Genetic effects on refraction and correlation with hemodynamic variables: a twin study

Spherical equivalent (SE) has not been linked to increased cardiovascular morbidity. Methods:
132 Hungarian twins
(age 43.3±16.9 years) underwent refraction measurements (Huvitz MRK-3100 Premium AutoRefractokeratometer)
and oscillometry (TensioMed Arteriograph).
Results:
Heritability analysis indicated major role for genetic
components in the presence of right and left SE (82.7%, 95%CI, 62.9 to 93.7%, and 89.3%, 95%CI, 72.8 to 96.6%),
while unshared environmental effects accounted for 17% (95%CI, 6.3% to 37%), and 11% (95%CI, 3.4% to 26.7%)
of variations adjusted for age and sex. Bilateral SE showed weak age-dependent correlations with augmentation
index (AIx), aortic pulse wave velocity (r ranging between 0.218 and 0.389, all
p
< 0.01), aortic systolic blood
pressure and pulse pressure (r between 0.188 and 0.289,
p
< 0.05).
Conclusions:
These findings support heritability
of spherical equivalent, which does not coexist with altered hemodynamics (e.g. accelerated arterial aging).
Accordingly, SE and the investigated hemodynamic parameters seem neither phenotypically nor genetically
associated.
Keywords:
arterial stiffness, augmentation index, genetics, heritability, refraction