Myopia outcome study of atropine in children: Two-year result of daily 0.01% atropine in a European population

PURPOSE

The Myopia Outcome Study of Atropine in Children (MOSAIC) is an investigator-led, double-masked, randomized controlled trial investigating the efficacy and safety of 0.01% atropine eye drops for managing myopia progression in a predominantly White, European population.

METHODS

Children aged 6-16 years with myopia were randomly allocated 2:1 to nightly 0.01% atropine or placebo eye drops in both eyes for 2 years. The primary outcome was cycloplegic spherical equivalent (SE) progression at 24 months. Secondary outcomes included axial length (AL) change, safety and acceptability. Linear mixed models with random intercepts were used for statistical analyses.

RESULTS

Of 250 participants enrolled, 204 (81.6%) completed the 24-month visit (136 (81.4%) treatment, 68 (81.9%) placebo). Baseline characteristics, drop-out and adverse event rates were similar between treatment and control groups. At 24 months, SE change was not significantly different between 0.01% atropine and placebo groups (effect = 0.10 D, p = 0.07), but AL growth was lower in the 0.01% atropine group, compared to the placebo group (-0.07 mm, p = 0.007). Significant treatment effects on SE (0.14 D, p = 0.049) and AL (-0.11 mm, p = 0.002) were observed in children of White, but not non-White (SE = 0.05 D, p = 0.89; AL = 0.008 mm, p = 0.93), ethnicity at 24 months. A larger treatment effect was observed in subjects least affected by COVID-19 restrictions (SE difference = 0.37 D, p = 0.005; AL difference = -0.17 mm, p = 0.001).

CONCLUSIONS

Atropine 0.01% was safe, well-tolerated and effective in slowing axial elongation in this European population. Treatment efficacy varied by ethnicity and eye colour, and potentially by degree of COVID-19 public health restriction exposure during trial participation.

Parapapillary drusen of the retinal pigment epithelium

PURPOSE

To describe the occurrence, morphology and associations of parapapillary drusen of the retinal pigment epithelium (RPE-drusen).

METHODS

Using light microscopy, we histomorphometrically examined enucleated human eyes.

RESULTS

The study included 83 eyes (axial length: 25.9 ± 3.2 mm; range: 20.0-35.0 mm). Eyes with parapapillary RPE-drusen (n = 29 (35%) eyes) as compared to those without drusen had a significantly shorter axial length (24.0 ± 1.8 mm vs 27.0 ± 3.3 mm; p < 0.001), higher prevalence (27/29 vs 12/54; p < 0.001) and longer width (213 ± 125 μm vs 96 ± 282 μm; p < 0.0001) of parapapillary alpha zone, and thicker BM in parapapillary beta zone (8.4 ± 2.7 μm vs 3.9 ± 2.0 μm; p < 0.001) and alpha zone (6.6 ± 3.9 μm vs 4.4 ± 1.5 μm; p = 0.02). Prevalence of parapapillary RPE-drusen was 27 (69%) out of 39 eyes with alpha zone. Beneath the RPE-drusen and in total alpha zone, choriocapillaris was open, while it was closed in the central part of parapapillary beta zone. BM thickness was thicker (p = 0.001) in alpha zone than beta zone, where it was thicker (p < 0.001) than in the region outside of alpha/beta zone. BM thickness outside of alpha/beta zone was not correlated with prevalence of parapapillary RPE-drusen (p = 0.47) or axial length (p = 0.31). RPE cell density was higher in alpha zone than in the region adjacent to alpha zone (22.7 ± 7.3 cells/240 μm vs 18.3 ± 4.1 cells/240 μm; p < 0.001). In the parapapillary RPE-drusen, RPE cells were connected with a PAS-positive basal membrane.

CONCLUSIONS

Parapapillary RPE-drusen as fibrous pseudo-metaplasia of the RPE were associated with shorter axial length, higher prevalence and larger size of alpha zone, and thicker BM in alpha zone and beta zone. The RPE-drusen may be helpful to differentiate glaucomatous parapapillary beta zone from myopic beta zone.

A systematic review and meta-analysis of the efficacy of different optical interventions on the control of myopia in children

To compare the treatment efficacy of childhood myopia control optical interventions [spectacles, soft contact lenses (SCLs) and orthokeratology (OK) lenses], explore the consistency of treatment efficacies during the treatment period and evaluate the impact of baseline spherical equivalent refraction (SER), axial length (AL) and age on the treatment effect. A literature search of EMBASE, PubMed and Google Scholar databases identified 220 articles published between January 2000 and April 2022, which reported the treatment efficacy by differences in the SER and AL change between intervention and control groups. Thirty-five articles were included in the analysis. Treatment effect sizes (ESs) were calculated, where more positive and negative directions indicated greater treatment efficacy for SER and AL respectively. For SER, the ESs with peripheral add design spectacles (0.66) and SCLs (0.53) were large but not significantly different between treatment types (p = 0.69). For AL, ESs with peripheral add design spectacles (-0.37), SCLs (-0.55) and OK lenses (-0.93) were large, but OK lenses had a significantly greater effect than peripheral add design spectacles (p ≤ 0.001). ESs were large during the first 12 months of treatment for all interventions [peripheral add design SCLs and OK (F ≥ 5.39, p ≤ 0.01), peripheral add design spectacles (F = 0.47, p = 0.63)] but reduced towards the end of 24-36 months of treatment. Baseline SER had an impact on the treatment effect with peripheral add design spectacles only. Optical interventions are efficacious in controlling childhood myopia progression. However, treatment effects were largest only during the first 12 months of treatment and reduced over time.

Axial length and pharmacologic pupillary dilation in highly myopic patients

PURPOSE

To determine how high myopia impacts pharmacological pupillary dilation, and to evaluate the relationship between the extent of pharmacologic pupillary dilation and axial length.

METHODS

Patients were grouped into high myopes, defined as one or both eyes having a refractive error greater than - 6 diopters, and controls (between - 2 and + 2 diopters). Dilation was achieved with 1 drop each of tropicamide 1% and phenylephrine 2.5%. Pupil size was measured at full and dim light prior to dilation, then 15 and 30 min after dilation. Biometry was measured for each patient. Statistical analyses were performed using the Mann-Whitney-Wilcoxon tests, two-sample Welch's t-tests, and linear mixed effect models and generalized estimating equations models accounting for inter-eye correlation.

RESULTS

Forty patients (20 high myopes and 20 controls, 80 eyes total) participated in the study. High myopes had larger pupils at baseline and achieved significantly greater pupillary size (7.08 mm, 95% CI: 6.97 to 7.19 mm) than controls (6.23 mm, 95% CI: 5.94 to 6.52 mm) after 30 min of dilation (P < .0005). Fully dilated pupil size at 30 min was significantly correlated with both refractive error (r =  - 0.57, P < .0005) and axial length (r = 0.47, P < .0005). Generalized estimating equations and linear mixed effect models identified other predictive variables of pupil size after dilation including age and white-to-white diameter.

CONCLUSIONS

Highly myopic patients dilate to a larger pupillary size compared to other patients. Predicting dilation based on extent of myopia could facilitate intraocular surgery planning and reduce clinic wait times for myopic patients.

Ciliary muscles contraction leads to axial length extension--The possible initiating factor for myopia

PURPOSE

This study aimed to investigate the underlying factors driving the onset of myopia, specifically the role of the ciliary muscle's contraction in the elongation of the axial length of the eye.

METHODS

The retrospective study was conducted utilizing data from three ophthalmic centers in Shanghai and Beijing. Both Chinese and Caucasian children were involved. The axial length of the subjects' eyes was measured in both relaxed and contracted state of the ciliary muscle. A comprehensive mechanical model was also developed to observe the influence of ciliary muscle contraction on the axial length.

RESULTS

This study included a sample of 198 right eyes of 198 myopic children. Of these, 97 were male and 101 were female, 126 were of Chinese ethnicity and 72 were Caucasian. The age of onset for myopia ranged from 5.9 to 16.9 years old. The axial length of the eye decreased 0.028 ± 0.007mm following dilation, indicating relaxation of the ciliary muscle (t paired student = 15.16, p = 6.72 x 10-35). In contrast, ciliary muscle contraction resulted in an increase in axial length. Considering proportionality, a significant 90.4% (179 eyes) exhibited a reduced axial length, while a minor 9.6% (19 eyes) demonstrated an increase post-mydriasis. Finite element modeling demonstrated that muscle contraction caused a tension force that transmits towards the posterior pole of the eye, causing it to extend posteriorly.

CONCLUSION

The contraction of the ciliary muscle leads to an extension of the axial length. This could potentially be the initiating factor for myopia.

[Effect of corneal e-value on myopia control in children and adolescents with orthokeratology]

Objective: To investigate the influence of corneal e-value on the effectiveness of orthokeratology in controlling myopia in children and adolescents. Methods: A retrospective cohort study was conducted, involving the data from 1 563 myopic patients (1 563 eyes) who underwent orthokeratology at the Affiliated Eye Hospital of Shandong University of Traditional Chinese Medicine from June 2015 to August 2021 and adhered to lens wear for at least 2 years. The cohort consisted of 737 males and 826 females with an average age of (10.84±2.13) years. Based on corneal e-value parameters obtained from corneal topography, patients were categorized into a low e-value group (n=425) and a high e-value group (n=1 138). Data on gender, age, parental myopia history, and baseline measures such as spherical equivalent (SE), axial length, and corneal e-value were collected. Differences in axial length change and corneal fluorescein staining rates were compared between the two groups at 1 and 2 years after the start of lens wear. A generalized linear mixed model was established with axial length change as the dependent variable to analyze the correlation between axial length change and baseline corneal e-value. Results: The initial age of the 1 563 myopic patients was (10.84±2.13) years, with a baseline SE of (-3.05±1.30) D. After 1 year of lens wear, the axial length change was (0.20±0.19) mm in the low e-value group and (0.24±0.20) mm in the high e-value group. After 2 years, the changes were (0.38±0.25) mm and (0.43±0.27) mm, respectively, with statistically significant differences (all P<0.05). The incidence of corneal staining after 1 year of lens wear was 9.2% (39/425) in the low e-value group and 14.1% (160/1 138) in the high e-value group. After 2 years, the rates were 15.8% (67/425) and 21.8% (248/1 138), respectively, with statistically significant differences (all P<0.05). After adjusting for parental myopia history, age, SE, and baseline axial length, the baseline corneal e-value was positively correlated with axial length change at 1 and 2 years after lens wear (all P<0.05). Conclusions: Corneal e-value is an independent factor influencing the effectiveness of orthokeratology in controlling myopia. A smaller corneal e-value is associated with slower axial length growth after orthokeratology, indicating better control of myopia in treated eyes.

