Choroidal thickness at age 66years in the Danish high myopia study cohort 1948 compared with follow-up data on visual acuity over 40years: a clinical update adding spectral domain optical coherence tomography.

Abstract

A population-based Copenhagen birth year 1948 cohort with high myopia recorded since age 14years (spherical equivalent less than or equivalent to -6D) has been followed over 50years. Despite complications, current follow-ups have outlined a better visual prognosis than usually drawn from selected clinical series in the literature. For the present status at age 66years, focus was on visual ability and choroidal thickness. Twenty-eight of the original 39 participants were available in 2014. Medical history was updated. Best-corrected visual acuity (BCVA) data were compared with subfoveal choroidal thickness (SFCT), now measured by enhanced depth optical coherence tomography. Due to at least better eye visual acuity (VA), all patients had maintained their everyday visual capacity. Only one participant was marginal regarding visual status for a driver's licence; low vision was not on record. Based on all eyes, choroidal thickness correlated negatively with axial length (AL), which also held for the fraction with high myopia (AL >26.5mm). In high myopia, the mean choroidal subfoveal thickness was 114±75μm versus 182±94μm in lower myopia (p=0.01). Despite the generally maintained individual visual capacity in the series, significant correlation could be demonstrated between SFCT and (i) axial elongation and (ii) recorded VA, with a negative and a positive sign, respectively. Overall, the visual prognosis was relatively benign, in particular when compared with the selected high myopia hospital series that predominate in the ophthalmic literature.