Ocular biometric characteristics of Han ethnicity in Tianjin and Uyghur ethnicity in Xinjiang undergoing cataract surgery

AIM:To analyze and compare the differences among ocular biometric parameters in Han and Uyghur populations undergoing cataract surgery.METHODS:In this hospital-based prospective study,410 patients undergoing cataract surgery(226 Han patients in Tianjin and 184 Uyghur patients in Xinjiang)were enrolled.The differences in axial length(AL),anterior chamber depth(ACD),keratometry[steep K(Ks)and flat K(Kf)],and corneal astigmatism(CA)measured using IOL Master 700 were compared between Han and Uyghur patients.RESULTS:The average age of Han patients was higher than that of Uyghur patients(70.22±8.54 vs 63.04±9.56y,P<0.001).After adjusting for age factors,Han patients had longer AL(23.51±1.05 vs 22.86±0.92 mm,P<0.001),deeper ACD(3.06±0.44 vs 2.97±0.37 mm,P=0.001),greater Kf(43.95±1.40 vs 43.42±1.69 D,P=0.001),steeper Ks(45.00±1.47 vs 44.26±1.71 D,P=0.001),and higher CA(1.04±0.68 vs 0.79±0.65,P=0.025)than Uyghur patients.Intra-ethnic male patients had longer AL,deeper ACD,and lower keratometry than female patients;however,CA between the sexes was almost similar.In the correlation analysis,we observed a positive correlation between AL and ACD in patients of both ethnicities(rHan=0.48,rUyghur=0.44,P<0.001),while AL was negatively correlated with Kf(rHan=-0.42,rUyghur=-0.64,P<0.001)and Ks(rHan=-0.38,rUyghur=-0.66,P<0.001).Additionally,Kf was positively correlated with Ks(rHan=0.89,rUyghur=0.93,P<0.001).CONCLUSION:There are differences in ocular biometric parameters between individuals of Han ethnicity in Tianjin and those of Uyghur ethnicity in Xinjiang undergoing cataract surgery.These ethnic variances can enhance our understanding of ocular diseases related to these parameters and provide guidance for surgical procedures.

Relative peripheral refractive errors in Chinese children with myopic anisometropia

AIM:To compare relative peripheral refractive errors(RPREs)in Chinese children with and without myopic anisometropia(MAI)and to explore the relationship between RPRE and myopia.METHODS:This observational cross-sectional study included 160 children divided into two groups according to the interocular spherical equivalent refraction(SER)difference≥1.0 D in the MAI group(n=80)and<1.0 D in the non-MAI group(n=80).The MAI group was further divided into two subgroups:ΔSER<2.0 D group and ΔSER≥2.0 D group.Basic ocular biometric parameters of axial length(AL),average keratometry(Ave K),cylinder(CYL),surface regularity index(SRI),and surface asymmetry index(SAI)were recorded.In addition,multispectral refraction topography was performed to measure RPRE,and the parameters were recorded as total refraction difference value(TRDV),refraction difference value(RDV)0-10,RDV10-20,RDV20-30,RDV30-40,RDV40-53,RDV-superior(RDV-S),RDV-inferior(RDV-I),RDV-temporal(RDV-T)and RDV-nasal(RDV-N).RESULTS:In the non-MAI group,the interocular differences of all parameters of RPRE were not significant.In the MAI group,the interocular differences of TRDV,RDV10-53,RDV-S,RDV-I,RDV-T,and RDV-N were significant.In subgroup analysis,the interocular differences of TRDV,RDV30-53,RDV-I,and RDV-T were significant in ΔSER<2.0 D group and ΔSER≥2.0 D group,but the interocular differences of RDV10-30,RDV-S and RDV-N were only significant in the ΔSER≥2.0 D group.In correlation analysis,ΔTRDV,ΔRDV 10-53,ΔRDV-S,and ΔRDV-N were negatively correlated with ΔSER but positively correlated with ΔAL.CONCLUSION:The more myopic eyes have larger hyperopic RPRE in Chinese children with MAI in certain retinal range,and partialΔRPRE is closely associated with ΔSER and ΔAL.

Effects of diode laser photocoagulation treatment on ocular biometric parameters in premature infants with retinopathy of prematurity

AIM:To investigate the effects of diode laser treatment on ocular biometric parameters in premature infants with retinopathy of prematurity(ROP).METHODS:Premature infants who received diode laser treatment for ROP(n=68)and premature infants with spontaneous regressed ROP without treatment(n=50)were performed longitudinal ocular biometric measurements including anterior chamber depth,lens thickness and axial length as follows:1 d prior to laser treatment,and 3,6,9,and 12 mo after the laser treatment.RESULTS:The mean birth weight,gestational age and initial examination time values were 936.53±302.07 g,26.66±2.42 wk,36.26±2.73 wk in the treatment group and 959.78±260.08 g,27.28±2.10 wk,36.56±2.54 wk in the control group.There was no statistically significant difference in these demographic characteristics of the groups.Anterior chamber depth,lens thickness and axial length demonstrated statistically significant linear increases during the study period in the two groups(P<0.001 for each).There were no statistically significant differences between the two groups in terms of anterior chamber depth after laser treatment.Measurements of the lens thickness at 9 th and 12 th months(9 th month 3.70±0.22 vs 3.60±0.21 mm,P=0.017;12 th month 3.81±0.21 vs 3.69±0.22 mm,P=0.002)and the axial length at 12 th month(19.35±0.79 vs 19.13±0.54 mm,P=0.031)after laser treatment were statistically higher in the treatment group.CONCLUSION:Diode laser retinal photocoagulation treatment in premature infants seems to increase the lens thickness and axial length.

AB081.Multi-unit ocular biometric system based on corneal shapes

Background:Our goal is to build a multi-unit ocular biometric system based on the fusion of left and right corneal shapes for identity authentication.Methods:Ocular biometrics such as iris,periocular,retina,sclera and eye movement have become established biometric traits,primarily due to extensive efforts made by the biometrics community in the field of iris recognition.In this work,we propose an ocular biometric trait based on the 3D shape of the cornea to improve biometric authentication.We show how the fusion of the left and right corneas can be used as a biometric trait for person recognition.First,we started by realizing our own cornea database by using a Pentacam Topographer(Oculus)which contains 288 corneal topographies of both eyes captured from 36 different people of different ages.For each eye,data acquisition was done during two different sessionsto establish the repeatability of the measurements over time.The time interval between the two sessions was equal or greater than one month.In each session;8 acquisitions(4 left eyes end 4 right eyes)were taken.Then,features were extracted by modeling the shape of the left and right corneas with a Zernike polynomial expansion.The fusion of the left and right shapes of cornea was performed at the matching score level using the weighted-sum rule.Results:For each individual,we had eight feature vectors(eight measures in two sessions)of size 36(Zernike polynomial coefficients)from their corneal topographies.The experimental results on our cornea database constructed for this study showed encouraging performance of the proposed ocular biometric system with Equal Error Rate decreasing to 1.38%with the weighted-sum rule compared to the analysis of the left(4.5%)or right(3.7%)cornea alone.Conclusions:The objective of this work was to investigate corneal topographyas an accurate biometric modality using shape discriminating features.Our idea was to propose an ocular multi-unit system based on the fusion of the left and right corneal shapes.The corneal feature extraction was done by Zernike polynomial decomposition.Multi-unit cornea fusion was performed at the matching score level to generate a unique score.This allowed a significative decrease of the EER to 1.38%.