Analysis of ocular biometric parameters in Tibetan patients with age-related cataract / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To compare the differences of ocular biometric parameters of age-related cataract between Tibetan and Han ethnic groups, and to analyze the distribution characteristics of ocular biometric parameters in Tibetan cataract patients.METHODS:Retrospective cohort study. A total of 661 patients(1 030 eyes)with age-related cataract confirmed in the hospital between January 2019 and December 2020 were enrolled. The parameters of axial length, anterior chamber depth, keratometry, corneal astigmatism and astigmatic axis were measured by IOL Master 500 in 483 cases(739 eyes)of Tibetan age-related cataract patients and 178 cases(291 eyes)of Han patients.RESULTS:The axial length, anterior chamber depth and corneal astigmatism of the Tibetan patients with age-related cataract were 23.33(22.81, 23.86)mm, 3.04(2.79, 3.30)mm and 0.73(0.47, 1.07)D. The mean keratometry was 43.89±1.35 D. The results indicated that Tibetan cataract patients had shorter axial lengths and smaller keratometry compared to Han patients(all P<0.05). Age in Tibetan patients was negatively correlated with axial length and anterior chamber depth, and positively correlated with keratometry(all P<0.05). Tibetan male patients had longer axial lengths, deeper anterior chambers, and flatter corneas compared to female patients(all P<0.05).CONCLUSION:There were differences in ocular biometric parameters between age-related cataract patients of Tibetan and Han ethnicities. The distribution of ocular biometric parameters in Tibetan cataract patients varied across different age groups and gender groups.

Comparison of IOL Master 700 versus Lenstar LS900 for preoperative biometric measurement and intraocular lens calculation in cataract patients with high myopia / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To compare the differences, correlations and consistency of IOL Master 700 or Lenstar LS900 in preoperative ocular biometry and the accuracy of intraocular lens(IOL)degree calculation of cataract patients with high myopia.METHODS: Retrospective study. A total of 136 cases(136 eyes)of high myopia and cataract patients who underwent phacoemulsification at the ophthalmology department of Army Medical Center of PLA from March 2021 to March 2023 were collected, with a mean age of 57.38±8.08 years. Patients were divided into 3 groups based on axial length(AL): 41 eyes in group A(26 mm≤ AL ≤28 mm), 43 eyes in group B(28 mm< AL ≤30 mm)and 52 eyes in group C(AL >30 mm). AL, mean keratometry(Km), anterior chamber depth(ACD), lens thickness(LT)and white-to-white(WTW)were preoperatively measured by two instruments, respectively. Barrett Universal II formula was used to calculate the IOL degrees of all patients, the appropriate reserved diopter was decided individually, and the prediction error(PE)and absolute error(AE)of the two instruments were compared.RESULTS:The AL and ACD of patients in the three groups measured by Lenstar LS900 were higher than the AL measurd by IOL Master 700(all P<0.05), with a difference of AL measured by the two devices: group C>group B>group A. However, there was no statistical significance in LT, Km, and WTW measured by the two instruments(all P>0.05). All biometric parameters measured by the two devices were positively correlated(all r>0.9, P<0.05), and consistent(95% LoA of all groups were narrow). There was no statistically significant difference in AE calculated by the two devices(P>0.05), but the IOL Master 700 calculated a smaller PE than Lenstar LS900(P<0.05), with lower percentage of hyperopic shift in IOL Master 700.CONCLUSION:In cataract patients with high myopia, AL measured by Lenstar LS900 is longer than that by IOL Master 700, and the differences of AL increase along with the growth of AL. Both devices have a good prediction for IOL calculation, but IOL Master 700 has less refractive error, lower percentage of hyperopic shift, and greater clinical advantages IOL Master 700.

Advances in peripheral defocus and myopia prevention and control / 国际眼科杂志(Guoji Yanke Zazhi)

The global prevalence of myopia is increasing year by year, leading to many ocular health issues and social problems. In recent years, it has been confirmed that peripheral defocus is closely related to the occurrence and development of myopia. Alteration of the state of peripheral defocus can significantly influence the progression of myopia and emmetropization, but the exact mechanisms are still unclear. At present, there is no method that can completely control myopia. Nowadays, the main controlling methods, including orthokeratology lens, peripheral defocus lens and multi-focal soft lens, have been confirmed to be closely related to peripheral defocus. In this paper, we will review and summarize the development and effect of these peripheral defocus relating control methods. In addition, the researches on the related mechanisms of peripheral retinal defocus and myopia prevention and control at home and abroad are reviewed, as well as the potential mechanisms of peripheral defocus, with a view to further improving the controlling effects of existing methods, developing new prevention and control methods and reducing the incidence and progression of myopia.

