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.

Optical biometry intraocular lens power calculation using different formulas in patients with different axial lengths

AIM: To investigate the predictability of intraocular lens (IOL) power calculation using the IOLMaster and different IOL power calculation formulas in eyes with various axial length (AL). METHODS: Patients were included who underwent uneventful phacoemulsification with IOL implantation in the Department of Ophthalmology, Far Eastern Memorial Hospital, Taipei, Taiwan, China from February 2007 to January 2009. Preoperative AL and keratometric values (Ks) were measured by IOLMaster optical biometry. Patients were divided into 3 groups based on AL less than 22mm (Group 1), 22-26mm (Group 2), and more than 26mm (Group 3). The power of the implanted IOL was used to calculate the predicted postoperative spherical equivalence (SE) by various formulas: the Haigis, Hoffer Q, Holladay 1, and SRK/T. The predictive accuracy of each formula was analyzed by comparing the difference between the actual and predicted postoperative SE (MedAE, median absolute error). All the patients had follow-up periods exceeding 3 months. RESULTS: Totally, there were 200 eyes (33 eyes in Group 1, 92 eyes in Group 2, 75 eyes in Group 3). In all patients, the Haigis had the significantly lower MedAE generated by the other formulas (P【0.05). In Group 1 to 3, the MedAE calculated by the Haigis was either significantly lower or comparable to those calculated by the other formulas.CONCLUSION: Compared with other formulas using IOLMaster biometric data, the Haigis formula yields superior refractive results in eyes with various AL.

Impact of ultrasound and optical biometry on refractive outcomes of cataract surgery after penetrating keratoplasty in keratoconus

AIM: To analyse the impact of ultrasound and optical intraocular lens(IOL) calculation methods on refractive outcomes of cataract phacoemulsification performed after penetrating keratoplasty(PK) in keratoconus. METHODS: Phacoemulsification cataract surgery was performed on 42 eyes of 34 patients with keratoconus who had previously undergone PK. The IOL power was determined by using both standard and corneal topography-derived keratometry using the SRK/T formula. We used two independent methods-ultrasound biometry(UB) and interferometry [optical biometry(OB)] for IOL calculation. The analysed data from medical records included demographics, medical history, best corrected visual acuity(BCVA) on Snellen charts, technique of IOL calculation and calculation formula and its impact on final refractive result.RESULTS: BCVA ranged from 0.01 to 0.4(mean 0.09±0.19) before surgery and ranged from 0.2 to 0.7(mean 0.38±0.14) at 1 mo and from 0.2 to 1.0(mean 0.56±0.16)(P<0.05) at 3 mo, postoperatively. The refractive aim differed significantly from the refractive outcome in both the UB and OB groups(P<0.05). There was no statistically significant difference in the accuracy of the two biometry methods.CONCLUSION: The refractive aim in keratoconus eyes post-PK is not achieved with either ultrasound or OB.

Comparison of immersion ultrasound and low coherence reflectometry for ocular biometry in cataract patients

AIM： To compare the results of axial length （AL） biometry in cataract eyes by three methods： immersion B-ultrasound （IB） biometry, immersion A-ultrasound （IA） biometry and optical low coherence reflectometry. METHODS： In this prospective observational study of eyes with cataract AL measurements were performed using immersion ultrasound and optical low coherence reflectometry device. The results were evaluated using Bland-Altman analyses. The differences between both methods were assessed using the paired t-test, and its correlation was evaluated by Pearson coefficient. RESULTS： Eighty eyes of 80 patients （39 men and 41 women） for cataract surgery were included in the study. The values of AL could be got from all 80 eyes by IB and IA, the difference of AL measurements between IA and IB was of no statistical significance （P=0.97）; the mean difference in AL measurements was -0.031 mm （P=0.26; 95%CI, -0.09 to 0.02）; linear regression showed an excellent correlation （r=0.98, P〈0.0001）. Forty-five of eighty eyes with results of AL measurements, which can be obtained by three methods; the difference of AL measurements was of no statistical significance （IA vs IB, P=0.18; IA vs Lenstar, P=0.51; IB vs Lenstar, P=0.07）; linear regression showed an excellent correlation （IA vs IB, r=0.99; IA vs Lenstar, r=0.96; IB vs Lenstar, r=0.96）; Bland-Altman analysis also showed good agreement between the two methods [IA vs IB, 95% limits of agreement （LoA）, -0.36 to 0.28 mm; IA vs Lenstar, 95% LoA, -0.65 to 0.69 mm; IB vs Lenstar, 95% LoA, -0.55 to 0.68 mm]. CONCLUSION： Measurements with the optical low coherence reflectometry correlated well with IB and IA. In the eyes with serious refractive medium opacity, the measurements of AL could not be achieved or existed deviations when using optical low coherence reflectometry device. Under such circumstances, we should choose IA or IB as the optimization method to obtain measurements, in order to get much more accurate results.