Influence of Aberration-Free, Narrowband Light on the Choroidal Thickness and Eye Length

Purpose

To determine whether light chromaticity without defocus induced by longitudinal chromatic aberration (LCA) is sufficient to regulate eye growth.

Methods

An interferometric setup based on a spatial light modulator was used to illuminate the dominant eyes of 23 participants for 30 minutes with three aberration-free stimulation conditions: (1) short wavelength (450 nm), (2) long wavelength (638 nm), and (3) broadband light (450-700 nm), covering a retinal area of 12°. The non-dominant eye was occluded and remained as the control eye. Axial length and choroidal thickness were measured before and after the illumination period.

Results

Axial length increased significantly from baseline for short-wavelength (P < 0.01, 7.4 ± 2.2 µm) and long-wavelength (P = 0.01, 4.8 ± 1.7 µm) light. The broadband condition also showed an increase in axial length with no significance (P = 0.08, 5.1 ± 3.5 µm). The choroidal thickness significantly decreased in the case of long-wavelength light (P < 0.01, -5.7 ± 2.2 µm), but there was no significant change after short-wavelength and broadband illumination. The axial length and choroidal thickness did not differ significantly between the test and control eyes or between the illumination conditions (all P > 0.05). Also, the illuminated versus non-illuminated choroidal zone did not show a significant difference (all P > 0.05).

Conclusions

All stimulation conditions with short- and long-wavelength light and broadband light led to axial elongation and choroidal thinning. Therefore, light chromaticity without defocus induced by LCA is suggested to be insufficient to regulate eye growth.

Translational Relevance

This study helps in understanding if light chromaticity alone is a sufficient regulator of eye growth.

Different efficacy in myopia control: Comparison between orthokeratology and defocus-incorporated multiple segment lenses

PURPOSE

To compare the efficiency of orthokeratology (OK) and defocus-incorporated multiple segment (DIMS) lenses in myopia control in children.

METHODS

This prospective study involved 540 subjects (7-14 years) categorized into three groups: DIMS lenses (180 cases), OK lenses (180 cases), or single-vision spectacles (SVS) (180 cases). After a one-year follow-up, changes in axial length (AL) and differences among the groups were analyzed. The subjects were further divided into a low myopia degree subgroup (LM, -1.50 D ≤ SE ≤ -0.50 D), a moderate myopia degree subgroup (MM, -3.00 D ≤ SE ＜ -1.50 D), and a high myopia degree subgroup (HM, -5.00 D ≤ SE ＜ -3.00 D). A one-way ANOVA and multiple linear regression analysis were used to compare AL elongation and the factors influencing the different groups.

RESULTS

A total of 496 (92 %) subjects completed the study. The mean AL change in the OK lenses, DIMS lenses, and SVS were 0.20±0.18 mm, 0.30±0.22 mm, and 0.38±0.19 mm, respectively (P < 0.001). In the LM subgroup, the OK and DIMS groups showed similar AL changes, but both exhibited slower changes than the SVS group (P = 0.001). In the MM and HM subgroups, the OK lens performed the shortest AL elongation compared with the DIMS lenses and SVS (P < 0.001). Multiple regression analysis showed that the AL change was associated with age (β = -0.038 and P = 0.005), initial AL (β = -0.010 and P = 0.011), initial SE (β = 0.028 and P = 0.007), and interventions using OK lenses (β = -0.172 and P = 0.020) and DIMS lenses (β = -0.089 and P = 0.020).

CONCLUSION

Over a one-year treatment period, OK and DIMS lenses can significantly retard AL elongation compared with SVS. In addition, the OK lenses were more effective than the DIMS lenses in controlling AL in patients with higher degrees of myopia.

The effect of the back optic zone diameter on the treatment zone area and axial elongation in orthokeratology

PURPOSE

To investigate the influence of corneal parameters on the treatment zone area (TZA) after Corneal Refractive Therapy (CRT) with a 5.0-mm back optical zone diameter (BOZD) were worn and to compare changes in the axial length (AL) with traditional 6.0-mm BOZD lenses.

METHODS

This retrospective study involved 146 subjects (7-12 years) who wore orthokeratology (ortho-K) lenses for one year: 86 subjects were treated with CRT 5.0-mm lenses, and 60 subjects were treated with CRT 6.0-mm lenses. The TZA was measured after one year of ortho-K treatment. Both TZA and AL elongation after wearing the two kinds of lenses was compared. The parameters were recorded in the CRT 5.0 group: flat K, steep K, corneal toricity, e value, and anterior corneal elevation values at the 3-, 4-, and 5-mm chords along the principal meridians of the superior, inferior, nasal, and temporal sides. The relationships between these data and the TZA were analyzed.

RESULTS

The TZA was 12.90 ± 5.15 mm2 and 20.61 ± 4.54 mm2, and the AL elongation was 0.15 ± 0.18 mm and 0.26 ± 0.18 mm in the CRT 5.0 group and the CRT 6.0 group, respectively (all p < 0.001). The one-year AL elongation was significantly associated with initial age and the TZA (r =  - 0.394, 0.393; all p < 0.001) in the CRT 5.0 group. The following corneal parameters were found to have statistically significant correlations with the TZA: the e value, difference in corneal elevation (nasal-temporal at the 3-, 4-, and 5-mm chord), and the absolute value of elevation difference (nasal-temporal at the 3- and 4-mm chord and inferior-superior at the 3-, 4-, and 5-mm chord). The e value was the only relevant factor for the TZA by multiple regression analysis (unstandardized β = 14.219, p = 0.008). In the CRT 6.0 group, the one-year AL elongation was statistically significantly associated only with initial age (r =  - 0.605, p = 0.005), but not with the TZA (p = 0.161).

CONCLUSIONS

A smaller TZA induced by a smaller BOZD may be beneficial for retarding AL elongation in children undergoing ortho-K treatment. The morphology and eccentricity of the cornea may show effects on the TZA.

A pilot study of axial length changes associated with myopia control spectacles in subjects reading under mesopic conditions

PURPOSE

To investigate whether axial length changes in subjects wearing myopia control spectacles under mesopic conditions.

METHODS

Young users of monofocal spectacles with myopic spherical equivalent ranging from -1.00 D to -5.00 D were enrolled prospectively. Subjects were tested while using a pair of special defocus spectacles with a central zone including the distance myopic correction and a peripheral zone with an addition of +3.50 D. Subjects first read an online book with black letters on white background on a desktop computer with their monofocal spectacles for 20 minutes and then read with special defocus spectacles for another 20 minutes. Reading took place in a darkened room under 20 lux illumination. Before and after these periods, axial length of the right eye was measured ten times using the Lenstar, and average measurements were recorded.

RESULTS

The 11 subjects in this pilot study had a mean age of 20.9 ± 7.7 years, and 1 was female. Their mean spherical equivalent of the right eyes was -3.20 ± 2.29 D. As expected, axial length increased by 8.2 ± 9.4 μm (P < 0.01) after 20 minutes of reading with monofocal spectacles in low light. When reading with defocus spectacles under the same conditions, the axial length saw an additional, nonsignificant change of 2.2 ± 12.2 μm (P = 0.56).

CONCLUSIONS

When reading in mesopic conditions, the axial length in study subjects did not return to baseline values with myopia control spectacles.

Relative corneal refractive power shift and inter-eye differential axial growth in children with myopic anisometropia treated with bilateral orthokeratology

PURPOSE

To investigate the relationship between relative corneal refractive power shift (RCRPS) and axial length growth (ALG) in bilateral myopic anisometropes treated with orthokeratology.

METHODS

A total of 102 children with myopic anisometropia in this prospective interventional study were randomly assigned to the spectacle group and orthokeratology group. Axial length (AL) and corneal topography was measured at baseline and the 12-month follow-up visit. ALG was defined as the difference between the two measurements, and RCRPS profiles were calculated from two axial maps obtained.

RESULTS

In the orthokeratology group, the ALG in the more myopic eye (0.06 ± 0.15 mm) was significantly smaller than that in the less myopic eye (0.15 ± 0.15 mm, p < 0.001), and the interocular difference in AL significantly decreased following 1-year treatment, from 0.47 ± 0.32 to 0.38 ± 0.28 mm (p < 0.001). However, in the spectacle group, the ALG was similar between the two eyes, and the interocular difference in AL did not change significantly over one year (all p > 0.05). The interocular difference in ALG in the orthokeratology group was significantly correlated with the interocular difference in RCRPS (dRCRPS, β=-0.003, p < 0.001) and the interocular difference in baseline AL (β=-0.1179, p < 0.001), with R2 being 0.6197.

CONCLUSION

Orthokeratology was effective in decreasing the magnitude of anisometropia. The interocular variation in RCRPS is an important factor accounting for the reduction of interocular ALG difference in anisomyopic children post-orthokeratology. These results provide insight into establishing eye-specific myopia control guidelines during orthokeratology treatment for myopic anisometropes.

Assessment of dynamic corneal response parameters in Chinese patients of different ages with myopia and orthokeratology lenses using the Corvis ST

OBJECTIVE

To investigate the effects of orthokeratology lenses (OK lenses) on corneal biomechanics in subjects of different ages.