Advances in the effect of ocular hypertension on ocular refraction / 国际眼科杂志(Guoji Yanke Zazhi)

Ocular hypertension(OH)can cause a variety of ocular structural and functional damage, among which the effect on ocular refraction has long been recognized in the clinic. The effect of OH on ocular refraction is related to the transparency and shape of refractive media, as well as the changes of the axial length. Due to the different speed and degree of intraocular pressure(IOP)elevation, the changes of refraction are reversible or irreversible. Irreversible changes in refraction are often accompanied by visual transmission impairment, and have a certain reference value for the evaluation of the latter condition. IOP changes lead to changes in the axial length, which are related to scleral remodeling and choroidal perfusion changes, and have a certain impact on the development of myopia and refractive error after cataract surgery. In this paper, the research progress of the changes of refractive media and axial length caused by OH, as well as the characteristics of the effects on ocular refraction are summarized, hoping to deepen the understanding of the effect of OH on ocular refraction, and provide reference for preventing irreversible ocular refractive changes, guiding the assessment of visual transmission damage and preventing or controlling the development of axial myopia.

Efficacy of orthokeratology lenses with increased compression factor in the control of axial length for myopic patients of different ages / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To compare the changes in axial length of myopic patients of different ages after wearing orthokeratology lenses with increased compression factor(ICF)or conventional compression factor(CCF)for 2 a.METHODS: Retrospective study. A total of 141 myopia patients(141 right eyes)aged 8 to 15 years who fitted with orthokeratology lenses in the General Hospital of Foshan Aier Eye Hospital from July 2020 to July 2021 were continuously included. They were divided into the CCF group(70 cases, 70 eyes)and the ICF group(71 cases, 71 eyes). The patients in the CCF group were fitted with orthokeratology lens of 0.75 DS CCF, while patients in the ICF group were fitted with orthokeratology lens of 1.25 D ICF. Taking 12 years old as a boundary, these two groups were divided into 8-11 years old and 12-15 years old group. The uncorrected visual acuity(UCVA), horizontal corneal curvature(K1)and corneal staining were recorded for all subjects after wearing lenses for 1 d, 1 wk, 1, 6 mo, 1 and 2 a. The axial length(AL)was recorded after wearing lenses for 6 mo, 1 and 2 a, and the complication and corneal epithelial staining were observed during lens wearing.RESULTS:The improvement of UCVA in the ICF group was faster than that in the CCF group, which were statistical significant after wearing lenses for 1 d, 1 wk and 1 mo, respectively(all P<0.001); however, there was no statistical significance between the two groups after 6 mo, 1 and 2 a(all P>0.05); K1 of the ICF group decreased faster than that of the CCF group, and there were statistical significance at 1 d, 1 wk, and 1 mo after wearing lenses(all P<0.05); there was no statistical significance at 6 mo, 1 and 2 a(all P>0.05). The axial length growth of patients aged 8-11 years old in the ICF group and CCF group was 0.35±0.17 and 0.48±0.26 mm, respectively(P=0.010), after wearing lenses for 2 a, and the axial length growth of patients aged 12-15 years old in the ICF group and CCF group was 0.16±0.15 and 0.31±0.29 mm, respectively(P=0.011). During the follow-up period, corneal spotting occurred in 6 eyes(8.5%)in the ICF group, and 7 eyes(10%)in the CCF group(P>0.05), all of which were grade 1 spotting.CONCLUSION:Wearing ICF orthokeratology lens is more effective than wearing CCF lenses in controlling the growth of axial length, with faster shaping and more obvious improvement in UCVA, especially for the prevention of high myopia in children under 12 years. Therefore, young children can give priority to wearing lenses that increase the compression factor, and for children over 12 years old, the compression factor of the lens can be selectively increased according to the wearer's eye habits, health status of ocular surface and visual function.

Changes of axial length in primary and secondary school students in Yunnan and associated factors / 中国学校卫生

