Comparison of ocular biometry in Chinese patients using two swept-source optical coherence tomography devices

Background:To compare two swept-source optical coherence tomography(SS-OCT)biometers,IOLMaster 700 and ANTERION.Methods:This is a retrospective study.Biometric measurements of cataract patients performed between March and July 2021 in the Department of Ophthalmology,United Christian Hospital,Hong Kong,were reviewed.Patients scheduled for cataract surgery were measured with both SS-OCT devices on the same day.The following biometry parameters were compared:keratometry(K),total keratometry(TK),axial length(AL),central corneal thickness(CCT),anterior chamber depth(ACD),lens thickness(LT),white-to-white(WTW)and the predicted intraocular lens(IOL)power to achieve emmetropia.To assess the agreement between the devices,Bland-Altman analysis with 95%limits of agreement(LoA)were used.Results:In total,92 eyes of 47 subjects were measured with both devices.There were statistically significant differences between the two biometers for most measurements(P<0.05)except for flat K,AL and IOL power when using the right eyes for analysis.For the left eyes,there were statistically significant differences in the measurements from the two biometers in all parameters except for flat and steep K.The ANTERION did not obtain ACD,AL and LT in 2(2.17%),1(1.09%)and 5 cases(5.43%)respectively.Conclusions:The two biometers showed a clinically acceptable agreement in most parameters.Comparisons showed significant differences in most parameters but not clinically relevant except for the TK and WTW,and these two parameters should not be used interchangeably between the devices.

Prevalence and inconformity of refractive errors and ocular biometry of 3573 medical university freshman students for 4 consecutive years

AIM:To evaluate the prevalence of refractive errors and ocular biometry in 3573 freshman students at Tianjin Medical University for 4 consecutive years.METHODS:In this university-based, cross-sectional study, comprising 3573 students, visual acuity(VA), slitlamp examination, non-cycloplegic auto-refraction, and ocular biometry were recorded.RESULTS:The prevalence of myopia increased annually, from 2017 to 2020 were 93.5%, 94.5%, 95.9%, and 96.2%, respectively(P=0.03), and the prevalence of high myopia was 25.7%, 26.9%, 28.6%, and 28.6%, respectively. Males tended to have a higher percentage of total astigmatism than females, with astigmatism ≥0.75 and ≥1.0 D criteria. The percentage of with-the-rule astigmatism, against-therule astigmatism, and oblique astigmatism was 90.3%, 5.8%, and 3.9%, respectively, with astigmatism ≥1.00 D criteria. The mean spherical equivalent, axial length(AL), central corneal thickness(CCT), anterior chamber depth(ACD), lens thickness(LT), corneal radius(CR), and lens position(LP) were 4.37±2.52 D, 25.28±1.24 mm, 539.49±34.98 μm, 3.31±0.34 mm, 3.47±0.21 mm, 7.8±0.28 mm, and 5.04±0.32 mm, respectively. With diopter increase in myopia, the AL became longer, CR became steeper, ACD became deeper, LT became thinner, and LP became more posterior(all P<0.01). Females had a shorter AL, thinner CCT, smaller CR, shallower ACD, thicker lens, and more anterior LP than males(P<0.01). The 64% of high myopia had AL≥26 mm, meanwhile, 5.8% mild myopia and 21.1% moderate myopia had AL≥26 mm. With AL≥26 mm, mild and moderate myopia compared to high myopia, AL was shorter(26.51±0.46 vs 26.87±0.70 mm), CR was larger(8.10±0.3 vs 7.85±0.23 mm) and LT was thinner(3.39±0.19 vs 3.45±0.19 mm, P<0.001).CONCLUSION:The prevalence of myopia and high myopia is significantly high in freshman students. The majority of astigmatism is with-the-rule. Inconformity of refractive errors and ocular biometry existed in some students. Attention should be paid to the ocular biometry of myopia.

Preoperative Characteristics of Ocular Biometry in Children with Unilateral Congenital Cataracts

The ocular biometry characteristics are clinically significant for children with unilateral congenital cataracts,but there is a lack of data analysis concerning the preoperative measurements.The axial length(AL),mean keratometry(Km),cor-neal astigmatism(CA),and the anterior chamber depth(ACD)from both eyes before cataract surgery were obtained from 205 patients(410 eyes,3-15 years of age)with unilateral congenital cataracts.In the congenital cataract eyes,shorter AL(22.44±1.52 mm vs.22.57±1.04 mm,p=0.036)and higher CA(-1.89±0.91 D vs.-1.24±0.67 D,p<0.001)were found,and no significant difference was found in the Km and the ACD measurements compared to the contralateral normal eyes.Females had shorter AL and shallower ACD compared to males.However,the Km and CA in the females were significantly larger than that in males.Shorter AL,larger Km,higher CA,and shallower ACD were also found in females who had a binocular axial difference(the value obtained by subtraction of the contralateral normal eye from the congenital cataract eye)that less than zero.The preoperative ocular biometry of shorter AL,larger Km,higher CA,and shallower ACD should be considered in females with unilateral congenital cataracts.The age and the binocular axial differences had a statistically significant correlation(r=-0.192,p=0.006).Therefore,changes in the binocular axial differences associated with aging may enhance the guidelines for intraocular lens selection and the management of congenital cataracts.

