Cornea biomechanical characteristics measured using the Ocular Response Analyzer in Singapore children

Abstract

Purpose To determine the corneal biomechanical parameters measured with the Reichert Ocular Response Analyser(ORA) in Singaporean children, and to assess their correlations with refractive error and biometry Methods This was a cross sectional study of 271 subjects from the Singapore Cohort Study of Risk Factors for Myopia(SCORM). Corneal hysteresis (CH), corneal resistance factor(CRF), central corneal thickness(CCT) and intraocular pressure(IOPcc) were measured with the ORA. Spherical equivalent refraction, axial length, height, weight, and blood pressure were measured. Results The mean age of the study population was 13.97±0.89years, the gender distribution was almost equal(138 males,50.9%),and the majority were Chinese.The mean CH and CRF were 11.78±1.55mmHg and 11.81±1.71mmHg. CH and CRF did not vary with age, sex or race. CH and CRF did not vary with myopia (p=0.79;0.83), or axial length (r=‐0.11 and ‐0.05,p=0.08 and 0.40). Multivariate analyses were performed with CH, CRF or CCT as the dependent and age, gender, race, weight, IOPcc, CCT, SE refraction, and corneal curvature as covariates. CH was significantly associated with IOP (beta=‐0.22(95%CI ‐0.27,‐0.17)), CCT (beta=0.03(0.02,0.03)) and corneal curvature (beta=‐1.13(‐2.08,‐0.19)). CRF was significantly associated with IOP, CCT and corneal curvature.(beta=0.08(0.02,0.14);0.03(0.03,0.04) and ‐1.39(‐2.54,‐0.23) respectively). The only factor predictive of decreased CCT was Malay or Indian race compared with Chinese. Conclusion The CH and CRF values in our study on children are slightly higher than in adult studies. CH and CRF are not associated with refractive error or axial length. Flatter corneas are associated with lower CH and CRF readings

Visual and Corneal Changes in Overnight Orthokeratology Using Menicon Z Lenses – A Malaysian Study

“…Some of the unique features found in the Menicon Z lenses such as fenestration may also contribute to the ease of fitting and adaptation to the OK lens by participants. Moderate myopia with relatively flatter corneal curvature has also been cited to be less rigid (Lim et al, 2008) and this may also contribute to the successful outcome after one night of wearing an OK lens. This study did not show any change in toricity for six months.…”

Valores de normalidad en parámetros oculares en niños caucásicos españoles

“…Con estas afirmaciones, y en función de los resultados obtenidos, consideramos que en esta edad, cuando los cambios producidos son muy importantes, sería clave la evaluación de la biomecánica corneal en niños miopes. Lim et al (2008aLim et al ( , 2008b no encontraron correlaciones similares en niños con discos ópticos oblicuos o normales. Tampoco se encontró correlación entre el CRF y los parámetros evaluados del segmento posterior.…”

“…En la literatura hay limitación en cuanto a los factores que pueden afectar tanto a la histéresis corneal como al factor de resistencia corneal, particularmente en niños. En este sentido, Lim et al (2008aLim et al ( , 2008b refieren que no hay resultados publicados sobre la posible correlación entre la CH y el error refractivo o la LA, y entienden que la relación de esta última con la miopía está asociada con cambios estructurales de la córnea; por ello, evaluaron los parámetros biomecánicos corneales con el ORA en niños de Singapur y su posible correlación con errores refractivos y medidas biométricas en 271 sujetos cuya media de edad fue de 13,97 ± 0,89.…”