Objective@#To explore the pattern of change of axial length/curvatrue radius ratio (AL/CR) and associated factors in primary and secondary school students in Yunnan, so as to provide scientific basis and prospective guidance for early myopia intervention and control.@*Methods@#A total of 685 students from grades 2 to 3 and grade 7 in 2 cities/counties in Yunnan Province were selected by multi stage stratified random cluster sampling method in 2020. All the participants were followed up twice with questionnaire of myopia related factors, uncorrected distance visual acuity, and refractive parameter measurement from October,2021 and March,2023,respectivelty. The distribution and change of AL/CR in different classes and groups were analyzed, and the influencing factos of AL/CR cumulative progression were explored using generalized linear model.@*Results@#AL/CR ratio in primary school students was (2.95±0.09) at baseline, increased to (2.99±0.11) at the first follow up and (3.04±0.12) at the second follow up. AL/CR ratio in middle school students(3.08±0.13) at baseline, increased to (3.12±0.15) at the first follow up and (3.15±0.14) at the second follow up. The generalized linear model showed that after controlling for environmental factors, ethnicity ( β =-0.017) , cumulative progression of the SE ( β =-0.027) influenced the changes of AL/CR ratio among the primary school students, whereas the changes of AL/CR ratio were associated with baseline AL ( β =-0.005), baseline corneal curvatrue radius ( β =0.032) and cumulative progression of SE( β =-0.035) among middle school students ( P <0.05).@*Conclusions@#The AL/CR ratio of primary and secondary school students in Yunnan can be used to judge different refractive status types, but its variation is not only related to SE progression, but also affected by different ethnic groups and baseline ocular biological parameters. so the value of AL/CR application in assessing the progression of myopia needs to be further confirmed.

Accuracy of the ratio of axial length to corneal radius in the assessment of myopia in children and adolescents / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To explore the accuracy of the ratio of axial length(AL)to the average corneal radius(CR)(AL/CR value, i.e., axial ratio)in assessing myopia in children and adolescents.METHOD:Cross-sectional study. A total of 340 cases(680 eyes)of children and adolescents aged 4-16 years old were collected from the ophthalmology clinic of Shangyu People's Hospital of Shaoxing between January 2022 and October 2022. All patients were subjected to optometry after cycloplegia to obtain spherical equivalent(SE), check and record the patient's AL, average CR, and calculate the AL/CR value.RESULTS:All subjects in this study underwent optometry after cycloplegia, and a total of 609 eyes(89.6%)were found to have myopia(SE≤-0.50 D), 58 eyes(8.5%)with hyperopia(SE≥+0.50 D)and 13 eyes(1.9%)with emmetropia(-0.50 D&#x0026;#x003E;SE&#x0026;#x003E;+0.50 D). There was a statistically significant difference in SE, AL and AL/CR values among different refractive states(P&#x0026;#x003C;0.01), but there was no difference in CR(P&#x0026;#x003E;0.05). All subjects have refractive parameters: SE +8.75--8.75(average -2.25±2.38)D; AL 19.91-27.54(average 24.41±1.22)mm; CR 7.17-8.71(average 7.83±0.27); AL/CR values range from 2.50-3.50(average 3.12±0.14), correlation analysis showed a relative strong negative correlation between SE and AL/CR and AL(r=-0.891, P&#x0026;#x003C;0.01; r=-0.758, P&#x0026;#x003C;0.01), but no significant correlation between SE and CR(r=0.067, P&#x0026;#x003E;0.05), there was a positive correlation between AL and CR(r=0.483, P&#x0026;#x003C;0.01). The linear relationships between SE and AL/CR, AL were SE=45.026-15.162×AL/CR, R2=0.794, SE=33.741-1.474×AL, R2=0.574, respectively. The gold standard was based on the optometric results of cycloplegia, the sensitivity, specificity, misdiagnosis rate and missed diagnosis rate of AL/CR value for myopia were 0.962, 0.839, 0.169, 0.038, respectively, and the accuracy was 94.85%, the Kappa coefficient was 0.742, and the area under the ROC curve was 0.972.CONCLUSION:With high qualitative diagnostic value for myopia and a certain clinical significance for myopia monitoring, AL/CR value can be used to guide myopia prevention and control and other related ophthalmic clinical work.

Control effect of high aspherical lenticule in children and adolescents with low myopia / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To explore the effect of high aspherical lenticule on controlling low myopia.METHODS: Prospective study. A total of 100 patients aged 7 to 12 years old with low myopia who visited our hospital from May 1 to 31, 2022 were collected. They were divided into two groups with 50 cases in each group according to the wishes of patients. The control group was given single vision glasses after optometry, while the study group was given high aspherical lenticule. The myopia progression(absolute value), axial length(AL)growth, transition rate to moderate myopia, and AL negative growth rate over 6 mo and 1 a were compared between the two groups.RESULTS: The myopia progression and the AL growth of study group was lower than that of the control group after 6 mo and 1 a(all P&#x0026;#x003C;0.001).The negative growth rate of AL after 6 mo of treatment was significantly higher than that of the control group(P&#x0026;#x003C;0.001). The transition rate to moderate myopia between the two groups was not statistically significant(P=0.62); while the transition rate to moderate myopia in the study group was significantly lower than that in the control group after wearing lens for 1 a(P&#x0026;#x003C;0.001), and there was no statistically significant difference in AL negative growth rate between the two groups(P=0.12). Compare with single vision glasses, high aspherical lenticule achieved an 88.2% control rate for low myopia progression over 6mo and a 90.0% control rate of AL growth. The control rate for low myopia to moderate myopia was 66.7%; while the control rate of myopia progression growth was 75.6% after wearing lens for 1a, the control rate of AL growth was 69.2%, and the control rate of the transition rate to moderate myopia was 88.9%.CONCLUSION: For children and adolescents aged 7 to 12 with low myopia, high aspherical lenticule was more effective than single vision glasses in controlling myopia, making it one of the optimal choices for myopia control.