Distribution and associated factors of intraocular pressure in the older population:Tehran Geriatric Eye Study

AIM:To determine the distribution and associated factors of intraocular pressure(IOP) in an Iranian elderly population 60 years of age and above.METHODS:The present report is part of the Tehran Geriatric Eye study(TGES),a population-based cross-sectional study that was conducted on the residents of Tehran 60 years of age and above.The sampling was performed using multistage stratified random cluster sampling methods from 22 districts of Tehran,Iran.Demographic and history information,blood samples,and blood pressure were collected from all participants.Ocular examinations included measurement of uncorrected and best-corrected visual acuity,objective and subjective refraction,and slit-lamp biomicroscopy.The IOP was measured using Goldmann applanation tonometry(GAT).Corneal imaging and ocular biometry were performed using Pentacam AXL.RESULTS:The data of 3892 eyes of 2124 individuals were analyzed for this report.The mean age of the study participants was 66.49±5.31y(range:60 to 95y).The mean IOP was 15.2 mm Hg(95%CI:15.1 to 15.4),15.3 mm Hg(95%CI:15.1 to 15.5) and 15.1 mm Hg(95%CI:15.0 to 15.3) in all participants,males,and females,respectively.Of the study participants,1.3% had an IOP of ≥20 mm Hg.The mean IOP increased from 15.1 mm Hg in the age group 60-64y to 16.3 mm Hg in the age group ≥80y.According to the final multiple GEE model,the IOP was statistically significantly higher in men than in women.All the studied age groups,except for the 75-79-year-old age group,had significantly higher IOP compared to the 60-64-year-old age group.The IOP was significantly higher in underweight compared to other body mass index groups.Moreover,the IOP had a statistically significant direct relationship with the mean corneal power(mean CP),central corneal thickness(CCT),and systolic blood pressure.CONCLUSION:The present study presents the distribution of IOP in an Iranian elderly population.A higher IOP(within the range 14 to 17 mm Hg) is significantly associated with older age,male sex,high systolic blood pressure,increased mean CP,and CCT.These factors should be considered in the clinical interpretation of IOP.

Age-specific distribution of oculometric parameters and myopia in children aged 8-12y

AIM:To describe the distribution of ocular biometrics and to evaluate its associations with refractive error and to assess the contribution from ocular parameters to refractive error among Chinese myopic children.METHODS:This cross-sectional study evaluated subjects aged 8-12y.Keratometry,ocular biometry,and cycloplegic autorefraction were performed on each subject.Spherical equivalent refraction(SER)and ocular biometrics were assessed as a function of age and gender.The Pearson correlation analysis between SER and ocular biometrics was carried out.Multiple linear regression was performed to analyze the association between SER and ocular parameters.RESULTS:A total of 689 out of 735 participants(321 boys,48.1%)were analyzed,with a mean SER of-2.98±1.47 diopter(D).Axial length(AL),anterior chamber depth(ACD),corneal radius of curvature(CR),horizontal visible iris diameter(HVID),central corneal thickness(CCT)and lens power(LP)showed normal distribution.The AL,AL/CR ratio,ACD and CR increased from 8 to 12y of age,while SER and LP decreased,HVID and CCT remained stable.There was no difference in gender.SER decreased by 0.929 D for every 1 mm increase in AL and decreased by 1.144 D for every 0.1 increase in AL/CR ratio.The Pearson correlation coefficient between SER and AL was-0.538(P<0.01)and-0.747(P<0.01)between SER and AL/CR ratio.For the SER variance,AL explained 29.0%,AL/CR ratio explained 55.7%,while AL,CR,ACD and LP explained 99.3%after adjusting for age and gender.CONCLUSION:The AL,CR,ACD and LP are the most important determinants of myopic refractive error during myopia progression.

