Corneal endothelial morphology of healthy myopic Malaysian children of Chinese ethnicity aged 8-9 years and its association with axial length

Clinical Relevance: This study is to further understand the effects of
axial length elongation on the corneal endothelial cell's morphology
in myopic children. Abnormal changes in the morphology of cornea
endothelium are indicators of corneal stress or instability which could be
linked to myopia.  Background: To examine the morphology of
corneal endothelium cells in healthy Chinese Malaysian school children
with emmetropia and mild to moderate myopia and its association with axial
length.  Methodology: A total of 111 school children comprising
of 37 emmetropes, 37 mild myopes and 37 moderate myopes aged 8-9 years old
were recruited. Visual Acuity was measured using the LogMar chart,
cycloplegic refraction was determined using an open-field autorefractor
(Grand Seiko WAM-5100, Hiroshima, Japan) and refined using subjective
refraction. Morphology of cornea endothelial cells [ECD- endothelial cells
density, COV- coefficient of variation, HEX- Hexagonility and CCT-central
corneal thickness] was evaluated using a non-contact specular miscroscope
(Topcon SP-2000P). Axial length was measured with A-Scan ultrasound
biometry (PacScan Plus, Sonomed Escalon, NY). The correlation between
morphology of cornea endothelial cells and axial length were assessed
using Pearson Correlation and Linear Regression Analysis. 
Results: There was no significant difference in cornea endothelial cells
and axial length between gender (p>0.05). Significant reduction in
ECD and HEX and increased COV was found in eyes of higher myopic power
which had longer AL when compared to emmetropes (p<0.001). Except
for CCT, all corneal endothelial cells parameters correlated significantly
with axial length (p<0.05). For every 1mm increase in axial length,
endothelial cells density decreased by 73.27 cells/mm2, hexagonality
decreased by 2.32% and coefficient of variation increased by
1.75%.  Conclusion: There were significant changes in morphology
of cornea endothelial cells in young moderate myopic children of Chinese
ethnicity at 8-9 years of age. This result provides normative data for
Malaysian children of Chinese ethnicity that can be used for comparison
and reference for clinical procedures, thereby facilitating decision
making with respect to interventions for myopia control, especially in
prescribing contact lens for children.