Heritability of Corneal Curvature and Pentacam Topometric Indices: A Population Based Study

Purpose: to investigate familial aggregation of anterior and posterior corneal curvature, corneal astigmatism and some corneal topometric indices using Pentacam.Methods: Of the 3851eligible individuals who resided in the selected areas, 2779 people had the conditions for analysis. However, analysis was limited to families whose Pentacam measures were available for at least 2 family members, resulting in 1383 individuals in 382 families. All selected subjects had a set of examinations including refraction, uncorrected and corrected visual acuity, slit lamp Biomicroscopy and Pentacam imaging. Heritability estimation was used to calculate familial aggregation. Results: The results of our study showed fairly high corneal curvature heritability. The heritability of K2 and K1 in the anterior surface was 58.60% and 55.82%, respectively. The heritability of posterior corneal curvature was slightly higher than that of anterior corneal curvature. The heritability of K2 and K1 in the posterior surface was 63.42% and 59.67%, respectively. In investigating the quantitative topographic indices of the cornea, index of surface variance (ISV), Central Keratoconus Index (CKI) and index of vertical asymmetry (IVA) had the highest levels of heritability (81.2%, 74.99% and 66.46%, respectively) while Keratometric power deviation (KPD) and Index of height asymmetry (IHA) had the lowest heritability levels (7.48% and 18.31% respectively). Conclusion: the familial aggregation and relatively high heritability of corneal curvatures and some keratoconus related indices such as ISV and IVA confirm a high correlation between these phenotypes and genetic factors and warrant further investigation of the genetic mechanisms in keratoconus