METHODS

Fifty subjects with mild to moderate myopia were categorized into three groups (Group I-III) based on their age. Corvis ST was used to collect dynamic corneal response parameters (DCRs) at different follow-up time points. Repeated measures analysis of variance combined with simple effect analysis was used to analyze the changes in DCRs in different groups during the follow-up period. Multiple linear regression analysis was used to analyze the correlations between axial length growth (ALG) at 6 months (ALG-6M) or 12 months (ALG-12M) and sex, baseline spherical equivalent refraction (SER), and DCRs.

RESULTS

The DCRs changed in all three groups after wearing OK lenses. Most DCRs showed significant differences between baseline and 6 months after wearing OK lenses, while the differences between DCRs at 6 months and 12 months were not statistically significant. No significant differences in DCRs were observed among the three groups at the same follow-up time point. Additionally, at 6 months post-OK lens wear, ALG-6M was significantly correlated with velocity of the corneal apex at the first applanation (A1V-6M) (P = 0.002), Corvis biomechanical index (CBI-6M) (P = 0.004), the maximum amount of corneal movement (DAM-6M) (P = 0.010), deformation amplitude ratio of 2 mm (DAR2-6M) (P = 0.010), and stress-strain index (SSI-6M) (P = 0.038) in Group I. Furthermore, ALG-12M showed significant correlations with SSI-6M (P = 0.031), peak distance at the DAM (PD)-6M (P = 0.037), baseline Ambrósio Relational Thickness to the horizontal profile (P = 0.013) in Group I.

CONCLUSIONS

The majority of DCRs displayed significant changes within the initial 6 months of OK lens wear. Minimal variation in DCRs was observed across different age groups at the same follow-up time point. Certain DCR parameters exhibited correlations with ALG, suggesting their potential in predicting ALG in myopic children undergoing OK lenses correction.

Correlation analysis of angles κ and α with the refraction and anterior segment parameters in children

AIM

To investigate the correlation of angles α and κ with the refractive and biological parameters in children.

METHODS

This case-series study included 438 eyes of 219 children (males/females = 105/114, age: 3-15 years). Ocular biometric parameters, including axial length, corneal radius of curvature (CR), white-to-white distance (WTW), angle κ and angle α, were measured using IOL Master 700; auto-refraction were assessed under cycloplegia. The eyes were assigned to different groups based on CR, WTW, and gender to compare the angles α and κ, and analyze the correlations between the differences of biological parameters on angles α and κ.

RESULTS

The means of axial length, CR, WTW, angle α, and angle κ were 23.24 ± 1.14 mm, 7.79 ± 0.27 mm, 11.68 ± 0.41 mm, 0.45 ± 0.25 mm, and 0.27 ± 0.22 mm, respectively. Angle α was correlated with CR and WTW (fixed effect coefficient [FEC] = 0.237, p = 0.015; FEC = -0.109, p = 0.003; respectively), and angle κ also correlated with CR and WTW (FEC = 0.271, p = 0.003; FEC = -0.147, p < 0.001, respectively). Comparing subgroups, the large CR and small WTW group had larger angles α (0.49 ± 0.27 vs. 0.41 ± 0.21, p < 0.001; 0.46 ± 0.27 vs. 0.44 ± 0.21, p < 0.05, respectively) and κ (0.29 ± 0.25 vs. 0.24 ± 0.15, p < 0.01; 0.29 ± 0.25 vs. 0.26 ± 0.19, p < 0.05, respectively). The differences in interocular angles α and κ showed correlation with interocular WTW (r = - 0.255, p < 0.001; r = - 0.385, p < 0.001). Eyes with smaller WTW tended to have larger angle κ (0.28 ± 0.27 vs. 0.25 ± 0.15, p < 0.05).

CONCLUSION

The size of angle α/κ may be correlated to CR and WTW, and a larger WTW eye may suggest a smaller angle κ compared with the fellow eye.

Prevalence and associated factors of myopia in children and adolescents in Russia: the Ural Children Eye Study

BACKGROUND

To assess the prevalence of myopia and the distribution of ocular axial length as surrogate for myopic refractive error in school children in a population in Russia.

METHODS

The Ural Children Eye Study, a school-based case-control study, was conducted in Ufa/Bashkortostan/Russia from 2019 to 2022 and included 4933 children (age: 9.7±2.6 years; range: 6.2-18.8 years). The parents underwent a detailed interview and the children an ophthalmological and general examination.

RESULTS

Prevalence of any myopia (≤-0.50 dioptres (D)), minor myopia (-0.50 D to -1.0 D), moderate myopia (-1.01 D to -5.99 D) and high myopia (≤-6.0D) was 2187/3737 (46.2%; 95% CI 44.8% to 48.6%), 693/4737 (14.6%; 95% CI 13.6% to 15.6%), 1430/4737 (30.2%; 95% CI 28.9% to 31.5%) and 64/4737 (1.4%; 95% CI 1.0% to 1.7%), respectively. In the children aged 17+ years, prevalence of any, minor, moderate and high myopia was 170/259 (65.6%; 95% CI 59.8% to 71.5%), 130/259 (50.2%; 95% CI 44.1% to 56.3%), 28/259 (10.8%; 95% CI 7.0% to 14.6%) and 12/259 (4.6%; 95% CI 2.1% to 7.2%), respectively. After adjusting for corneal refractive power (beta: 0.09) and lens thickness (beta: -0.08), larger myopic refractive error was associated (r2=0.19) with older age (beta: 0.33), female sex (beta: 0.04), higher prevalence of maternal (beta: 0.15) and paternal (beta: 0.12) myopia, more time spent in school, with reading books or playing with the cell phone (beta: 0.05) and less total time spent outdoors (beta: 0.05). Axial length and myopic refractive error increased by 0.12 mm (95% CI 0.11 to 0.13) and -0.18 D (95% CI 0.17 to 0.20), respectively, per year of age.

CONCLUSIONS

In this ethnically mixed urban school children population from Russia, prevalence of any myopia (65.6%) and high myopia (4.6%) in children aged 17+ years was higher than in adult populations in the same region and it was lower than in East Asian school children, with similar associated factors.

The effect of corneal power on the accuracy of 14 IOL power formulas

BACKGROUND

This study evaluates the impact of corneal power on the accuracy of 14 newer intraocular lens (IOL) calculation formulas in cataract surgery. The aim is to assess how these formulas perform across different corneal curvature ranges, thereby guiding more precise IOL selection.

METHODS

In this retrospective case series, 336 eyes from 336 patients who underwent cataract surgery were studied. The cohort was divided into three groups according to preoperative corneal power. Key metrics analyzed included mean prediction error (PE), standard deviation of PE (SD), mean absolute prediction error (MAE), median absolute error (MedAE), and the percentage of eyes with PE within ± 0.25 D, 0.50 D, ± 0.75 D, ± 1.00 D and ± 2.00 D.

RESULTS

In the flat K group (Km < 43 D), VRF-G, Emmetropia Verifying Optical Version 2.0 (EVO2.0), Kane, and Hoffer QST demonstrated lower SDs (± 0.373D, ± 0.379D, ± 0.380D, ± 0.418D, respectively) compared to the VRF formula (all P < 0.05). EVO2.0 and K6 showed significantly different SDs compared to Barrett Universal II (BUII) (all P < 0.02). In the medium K group (43 D ≤ Km < 46 D), VRF-G, BUII, Karmona, K6, EVO2.0, Kane, and Pearl-DGS recorded lower MAEs (0.307D to 0.320D) than Olsen (OLCR) and Castrop (all P < 0.03), with RBF3.0 having the second lowest MAE (0.309D), significantly lower than VRF and Olsen (OLCR) (all P < 0.05). In the steep K group (Km ≥ 46D), RBF3.0, K6, and Kane achieved significantly lower MAEs (0.279D, 0.290D, 0.291D, respectively) than Castrop (all P < 0.001).

CONCLUSIONS

The study highlights the varying accuracy of newer IOL formulas based on corneal power. VRF-G, EVO2.0, Kane, K6, and Hoffer QST are highly accurate for flat corneas, while VRF-G, RBF3.0, BUII, Karmona, K6, EVO2.0, Kane, and Pearl-DGS are recommended for medium K corneas. In steep corneas, RBF3.0, K6, and Kane show superior performance.

[Preliminary study on automatic quantification and grading of leopard spots fundus based on deep learning technology]