Research progress on the stress-strain index of Corvis ST / 国际眼科杂志(Guoji Yanke Zazhi)

Corneal visualization Scheimpflug technology(Corvis ST)is currently the most commonly used clinical device for assessing in vivo corneal biomechanics. The new parameter stress-strain index(SSI)has been a hot topic of clinical research in recent years, which not only directly reflect corneal biomaterial stiffness, but also closely correlates with the progression of certain diseases. SSI was generated based on the predictions of corneal behavior using finite element(FE)numerical modeling to simulate the effects of intraocular pressure and Corvis ST jets. The SSI algorithm does not change with central corneal thickness(CCT), intraocular pressure, or biomechanically corrected intraocular pressure(BIOP), but it is clearly associated with altered collagen fibres in the corneosclera. The principles of SSI, the relationship between age and SSI, the relationship between axial length and SSI, the relationship between myopia and SSI, and the application of SSI are summarized and concluded.

Role of spherical aberration and coma in orthokeratology for myopia control / 国际眼科杂志(Guoji Yanke Zazhi)

As a highly prevalent global condition, myopia significantly impacts the ocular health of young individuals in China. Orthokeratology lens, as a rigid corneal contact lens, has demonstrated effective control over the progression of myopia; however, its mechanism of action remains incompletely elucidated. As one of the factors influencing visual acuity, higher-order aberrations will undergo marked changes after orthokeratology, with particular emphasis on the alterations in spherical aberrations and coma. The changes in corneal morphology induced by orthokeratology lead to significant positive increase in both spherical aberration and coma. Furthermore, the elevation of spherical aberration and coma demonstrates a negative correlation with the rate of axial length growth following orthokeratology. The interplay among spherical aberration, coma, defocus, accommodation, astigmatism, and pseudo-accommodation may constitute the underlying mechanism governing the control of myopia through orthokeratology.

Therapeutic effects of orthokeratology lens combined with 0.01% atropine eye drops on juvenile myopia / Efeitos terapêuticos da lente de ortoceratologia combinados com colírio atropina 0,01% em miopia juvenil

ABSTRACT Purpose: To explore the therapeutic effects of orthokeratology lens combined with 0.01% atropine eye drops on juvenile myopia. Methods: A total of 340 patients with juvenile myopia (340 eyes) treated from 2018 to December 2020 were divided into the control group (170 cases with 170 eyes, orthokeratology lens) and observation group (170 cases with 170 eyes, orthokeratology lens combined with 0.01% atropine eye drops). The best-corrected distance visual acuity, best-corrected near visual acuity, diopter, axial length, amplitude of accommodation, bright pupil diameter, dark pupil diameter, tear-film lipid layer thickness, and tear break-up time were measured before treatment and after 1 year of treatment. The incidence of adverse reactions was observed. Results: Compared with the values before treatment, the spherical equivalent degree was significantly improved by 0.22 (0.06, 0.55) D and 0.40 (0.15, 0.72) D in the observation and control groups after the treatment, respectively (p<0.01). After the treatment, the axial length was significantly increased by (0.15 ± 0.12) mm and (0.24 ± 0.11) mm in the observation and control groups, respectively, (p<0.01). After the treatment, the amplitude of accommodation significantly declined in the observation group and was lower than that in the control group, whereas both bright and dark pupil diameters significantly increase and were larger than those in the control group (p<0.01). After the treatment, the tear-film lipid layer thickness and tear break-up time significantly declined in the two groups (p<0.01). Conclusions: Orthokeratology lens combined with 0.01% atropine eye drops can synergistically enhance the control effect on juvenile myopia with high safety.

