocular lens was less than 5 degrees.Astigmatism was significantly lower than that before the operation(P<0.05).After the operation,the intraocular pressure increased in 11 cases,accounting for 3.55%,with no adverse complications such as lens turbidity,glare and obvious halo occurring.Conclusion:The posterior chamber intraocular lens implantation with phakic eyes has an ideal correction effect in the treatment of high myopia and astigmatism,which can effectively improve the vision level of patients and reduce the degree of astigmatism,and has high effectiveness and safety.

Fine upper crustal structure of Jiashi strong earthquake swarm region in Xinjiang in-ferred from high resolution seismic refraction profile data

The data obtained from a high resolution seismic refraction profile, which was carded out in Jiashi, Xinjiang, strong earthquake swarm area, were processed with both finite difference inversion and Hagedoorn refractor wavefront imaging technique and the fine upper crustal structure was determined. The results show that the upper crustal structure is relatively well-distributed in laterally and obviously by layers vertically.From surface to 11.0 km depth, there are about four layers. The P wave velocity of top two layers range from 1.65 to 4.5 km/s and their bottom boundaries, the buried depths of which are 0.4, 2.96-3.0 km respectively, are almost horizontal; The third layer is comparatively complicated and its P wave velocity presents inhomogeneous in both laterally and vertically. The bottom boundary of third layer is crystalline basement and shows a little uplift, which seemly suggest that the upper crust had been resisted while the hard Tarim block inserting into Tianshan Mountain; The forth layer is relatively even and its P wave velocity is about 6.3 km/s. There are a lateral velocity variation at the depth of about 4.0 km, and suggest that it has something to do with the hidden Meigaiti fault and Meigaiti-Xiasuhong fault but there are no the structure features about these faults stretching to the surface and passing through the crystalline basement. The seismogenic tectonic of Jiashi strong earthquake swarm at least lies in middle or lower crust beneath 11.0 km depth.

High index of refraction via quantum interference in a three-level system of Er^3＋-doped yttrium aluminium garnet crystal

A simple three-level system is proposed to produce high index of refraction with zero absorption in an Er^3＋-doped yttrium aluminium garnet （YAG） crystal, which is achieved for a probe field between the excited state 4I13/2 and ground state 4I15/2 by adjusting a strong coherent driving field between the upper excited state 4I11/2 and 4I15/2. It is found that the changes of the frequency of the coherent driving field and the concentration of Er^3＋ ions in the YAG crystal can maximize the index of refraction accompanied by vanishing absorption. This result could be useful for the dispersion compensation in fibre communication, laser particle acceleration, high precision magnetometry and so on.

Analysis of the clinical characteristics and refraction state in premature infants: a 10-year retrospective analysis

AIM: To report the visual outcomes and refractive status in premature infants with and without retinopathy of prematurity(ROP) who were or not treated. METHODS: The clinical records of all premature infants with or without ROP and with or without treatment between 2007 and 2017 were retrospectively reviewed. Basic demographic data, serial changes in ROP incidence, treatment and outcomes, and the refractive states were analyzed. Correlations among myopia and astigmatism progression, birth weight, gestational age, and treatment methods were also analyzed.RESULTS: A total of 562 screened premature infants(all Chinese, 1124 eyes), were recruited with a 378:184 maleto-female ratio. Birth weight did not directly influence ROP incidence. The overall ROP incidence was 16.55%(93/562 cases). The incidences in boys and girls were 16.14%(33/378 cases) and 17.39%(32/184 cases), respectively, and this difference was not significant. However, all infants with serious ROP(stage IV and V) were male. Myopia combined with astigmatism was common in premature infants with and without ROP(30.99%, 172/555 cases), and myopic refraction(including myopia and myopia combined with astigmatism) was more common in premature infants with ROP(48.84%, 42/86 cases). In the >8.00 diopter group, there were significantly more ROP infants than without ROP. Myopic refraction(including myopia and myopia combined with astigmatism) was most common in infants with ROP after treatment(63.63%, 7/11 cases). CONCLUSION: The refractive state is different between premature infants and mature infants. Those treated for ROP had a higher chance of developing myopia, astigmatism, and higher diopter.

Relationship between higher-order aberrations and myopia progression in schoolchildren: a retrospective study

AIM: To investigate the relationship between higher- order aberration (HOA) and myopic progression in schoolchildren. ·METHODS: Between April 23 2011 and August 29, 2011 in the children’s myopia outpatient clinic of the West China Hospital of Sichuan University, 148 eyes of 74 schoolchildren were reviewed. HOAs for a 6 -mm pupil were measured with an aberrometer. Myopic progression rate was defined according to the change in spherical equivalent refraction (SER) divided by the time span (years). Subjects with myopic progression rate of ≥0.50 diopters (D) were classified as the ’fast’group and the subjects with myopic progression rate of 【0.50D were classified as the’slow’group. A retrospective study was conducted to compare HOA between the two groups, using root mean square (RMS) values and Zernike coefficients. ·RESULTS: The RMS values of HOA (t =2.316, P =0.02), HOA without Z 4 0 (t =2.224, P =0.03),third-order aberrations (t’ =2.62, P =0.01), and coma (t’ =2.49, P =0.01) were significantly higher in the fast group than those in the slow group. The individual Zernike coefficients of Z 3 -1 (t = -2.072, P =0.04) and Z 5 1 (Z =-2.627, P =0.01) displayed statistically significant differences between the two groups. Significant correlations were found between the RMS values of HOA (r =0.193, P =0.019), RMS values of HOA without Z 4 0 (r =0.23, P =0.005), RMS values of coma(r =0.235,P =0.004),RMS values of third-order aberrations (r =0.243, P =0.003), and the progression rate. · CONCLUSION: Our results provide evidence of a relationship between HOA and myopic progression. In a future prospective longitudinal study, we aim to verify whether HOA is a risk factor for myopic progression.

