Upon investigating the relationship between age-related macular degeneration (AMD), refractive error and axial length as well as the socio-demographic characteristics and biochemical variables that may affect this relationship, a team of Turkish researchers found that hyperopic refractive error and shorter axial length are associated with AMD.

This cross-sectional study evaluated 196 eyes of 98 AMD patients over 50 years of age. The researchers categorized early and late AMD findings according to the age-related eye disease study grading scale. They then measured objective refractive error by autorefractometer, confirmed it by subjective examination and calculated spherical equivalent. The team classified refractive errors of <-0.50D as myopia, -0.50D-0.50D as emmetropia and >0.50D as hyperopia. They measured axial length by ultrasonic biometry, and values ≤23.00mm were classified as short, >23.00mm and <24.00mm as normal and ≥24.00mm as long axial length. Finally, they investigated demographic, systemic and biochemical patient parameters.

Of the key findings, the researchers discovered that hypermetropic refractive error and shorter axial length were significantly more common than the other groups. They did not observe any differences between early- and late-stage groups in terms of refractive error and axial length. They note that patients with myopia had significantly lower values for total cholesterol, triglyceride, fasting blood glucose and proportion of smokers. The team also found that rates of oral nutritional supplement use and fish consumption were significantly higher in the early AMD group. They add that the most common comorbidity among the AMD patients was essential hypertension.

The study concludes, “Longitudinal studies including larger patient numbers are needed to elucidate the causal and temporal relationship between hyperopic refractive error and AMD.”