RESUMO Objetivo: Explorar os efeitos terapêuticos das lentes de ortoceratologia combinados com colírio atropina 0,01% em miopia juvenil. Métodos: Um total de 340 pacientes com miopia juvenil (340 olhos) tratados entre 2018 e Dezembro de 2020 foram divididos em Grupo Controle (170 casos com 170 olhos, lentes de ortoceratologia) e Grupo Observação (170 casos com 170 olhos, lentes de ortoceratologia combinadas com colírio atropina 0,01%). A acuidade visual melhor corrigida para longe, acuidade visual melhor corrigida para perto, dioptria, comprimento axial, amplitude de acomodação, diâmetro da pupila brilhante, diâmetro da pupila escura, espessura da camada lipídica da película lacrimal e tempo de ruptura do rasgo foram medidos antes do tratamento e 1 ano depois. A incidência de reações adversas foi observada. Resultados: Antes do tratamento, o grau esférico equivalente foi significativamente melhorado em 0,22 (0,06, 0,55) D e 0,40 (0,15, 0,72) D respectivamente no Grupo Observação e no Grupo Controle após o tratamento (p<0,01). Após tratamento, o comprimento axial foi significativamente aumentado em (0,15 ± 0,12) mm e (0,24 ± 0,11) mm respectivamente nos Grupos Observação e controle (p<0,01), enquanto, no grupo de observação, a amplitude de acomodação diminuiu significativamente e foi inferior a do Grupo Controle, e o diâmetro da pupila brilhante e o diâmetro da pupila escura aumentaram significativamente e foram maiores do que os do Grupo Controle (p<0,01). A espessura da camada lipídica da película lacrimal e o tempo de ruptura do rasgo diminuíram significativamente nos dois grupos (p<0,01) após o tratamento. Conclusões: As lentes de ortoceratologia combinadas com colírio atropina 0,01% podem melhorar significativamente o efeito controle em miopia juvenil com elevada segurança.

Modificaciones biométricas en paciente miopes con implante de la lente fáquica ACRIOL 128

Objetivo: Determinar las modificaciones biométricas en pacientes miopes con implante de la lente fáquica ACRIOL 128. Métodos: Se realizó un estudio transversal con 31 ojos (17 pacientes) con alta miopía tratados con implante de lente fáquica ACRIOL 128, entre septiembre 2016 y febrero 2019, los cuales tenían mediciones biométricas preoperatorias con el sistema IOL Master 3.0.2 y estabilidad refractiva posoperatoria (≤ 0,5 dioptrías) después de los tres meses del implante. Se les efectuaron las mediciones posoperatorias con el propio IOL Master 3.0.2 en modo lente fáquica y con el sistema Scheimpflug Pentacam AXL para compararlas, mediante la prueba t para datos pareados, con una significación del 95 %. Resultados: La edad promedio fue de 29,82 ± 5,99 años, el 82,4 % del sexo femenino. El equivalente esférico preoperatorio medio fue de -12,00 ± 4,10 dioptrías. La diferencia de longitud axial y profundidad de la cámara anterior en milímetros entre el pre- y posoperatorio fue significativa con IOL Master 3.0.2 (0,13 ± 0,33 y -0,08 ± 0,17) y Pentacam AXL (0,12 ± 0,32 y -0,10 ± 0,24), respectivamente. Sin embargo, las posoperatorias entre ambos equipos no fueron significativas (p>0,05) para estas variables, pero sí para las queratometrías. Conclusiones: El implante de la lente fáquica ACRIOL 128 modifica la medición de la longitud axial y la profundidad de la cámara anterior. El IOL Master 3.0.2 y el Pentacam AXL ofrecen mediciones de longitud axial y profundidad de cámara anterior posoperatorias similares, no así para las queratometrías.

Objective: To determine the biometric modifications in myopic patients with ACRIOL 128 phakic lens implantation. Methods: A cross-sectional study was performed on 31 eyes (17 patients) with high myopia treated with ACRIOL 128 phakic lens implant, between September 2016 and February 2019, which had preoperative biometric measurements with the IOL Master 3.0.2 system and postoperative refractive stability (≤ 0.5 diopters) after three months of implantation. Postoperative measurements were performed with the IOL Master 3.0.2 in phakic lens mode and with the Scheimpflug Pentacam AXL system for comparison, using the t-test for paired data, with 95% significance. Results: The average age was 29.82 ± 5.99 years, 82.4% female. The mean preoperative spherical equivalent was -12.00 ± 4.10 diopters. The difference in axial length and anterior chamber depth in millimeters between pre- and postoperative was significant with IOL Master 3.0.2 (0.13 ± 0,33 and -0.08 ± 0.17) and Pentacam AXL (0.12 ± 0.32 and -0.10 ± 0.24), respectively. However, postoperative between the two teams were not significant (p > 0.05) for these variables but significant for keratometries. Conclusions: Implantation of the ACRIOL 128 phakic lens modifies the measurement of axial length and anterior chamber depth. The IOL Master 3.0.2 and Pentacam AXL provide similar postoperative axial length and anterior chamber depth measurements, but not for keratometries.