Objective: To achieve automatic segmentation, quantification, and grading of different regions of leopard spots fundus (FT) using deep learning technology. The analysis includes exploring the correlation between novel quantitative indicators, leopard spot fundus grades, and various systemic and ocular parameters. Methods: This was a cross-sectional study. The data were sourced from the Beijing Eye Study, a population-based longitudinal study. In 2001, a group of individuals aged 40 and above were surveyed in five urban communities in Haidian District and three rural communities in Daxing District of Beijing. A follow-up was conducted in 2011. This study included individuals aged 50 and above who participated in the second 5-year follow-up in 2011, considering only the data from the right eye. Color fundus images centered on the macula of the right eye were input into the leopard spot segmentation model and macular detection network. Using the macular center as the origin, with inner circle diameters of 1 mm, 3 mm, and outer circle diameter of 6 mm, fine segmentation of the fundus was achieved. This allowed the calculation of the leopard spot density (FTD) and leopard spot grade for each region. Further analyses of the differences in ocular and systemic parameters among different regions' FTD and leopard spot grades were conducted. The participants were categorized into three refractive types based on equivalent spherical power (SE): myopia (SE<-0.25 D), emmetropia (-0.25 D≤SE≤0.25 D), and hyperopia (SE>0.25 D). Based on axial length, the participants were divided into groups with axial length<24 mm, 24-26 mm, and>26 mm for the analysis of different types of FTD. Statistical analyses were performed using one-way analysis of variance, Kruskal-Wallis test, Bonferroni test, and Spearman correlation analysis. Results: The study included 3 369 participants (3 369 eyes) with an average age of (63.9±10.6) years; among them, 1 886 were female (56.0%) and 1, 483 were male (64.0%). The overall FTD for all eyes was 0.060 (0.016, 0.163); inner circle FTD was 0.000 (0.000, 0.025); middle circle FTD was 0.030 (0.000, 0.130); outer circle FTD was 0.055 (0.009, 0.171). The results of the univariate analysis indicated that FTD in various regions was correlated with axial length (overall: r=0.38, P<0.001; inner circle: r=0.31, P<0.001; middle circle: r=0.36, P<0.001; outer circle: r=0.39, P<0.001), subfoveal choroidal thickness (SFCT) (overall: r=-0.69, P<0.001; inner circle: r=-0.57, P<0.001; middle circle: r=-0.68, P<0.001; outer circle: r=-0.72, P<0.001), age (overall: r=0.34, P<0.001; inner circle: r=0.30, P<0.001; middle circle: r=0.31, P<0.001; outer circle: r=0.35, P<0.001), gender (overall: r=-0.11, P<0.001; inner circle: r=-0.04, P<0.001; middle circle: r=-0.07, P<0.001; outer circle: r=-0.11, P<0.001), SE (overall: r=-0.20; P<0.001; inner circle: r=-0.19, P<0.001; middle circle: r=-0.20, P<0.001; outer circle: r=-0.20, P<0.001), uncorrected visual acuity (overall: r=-0.18, P<0.001; inner circle: r=-0.26, P<0.001; middle circle: r=-0.24, P<0.001; outer circle: r=-0.22, P<0.001), and body mass index (BMI) (overall: r=-0.11, P<0.001; inner circle: r=-0.13, P<0.001; middle circle: r=-0.14, P<0.001; outer circle: r=-0.13, P<0.001). Further multivariate analysis results indicated that different region FTD was correlated with axial length (overall: β=0.020, P<0.001; inner circle: β=-0.022, P<0.001; middle circle: β=0.027, P<0.001; outer circle: β=0.022, P<0.001), SFCT (overall: β=-0.001, P<0.001; inner circle: β=-0.001, P<0.001; middle circle: β=-0.001, P<0.001; outer circle: β=-0.001, P<0.001), and age (overall: β=0.002, P<0.001; inner circle: β=0.001, P<0.001; middle circle: β=0.002, P<0.001; outer circle: β=0.002, P<0.001). The distribution of overall (H=56.76, P<0.001), inner circle (H=72.22, P<0.001), middle circle (H=75.83, P<0.001), and outer circle (H=70.34, P<0.001) FTD differed significantly among different refractive types. The distribution of overall (H=373.15, P<0.001), inner circle (H=367.67, P<0.001), middle circle (H=389.14, P<0.001), and outer circle (H=386.89, P<0.001) FTD differed significantly among different axial length groups. Furthermore, comparing various levels of FTD with systemic and ocular parameters, significant differences were found in axial length (F=142.85, P<0.001) and SFCT (F=530.46, P<0.001). Conclusions: The use of deep learning technology enables automatic segmentation and quantification of different regions of theFT, as well as preliminary grading. Different region FTD is significantly correlated with axial length, SFCT, and age. Individuals with older age, myopia, and longer axial length tend to have higher FTD and more advanced FT grades.

Impact of pupil and defocus ring intersection area on retinal defocus

PURPOSE

With the rising prevalence of myopia, especially among the young, orthokeratology (Ortho-K) stands out as a promising approach, not only to reduce myopia but also to control the progression of axial length (AL). This study examined how the intersection area between the pupil and defocus ring influenced retinal defocus and axial growth after Ortho-K.

METHODS

A case-control study was conducted with 100 participants (100 eyes). Both AL and the refraction difference value (RDV), that is, the peripheral refractive error measured with respect to the central value after wearing Ortho-K lenses, were determined. Subjects were categorised into two groups based on the size of the intersection area after 3 months of lens wear: Group A (<4.58 mm2 ) and Group B (≥4.58 mm2 ).

RESULTS

Group B demonstrated significantly lower changes in AL and RDV at 30-40° and 40-53° compared with Group A after 3 months of lens wear (all p < 0.05). After 6 months of lens wear, Group B showed significantly lower changes in AL and RDV in the 40-53° region compared with Group A (all p < 0.05). Correlation analysis revealed that as the intersection area increased, the changes in AL and RDV at 0-53°, 30-40° and 40-53° eccentricity decreased after both 3 and 6 months of lens wear (all p < 0.01).

CONCLUSIONS

A larger intersection area between the pupil and defocus ring within a certain time period can cause a greater amount of myopic defocus at 30-53° from the fovea. The results suggest that a larger intersection area might lead to more effective control of axial growth.

Limitations of constant optimization with disclosed intraocular lens power formulae

PURPOSE

To investigate the effect of formula constants on predicted refraction and limitations of constant optimization for classical and modern intraocular lens (IOL) power calculation formulae.

SETTING

Tertiary care center.

DESIGN

Retrospective single-center consecutive case series.

METHODS

This analysis is based on a dataset of 888 eyes before and after cataract surgery with IOL implantation (Hoya Vivinex). Spherical equivalent refraction predSEQ was predicted using IOLMaster 700 data, IOL power, and formula constants from IOLCon ( https://iolcon.org ). The formula prediction error (PE) was derived as predSEQ minus achieved spherical equivalent refraction for the SRKT, Hoffer Q, Holladay, Haigis, and Castrop formulae. The gradient of predSEQ (gradSEQ) as a measure for the effect of the constants on refraction was calculated and used for constant optimization.

RESULTS

Using initial formula constants, the mean PE was -0.1782 ± 0.4450, -0.1814 ± 0.4159, -0.1702 ± 0.4207, -0.1211 ± 0.3740, and -0.1912 ± 0.3449 diopters (D) for the SRKT, Hoffer Q, Holladay, Haigis, and Castrop formulas, respectively. gradSEQ for all formula constants (except gradSEQ for the Castrop R) decay with axial length because of interaction with the effective lens position (ELP). Constant optimization for a zero mean PE (SD: 0.4410, 0.4307, 0.4272, 0.3742, 0.3436 D) results in a change in the PE trend over axial length in all formulae where the constant acts directly on the ELP.

CONCLUSIONS

With IOL power calculation formulae where the constant(s) act directly on the ELP, a change in constant(s) always changes the trend of the PE according to gradSEQ. Formulae where at least 1 constant does not act on the ELP have more flexibility to zero the mean or median PE without coupling with a PE trend error over axial length.

ASSOCIATION OF TESSELLATION DENSITY WITH PROGRESSION OF AXIAL LENGTH AND REFRACTION IN CHILDREN: An Artificial Intelligence-Assisted 4-Year Study

PURPOSE

To investigate fundus tessellation density (TD) and its association with axial length (AL) elongation and spherical equivalent (SE) progression in children.

METHODS

The school-based prospective cohort study enrolled 1,997 individuals aged 7 to 9 years in 11 elementary schools in Mojiang, China. Cycloplegic refraction and biometry were performed at baseline and 4-year visits. The baseline fundus photographs were taken, and TD, defined as the percentage of exposed choroidal vessel area in the photographs, was quantified using an artificial intelligence-assisted semiautomatic labeling approach. After the exclusion of 330 ineligible participants because of loss to follow-up or ineligible fundus photographs, logistic models were used to assess the association of TD with rapid AL elongation (>0.36 mm/year) and SE progression (>1.00 D/year).

RESULTS

The prevalence of tessellation was 477 of 1,667 (28.6%) and mean TD was 0.008 ± 0.019. The mean AL elongation and SE progression in 4 years were 0.90 ± 0.58 mm and -1.09 ± 1.25 D. Higher TD was associated with longer baseline AL (β, 0.030; 95% confidence interval: 0.015-0.046; P < 0.001) and more myopic baseline SE (β, -0.017; 95% confidence interval: -0.032 to -0.002; P = 0.029). Higher TD was associated with rapid AL elongation (odds ratio, 1.128; 95% confidence interval: 1.055-1.207; P < 0.001) and SE progression (odds ratio, 1.123; 95% confidence interval: 1.020-1.237; P = 0.018).

CONCLUSION

Tessellation density is a potential indicator of rapid AL elongation and refractive progression in children. TD measurement could be a routine to monitor AL elongation.

Effect of capsular tension ring on the refractive outcomes of patients with extreme high axial myopia after phacoemulsification

PURPOSE

The aim of the study is to evaluate the effect of capsular tension ring (CTR) implantation following cataract surgery on the refractive outcomes of patients with extreme high axial myopia.

METHODS

Sixty eyes (with an axial length of ≥26 mm) were retrospectively reviewed and classified into two groups: CTR group (n = 30), which underwent CTR implantation following phacoemulsification, and control group (n = 30), which did not undergo CTR implantation. Intraocular lens (IOL) calculation was performed using Barrett Universal II (UII), Haigis, and SRK/T formulas. The refractive prediction error (PE) was calculated by subtracting the postoperative refraction from predicted refraction. The mean PE (MPE), mean absolute error (MAE), and percentages of eyes that had a PE of ±0.25, ±0.50, ±1.00, or ±2.00 diopters (D) were calculated and compared.

RESULTS

No significant differences were observed in PE between the two groups. The Barrett UII formula revealed a lower AE in the CTR group than in the control group (p = 0.015) and a lower AE than the other two formulas (p = 0.0000) in both groups. The Barrett UII formula achieved the highest percentage of eyes with a PE of ±0.25 D (66.67%).

CONCLUSIONS

The refractive outcomes were more accurate in eyes with CTR implantation than in those with routine phacoemulsification based on the Barrett UII formula. The Barrett UII formula was recommended as the appropriate formula when planning CTR implantation in high myopia.

