Corneal Characteristics of Myopic Malay School Children and Their Association with Axial Length

Introduction

Corneal characteristics are unique to each eye and can vary among different levels of refractive errors. However, minimal data are available in the literature on corneal characteristics in myopic Malay school children including the difference between the low myopic group and the moderate myopic group. Therefore, this study aims to determine the corneal characteristics of myopic Malay school children and their associations with axial length.

Methods

A total of eighty-four data samples were extracted from forty-two myopic Malay school children. Measurements of the central corneal thickness (CCT), corneal curvature, corneal diameter, and axial length were measured using Lenstar LS900, a non-contact optical biometer. Data were later stratified by the spherical equivalent refraction (SER) into a low myopic group and a moderate myopic group, and paired t-test were employed to determine the differences in the corneal characteristics between these two groups. Univariate and multivariate linear regressions were performed to identify factors that are significantly associated with axial length.

Results

There was no significant difference in the CCT, corneal curvature and corneal diameter between the low myopic group and the moderate myopic group (t82=0.015, P=0.99), (t82=-0.802, P=0.43) and (t82=-0.575, P=0.57), respectively. Pearson univariate correlation analysis found that axial length significantly correlated with corneal curvature (r=-0.765, P<0.001) and corneal diameter (r=0.614, P<0.001) but no significant correlation found with CCT (r=0.046, P=0.68). Multiple regression analysis showed that axial length was significantly associated with a flatter corneal curvature (P<0.001), older age (P<0.001) and larger corneal diameter (P=0.02).

Conclusion

This study reported the corneal characteristics in myopic Malay school children and its associations with axial length. Results of this study can serve as a reference value for the myopic Malay schoolchild population.

Relative apical sparing in cardiac amyloidosis is not always explained by an amyloid gradient

AIMS

Myocardial longitudinal strain (LS) by two-dimensional (2D) speckle-tracking echocardiography has a diagnostic and prognostic role in cardiac amyloidosis (CA). Typically, the apical segments of the left ventricle (LV) are less affected by LS abnormalities, a finding called relative apical sparing (RELAPS). Whether a variable burden of CA might explain the RELAPS remains unknown.We aimed to evaluate the extent, distribution, and deposition pattern of amyloid in autopsy hearts of CA patients and to correlate the histopathology findings with 2D echocardiography.

METHODS AND RESULTS

This is a retrospective study of whole heart specimens of CA patients who died and underwent autopsy and 2D echocardiography. Amyloid burden quantification was assessed by histomorphometry in each segment at different LV levels. The LS analysis results were compared with the amyloid burden and the base-to-apex distribution.Histopathology investigation of 27 hearts with CA [immunoglobulin light chains (AL) 17 cases and transthyretin (ATTR) 10 cases] demonstrated an amyloid base-to-apex gradient. In 11 CA patients with 2D echocardiography, analysis of LS and histological amyloid burden allowed to identify different patterns: RELAPS (8 cases, 73%), with (2) or without (6) amyloid gradient, normal or mildly reduced LS with diffuse low amyloid (2, 18%), and severely reduced LS with diffuse high amyloid (1, 9%).

CONCLUSION

The typical RELAPS pattern at echocardiography is not always explained by a base-to-apex gradient of amyloid burden at histopathology, suggesting that RELAPS might be an epiphenomenon of complex interactions among amyloid infiltration, myocardial structure, and adaptation.