Comparison between ocular biometry parameters in patients with unilateral congenital glaucoma

Purpose: To compare the axial length (AL) and corneal diameter between glaucomatous eye (GE) and fellow normal eye (NE) in patients with unilateral congenital glaucoma and to obtain a normative database for ocular growth among Indian children below 3 years of age. Methods: Retrospective longitudinal study. Patients who had a follow?up of 3 years from diagnosis with ocular biometry parameters being recorded at least thrice (once a year) and fellow eye being normal were included. Data collected were age, gender, intraocular pressure (IOP), AL, corneal diameter, optic disc findings, diagnosis, and surgery details. Results: Eleven patients were analyzed. All GE underwent combined trabeculotomy with trabeculectomy. Mean (SD) baseline IOP, AL, and corneal diameter were 17.1 (6.7) mmHg, 18.9 (1.1) mm and 12 (0.91) mm in GE, and 11.1 (3.8) mmHg, 17.8 (0.44) mm, and 10.5 (0.58) mm in NE, respectively. Increase in AL was 3.1 mm in the first year followed by 0.6 mm in second year and 0.4 mm in third year in GE compared to 2.6, 0.6, and 0.5 mm in NE, respectively. Corneal diameter increased by 1.1 mm in GE in the first year and remained stable thereafter compared to 0.7 mm in first year followed by 0.3 mm in second year and stable thereafter in NE. The percentage of success was 73% at 3 years. Conclusion: Axial length and corneal diameter were higher in GE than NE at all?time points. With prompt intervention, the growth curve of the GE was made parallel to that of NE.

Simplifying biometry in oil-filled eyes: A novel formula for axial length calculation in eyes with 1000 cSt silicone oil

Purpose: To derive a formula for accurate axial length (AL) assessment using routine ultrasound in silicone oil?filled eyes, where optical biometry is unavailable or not possible. Methods: This was a prospective, consecutive, nonrandomized study of 50 eyes of 50 patients conducted in a tertiary care hospital in North India. AL measurements were taken using both manual A?scan and IOL master, both in silicone oil?filled status and 3 weeks after silicone oil removal. A correction factor of 0.7 was used for AL adjustment in oil?filled eyes. The corrected AL (cAL) was compared with IOL master values in oil?filled eyes. Agreement analysis was carried out using Bland Altman plot. Linear regression analysis was done using uncorrected manual AL to find a new equation. Data was analyzed using Stata 14. A P value <0.05 was taken as significant. Results: The study included 40 males and 10 females, with an age range of 6–83 years (mean 41.9 years). The mean AL of the oil?filled eye as measured by manual A?scan was 31.76 mm ± 3.09 and by IOL master was 24.7 mm ± 1.74. Linear regression analysis was performed in randomly selected 35 eyes of the observed data to obtain a new equation: predicted AL (PAL) = 14 + 0.3 × manual AL. The mean difference between PAL and optically measured AL with silicone oil in situ was 0.98 ± 1.67. Conclusion: We propose a new formula for better prediction of the correct AL in silicone oil?filled eyes using ultrasound?based AL measurement.

Prediction of spherical equivalent refraction and axial length in children based on machine learning

Purpose: Recently, the proportion of patients with high myopia has shown a continuous growing trend, more toward the younger age groups. This study aimed to predict the changes in spherical equivalent refraction (SER) and axial length (AL) in children using machine learning methods. Methods: This study is a retrospective study. The cooperative ophthalmology hospital of this study collected data on 179 sets of childhood myopia examinations. The data collected included AL and SER from grades 1 to 6. This study used the six machine learning models to predict AL and SER based on the data. Six evaluation indicators were used to evaluate the prediction results of the models. Results: For predicting SER in grade 6, grade 5, grade 4, grade 3, and grade 2, the best results were obtained through the multilayer perceptron (MLP) algorithm, MLP algorithm, orthogonal matching pursuit (OMP) algorithm, OMP algorithm, and OMP algorithm, respectively. The R2 of the five models were 0.8997, 0.7839, 0.7177, 0.5118, and 0.1758, respectively. For predicting AL in grade 6, grade 5, grade 4, grade 3, and grade 2, the best results were obtained through the Extra Tree (ET) algorithm, MLP algorithm, kernel ridge (KR) algorithm, KR algorithm, and MLP algorithm, respectively. The R2 of the five models were 0.7546, 0.5456, 0.8755, 0.9072, and 0.8534, respectively. Conclusion: Therefore, in predicting SER, the OMP model performed better than the other models in most experiments. In predicting AL, the KR and MLP models were better than the other models in most experiments.

