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.