Comparison of the formula accuracy for calculating multifocal intraocular lens power: a single center retrospective study in Korean patients

This study evaluated the accuracy of newer formulas (Barrett Universal II, EVO 2.0, Kane, Hoffer QST, and PEARL-DGS) and the Haigis formula in Korean patients with the Alcon TFNT multifocal intraocular lens. In total, 3100 randomly selected eyes of 3100 patients were retrospectively reviewed. After constant optimization, the standard deviation (SD) of the prediction error was assessed for the entire group, and the root mean square error was compared for short and long axial length (AL) subgroup analysis. The Cooke-modified AL (CMAL) was experimentally applied to the Haigis formula. All the newer formulas performed well, but they did not significantly outperform the Haigis formula. In addition, all the newer formulas exhibited significant myopic outcomes (- 0.23 to - 0.29 diopters) in long eyes. Application of the CMAL to the Haigis formula with single constant optimization produced similar behavior and higher correlation with the newer formulas. The CMAL-applied triple-optimized Haigis formula yielded a substantially smaller SD, even superior to the Barrett and Hoffer QST formulas. The AL modification algorithms such as the CMAL used in newer formulas to cope with optical biometry's overestimation of the AL in long eyes seemed to overcompensate, particularly in the long eyes of the East Asian population.

Sympathetic nervous system activity is associated with choroidal thickness and axial length in school-aged children

BACKGROUND/AIMS

We aim to explore the effect of sympathetic nervous system (SNS) on choroid thickness (ChT) and axial length (AL).

METHODS

Students of grade 2 and 3 from a primary school were included and followed for 1 year. Visual acuity, refraction, AL and ChT were measured. Morning urine samples were collected for determining SNS activity by analysing concentrations of epinephrine, norepinephrine and dopamine using the liquid chromatography-tandem mass spectrometry. The most important factor (factor 1) was calculated using factor analysis to comprehensively indicate the SNS activity.

RESULTS

A total of 273 students were included, with an average age of 7.77±0.69 years, and 150 (54.95%) were boys. Every 1 µg/L increase in epinephrine is associated with 1.60 µm (95% CI 0.30 to 2.90, p=0.02) decrease in average ChT. Every 1 µg/L increase in norepinephrine is associated with 0.53 µm (95% CI 0.08 to 0.98, p=0.02) decrease in the ChT in inner-superior region. The factor 1 was negatively correlated with the ChT in the superior regions. Every 1 µg/L increase in norepinephrine was associated with 0.002 mm (95% CI 0.0004 to 0.004, p=0.016) quicker AL elongation. The factor 1 was positively correlated with AL elongation (coefficient=0.037, 95% CI 0.005 to 0.070, p=0.023).

CONCLUSIONS

We hypothesised that chronic stress characterised by elevated level of the SNS, was associated with significant increase in AL elongation, probably through thinning of the choroid.

Refractive outcomes of immediately sequential bilateral cataract surgery in eyes with long and short axial lengths

PURPOSE

To report the refractive outcomes of long (≥25.00 mm) and short (≤22.00 mm) axial length (AL) eyes undergoing immediately sequential bilateral cataract surgery (ISBCS).

METHODS

In this retrospective cohort study, patients who underwent ISBCS were identified and eyes of patients with bilateral long and short ALs were included. Pre- and postoperative biometry, autorefraction, and ocular comorbidities or complications were recorded. The primary outcome was the mean refractive prediction error.

RESULTS

Thirty-seven patients (74 eyes) with long ALs and 18 patients (36 eyes) with short ALs were included. The means ± standard deviations of the ALs were 26.40 ± 1.38 mm and 21.44 ± 0.46 mm in the long and short AL groups, respectively. In long AL eyes, the mean absolute error from the biometry-predicted refraction was - 0.16 ± 0.46 D, corresponding to 74% of eyes achieving a refraction within ±0.50 D of the predicted value. In short AL eyes, the mean absolute error was - 0.63 ± 0.73 D, corresponding to 44% of eyes achieving a refraction within ±0.50 D of the predicted value. Eight (44.4%) patients with short AL eyes had a myopic deviation greater than ±0.50 D from the predicted result in both eyes.

CONCLUSIONS

Compared to patients with long AL eyes, ISBCS in patients with short ALs had a wider variance in refractive outcome and a lower rate of achieving a postoperative refraction within ±0.50 D of the predicted target.

Modified intraocular lens power selection method according to biometric subgroups Eom IOL power calculator

This study evaluates the accuracy of a newly developed intraocular lens (IOL) power calculation method that applies four different IOL power calculation formulas according to 768 biometric subgroups based on keratometry, anterior chamber depth, and axial length. This retrospective cross-sectional study was conducted in at Korea University Ansan Hospital. A total of 1600 eyes from 1600 patients who underwent phacoemulsification and a ZCB00 IOL in-the-bag implantation were divided into two datasets: a reference dataset (1200 eyes) and a validation dataset (400 eyes). Using the reference dataset and the results of previous studies, the Eom IOL power calculator was developed using 768 biometric subgroups. The median absolute errors (MedAEs) and IOL Formula Performance Indexes (FPIs) of the Barrett Universal II, Haigis, Hoffer Q, Holladay 1, Ladas Super, SRK/T, and Eom formulas using the 400-eye validation dataset were compared. The MedAE of the Eom formula (0.22 D) was significantly smaller than that of the other four formulas, except for the Barrett Universal II and Ladas Super formulas (0.24 D and 0.23 D, respectively). The IOL FPI of the Eom formula was 0.553, which ranked first, followed by the Ladas Super (0.474), Barrett Universal II (0.470), Holladay 1 (0.444), Hoffer Q (0.396), Haigis (0.392), and SRK/T (0.361) formulas. In conclusion, the Eom IOL power calculator developed in this study demonstrated similar or slightly better accuracy than the Barrett Universal II and Ladas Super formulas and was superior to the four traditional IOL power calculation formulas.

Unexpected findings: loss of corneal endothelial cells in Uygur patients with exfoliation syndrome

PURPOSE

This study aimed to investigate anterior segment parameters in patients with exfoliation syndrome (XFS) and exfoliation glaucoma (XFG).

METHODS

The study adopted a retrospective case series design, involving a total of 56 patients (112 eyes) with unrelated XFS/XFG (XFS: 26 patients/60 eyes; XFG: 30 patients/44 eyes) and 100 age-related cataract cases as the control group (200 eyes). The participants were evaluated at the ophthalmology department of the First Affiliated Hospital of Xinjiang Medical University. Clinical data, including eye axial length, anterior chamber depth, white-to-white distance, central corneal thickness, and corneal endothelial cell density (ECD), were collected for statistical analysis.

RESULTS

ECD exhibited a significant difference between the XFS/XFG and age-related cataract groups (P < 0.001), while the remaining indexes did not show statistical differences (P > 0.05). Ocular parameters in patients with XFS and XFG were distinct from those in age-related cataract cases, with consistent results. Notably, there were no statistically significant differences between XFS and XFG patients.

CONCLUSIONS

ECD is reduced in XFS/XFG patients compared with age-related cataract subjects. It is crucial to remain vigilant to enhance surgical safety in XFS/XFG patients and prevent complications proactively.

Association of refractive outcome with postoperative anterior chamber depth measured with 3 optical biometers

PURPOSE

This study evaluated the relationship between refractive outcomes and postoperative anterior chamber depth (ACD, measured from corneal epithelium to lens) measured by swept-source optical coherence tomography (SS-OCT), optical low-coherence reflectometry (OLCR), and Scheimpflug devices under the undilated pupil.

METHODS

Patients undergoing cataract phacoemulsification with intraocular lens (IOL) implantation in a hospital setting were enrolled. Postoperative ACD (postACD) was performed with an SS-OCT device, an OLCR device, and a Scheimpflug device at least 1 month after cataract surgery. After adjusting the mean predicted error to 0, differences in refractive outcomes were calculated with the Olsen formula using actual postACD measured from 3 devices and predicted value.

RESULTS

Overall, this comparative case study included 69 eyes of 69 patients, and postACD measurements were successfully taken using all 3 devices. The postACD measured with the SS-OCT, OLCR, and Scheimpflug devices was 4.59 ± 0.30, 4.50 ± 0.30, and 4.54 ± 0.32 mm, respectively. Statistically significant differences in postACD were found among 3 devices (P < 0.001), with intraclass correlation coefficients (ICCs) and Bland-Altman showing good agreement. No significant difference in median absolute error was found with the Olsen formula using actual postACD obtained with 3 devices. Percentage prediction errors were within ± 0.50 D in 65% (OLCR), 70% (Scheimpflug), and 67% (SS-OCT) calculated by actual postACD versus 64% by predicted value.

CONCLUSION

Substantial agreement was found in postACD measurements obtained from the SS-OCT, OLCR, and Scheimpflug devices, with a trend toward comparable refractive outcomes in the Olsen formula. Meanwhile, postACD measurements may be potentially superior for the additional enhancement of refractive outcomes.

Repeatability of biometric measures from the IOLMaster 700 in a cataractous population

PURPOSE

The purpose of this study was to investigate the repeatability of biometric measures and also to assess the interactions between the uncertainties in these measures for use in an error propagation model, using data from a large patient cohort.

METHODS

In this cross-sectional non-randomised study we evaluated a dataset containing 3379 IOLMaster 700 biometric measurements taken prior to cataract surgery. Only complete scans with at least 3 successful measurements for each eye performed on the same day were considered. The mean (Mean) and standard deviations (SD) for each sequence of measurements were derived and analysed. Correlations between the uncertainties were assessed using Spearman rank correlations.

RESULTS

In the dataset with 677 eyes matching the inclusion criteria, the within subject standard deviation and repeatability for all parameters match previously published data. The SD of the axial length (AL) increased with the Mean AL, but there was no noticeable dependency of the SD of any of the other parameters on their corresponding Mean value. The SDs of the parameters are not independent of one another, and in particular we observe correlations between those for AL, anterior chamber depth, aqueous depth, lens thickness and corneal thickness.

CONCLUSIONS

The SD change over Mean for AL measurement and the correlations between the uncertainties of several biometric parameters mean that a simple Gaussian error propagation model cannot be used to derive the effect of biometric uncertainties on the predicted intraocular lens power and refraction after cataract surgery.