Effectiveness of 0.01% atropine in anisomyopic children

Purpose: To investigate the change in ocular parameters of anisomyopic children treated with 0.01% atropine. Methods: This retrospective study analyzed the data of anisomyopic children who underwent comprehensive examination at a tertiary eye center in India. Anisomyopic subjects (difference of ?1.00 D) of age 6–12 years who were treated with 0.01% atropine or prescribed regular single vision spectacle and had follow?ups of more than 1 year were included. Results: Data from 52 subjects were included. No difference was observed in the mean rate of change of spherical equivalent (SE) of more myopic eyes between 0.01% atropine (?0.56 D; 95% confidence interval [CI]: ?0.82, ?0.30) and single vision lens wearers (?0.59 D; 95% CI: ?0.80, ?0.37; P = 0.88). Similarly, insignificant change in the mean SE of less myopic eyes was noted between the groups (0.01% atropine group, ?0.62 D; 95% CI: ?0.88, ?0.36 vs. single vision spectacle wearer group, ?0.76 D; 95% CI: ?1.00, ?0.52; P = 0.43). None of the ocular biometric parameters showed any difference between the two groups. Though anisomyopic cohort treated with 0.01% atropine revealed a significant correlation between the rate of change of mean SE and axial length in both eyes (more myopic eyes, r = ?0.58; P = 0.001 and less myopic eyes, r = ?0.82; P < 0.001) compared to single vision spectacle wearer group, the change was not significant. Conclusion: Administration of 0.01% atropine had minimal effect on reducing the rate of myopia progression in anisomyopic eyes.

Relatively anterior lens position in primary angle-closure glaucoma eyes with long axial length

Purpose: To evaluate the refractive status and ocular biometric parameters in primary angle?closure glaucoma (PACG) eyes with different axial lengths (ALs). Methods: In total, 742 Chinese PACG subjects with complete ophthalmic examinations were enrolled. The refractive status was categorized as myopia (spherical equivalent [SE] ??0.5 D), emmetropia (?0.5 D < SE < +0.5 D), and hyperopia (SE ?+0.5 D), whereas the AL was divided into short (AL <22.5 mm), regular (22.5 ? AL <23.5 mm), and long (AL ?23.5 mm). The refractive status and ocular biometric parameters were compared among different AL groups. Results: The mean AL of the PACG eyes was 22.53 ± 0.84 mm (range: 19.68–25.57 mm). The refractive status was significantly different among different AL groups (P < 0.001). Also, 92.6% of hyperopic PACG eyes showed AL <23.5 mm, and 19.0% of myopic PACG eyes showed AL ?23.5 mm. The SE showed significant differences among different AL groups only in the hyperopic subjects (P = 0.012). The AL was significantly longer in myopic eyes (P < 0.001). The PACG eyes with longer AL exhibited lower keratometry, longer central anterior chamber depth and corneal diameter, and lens position and relative lens position closer to the anterior (P < 0.001). Conclusion: Axial hyperopia was common in PACG eyes, and axial myopia was not uncommon. Relatively anterior lens position could explain the occurrence of PACG in the eyes with long AL.

Myopia, axial length, and optic coherence tomography characteristics of the macula in Indian children

Background: Myopia is a common condition affecting a significant proportion of the pediatric population in Asian countries. Aim and Objectives: This study was undertaken to investigate the associations of optical coherence tomography measurements of macular volume and macular thickness with refractive error and axial length in Indian children. Materials and Methods: The prospective observational study was carried out at MRA Medical College, Ambedkar Nagar, Uttar Pradesh. We enrolled 300 consecutive cases (190 cases and 110 controls) of pediatric age group (6–18 years) between January 2015 and December 2018. Pearson’s correlation was performed with refractive errors, axial length, macular thickness, and volume. Results: Children with myopia (SE ?0.5–?4.57 D) tended to have smaller total macular volume and thinner macular thickness as, compared to control. The correlation of macular thickness and macular volume was analyzed with spherical equivalent (SE) and axial length. Macular thickness had negative correlation with SE and positive with axial length, correlation coefficients being observed as (r = ?0.886 and 0.880, P ? 0.001). Total macular volume correlated negatively with SE, (r= ?0.771, P ?0.001) and positively with axial length (r = 0.764, P ?0.001). Conclusion: Increasing axial myopia was associated with increased macular volume and thickness. It establishes the importance of the fact that refractive error should be considered in the interpretation of macular thickness.