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.

Anti-Spoof Reliable Biometry of Fingerprints Using <i>En-Face</i>Optical Coherence Tomography

Optical coherence tomography (OCT) is a relatively new imaging technology which can produce high resolution images of three-dimensional structures. OCT has been mainly used for medical applications such as for ophthalmology and dermatology. In this study we demonstrate its capability in providing much more reliable biometry identification of fingerprints than conventional methods. We prove that OCT can serve secure control of genuine fingerprints as it can detect if extra layers are placed above the finger. This can prevent with a high probability, intruders to a secure area trying to foul standard systems based on imaging the finger surface. En-Face OCT method is employed and recommended for its capability of providing not only the axial succession of layers in depth, but the en-face image that allows the traditional pattern identification. Another reason for using such OCT technology is that it is compatible with dynamic focus and therefore can provide enhanced transversal resolution and sensitivity. Two En-Face OCT systems are used to evaluate the need for high resolution and conclusions are drawn in terms of the most potential commercial route to ex- ploitation.

Preoperative evaluation of human crystalline lens hardness using A-scan ultrasound biometry： a pilot study

Dear Editor,I write to present the results of a study on the correlation between the ultrasound energy consumed during phacoemulsification with various preoperative parameters,including best corrected distance visual acuity（BCDVA）,the signal to noise ratio（SNR）obtained by partial coherence laser interferometry and primarily,lens spikes measurements derived by A-scan ultrasound biometry.Quantification of crystalline lens hardness before cataract removal has been attempted by several researchers in the past.These have been in humans and in animals,in vivo and in vitro,and have used a variety of imaging modalities.

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.

Axial length and anterior chamber indices in elderly population: Tehran Geriatric Eye Study

AIM:To determine the normative distribution of axial length(AL),anterior chamber depth(ACD),anterior chamber volume(ACV),anterior chamber angle(ACA),and some of their associated factors in subjects aged 60 and over.METHODS:In this cross-sectional study,160 clusters were sampled using multi-stage cluster sampling in Tehran,Iran.After a preliminary interview,the participants underwent optometric examinations including visual acuity and refraction measurement followed by slit lamp biomicroscopy.Finally,ocular imaging was done using the Pentacam AXL to measure AL,ACD,ACV,and ACA.RESULTS:A total of 4519 eyes of 2436 participants were evaluated,of whom 58.0%(n=1412)were female.The mean age of the subjects was 67.32±6.05y(range:60-95y).The mean AL,ACD,ACV,and ACA was 23.22 mm(23.18-23.27 mm),2.61 mm(2.59-2.62 mm),126.56 mm3(125.08-128.04 mm3),and 30.61°(30.3°-30.92°),respectively.In the multivariable model,after adjusting for the effect of both eyes,the longest and shortest AL was seen in myopic and hyperopic subjects,respectively.AL,ACD,ACV and ACA were significantly larger in men compared to women(P<0.001).Except ACA,other evaluated parameters showed an inverse correlation with age(P<0.001),however,this correlation was insignificant for AL(P=0.623).CONCLUSION:Normative value of AL,and other biometric parameters are specific for each ethnicity,age and sex group.Any alteration in these parameters and their effect on refraction should be considered in this age group,especially in case of cataract surgery.

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.

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.