Agreements’profile of Scheimpflug-based optical biometer with gold standard partial coherence interferometry

AIM:To determine the agreement of ocular biometric indices including axial length,keratometric readings,anterior chamber depth,and horizontal corneal diameter between the Pentacam AXL and IOL Master 500.METHODS:The study was a large cross-sectional population-based study(Tehran Geriatric Eye Study)conducted from Jan 2019 to Jan 2020.A total of 160 clusters were randomly selected proportional to size(each cluster contained 20 individuals)from 22 strata of Tehran city.All people aged 60y and above were invited to participate in the study.For all participants,preliminary ocular examinations were performed including the measurement of uncorrected and best-corrected visual acuity,objective and subjective refraction,anterior and posterior segment examinations.All participants underwent an ocular biometry using the Pentacam AXL and IOL Master 500.RESULTS:The 95%limits of agreement(LoA)between the two devices were-0.13 to 0.19,-0.15 to 0.17,and-0.13 to 0.19 in normal,pseudophakic,and cataractous eyes,respectively.With increasing the axial length,the difference between the two devices significantly increased in all three groups of normal,pseudophakic,and cataractous eyes(P<0.001).The 95% LoAs between the two devices regarding the mean keratometry shows that the best LoAs were seen in cataractous(-0.33 to 0.81)and followed by normal eyes(-0.36 to 0.86)and the pseudophakic eyes(-0.48 to 0.90)had the widest LoA.The 95% LoAs for horizontal corneal diameter measurements were-0.08 to 0.86,-0.03 to 0.83,and-0.07 to 0.87 in normal,pseudophakic,and cataractous eyes,respectively.The 95% LoAs of anterior chamber depth measurements between the two devices was-0.39 to 0.19 and-0.37 to 0.13 in normal eyes and cataractous,respectively.CONCLUSION:The Pentacam AXL has excellent agreement with the gold standard,IOL Master 500 in measuring axial length.In eyes with cataracts,the difference between the two devices is more scattered.With the increasing of axial length,the difference between the two devices increased,which should be considered when using Pentacam AXL.

Anterior and posterior segment structural features of acute primary angle-closure eyes:date based on AS-OCT and SS-OCT

Background:To measure the anterior and posterior segment structural features of acute primary angle-closure(APAC)eyes.Methods:A total of 36 subjects with unilateral APAC were recruited in this study.The ocular biometric characteristics were measured by anterior segment optical coherence tomography(AS-OCT)and swept source optical coherence tomography(SS-OCT),respectively at baseline,2 weeks,and 1 month after surgical intervention.Results:At baseline,when compared with the fellow eyes,APAC-affected eyes showed significantly greater corneal thickness(P=0.004),shallower anterior chamber depth(ACD)(P<0.001),smaller anterior chamber area(ACA)(P=0.013),angle opening distance at 750μm from the scleral spur(AOD750)(P=0.002),trabecular-iris space area at 750μm from the scleral spur(TISA750)(P=0.033),angle recess area(ARA)(P=0.014),and iris area(IARE)(P=0.003),less iris curvature(ICURVE)(P=0.003),and larger lens vault(LV)(P=0.030).After intervention,the corneal thickness was significantly decreased at 1 month(P<0.001),while ACD,ACA,and AOD750 were significantly increased at 2 weeks and 1 month(all P<0.017).Changes in ACD were correlated with decreasing LV(P<0.05).The posterior segment parameters did not change over the 4-week period.Conclusions:When compared with the fellow eyes,APAC-affected eyes had greater corneal thickness,shallower anterior chamber,narrower angle,less ICURVE,and larger LV.After intervention,the corneal thickness was decreased,while the shallower anterior chamber was relieved to some extent.

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.

New loci for refractive errors and ocular biometric parameters in young Chinese Han adults

Myopia has become a major public health issue with an increasing prevalence.There are still individuals who experience similar environmental risk factors and,yet,remain non-myopic.Thus,there might be genetic factors protecting people from myopia.Considering the opposite ocular characteristics of primary angle closure glaucoma(PACG)to myopia and possible common pathway between them,we propose that certain risk genes for PACG might act as a protective factor for myopia.In this study,2,678 young adults were genotyped for 37 targeted single nucleotide polymorphisms.Compared with emmetropia,rs1401999(allele C:OR=0.795,P=0.03;genotype in dominant model:OR=0.759,P=0.02)and rs1258267(allele A:OR=0.824,P=0.03;genotype in dominant model:OR=0.603,P=0.01)were associated with low to moderate myopia and high myopia,respectively.Genotype under recessive model of rs11024102 was correlated with myopia(OR=1.456,P=0.01),low to moderate myopia(OR=1.443,P=0.02)and high myopia(OR=1.453,P=0.02).However,these associations did not survive Bonferroni correction.Moreover,rs1401999,rs1258267,and rs11024102 showed associations with certain ocular biometric parameters in different groups.Our study suggests that ABCC5,CHAT and PLEKHA7 might be associated with refractive errors by contributing to the regulation of ocular biometry,in terms of uncorrected results and their biological functions.