Jian Lin

Purpose: To investigate the influence of ocular residual astigmatism (ORA) on the therapeutic outcomes of orthokeratology in pediatric myopia management. Methods: In this retrospective cohort study, 60 myopic children (7-12 years) were classified into high-ORA (≥1.00 D; n=30) and low-ORA (0.05). The high-ORA cohort exhibited significantly greater mean axial elongation compared to low-ORA controls at all post-baseline intervals except 1-month (3-month: 0.073±0.082 vs 0.019±0.076 mm, P =0.011; 6-month: 0.139±0.115 vs 0.055±0.098 mm, P =0.003; 12-month: 0.309±0.156 vs 0.137±0.137 mm, P <0.001). Regression analysis revealed baseline ORA magnitude (β=0.219, P <0.001) and spherical equivalent refraction (β=0.043, P =0.038) as positive predictors of annual ΔAL, while patient baseline age showed negative correlation (β=-0.056, P<0.001). Conclusions: High ORA (≥1.00 D) constitutes an independent risk factor for reduced orthokeratology efficacy in pediatric myopia control. This result emphasizes the importance of incorporating ORA assessment into the pre-treatment assessment of orthokeratology lenses fitting. Children with high ORA may benefit from alternative interventions such as peripheral defocus soft contact lenses to optimize myopia management outcomes.

Objectives To determine the main sources of ocular residual astigmatism (ORA) and the contribution of posterior corneal astigmatism (PCA) to ORA. Methods This cross-sectional study was conducted on 177 right eyes of 177 patients. Anterior corneal astigmatism (ACA) and PCA were obtained from Pentacam. ORA was calculated by the vector difference between refractive astigmatism (RA) and ACA. Pearson correlation coefficient was used to assess relationships between variables. The contribution of PCA to ORA was evaluated by a physical method. Results Mean magnitude of PCA was 0.40 ± 0.15 D (rang 0.10 to 0.70 D). Mean amount of ORA was 0.69 ± 0.33 D (rang 0.05 to 1.63 D). There was a statistically significant correlation between the magnitudes of PCA and ORA (r = 0.38, P < 0.001). The PCA in 171 eyes (96.61%) supplemented ORA. The mean superimposed value (SV) was 0.37 ± 0.16 D (rang 0.01 to 0.70 D). The against-the-rule PCA can not only superimpose but also counteract with-the-rule and oblique ORA. The against-the-rule ORA can be superimposed by with-the-rule, against-the-rule and oblique PCA. Of the 171 eyes, the SV of 85 eyes(49.71%) were larger than half of the magnitude of ORA. In a minority of eyes, PCA can have a negative effect on ORA and may be greater than it. Conclusions Approximately half of the magnitude of ocular residual astigmatism comes from posterior corneal astigmatism. The SV/ORA ratio may be used to personalize the surgical

Background: To assess the correlation between ocular residual astigmatism and anterior corneal astigmatism in children with low and moderate myopia. Methods: Refractive astigmatism was determined by subjective manifest refraction. Anterior corneal astigmatism was determined by IOL Master. Thibos vector analysis was used to calculate ocular residual astigmatism. Correlation analysis was used to assess the relationship between the amounts of ocular residual astigmatism and anterior corneal astigmatism. The relationship between the vectors of ocular residual astigmatism and anterior corneal astigmatism was evaluated by a physical method. Results: The study analysed 241 right eyes of 241 children aged 8 to 18 years old. In this study, the median magnitude of ocular residual astigmatism was 1.02 D, with an interquartile range was of 0.58 D. Against-the-rule ocular residual astigmatism was seen in 232 eyes (96.3%). There was a significant and moderate correlation between ocular residual astigmatism and anterior corneal astigmatism (r = 0.50, P < 0.001). Ocular residual astigmatism compensated for anterior corneal astigmatism in 240 eyes (99.6%). The mean compensation value was 1.00 ± 0.41 D (range 0.02 D to 2.34 D). Based on this effect, 37 eyes had a different axial classification of anterior corneal astigmatism and refractive astigmatism. In contrast, one eye (0.4%) had oblique ocular residual astigmatism and the ocular residual astigmatism superimposed with-the-rule anterior corneal astigmatism. Conclusions: The magnitude of ocular residual astigmatism was relatively large in myopic children and predominantly compensated for anterior corneal astigmatism. Ocular residual astigmatism should be assessed in patients before fitting them with orthokeratology lenses.

To determine the distribution of ocular residual astigmatism (ORA) in astigmatic eyes and the influence on the anterior corneal (ACA) and refractive astigmatism (RA). A total of 165 children met the inclusion criteria. Right eyes’ data were analyzed. Using Thibos vector analysis to calculate ORA. Spearman correlation analysis was used to obtain the correlation between the magnitude of ORA, ACA and RA. The median magnitude of ORA in astigmatic eyes was 0.57 D, with interquartile range was 0.42 D. And they were main against-the-rule (57.6–75.8%) and oblique astigmatism (13.9–34.5%) ORA. The ORA in 140 eyes (84.8%) acted as an offset to ACA, meanwhile, 25 eyes (15.2%) superimposed it. About 98% (97.9–98.4%) against-the-rule and 75% (73.9–82.5%) oblique ORA counteracted ACA, nevertheless, all with-the-rule ORA had a superimposed effect on ACA. For with-the-rule ACA, about 86% (85.4–85.9%) ORA worked to offset it. There was statistically correlations between ORA and ACA (r = 0.17, P = 0.03), ORA and RA (r = − 0.27, P = 0.001). The magnitude of ocular residual astigmatism was relatively small in children’s astigmatic eyes. Both against-the-rule and oblique ORA can counteract with-the-rule ACA.

Significance: It is generally believed that cycloplegia optometry had no effect on astigmatism. The comparison was all made on the spectacle plane. There is a dearth of studies on the influence from corneal plane. Purpose: Study on the difference between cycloplegic and noncycloplegic measurements of astigmatism on corneal plane. Methods: This is a retrospective study. Vertexing the total ocular astigmatism to the corneal plane. To transpose astigmatism into J₀ and J₄₅ components by Fourier transformation. The changes of astigmatism measured with and without cycloplegic were compared from corneal plane. Data were compared by paired t test. Results: The changes of the total ocular astigmatism were significantly different on corneal plane (total ocular astigmatism: t = -2.31, P < .05; J₀ components: t = -2.71, P < .01; J₄₅ components: t = -1.09, P༞.05). The magnitude of total ocular astigmatism generally increased after cycloplegia (2.12 ± .87 D vs 2.07 ± .89 D). 37 eyes (32.17%) had a change value greater than 0.25 D. The proportion of with-the-rule total ocular astigmatism increased (from 90.43–92.17%) and that of oblique total ocular astigmatism decreased (from 9.57–7.83%). While the changes of anterior corneal astigmatism were no significantly different . Conclusion: There were underestimation of total ocular astigmatism without cycloplegic refraction in preschool children. The proportion of with-the-rule astigmatism increases after cycloplegia.