Central anterior chamber depth correlated with white-to-white distance in normal, long, and short eyes

PURPOSE

To explore the associations between central anterior chamber depth (CACD) and other anterior segment biometric parameters and to determine the possible determinants of CACD in short, normal, and long eyes.

METHODS

The biometric data of pre-operation patients aged 50-80 years with coexisting cataract and primary angle-closure disease or senile cataract were reviewed. Axial length (AL), CACD, lens thickness (LT), central corneal thickness (CCT), and white-to-white distance (WTW) were measured by Lenstar optical biometry (Lenstar 900). The data of 100 normal eyes (AL = 22 to 26 mm), 100 short eyes (AL ≤ 22 mm), and 100 long eyes (AL ≥ 26 mm) were consecutively collected for subsequent analyses.

RESULTS

The mean age of the subjects was 66.60 ± 7.85 years, with 25.7% of the sample being men. Both CACD and WTW were found to be smallest in short eyes and were smaller in normal eyes than in long eyes (F = 126.524, P < 0.001; F = 28.458, P < 0.001). The mean LT was significantly thicker in short eyes than in normal and long eyes (4.66 mm versus 4.49 mm versus 4.40 mm; F = 18.099, P < 0.001). No significant differences were observed in CCT between the three AL groups (F = 2.135, P = 0.120). Stepwise regression analysis highlighted AL, LT, and WTW as three independent factors associated with CACD in the normal AL group. In the short AL group and long AL group, LT and WTW were independent factors associated with CACD.

CONCLUSIONS

CACD increases as AL elongates and reaches a peak when AL exceeds 26 mm. Furthermore, CACD showed inverse correlation with LT and positive correlation with WTW. A relatively small WTW results in an anteriorly positioned lens, and thus, a decrease in CACD.

The corneal biomechanical differences after wearing orthokeratology lenses and multifocal soft lenses in children: A self-control study

BACKGROUND

To compare the changes in corneal biomechanics after orthokeratology (OK) lens and Defocus Incorporated Soft Contact (DISC) lens treatment.

METHODS

Of 28 myopic children were recruited, with one eye wearing OK lens and the other eye wearing DISC lens for one year, and the data after discontinued for 4 weeks were also collected. Major outcomes were corneal biomechanics and axial length (AL) elongation.

RESULTS

Throughout the follow-up period, the DISC group had longer the first applanation (A1) time, larger A1 deformation amplitude, A1 deflection length (A1 DLL), and A1 deflection amplitude than the OK group. AL elongation was less in the OK group at each visit (all P < 0.05) but faster in the OK group than in the DISC group after discontinuation (P = 0.006). Moreover, AL elongation was related to baseline A1 time, A1 velocity and whole eye movement max in the DISC group, and in the OK group, was related to the baseline the second applanation (A2) DLL, A2 delta arc length and stiffness parameter A1 (all P < 0.05).

CONCLUSIONS

The cornea was more deformable after wearing DISC lens than OK lens, and corneal biomechanical parameters were associated with AL elongation. Eyes showed less AL elongation during OK lens treatment while faster AL elongation after discontinuation than DISC lens. The baseline corneal biomechanics may help to predict AL elongation in myopic control strategies.

Orthokeratology combined with spectacles in moderate to high myopia adolescents

PURPOSE

Wearing ortho-k lenses overnight may not fully correct their daytime refractory errors of adolescents with moderate to high myopia. There are three common ways to deal with the daytime residual refractive error (RRE): 1) wearing spectacles to correct the RRE; 2) wear ortho-k lenses during the daytime instead of overnight.; 3) not correcting the residual refractive error. According to previous laboratory studies, myopic peripheral refraction is associated with better myopic control. This study had two aims:1) to compare relative peripheral refractive error (RPRE) among these ways after one-month stabilization; 2) to assess the axial length changes over 2 years of ortho-k lens overnight wear combined with spectacle glasses.

METHODS

This was a prospective, non-controlled, non-randomized, observational study in which a total of 27 subjects (20 females, 7 males, mean age 12.48 ± 2.23Y) with spherical equivalent refractive error from -5.00 to -8.25D were enrolled. All participants in the study wore orthokeratology (ortho-k) lenses overnight for a minimum of one month. Subsequently, their peripheral refractive error (PRE) was assessed using an open-field autorefractor. During the assessment, the participants underwent three conditions in a random order in a same morning: 1) unaided eye after orthokeratology (referred to as the Unaided-eye condition), 2) wearing glasses to correct any remaining refractive errors after orthokeratology (referred to as the Spec-RE condition), and 3) wearing ortho-k lenses during the daytime (referred to as the Continuous OK wear condition). After testing, all subjects were instructed to wear ortho-k lenses overnight and glasses during the daytime to correct their RRE for the next 2 years, during which time the progression of their axial length was followed up.

RESULTS

1) RPRE in either Unaided-eye or Spec-RE condition subjects were significantly more myopic than those in the Continuous OK wear condition. 2) No difference in RPRE was seen between Unaided-eye and Spec-RE conditions. 3) Axial length growth was 0.05 ± 0.20 mm and 0.17 ± 0.32 mm (mean ± standard deviation) at 1-year and 2-year follow-ups after the initial visit, respectively, which were comparable to mild myopia patients after orthokeratology. 4) After orthokeratology, axial length change had negative correlation with the initial age (p = 0.001, r = -0.616) and residual diopter (p = 0.022).

CONCLUSIONS

For myopes above refraction < -5.00D, wearing Ortho-k lenses overnight and glasses to correct the RRE in the daytime is recommended to ensure good visual quality and have more myopic RPRE for potential myopia control.

Comparison of the clinical efficacy of orthokeratology and 0.01% atropine for retardation of myopia progression in myopic children

OBJECTIVE

To compare the clinical efficacy of orthokeratology (ortho-k) and 0.01% atropine for retardation of myopia progression in myopic children.

METHODS

This was a retrospective cohort study. A total of 282 patients, aged 8-17 years, were enrolled, including 100 children treated with ortho-k, 84 with 0.01% atropine, and 98 with single-vision spectacles. During the follow-up of 1 year, ortho-k wearers were examined at 1 day, 1 week, 1 month, 3 months after treatment, and thereafter every 3 months, while the others were examined every 3 months by measurements of uncorrected vision, intraocular pressure, refractive power, slit-lamp microscopy, corneal topography, and the lens fitting when necessary. The axial length was measured every 6 months.

RESULTS

Patients with ortho-k had stable uncorrected vision after 1 month of lens wear, all reaching 0 logMAR. The annual axial elongation was 0.23 ± 0.19 mm, 0.22 ± 0.20 mm, and 0.39 ± 0.27 mm in the ortho-k, atropine, and spectacle groups, respectively, with significant difference (F = 23.251, P = 0.000). The axial length was delayed to increase by 41.03% and 43.59% within a year in patients with ortho-k and atropine, respectively, as compared to patients with spectacles (F = 0.006, P = 0.936). The elongation was ≤ 0.3 mm in 69.0% and 66.7% of patients in the two groups, respectively, versus 38.8% in the spectacle group (χ2 = 17.251, P = 0.000). During the follow-up, the rate of corneal staining was 11.0% and 2.0% in the ortho-k and spectacle groups, respectively (χ2 = 8.076, P = 0.003). The use of atropine did not increase corneal staining, but the incidence of related photophobia was 4.8%. No other serious complications were observed.

CONCLUSION

Ortho-k lenses and 0.01% atropine can achieve similar efficacy of myopia retardation, which was significantly better than that obtained with single-vision spectacles, in myopic children. The risk of corneal staining after ortho-k wear may be slightly higher than that with spectacles, but could be well controlled.

Exploring the Location of Corneal Pigmented Arc and Myopia Control Efficacy in Orthokeratology-Treated Children Using Pentacam Measurements

OBJECTIVES

To determine the location and intensity of the corneal pigmented arc in orthokeratology (ortho-k)-treated children and its relationship with annual axial length (AL) change using Pentacam.

METHODS

This retrospective cohort study enrolled children aged 9 to 15 years who had been followed up for at least one year after ortho-k treatment for myopia control. A Pentacam was used to determine the location and intensity of pigmented arc after lens wear. Annual AL changes were further used as the outcome measurement to determine their relationships with the location and intensity of pigmented arc using generalized estimating equations (GEE).

RESULTS

In total, 62 eyes from 33 patients (mean age 10.9 years) were included in our final analysis. The mean follow-up time was 30.6 months. The mean annual AL changes were 0.10 mm. Age statistically correlated with annual AL change (GEE, P= 0.033). In addition, the annual AL change was negatively associated with the relative vertical distance of the lowest density of pigmented arc point based on the visual center, pupil center, and corneal thinnest point after adjustment with age ( P =0.005, P =0.004, and P< 0.001, respectively).

CONCLUSIONS

Pentacam could be a useful tool for evaluating the location and intensity of the corneal pigmented arc. In addition, there was a negative correlation between the vertical distance of the pigmented arc and annual AL change. These findings may provide important information regarding myopia control, next-generation ortho-k design, and prescription.

Optical interventions for myopia control

A range of optical interventions have been developed to slow the progression of myopia. This review summarizes key studies and their outcomes. Peer-reviewed, randomized controlled clinical trials of at least 18 months duration were identified. Randomized clinical trials were identified and summarised: 13 for spectacles, 5 for overnight orthokeratology, 5 for soft contact lenses, and 3 for orthokeratology combined with low concentration atropine. Overnight orthokeratology trials were the most consistent with 2-year slowing of axial elongation between 0.24 and 0.32 mm. Other modalities were more variable due to the wide range of optical designs. Among spectacle interventions, progressive addition lenses were the least effective, slowing axial elongation and myopia progression by no more than 0.11 mm and 0.31 D, respectively. In contrast, novel designs with peripheral lenslets slow 2-year elongation and progression by up to 0.35 mm and 0.80 D. Among soft contact lens interventions, medium add concentric bifocals slow 3-year elongation and progression by only 0.07 mm and 0.16 D, while a dual-focus design slows 3-year elongation and progression by 0.28 mm and 0.67 D. In summary, all three optical interventions have the potential to significantly slow myopia progression. Quality of vision is largely unaffected, and safety is satisfactory. Areas of uncertainty include the potential for post-treatment acceleration of progression and the benefit of adding atropine to optical interventions.