Comparison of the Refraction Precision Results between Pentacam AXL and IOL Master 700 Using Universal II Barrett Formula after Cataract Surgery

Background: The availability of premium intraocular lenses (IOL), including toric, multifocal, and EDOF, has become very sophisticated and now demands accurate biometric measurement accuracy. The Pentacam AXL and IOL Master 700 are often used for optical biometry and they are available in the market today. They can also be used to measure the parameters needed in the IOL calculation using the latest generation formulas, such as the Barett Universal II. Therefore, this study aims to compare the accuracy of refraction results between Pentacam AXL compared to IOL Master 700 after cataract surgery with the Barett Universal-II formula. Method: A total of 64 eyes from 64 patients who had a preoperative examination with IOL Master 700 and Pentacam AXL were included in this study. Parameters such as K, ACD, LT, WTW, and AL were then compared between the two tools. Prediction error values were also calculated and compared based on the difference between the Spherical equivalent (SE) of subjective refraction results after 4 weeks of surgery with their refractive prediction targets. Results: There was no statistically significant difference in the parameters measured from the two tools except ACD and WTW. Furthermore, LT was difficult to obtain on the Pentacam AXL due to penetration problems, as well as in patients with significant lens opacities. The percentage of error prediction values that reach ± 0.50 D on Pentacam AXL and IOL Master 700 was 70.3% and 73.5%, respectively. However, the average prediction error that was close to emmetropia with IOL Master 700 was greater compared to the other tool. Conclusion: Pentacam AXL has a fairly good accuracy for refraction prediction compared to IOL Master 700. However, it is still necessary to optimize its constants to obtain optimal results.

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.

Axial length development in children

AIM: To study ocular axial lengths in pediatric subjects without intraocular pathology. METHODS: An Institutional Review Board-approved consecutive retrospective chart review of axial lengths measured in pediatric subjects who underwent examination under anesthesia due to positive family history of retinoblastoma or other inherited ocular disease. Only subjects without any intraocular pathology in either eye were included. Subjects were stratified into age groups. An axial length model using a logarithmic regression algorithm was calculated.RESULTS: Data from 330 eyes of 165 subjects were included in the study. The mean age at the time of examination was 30.62(SD 18.04)mo. The steepest increase in axial length was present during the first 10 mo of life. After 36 mo, there was no statistically significant axial length growth. CONCLUSION: This study presents the biggest series of pediatric axial lengths in healthy eyes. The axial length model developed with these data may assist in the diagnosis and management of a wide variety of pediatric ophthalmic diseases.

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.

Differences in intraocular lens power calculation in patients with sub-foveal choroidal neovascularization

Dear Editor,I am Dr Xing-Chao Shentu,from the Eye Center of the Second Affiliated Hospital,Medical College of Zhejiang University,Hangzhou,China.I write to present case series of differences in intraocular lens (IOL)power calculation by partial coherence interferometry (PCI)and ultrasound A-scan biometry with sub-foveal choroidal neovascularization (CNV).

Accuracy of biometric formulae for intraocular lens power calculation in a teaching hospital

AIM: To evaluate the accuracy of three commonly used biometric formulae across different axial lengths(ALs) at one United States Veterans Affairs teaching hospital.METHODS: A retrospective chart review was conducted from November 2013 to May 2018. One eye of each patient who underwent cataract surgery with a monofocal intraocular lens(IOL) was included. The range of postoperative follow-up period was from 3 wk to 4 mo. The Holladay 2, Barrett Universal II, and Hill-Radial Basis Function(Hill-RBF) formulae were used to predict the postoperative refraction for all cataract surgeries. For each formula, we calculated the prediction errors [including mean absolute prediction error(MAE)] and the percentage of eyes within ±0.25 diopter(D) and ±0.5 D of predicted refraction. We performed subgroup analyses for short(AL<22.0 mm), medium(AL 22.0-25.0 mm), and long eyes(AL>25.0 mm).RESULTS: A total of 1131 patients were screened, and 909 met the inclusion criteria. Resident ophthalmologists were the primary surgeons in 710(78.1%) cases. We found no statistically significant difference in predictive accuracy among the three formulae over the entire AL range or in the short, medium, and long eye subgroups. Across the entire AL range, the Hill-RBF formula resulted in the lowest MAE(0.384 D) and the highest percentage of eyes with postoperative refraction within ±0.25 D(42.7%) and ±0.5 D(75.5%) of predicted. All three formulae had the highest MAEs(>0.5 D) and lowest percentage within ±0.5 D of predicted refraction(<55%) in short eyes.CONCLUSION: In cataract surgery patients at our teaching hospital, three commonly used biometric formulae demonstrate similar refractive accuracy across all ALs. Short eyes pose the greatest challenge to predicting postoperative refractive error.