Long-term vision-threatening complications of phakic intraocular lens implantation for high myopia

AIMTo report the long-term vision-threatening complications in patients who underwent phakic intraocular lens (pIOLs) implantation for high myopia.

Comparison of OA-2000 and IOL Master 500 using in cataract patients with high myopia

This study was designed to compare optical biometry measurements and predicted refraction in cataract patients with high myopia [axial length(AL) ≥26 mm] using OA-2000 and IOL Master 500. Ocular biometry measurements were performed using both biometers before surgery. Uneventful cataract surgery was performed in all patients. Postoperative manifest refraction was obtained 3 wk after surgery or later. A total of 67 eyes were examined. The AL, keratometry(K), and anterior chamber depth(ACD) of the two biometers showed excellent agreement. Predicted errors were similar and a strong positive correlation was observed(r=0.909). Out of 21 eyes(31.34%) with unsuccessful AL readings using the IOL Master 500, 20 eyes of them could be measured using OA-2000. Therefore, the biometric parameters measured by the two biometers showed good agreement. However, OA-2000 had a lower AL measurement failure rate.

Refractive errors in high myopic eyes after phacovitrectomy for macular hole

AIM: To examine the refractive prediction error in high myopic eyes after phacovitrectomy.METHODS: This retrospective comparative case series included 91 eyes(18 high myopic eyes and 73 non-high myopic eyes) of 91 patients who underwent successful phacovitrectomy(phacoemulsification, intraocular lens implantation, and pars plana vitrectomy). The high myopic eyes were defined as the eye with more than 26.0mm of axial length. The postoperative prediction error of mean error and mean absolute error were evaluated at4 mo postoperatively. Axial length and keratometry measurement were performed preoperatively and 4mo postoperatively using the IOL Master.RESULTS: The refractive outcome after phacovitrectomy showed significantly greater myopic shift in the high myopic eyes [-1.08 ±0.87 diopters(D)] than that in the non-high myopic eyes(-0.43 ±0.63 D, P =0.004). Axial length and keratometric value in the high myopic eyes were significantly increased(P =0.043, 0.037 respectively),whereas those in the non-high myopic group were not significantly increased(P =0.135, 0.347 respectively). The change of the axial length in the myopic eye(0.46±0.28 mm)was greater than that in the non- high myopic eye(0.11 ± 0.34 mm; P 【0.001).CONCLUSION: High myopic eyes showed more myopic shift than non-high myopic eyes after phacovitrectomy.The cause of myopic shift in high myopic eyes seems tobe attributed to actual elongation of the axial length in high myopia.

Comparison axial length measurements from three biometric instruments in high myopia

AIM： To compare the axial lengths （ALs） measured with Lenstar, IOLMaster and A-scan contact ultrasound （Ultrasound） in normal and high myopia （HM）. METHODS： Eighty-four normal eyes and 49 HM eyes were included. Three consecutive measurements were performed on each eye in the following order： Lenstar, IOLMaster, and Ultrasound. The repeatabilities of the AL measurements for each instrument were assessed by calculating the pooled coefficients of variation （CVs） of 18 eyes in each group. Comparisons between the HM and normal groups were made with independent sample t-tests. The inter-device agreements were evaluated with Bland-Altman analyses and paired two-tailed t-tests. RESULTS： For normal group, the CVs of the AL measurements taken with the Lenstar, IOLMaster and Ultrasound were 0.001%, 0.01% and 0.14%, respectively. The corresponding CVs for the HM group were 0.005%, 0.02% and 0.15%, respectively. There was significant difference between the Lenstar and the IOLMaster in normal group （P=0.031） but not in HM group （n=0.100）. In the two groups, the Lenstar and the IOLMaster produced higher values than did the Ultrasound （all P〈 0.001）. All three instruments exhibited good agreement in terms of AL values. For the intraocular lens （IOL） power calculation using SRK II formula, the Lenstar and the IOLMaster showed 0.5 D higher than Ultrasound in both groups （all P〈0.001）. No significant difference existed between the Lenstar and the IOLMaster for the IOL power calculation in both normal （n=0.474） and HM group （P= 0.103）. CONCLUSION： The three devices exhibited excellent intra-visit repeatabilities in the AL measurements. The AL and IOL power difference between partial coherence interferometry and ultrasound instruments should be noticed.

Diagnostic ability of ganglion cell complex thickness to detect glaucoma in high myopia eyes by Fourier domain optical coherence tomography

AIM：To evaluate the ability of macular ganglion cell complex（GCC） thickness using Fourier domain optical coherence tomography（FD-OCT） to detect glaucoma in highly myopic eyes.METHODS：Cross-sectional study.A total of 114 participants,consecutively were enrolled.Macular GCC thickness and peripapillary retinal nerve fiber layer（RNFL） thickness were obtained with RTVue FD-OCT.Receiver operating characteristics curves were constructed for each measurement parameter,and areas under the curves（AUCs） were compared.RESULTS：Both the average GCC and average RNFL thickness showed negative correlations with axial length（rGCC=-0.404,P=0.001;rRNFL=-0.561,P〈0.001）.The largest AUCs from GCC,and RNFL parameters were 0.968 [global loss volume（GLV）],and 0.855（average RNFL）,respectively.GLV was significantly better for detecting high myopic glaucoma than average RNFL（P〈0.001）.CONCLUSION：Macular GCC thickness has higher diagnostic power than peripapillary RNFL thickness to discriminate glaucoma patients from non-glaucoma subjects in high myopia.