Lens-induced myopization and body weight in young guinea pigs

BACKGROUND

To investigate the relationship between body weight and Axial length in guinea pigs.

METHODS

Forty pigmented guinea pigs were randomly divided into two groups, namely control group and negative lens-induced myopization (LIM) group. After measuring the baseline axial length and body weight (BW), guinea pigs of LIM group received bilateral negative lens-induced myopization using - 10.0 diopters lenses. One week later, the lenses were removed and biometric and ophthalmoscopic examinations were repeated.

RESULTS

Two groups of guinea pigs showed no statistical difference in initial body weight and eye axis length. Compared to the control group, the lens-induced group had a lower weight (P = 0.02) and a longer axial length (P < 0.01) at the end of study Neither at baseline nor at week 1 did AL correlate with BW in both groups (Control Baseline: r = 0.306, P = 0.19; Control Week1: r = 0.333, P = 0.15; LIM Baseline: r=-0.142, P = 0.55; LIM Week 1: r = 0.189, P = 0.42). Lens-induction had a significant effect on axial elongation (P < 0.01) while body weight had no impact on such aspect (P > 0.05).

CONCLUSION

In guinea pigs of the same age, axial length was not correlated with body weight. Also, baseline body weight had no impact on natural axial length growth or lens-induced myopia. Lens-induction caused a significant reduction in body weight gain.

Anisometropia and its association with refraction development in highly myopic children

CLINICAL RELEVANCE

Anisometropia can affect visual development in children. Investigations of anisometropia in high myopes would explore potential causes related to anisometropia, highlighting the management of anisometropia in high myopia.

BACKGROUND

The prevalence of anisometropia ranged from 0.6% to 4.3% in general paediatric population and from 7% to 14% in myopes. Anisometropia is regarded as an associated factor for myopia development, while myopia progression is a stimulus driving anisometropic development. The purpose of this study was to investigate the prevalence of anisometropia and its association with refraction development in Chinese children with high myopia.

METHODS

In the cohort study, a total of 1,577 highly myopic (spherical equivalent ≤-5.0D) children aged 4-18 years were included. Refractive parameters (dioptre of sphere, dioptre of cylinder, corneal curvature radius, and axial length) of both eyes were measured after cycloplegia. The prevalence and degree of anisometropia were compared among refractive groups (non-parametric tests or chi-square tests), and regression analyses were used to determine associated factors of anisometropia. The statistical significance was set to P < 0.05 (two-tailed).

RESULTS

In highly myopic children with a mean (standard deviation) age of 13.06 (2.80) years, the proportions of spherical equivalent anisometropia, cylindrical anisometropia and spherical anisometropia ≥1.00 D were 34.5%, 21.9% and 39.9%, respectively. There was more spherical equivalent anisometropia associated with more severe astigmatism (P for trend <0.001). In the multivariate regression analysis, more spherical equivalent anisometropia, cylindrical anisometropia and spherical anisometropia were associated with higher degrees of astigmatism (standard beta = -0.175, -0.148 and -0.191, respectively). More spherical anisometropia was associated with better spherical power (standard beta = 0.116).

CONCLUSION

The proportion of anisometropia in highly myopic children was high, compared with previously reported general population, and more severe anisometropia was associated with higher degree of cylindrical power, but not spherical power.

Network Meta-analysis of Intraocular Lens Power Calculation Formula Accuracy in 1016 Eyes With Long Axial Length

PURPOSE

To systematically review the literature and quantitatively synthesize the currently available evidence to compare the accuracy of different intraocular lens calculation formulas in eyes with long axial length (AL).

DESIGN

Network meta-analysis.

METHODS

PubMed, Embase, Web of Science, and the Cochrane Library were systematically searched for studies published between January 2000 and June 2022. Included were prospective or retrospective clinical studies reporting the following outcomes in cataract patients with long AL (ie, ≥26 mm): percentage of eyes with a prediction error (PE) within ±0.25, ±0.50, and ±1.00 diopters (D). Network meta-analysis was conducted using R software (version 4.2.1).

RESULTS

Ten prospective or retrospective clinical studies, including 1016 eyes and 11 calculation formulas, were identified. A traditional meta-analysis showed that for the percentage of eyes with PE within ±0.25 and ±0.50 D, the Olsen, Kane, and Emmetropia Verifying Optical (EVO) all had insignificantly higher percentages compared with others. Considering the percentage of eyes with PE within ±1.00 D, the original and modified Wang-Koch adjustment formulas for Holladay 1 (H1-WK and H1-MWK) and EVO formulas showed superiority, but the difference was insignificant. This network meta-analysis revealed that compared with the widely used Barrett Universal II (BUII) formula, the Olsen, Kane, and EVO formulas had higher percentages of eyes with PE within ±0.25, ±0.50, and ±1.00 D (all odds ratios >1 but P >.05). Based on the surface under the cumulative ranking area (SUCRA) values for the percentage of eyes with PE within ±0.25 D, the Olsen (96.4%), Kane (77.5%), and EVO (75.9%) formulas had the highest probability of being in the top 3 of the 11 formulas.

CONCLUSIONS

The Olsen, Kane, and EVO formulas may perform better than others in calculating IOL power in eyes with long AL. Nevertheless, there is still considerable uncertainty in this regard and the accuracy of these formulas in highly myopic eyes should be confirmed in studies based on large multicenter registries.

Deep Learning Based Prediction of Myopia Control Effect in Children Treated With Overnight Orthokeratology

OBJECTIVES

To develop and validate a deep learning-based model for predicting 12-month axial length (AL) elongation using baseline factors and early corneal topographic changes in children treated with orthokeratology (Ortho-K) and to investigate the association between these factors and myopia control impact.

METHODS

A total of 115 patients with Ortho-K were enrolled. Influential baseline factors that have a statistically significant correlation with 12-month AL from medical records were selected using Pearson correlation coefficients. Simultaneously, the height, area, and volume of the defocus region were directly calculated from the corneal topography. Then, the prediction model was developed by combining multiple linear regression and deep neural network and evaluated in an independent group (83 patients for developing the algorithm and 32 patients for evaluation).

RESULTS

Age ( r= -0.30, P <0.001), spherical equivalent refractive (SE; r =0.20, P =0.032), and sex ( r =0.19, P =0.032) were significantly correlated with the AL elongation while pupil diameter, flat k, steep k, horizontal corneal diameter (white to white), anterior chamber depth, and cell density were not ( P >0.1). The prediction model was developed using age, SE, and corneal topographic variation, and the validation of the model demonstrated its effectiveness in predicting AL elongation.

CONCLUSIONS

The AL elongation was accurately predicted by the deep learning model, which effectively incorporated both baseline factors and corneal topographic variation.

Interocular difference in crystalline lens morphology in children and adolescents with unilateral high myopia

PURPOSE

To investigate the between-eye differences of the crystalline lens in subjects with unilateral high myopia and assess its contribution to the interocular refractive error disparity.

METHODS

Children and adolescents with unilateral high myopia, defined as cycloplegic spherical equivalent (SE) ≤ -5D in one eye and ≥ -3D in the other eye, were recruited. Ocular biometric parameters, including axial length (AL) and lens thickness (LT), were measured by IOLMaster 700. Other lens-related parameters, including anterior lens radius of curvature (ALR) and posterior lens radius of curvature (PLR), were measured by CASIA2 swept-source optical coherence tomography. Lens power (LP) was calculated using Bennett's formula. Paired t-test was used to assess the between-eye difference in biometric parameters, and multiple regression analysis was used to assess factors associated with the between-eye SE difference.

RESULTS

Ninety-one participants (6-18 years of age; 52.75% girls) were included. The highly myopic eyes showed significantly lower LP (P < 0.001) and smaller ALR (P < 0.001) than the contralateral eyes, while no significant difference was found in central LT. In both eyes, ALR was significantly related to SE (P = 0.001 and P = 0.006, respectively); while LT was not associated with SE (P = 0.051 and P = 0.052, respectively). Paired-eye analysis showed that the between-eye difference in ALR was the only lenticular parameter significantly associated with the between-eye difference in SE (P = 0.005).

CONCLUSION

In highly myopic eyes, the crystalline lens reduced total power but morphologically changed to a more curved shape without significant lens thinning, suggesting that the LP loss is mainly achieved by reducing its internal power in high myopes.

Cylinder power progression associated with axial length in young children: a two-year follow-up study

PURPOSE

To describe the association of refraction development and axial length (AL) in young children and provide new insights into the progression of cylinder power.

METHODS

Children (2-3 grades) were enrolled from primary schools in Shanghai and followed up for two years. Cycloplegic refraction, AL, and corneal curvature radius were measured. Refraction parameters were compared among groups with different AL, AL1 (AL < 23.5 mm), AL2 (23.5 mm ≤ AL < 24.5 mm), and AL3 (AL ≥ 24.5 mm). Multiple regression analysis was used to explore risk factors of diopter of cylinder (DC) progression.

RESULTS

In total, out of 6891 enrolled children, 5961 participants (7-11 yrs) were included in the final analysis. Over the two-year period, the cylinder power significantly changed, and those with longer AL had more rapid DC progression over the two years (AL1, -0.09 ± 0.35 D; AL2, -0.15 ± 0.39 D; AL3, -0.29 ± 0.44 D) (P < 0.001). The change in DC was independently associated with AL at baseline (P < 0.001). The proportion of with-the-rule astigmatism increased from 91.3% to 92.1% in AL1 group, from 89.1% to 91.8% in AL2 group and from 87.1% to 92.0% in AL3 group.