Lens thickness assessment : anterior segment optical coherence tomography versus A-scan ultrasonography

AIMTo assess lens thickness measurements with anterior segment-optical coherence tomography (AS-OCT) in comparison with A-scan ultrasonography (A-scan US).METHODSThere were 218 adult subjects (218 eyes) aged 59.2&#x000b1;9.2y enrolled in this prospective cross-sectional study. Forty-three eyes had open angles and 175 eyes had narrow angles. Routine ophthalmic exam was performed and nuclear opacity was graded using the Lens Opacities Classification System III (LOCS III). Lens thickness was measured by AS-OCT (Visante OCT, Carl Zeiss Meditec, Dublin, CA, USA). The highest quality image was selected for each eye and lens thickness was calculated using ImageJ software. Lens thickness was also measured by A-scan US.RESULTSInterclass correlations showed a value of 99.7% for intra-visit measurements and 95.3% for inter-visit measurements. The mean lens thickness measured by AS-OCT was not significantly different from that of A-scan US (4.861&#x000b1;0.404 vs 4.866&#x000b1;0.351 mm, P=0.74). Lens thickness values obtained from the two instruments were highly correlated overall (Pearson correlation coefficient=0.81, P&#x0003c;0.001), and in all LOCS III specific subgroups except in grade 5 of nuclear opacity. Bland-Altman analysis revealed a 95% limit of agreement from -0.45 to 0.46 mm. Lens thickness difference between the two instruments became smaller as the lens thickness increased and AS-OCT yielded smaller values than A-scan US in thicker lens (&#x003b2;=-0.29, P&#x0003c;0.001)CONCLUSIONAS-OCT-derived lens thickness measurement is valid and comparable to the results obtained by A-scan US. It can be used as a reliable noncontact method for measuring lens thickness in adults with or without significant cataract.

Long-term follow-up of cataract surgery in eyes filled with silicone oil

AIM:To evaluate the refractive and long-term outcome of eyes filled with silicone oil(SO)undergoing phacoemulsification cataract surgery(PCS).METHODS:This retrospective study evaluated patients with SO tamponade who were scheduled for PCS.RESULTS:Subjects(n=26)were followed for 29.5±13.9 mo after cataract surgery.The median spherical equivalent refraction(SER)was+5.3 D[interquartile range(IQR)+2.9 to+6.7]before PCS,and+3.4 D(IQR+2.0 to+4.4)after PCS.Within the follow-up period retinal reattachment after SO removal was achieved in 15 out of 26 eyes(57.7%).In 13 eyes assessment of refraction after SO-removal was possible,and showed a myopic shift of-4.6 D(IQR-2.9 to-7.3)in the SER.After SO removal,5 of the 13 eyes(38.5%)were within±1.0 D of the target refraction,while 9 out of the 13 eyes(69.2%)were within±2.0 D.CONCLUSION:In our study,the refraction after PCS for eyes filled with SO manifested low predictability,as did the myopic shift following SO removal.A significant percentage of the eyes that underwent SO administration required a long-term tamponade.

Refractive Outcomes Using the Lenstar Optical Low Coherence Reflectometry Biometer in Phacovitrectomy for Epiretrinal Membranes and Macular Holes

Objective: To compare refractive outcomes using the Lenstar optical low-coherence reflectometry (OLCR) biometer in the following cases: phacovitrectomy for epiretinal membranes and macular holes (phacovitrectomy group);sequential cataract surgery after prior vitrectomy (sequential-phaco group);routine cataract surgery (phaco-only group). Methods: This study was a retrospective, consecutive comparative series. Main outcomes were mean prediction error (ME) and mean absolute prediction error (MAE). Secondary out-come was the variance in prediction error. Results: ME was significantly more myopic in the phacovitrectomy group (-0.08 ± 0.77D, mean ± SD, p = 0.04) and the sequentialphaco group (-0.09 ± 0.51D, p = 0.01) compared to the phaco-only group (+0.24 ± 0.53D). MAEs were not statistically different across the 3 groups. The phacovitrectomy group had a wider variance in prediction errors compared to the phaco-only group (p = 0.03). Conclusions: There is a myopic shift of approximately -0.3D in both phacovitrectomy and sequential-phaco cases compared to phaco-only cases when using OLCR-based optical biometry. Phacovitrectomy outcomes are more variable compared to phaco-only eyes.