Accuracy of Wang-Koch axial length adjustment formulas in calculating postoperative refractive power in cataract patients with high myopia / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To compare the accuracy between Wang-Koch axial length adjustment formulas(SRK/TWK, Holladay ⅠWK)and SRK/T, Haigis, Holladay Ⅰ, Hoffer Q in calculating intraocular lens power of cataract patients with high myopia.METHODS: A total of 42 cataract patients with high myopia(57 eyes)were collected. All eyes underwent phacoemulsification combined with intraocular lens implantation surgery in our Hospital from September 2019 to March 2022. They were divided into two groups according to the axial length(AL): group A(27mm≤AL&#x003C;30mm, 31 eyes)and group B(AL≥30mm, 26 eyes). Patients were followed up at 3mo. The actual postoperative diopter was recorded, and then the refractive mean numerical error(MNE)and mean absolute error(MAE)were calculated.RESULTS: MAE of each formulas was statistically different after surgery(P&#x003C;0.01), among which the MAE of Holladay ⅠWK and SRK/TWK [0.31(0.08, 0.57), 0.34(0.17, 0.63)D] was lower than other formulas. However, there were no statistical difference between SRK/TWK, Holladay ⅠWK and SRK/T, Haigis formulas [0.61(0.27, 1.02), 0.63(0.22, 1.01)D](P&#x003E;0.05). MAE were statistically different among the formulas in group A(27mm≤AL&#x003C;30mm; P&#x003C;0.01). The MAE of Holladay ⅠWK and SRK/TWK was lower than other formulas [0.18(0.05, 0.51), 0.28(0.16, 0.52)D], but there were no statistical difference with SRK/T and Haigis formulas [0.45(0.18, 0.65), 0.50(0.14, 0.75)D](P&#x003E;0.05). In group B(AL≥30mm), the MAE of each formulas was statistically different after surgery(P&#x003C;0.01), among which MAE of Holladay IWK and SRK/TWK was the lowest, followed by SRK/T and Haigis, whereas, Holladay I and Hoffer Q ranked the highest. Furthermore, there were statistical differences between MAE of SRK/TWK, Holladay ⅠWK [0.44(0.23, 0.67), 0.41(0.22, 0.66)D] and SRK/T, Haigis formulas [0.78(0.55, 1.07), 0.75(0.45, 1.25)D](all P&#x003C;0.05).CONCLUSION: For cataract patients with AL ≥30mm, the Wang-Koch axial length adjustment formulas were relatively accurate in calculating diopter of intraocular lens, and had clinical application value to some extent.

Analysis of refractive parameters and theirs correlation with spherical equivalent in preschool children aged 3 to 6 years / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To investigate the distribution of refractive parameters and theirs correlation with spherical equivalent(SE)in preschool children aged 3 to 6 years, and evaluate the accuracy of each screening index in diagnosing refractive errors.METHODS: Cross-sectional study. A total of 791 preschool children, ranging from 3 to 6 years old, who consented to undergo mydriatic refraction were selected. Axial length(AL), corneal refractive power(K), and SE were measured after microcoria optometry and mydriatic optometry. Additionally, the corneal radius of curvature(CR)and the axial length/corneal radius of curvature(AL/CR)ratio were calculated.RESULTS: A total of 791 students participated in the study, out of which 400(50.6%)were male and 391(49.4%)were female. The mean values for AL, CR, AL/CR, and SE were 22.62±0.94mm, 7.81±0.29mm, 2.90±0.09, and +1.95±1.31D, respectively. AL, CR, and AL/CR increased with age. AL and CR were significantly higher in males than in females(all P&#x003C;0.001), while there was no statistically significant difference between AL/CR and SE in males and females(P=0.82, 0.19). The correlation coefficients of SE and AL/CR, AL and CR were -0.86, -0.50 and 0.16, respectively. The results of multiple linear regression analysis indicate that for each unit increase in AL/CR, there was a corresponding shift of 10.91 towards myopia in SE. The sensitivity of AL/CR in screening for myopia was 94.44%, with a specificity of 90.46% and a Youden index of 0.84. For screening myopia under microcoria optometry, the sensitivity was 100%, with a specificity of 66.09% and a Youden index of 0.66. The area under the curve was 0.967 and 0.809 when the ROC curves were plotted using AL/CR and AL as indicators for screening myopia, respectively.CONCLUSION: For large group screening activities where mydriatic optometry is not feasible, AL/CR is better for evaluating refractive status and identifying children with myopia and hyperopia reserve that are lower than normal for their age, compared to AL and microcoria optometry.