CONCLUSIONS

Young children with long AL experienced rapid progression of cylinder power. Both the control of myopia progression and attention to the correction of astigmatism are necessary in the health management of children with long AL. The significantly increased AL in participants might contribute to both the extent and direction of astigmatism.

The effect of topical 1 % atropine on ocular dimensions and diurnal rhythms of the human eye

The effect of topical 1 % atropine on the diurnal rhythms of the human eye was investigated. Participants wore an activity monitor on Days 1-7. A set of measures (epochs) encompassing intraocular pressure (IOP), ocular biometry, and retinal imaging were obtained on Day 7 (baseline), followed by eight epochs on Day 8, and one on Day 9 from both eyes of healthy participants (n = 22, 19-25 years). The sleep time of participants (collected via actigraphy) was used as a reference in scheduling epochs. Topical 1 % atropine was instilled in the dominant eye on Day 8, 2 h after habitual wake time, using the fellow eye as control (paired-eye design). Sinusoids with a 24-h period were fitted to the data, and a non-linear mixed-effects model was used to estimate rhythmic statistics. There were no interocular differences in any of the measured parameters at baseline. Comparing pre- versus post-atropine in treated eyes revealed lower IOP, deeper anterior chamber (ACD), decreased crystalline lens thickness and shorter axial length (AL). The same trends were observed when comparing atropine-treated versus fellow control eyes, except for IOP and AL (no differences). Both atropine-treated and fellow control eyes showed significant diurnal variations in all ocular parameters, with atropine-treated eyes revealing larger AL and retinal thickness amplitudes, smaller vitreous chamber depth (VCD) amplitudes, and a significant phase advancement for ACD and VCD. There were no interocular differences in choroidal thickness rhythms. In conclusion, while ocular diurnal rhythms persisted after instillation of 1 % atropine, many rhythmic parameters were altered.

Six-year cumulative treatment effect and treatment efficacy of a dual focus myopia control contact lens

PURPOSE

Accumulated axial growth observed during a 6-year clinical trial of a dual focus myopia control contact lens was used to explore different approaches to assess treatment efficacy.

METHODS

Axial length measurements from 170 eyes in a 6-year clinical trial of a dual focus myopia control lens (MiSight 1 day, CooperVision) were analysed. Treatment groups comprised one having undergone 6 years of treatment and the other (the initial control group) having 3 years of treatment after 3 years of wearing a single vision control lens. Efficacy was assessed by comparing accumulated ocular growth during treatment to that expected of untreated myopic and emmetropic eyes. The impact of treatment on delaying axial growth was quantified by comparing the increased time required to reach criterion growths for treated eyes and survivor analysis approaches.

RESULTS

When compared to the predicted accumulated growth of untreated eyes, 6 years of treatment reduced growth by 0.52 mm, while 3 years of treatment initiated 3 years later reduced growth by 0.19 mm. Accumulated differences between the growth of treated and untreated myopic eyes ranged between 67% and 52% of the untreated myopic growth, and between 112% and 86% of the predicted difference in growth between untreated myopic and age-matched emmetropic eyes. Treated eyes took almost 4 years longer to reach their final accumulated growth than untreated eyes. Treatment increased the time to reach criterion growths by 2.3-2.7 times.

CONCLUSION

Estimated growth of age-matched emmetropic and untreated myopic eyes provided evidence of an accumulated slowing in axial elongation of 0.52 mm over 6 years, and the treated growth remained close to that expected of emmetropic eyes. Six years of dual focus myopia control delayed the time to reach the final growth level by almost 4 years.

Longitudinal analysis of refraction and ocular biometrics in preschool children with early-onset high myopia

We investigated changes in refraction and ocular biometrics in preschool children with early-onset high myopia. Sixty eyes of 60 children with a mean follow-up time of 58.5 months were included in this study. At baseline, mean age of children was 55.6 ± 13.1 months, mean spherical equivalent (SE) was - 8.59 ± 2.66 D, and 25.64 ± 1.16 mm for axial length (AL). The total annual rate of myopic progression and axial elongation were - 0.37 ± 0.39 D/year and 0.33 ± 0.18 mm/year, respectively. During follow-up period, there was a trend toward less myopic progression and axial elongation over time. Of the total participants, 24 children (40%) were in the myopia progression group and the remaining 36 children (60%) were in the myopia stability group. In multiple linear regression analysis, baseline SE and AL were independently associated with myopic progression, while age, sex, and baseline AL-to-CR ratio were not related to myopic progression. According to the model, more myopic SE (β = - 0.186, P = 0.035) and longer AL (β = - 0.391, P = 0.008) at baseline were significantly associated with myopic progression. Myopia progression in preschoolers with high myopia tended to be relatively modest, with 60% of subjects exhibited myopic stability. Higher myopic SE, and longer AL at baseline were associated with myopic progression in preschool children with high myopia.

Efficacy of corneal curvature on the accuracy of 8 intraocular lens power calculation formulas in 302 highly myopic eyes

PURPOSE

To investigate the effect of corneal curvature (K) on the accuracy of 8 intraocular lens formulas in highly myopic eyes.

SETTING

Eye Hospital and School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China.

DESIGN

Retrospective consecutive case series.

METHODS

302 eyes (302 patients) were analyzed in subgroups based on the K value. The mean refractive error, mean absolute error (MAE), median absolute error (MedAE), root-mean-square absolute prediction error (RMSAE) and proportions of eyes within ±0.25 diopter (D), ±0.50 D, ±0.75 D, ±1.00 D were statistical analyzed.

RESULTS

Emmetropia Verifying Optical (EVO) 2.0, Kane, and Radial Basis Function (RBF) 3.0 had the lower MAE (≤0.28) and RMSAE (≤0.348) and highest percentage of eyes within ±0.50 D (≥83.58%) in the flat (K ≤ 43 D) and steep K (K > 45 D) groups. Hoffer QST had the lowest MedAE (0.19), RMSAE (0.351) and the highest percentage of eyes within ±0.50 D (82.98%) in the normal K group (43 < K ≤ 45 D). When axial length (AL) ≤28 mm, all formulas showed close RMSAE values (0.322 to 0.373) in flat K group. When AL >28 mm, RBF 3.0 achieved the lowest MAE (≤0.24), MedAE (≤0.17) and RMSAE (≤0.337) across all subgroups.

CONCLUSIONS

EVO 2.0, Kane, and RBF 3.0 were the most accurate in highly myopic eyes with a flat or steep K. Hoffer QST is recommended for long eyes with normal K values. RBF 3.0 showed the highest accuracy when AL >28 mm, independent of corneal curvature.

Association between choriocapillaris perfusion and axial elongation in children using defocus incorporated multiple segments (DIMS) spectacle lenses

PURPOSE

To investigate choroidal and ocular biological variables that influence axial length (AL) elongation in children wearing defocused incorporated multiple segments (DIMS) spectacle lenses.

METHODS

This cohort study included 106 myopic children aged 7-14 years with a 1-year follow-up. Participants were divided into two groups according to the increase in AL in one year: rapid (>0.2 mm) and slow (≤0.2 mm) axial elongation groups. Cycloplegic autorefraction and AL were measured at baseline and after 6 and 12 months. The area of choriocapillaris flow voids (FVs) and choroidal thickness (ChT) at baseline were measured.

RESULTS

Univariate linear regression analysis showed that AL elongation were significantly associated with the FVs area (standardised β = 0.198, P < 0.05) and age (standardised β = -0.201, P < 0.05). Multiple linear regression showed that the FVs area, age, and average K reading were associated with AL elongation. Multiple logistic regression analyses showed that greater degrees of myopia and larger FVs areas were risk factors for rapid axial elongation, while older age, large pupil diameter and steeper cornea were protective factors. In estimating axial elongation, the FVs area alone demonstrated an area under the curve (AUC) of 0.672 (95% CI, 0.569-0.775, P < 0.01), and that of FVs area and other ocular variables was 0.788 (95% CI, 0.697-0.878, P < 0.001).

CONCLUSION

Larger choriocapillaris FVs area at baseline may help to predict axial elongation in myopic eyes. The association between FVs area and axial elongation should be taken into consideration in further myopic cohort studies.

Evaluation of a New All-in-One Optical Biometer and Comparison With a Validated Swept-source OCT Biometer

PURPOSE

To assess agreement between a new all-in-one non-contact optical biometer based on optical low coherence reflectometry (SW-9000 µm Plus; Suoer) and a swept-source optical coherence tomography biometer (OA-2000; Tomey).

METHODS

Each eye was scanned three times in a row by each device at random. The measured ocular parameters included central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), axial length (AL), flat keratometry (Kf), steep keratometry (Ks), mean keratometry (Km), astigmatism, corneal diameter (CD), and pupil diameter (PD). The paired t test was used to show the differences between the SW-9000 and OA-2000. Bland-Altman plots and the 95% limits of agreement (LoA) were applied to assess the consistency of the measurements.

RESULTS

Sixty eyes from 60 healthy participants were examined, with a mean spherical equivalent refraction of -5.58 ± 2.31 diopters and a mean age of 30.40 ± 6.07 years. The Bland-Altman plots showed high agreement for AL, ACD, LT, Kf, Ks, Km, astigmatism, and CD measurements (95% LoA: -0.06 to 0.04 mm, -0.10 to 0.06 mm, -0.12 to 0.11 mm, -0.30 to 0.29 D, -0.35 to 0.38 D, -0.29 to 0.30 D, -0.30 to 0.34 D, and -0.50 to 0.06 mm, respectively), whereas the agreement for CCT and PD were moderate (95% LoA: 7.12 to 20.43 µm, -0.75 to 1.19 mm, respectively).

CONCLUSIONS

The new all-in-one non-contact biometer had high agreement with the OA-2000 biometer on the AL, ACD, LT, Kf, Ks, Km, astigmatism, and CD measurements. For most of the ocular parameters assessed, they were clinically interchangeable. [J Refract Surg. 2023;39(12):825-830.].